Publications by authors named "Blaise A Clarke"

79 Publications

Maximizing cancer prevention through genetic navigation for Lynch syndrome detection in women with newly diagnosed endometrial and nonserous/nonmucinous epithelial ovarian cancer.

Cancer 2021 Sep 13;127(17):3082-3091. Epub 2021 May 13.

Division of Gynecologic Oncology, Princess Margaret Cancer Centre/University Health Network/Sinai Health Systems, Toronto, Ontario, Canada.

Background: Despite recommendations for reflex immunohistochemistry (IHC) for mismatch repair (MMR) proteins to identify Lynch syndrome (LS), the uptake of genetic assessment by those who meet referral criteria is low. The authors implemented a comprehensive genetic navigation program to increase the uptake of genetic testing for LS in patients with endometrial cancer (EC) or nonserous/nonmucinous ovarian cancer (OC).

Methods: Participants with newly diagnosed EC or OC were prospectively recruited from 3 cancer centers in Ontario, Canada. Family history questionnaires were used to assess LS-specific family history. Reflex IHC for MMR proteins was performed with the inclusion of clinical directives in pathology reports. A trained genetic navigator initiated a genetic referral on behalf of the treating physician and facilitated genetic referrals to the closest genetics center.

Results: A total of 841 participants (642 with EC, 172 with OC, and 27 with synchronous EC/OC) consented to the study; 194 (23%) were MMR-deficient by IHC. Overall, 170 women (20%) were eligible for a genetic assessment for LS: 35 on the basis of their family history alone, 24 on the basis of their family history and IHC, 82 on the basis of IHC alone, and 29 on the basis of clinical discretion. After adjustments for participants who died (n = 6), 149 of 164 patients (91%) completed a genetic assessment, and 111 were offered and completed genetic testing. Thirty-four women (4.0% of the total cohort and 30.6% of those with genetic testing) were diagnosed with LS: 5 with mutL homolog 1 (MLH1), 9 with mutS homolog 2 (MSH2), 15 with mutS homolog 6 (MSH6), and 5 with PMS2.

Conclusions: The introduction of a navigated genetic program resulted in a high rate of genetic assessment (>90%) in patients with gynecologic cancer at risk for LS.
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http://dx.doi.org/10.1002/cncr.33625DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8453540PMC
September 2021

Endometrial Stem/Progenitor cell (ES/PC) Marker Expression Profile in Adenosarcoma and Endometrial Stromal Sarcoma.

Cancer Treat Res Commun 2021 31;27:100363. Epub 2021 Mar 31.

Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Department of Pathology, Toronto General Hospital, Toronto, ON, Canada.

Background: The uterus is one of the most dynamic organs in the human body, and this dynamic homeostasis is supported by endometrial stem/progenitor cells (ES/PCs), which are heterogeneous in their phenotype and degree of differentiation. ES/PCs are generally localized in the endometrial stroma, the site of origin for adenosarcoma and endometrial stromal sarcoma (ESS). Subsets of ESSs and adenosarcomas harbor SUZ12 or DICER1 gene alterations, two genes with roles in embryonic stem cell biology. However, the possible contribution of ES/PCs to tumorigenesis is unexplored.

Method: We examined the expression of eleven ES/PC markers, along with three proteins expressed in the mature endometrial stroma (ER, PR and CD10) in 60 uterine tumors (24 low-, 11 high-grade ESS, 25 adenosarcomas). Protein expression profiles were assessed by unsupervised hierarchical clustering. miRNA expression profiles were examined in a subset of adenosarcoma with/without DICER1 mutations, using the NanoString platform.

Results: ES/PC markers were variably expressed, and the tumors exhibited limited immunophenotypic resemblance to different ES/PCs. Within the ESSs, the ES/PC marker clustering pattern was prognostic for both overall and disease-free survival. Comparing adenosarcomas and ESSs, most high-grade ESSs clustered with one another, while low-grade ESSs and adenosarcomas tended to cluster with one another. Among the adenosarcomas, the miRNA expression profiles were varied with respect to the DICER1 mutation status, with pathway analysis pointing to dysregulated signal transduction and stem cell biology.

Conclusions: ESSs and adenosarcomas exhibit varying immunophenotypic resemblance to ES/PCs. These expression profiles have prognostic implications and may be genetically driven.
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http://dx.doi.org/10.1016/j.ctarc.2021.100363DOI Listing
March 2021

Evaluation of treatment effects in patients with endometrial cancer and POLE mutations: An individual patient data meta-analysis.

Cancer 2021 Jul 1;127(14):2409-2422. Epub 2021 Apr 1.

Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada.

Background: Endometrial cancers (ECs) with somatic mutations in DNA polymerase epsilon (POLE) are characterized by unfavorable pathological features, which prompt adjuvant treatment. Paradoxically, women with POLE-mutated EC have outstanding clinical outcomes, and this raises concerns of overtreatment. The authors investigated whether favorable outcomes were independent of treatment.

Methods: A PubMed search for POLE and endometrial was restricted to articles published between March 1, 2012, and March 1, 2018, that provided individual patient data (IPD), adjuvant treatment, and survival. Following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) reporting guidelines for IPD, the authors used univariate and multivariate one-stage meta-analyses with mixed effects Cox models (random effects for study cohorts) to infer the associations of treatment, traditional prognostic factors, and outcome, which was defined as the time from first diagnosis to any adverse event (progression/recurrence or death from EC).

Results: Three hundred fifty-nine women with POLE-mutated EC were identified; 294 (82%) had pathogenic mutations. Worse outcomes were demonstrated in patients with nonpathogenic POLE mutations (hazard ratio, 3.42; 95% confidence interval, 1.47-7.58; log-rank P < .01). Except for stage (P < .01), traditional prognosticators were not associated with progression/recurrence or death from disease. Adverse events were rare (11 progressions/recurrences and 3 disease-specific deaths). Salvage rates in patients who experienced recurrence were high and sustained, with 8 of 11 alive without evidence of disease (range, 5.5-14.2 years). Adjuvant treatment was not associated with outcome.

Conclusions: Clinical outcomes for ECs with pathogenic POLE mutations are not associated with most traditional risk parameters, and patients do not appear to benefit from adjuvant therapy. The observed low rates of recurrence/progression and the high and sustained salvage rates raise the possibility of safely de-escalating treatment for these patients.

Lay Summary: Ten percent of all endometrial cancers have mutations in the DNA repair gene DNA polymerase epsilon (POLE). Women who have endometrial cancers with true POLE mutations experience almost no recurrences or deaths from their cancer even when their tumors appear to have very unfavorable characteristics. Additional therapy (radiation and chemotherapy) does not appear to improve outcomes for women with POLE-mutated endometrial cancer, and this supports the move to less therapy and less associated toxicity. Diligent classification of endometrial cancers by molecular features provides valuable information to inform prognosis and to direct treatment/no treatment.
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http://dx.doi.org/10.1002/cncr.33516DOI Listing
July 2021

Understanding the clinical implication of mismatch repair deficiency in endometrioid endometrial cancer through a prospective study.

Gynecol Oncol 2021 04 19;161(1):221-227. Epub 2021 Jan 19.

Division of Gynecologic Oncology, Princess Margaret Cancer Centre, University Health Network/Sinai Health Systems, Toronto, Ontario, Canada; Department of Obstetrics and Gynaecology, University of Toronto, Toronto, Canada; Zane Cohen Centre for Digestive Diseases, Familial Gastrointestinal Cancer Registry, Mount Sinai Hospital, Toronto, Ontario, Canada. Electronic address:

Objectives: Findings on impact of mismatch repair deficiency (MMRd) on patient outcomes in endometrial cancer (EC) have been inconsistent to date. The objective of this study was to compare the oncologic outcomes and recurrence patterns between MMRd and MMR-intact (MMRi) endometrioid EC (EEC).

Methods: Between 2015 and 2018, we prospectively recruited 492 EEC cases from three cancer centers in Ontario, Canada. Tumors were reflexively assessed for MMR protein expression by immunohistochemistry (IHC). Clinicopathological, survival and recurrence patterns were compared between MMRd and MMRi cases.

Results: Of 492 EEC, 348 were MMRi (71%) and 144 were MMRd (29%) with median follow-up of 16.8 months (0-69.6). MMRd tumors tended to be grade 2 or 3 (56% vs. 29%, p < 0.001), with propensity for lymphovascular space invasion (28% vs. 18%, p = 0.024), lymph node involvement (7% vs. 5%, p < 0.001) and received more adjuvant treatment (46% vs. 33%, p = 0.027). This group also had significantly lower 3-year recurrence-free survival (78% vs. 90%, p = 0.014) although there was no difference in OS (p = 0.603). MMRd cases were more likely to recur in retroperitoneal lymph nodes (p = 0.045). Upon subgroup analysis, MLH1 methylated tumors had the worst prognostic features and survival outcomes.

Conclusions: MLH1 methylated EECs exhibit more aggressive features compared to other MMRd and MMRi EECs. This may indicate an inherent difference in tumor biology, suggesting the importance of individualized management based on EC molecular phenotype.
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http://dx.doi.org/10.1016/j.ygyno.2021.01.002DOI Listing
April 2021

Assessment of Sentinel Lymph Node Biopsy vs Lymphadenectomy for Intermediate- and High-Grade Endometrial Cancer Staging.

JAMA Surg 2021 Feb;156(2):157-164

Department of Obstetrics and Gynaecology, University of Toronto, Toronto, Ontario, Canada.

Importance: Whether sentinel lymph node biopsy (SLNB) can replace lymphadenectomy for surgical staging in patients with high-grade endometrial cancer (EC) is unclear.

Objective: To examine the diagnostic accuracy of, performance characteristics of, and morbidity associated with SLNB using indocyanine green in patients with intermediate- and high-grade EC.

Design, Setting, And Participants: In this prospective, multicenter cohort study (Sentinel Lymph Node Biopsy vs Lymphadenectomy for Intermediate- and High-Grade Endometrial Cancer Staging [SENTOR] study), accrual occurred from July 1, 2015, to June 30, 2019, with early stoppage because of prespecified accuracy criteria. The study included patients with clinical stage I grade 2 endometrioid or high-grade EC scheduled to undergo laparoscopic or robotic hysterectomy with an intent to complete staging at 3 designated cancer centers in Toronto, Ontario, Canada.

Exposures: All patients underwent SLNB followed by lymphadenectomy as the reference standard. Patients with grade 2 endometrioid EC underwent pelvic lymphadenectomy (PLND) alone, and patients with high-grade EC underwent PLND and para-aortic lymphadenectomy (PALND).

Main Outcomes And Measures: The primary outcome was sensitivity of the SLNB algorithm. Secondary outcomes were additional measures of diagnostic accuracy, sentinel lymph node detection rates, and adverse events.

Results: The study enrolled 156 patients (median age, 65.5 years; range, 40-86 years; median body mass index [calculated as weight in kilograms divided by height in meters squared], 27.5; range, 17.6-49.3), including 126 with high-grade EC. All patients underwent SLNB and PLND, and 101 patients (80%) with high-grade EC also underwent PALND. Sentinel lymph node detection rates were 97.4% per patient (95% CI, 93.6%-99.3%), 87.5% per hemipelvis (95% CI, 83.3%-91.0%), and 77.6% bilaterally (95% CI, 70.2%-83.8%). Of 27 patients (17%) with nodal metastases, 26 patients were correctly identified by the SLNB algorithm, yielding a sensitivity of 96% (95% CI, 81%-100%), a false-negative rate of 4% (95% CI, 0%-19%), and a negative predictive value of 99% (95% CI, 96%-100%). Only 1 patient (0.6%) was misclassified by the SLNB algorithm. Seven of 27 patients with node-positive cancer (26%) were identified outside traditional PLND boundaries or required immunohistochemistry for diagnosis.

Conclusions And Relevance: In this prospective cohort study, SLNB had acceptable diagnostic accuracy for patients with high-grade EC at increased risk of nodal metastases and improved the detection of node-positive cases compared with lymphadenectomy. The findings suggest that SLNB is a viable option for the surgical staging of EC.
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http://dx.doi.org/10.1001/jamasurg.2020.5060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7658802PMC
February 2021

The Value of DICER1 Mutation Analysis in "Subtle" Diagnostically Challenging Embryonal Rhabdomyosarcomas of the Uterine Cervix.

Int J Gynecol Pathol 2021 Sep;40(5):435-440

Embryonal rhabdomyosarcoma of the uterine cervix is a rare neoplasm which is almost invariably associated with pathogenic somatic or germline DICER1 mutations; patients with germline mutations have DICER1 syndrome. We report 2 subtle cervical embryonal rhabdomyosarcoma, one occurring in a 21-yr-old woman with a known history of DICER1 syndrome and the other in a 19-yr-old woman with no history of DICER1 syndrome or DICER1-associated neoplasms. Both neoplasms focally involved otherwise benign endocervical polyps and were characterized histologically by subtle areas of increased stromal cellularity, nuclear atypia and mitotic activity; there was focal nuclear staining of these areas with the skeletal muscle markers myogenin and myoD1. In both cases, demonstration of a somatic DICER1 RNase IIIb mutation in the tumor was instrumental in establishing the diagnosis. We believe these neoplasms represent the earliest discernible phase of cervical embryonal rhabdomyosarcoma. Pathologists should have a high index of suspicion when atypical stromal elements are present in endocervical polyps and immunohistochemistry together with DICER1 sequencing will assist in diagnosis.
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http://dx.doi.org/10.1097/PGP.0000000000000718DOI Listing
September 2021

Performance characteristics of screening strategies to identify Lynch syndrome in women with ovarian cancer.

Cancer 2020 11 18;126(22):4886-4894. Epub 2020 Aug 18.

Division of Gynecologic Oncology, Princess Margaret Cancer Centre, University Health Network, Sinai Health Systems, Toronto, Ontario, Canada.

Background: For women with ovarian cancer (OC), the optimal screening strategy to identify Lynch syndrome (LS) has not been determined. In the current study, the authors compared the performance characteristics of various strategies combining mismatch repair (MMR) immunohistochemistry (IHC), microsatellite instability testing (MSI), and family history for the detection of LS.

Methods: Women with nonserous and/or nonmucinous ovarian cancer were recruited prospectively from 3 cancer centers in Ontario, Canada. All underwent germline testing for LS and completed a family history assessment. Tumors were assessed using MMR IHC and MSI. The sensitivity, specificity, and positive and negative predictive values of screening strategies were compared with the gold standard of a germline result.

Results: Of 215 women, germline data were available for 189 (88%); 13 women (7%) had pathogenic germline variants with 7 women with mutS homolog 6 (MSH6); 3 women with mutL homolog 1 (MLH1); 2 women with PMS1 homolog 2, mismatch repair system component (PMS2); and 1 woman with mutS homolog 2 (MSH2). A total of 28 women had MMR-deficient tumors (13%); of these, 11 had pathogenic variants (39%). Sequential IHC (with MLH1 promoter methylation analysis on MLH1-deficient tumors) followed by MSI for nonmethylated and/or MMR-intact patients was the most sensitive (92.3%; 95% confidence interval, 64%-99.8%) and specific (97.7%; 95% confidence interval, 94.2%-99.4%) approach, missing 1 case of LS. IHC with MLH1 promoter methylation analysis missed 2 patients of LS. Family history was found to have the lowest sensitivity at 55%.

Conclusions: Sequential IHC (with MLH1 promoter methylation analysis) followed by MSI was found to be most sensitive. However, IHC with MLH1 promoter methylation analysis also performed well and is likely more cost-effective and efficient in the clinical setting. The pretest probability of LS is high in patients with MMR deficiency and warrants universal screening for LS.
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http://dx.doi.org/10.1002/cncr.33144DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7693219PMC
November 2020

Distinct fibroblast functional states drive clinical outcomes in ovarian cancer and are regulated by TCF21.

J Exp Med 2020 08;217(8)

Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.

Recent studies indicate that cancer-associated fibroblasts (CAFs) are phenotypically and functionally heterogeneous. However, little is known about CAF subtypes, the roles they play in cancer progression, and molecular mediators of the CAF "state." Here, we identify a novel cell surface pan-CAF marker, CD49e, and demonstrate that two distinct CAF states, distinguished by expression of fibroblast activation protein (FAP), coexist within the CD49e+ CAF compartment in high-grade serous ovarian cancers. We show for the first time that CAF state influences patient outcomes and that this is mediated by the ability of FAP-high, but not FAP-low, CAFs to aggressively promote proliferation, invasion and therapy resistance of cancer cells. Overexpression of the FAP-low-specific transcription factor TCF21 in FAP-high CAFs decreases their ability to promote invasion, chemoresistance, and in vivo tumor growth, indicating that it acts as a master regulator of the CAF state. Understanding CAF states in more detail could lead to better patient stratification and novel therapeutic strategies.
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http://dx.doi.org/10.1084/jem.20191094DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7398174PMC
August 2020

Interlaboratory Concordance of ProMisE Molecular Classification of Endometrial Carcinoma Based on Endometrial Biopsy Specimens.

Int J Gynecol Pathol 2020 Nov;39(6):537-545

Molecular classifiers improve the consistency of categorization of endometrial carcinoma and provide valuable prognostic information. We aimed to evaluate the interlaboratory agreement in ProMisE assignment across 3 dedicated Canadian gynecologic oncology centers. Fifty cases of endometrial carcinoma diagnosed on biopsy were collected from 3 centers and 3 unstained sections were provided to each participating site so that immunohistochemistry for MSH6, PMS2, and p53 could be performed and interpreted at each center, blinded to the original diagnoses and the results from other centers. A core was taken for DNA extraction and POLE mutation testing. Overall accuracy and κ statistic were assessed. MSH6, PMS2, and p53 could be assessed for all 50 cases, with agreement for 140/150 results. There was a high level of agreement in molecular classification (κ=0.82), overall. Cases with a discordant result for one of the features used in classification (n=10) were reviewed independently and the most common reason for disagreement was attributable to the weak p53 staining in 1 laboratory (n=4). Interpretive error in PMS2 (n=1) and MSH6 (n=2) assessment accounted for 3 of the remaining disagreements. Interpretive error in the assessment of p53 was identified in 2 cases, with very faint p53 nuclear reactivity being misinterpreted as wild-type staining. These results show strong interlaboratory agreement and the potential for greater agreement if technical and interpretive factors are addressed. Several solutions could improve concordance: central quality control to ensure technical consistency in immunohistochemical staining, education to decrease interpretation errors, and the use of secondary molecular testing.
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http://dx.doi.org/10.1097/PGP.0000000000000654DOI Listing
November 2020

Equivalent Survival of p53 Mutated Endometrial Endometrioid Carcinoma Grade 3 and Endometrial Serous Carcinoma.

Int J Gynecol Pathol 2021 Mar;40(2):116-123

TP53 status is the most important prognostic biomarker in endometrial carcinoma. We asked the question whether p53 mutated endometrial endometrioid carcinomas grade 3 (EEC3) or endometrial serous carcinomas (ESC), the latter ubiquitously harboring TP53 mutation, have different outcomes. TP53 mutation status was assessed by surrogate p53 immunohistochemistry on 326 EEC3 and ESC from 2 major cancer centers in Canada. Mutant-type p53 expression, including overexpression, complete absence, or cytoplasmic expression, was distinguished from the wild-type pattern. Statistical associations with clinico-pathological parameter, other key biomarkers, and survival analyses were performed. P53 mutant-type immunohistochemistry was observed in all 126 ESC and in 47/200 (23.5%) EEC3. ESC and p53 mutated EEC3 had an unfavorable outcome compared with p53 wild-type EEC3 (hazard ratio=2.37, 95% confidence interval=1.48-3.80, P=0.003, hazard ratio=2.19, 95% confidence interval=1.16-4.12, P=0.016, respectively) in multivariable analyses adjusted for age, stage, center, and presence of lymph-vascular invasion. There was no significant difference in survival between ESC and p53 mutated EEC3 in multivariable analysis. Furthermore, p53 mutated EEC3 and ESC almost completely overlapped in univariate survival analysis when mismatch repair (MMR)-deficient cases were excluded, which suggests that EEC3 harboring combined MMR deficiency and TP53 mutations behave more according to the MMR status. Significant differences between p53 mutated MMR-proficient EEC3 and ESC in PTEN and p16 expression status remained. p53 mutated, MMR-proficient EEC3 and ESC have overlapping survival significantly different from p53 wild-type EEC3, which justifies a similar treatment with current non-targeted standard therapy. Although this is so, separate classification should continue due to biological differences that will become important for future targeted therapy.
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http://dx.doi.org/10.1097/PGP.0000000000000674DOI Listing
March 2021

IL6 Induces an IL22 CD8 T-cell Subset with Potent Antitumor Function.

Cancer Immunol Res 2020 03 21;8(3):321-333. Epub 2020 Jan 21.

Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada.

CD8 T cells can be polarized into several different subsets as defined by the cytokines they produce and the transcription factors that govern their differentiation. Here, we identified the polarizing conditions to induce an IL22-producing CD8 Tc22 subset, which is dependent on IL6 and the aryl hydrocarbon receptor transcription factor. Further characterization showed that this subset was highly cytolytic and expressed a distinct cytokine profile and transcriptome relative to other subsets. In addition, polarized Tc22 were able to control tumor growth as well as, if not better than, the traditional IFNγ-producing Tc1 subset. Tc22s were also found to infiltrate the tumors of human patients with ovarian cancer, comprising up to approximately 30% of expanded CD8 tumor-infiltrating lymphocytes (TIL). Importantly, IL22 production in these CD8 TILs correlated with improved recurrence-free survival. Given the antitumor properties of Tc22 cells, it may be prudent to polarize T cells to the Tc22 lineage when using chimeric antigen receptor (CAR)-T or T-cell receptor (TCR) transduction-based immunotherapies.
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http://dx.doi.org/10.1158/2326-6066.CIR-19-0521DOI Listing
March 2020

Significantly greater prevalence of DICER1 alterations in uterine embryonal rhabdomyosarcoma compared to adenosarcoma.

Mod Pathol 2020 06 3;33(6):1207-1219. Epub 2020 Jan 3.

Department of Human Genetics, McGill University, Montréal, QC, Canada.

Embryonal rhabdomyosarcomas (ERMS) account for 2-3% of cancers in pediatric and adolescent populations. They are rarer in adults. We and others have reported that ERMS arising in the uterine cervix may harbor mutations in the gene encoding the microRNA biogenesis enzyme, DICER1, but a large series of cases has not been published. In the uterus, distinguishing ERMS from adenosarcoma can be very challenging, even for expert pathologists, and DICER1 alterations have been identified in a variable subset of uterine adenosarcomas. We hypothesized that DICER1 genetic testing may be useful in distinguishing between ERMS and adenosarcoma. We conducted a central pathology review-based study of 64 tumors initially thought to be uterine ERMS or adenosarcoma; 19 neoplasms had a consensus diagnosis of ERMS, 27 of adenosarcoma and for 18, no consensus diagnosis was reached. The median age at diagnosis was 30 years (range 2.5-69) for ERMS, 57.5 years (range 27-82) for adenosarcoma, and 65.5 years (range 32-86) for no consensus cases. In our series, the DICER1 mutation prevalence differed between the three groups: DICER1 alterations were present in 18/19 (95%) ERMS, 7/27 (26%) adenosarcomas (p < 0.001), and 4/18 (22%) no consensus cases. A germline alteration was present in 6/12 ERMS patients tested versus 0/6 adenosarcoma patients. Thus, although DICER1 mutations are near ubiquitous in uterine ERMS and are significantly less common in uterine adenosarcoma, DICER1 testing is only of value in distinguishing between the two neoplasms when a DICER1 mutation is absent, as this is helpful in excluding ERMS. On review of the clinical and radiological features of the single DICER1 wild-type cervical ERMS, this was thought most likely to be of vaginal origin. Given the significant prevalence of DICER1 germline pathogenic variants in uterine ERMS, all patients with this diagnosis should be referred to a genetics service.
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http://dx.doi.org/10.1038/s41379-019-0436-0DOI Listing
June 2020

High expression of B7-H3 on stromal cells defines tumor and stromal compartments in epithelial ovarian cancer and is associated with limited immune activation.

J Immunother Cancer 2019 12 31;7(1):357. Epub 2019 Dec 31.

Department of Immunology, University of Toronto, Toronto, Ontario, Canada.

Background: B7-H3 and B7-H4 are highly expressed by many human malignancies making them attractive immunotherapeutic targets. However, their expression patterns and immune contexts in epithelial ovarian cancer have not been well characterized.

Methods: We used flow cytometry, immunohistochemistry, and genomic analyses to determine the patterns of B7-H3, B7-H4, and PD-L1 expression by tumor, stromal, and immune cells in the ovarian tumor microenvironment (TME). We analyzed immune cell frequency and expression of PD-1, TIM3, LAG3, ICOS, TIA-1, granzyme B, 2B4, CD107a, and GITR on T cells; CD20, CD22, IgD, BTLA, and CD27 on B cells; CD16 on monocytes; and B7-H3, B7-H4, PD-L1, PD-L2, ICOSL, CD40, CD86, and CLEC9a on antigen-presenting cells by flow cytometry. We determined intratumoral cellular location of immune cells using immunohistochemistry. We compared differences in immune infiltration in tumors with low or high tumor-to-stroma ratio and in tumors from the same or unrelated patients.

Results: On non-immune cells, B7-H4 expression was restricted to tumor cells whereas B7-H3 was expressed by both tumor and stromal cells. Stromal cells of the ovarian TME expressed high levels of B7-H3 compared to tumor cells. We used this differential expression to assess the tumor-to-stroma ratio of ovarian tumors and found that high tumor-to-stroma ratio was associated with increased expression of CD16 by monocytes, increased frequencies of PD-1 CD8 T cells, increased PD-L1 expression by APCs, and decreased CLEC9a expression by APCs. We found that expression of PD-L1 or CD86 on APCs and the proportion of PD-1 CD4 T cells were strongly correlated on immune cells from tumors within the same patient, whereas expression of CD40 and ICOSL on APCs and the proportion of PD-1 CD8 T cells were not.

Conclusions: This study provides insight into the expression patterns of B7-H3 and B7-H4 in the ovarian TME. Further, we demonstrate an association between the tumor-to-stroma ratio and the phenotype of tumor-infiltrating immune cells. We also find that some but not all immune parameters show consistency between peritoneal metastatic sites. These data have implications for the design of immunotherapies targeting these B7 molecules in epithelial ovarian cancer.
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http://dx.doi.org/10.1186/s40425-019-0816-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6937725PMC
December 2019

Tumor cell expression of B7-H4 correlates with higher frequencies of tumor-infiltrating APCs and higher CXCL17 expression in human epithelial ovarian cancer.

Oncoimmunology 2019;8(12):e1665460. Epub 2019 Sep 30.

Department of Immunology, University of Toronto, Toronto, Ontario, Canada.

B7-H4, an immune suppressive member of the B7 family, is highly expressed in a wide variety of human malignancies making it an attractive immunotherapeutic target. However, the association between B7-H4 expression in the tumor microenvironment and the immune infiltrate has not been comprehensively examined. To evaluate the immune tumor microenvironment, we analyzed epithelial ovarian tumors from 28 patients using flow cytometry, immunohistochemistry, functional, and genomic analyses. We determined B7-H4 expression patterns and compared the immune infiltrates of tumors with high and low surface expression of B7-H4. Frequencies and phenotypes of tumor and immune cells were determined using multiple flow cytometry panels. Immunohistochemistry was used to analyze cellular infiltration and location. Publicly available datasets were interrogated to determine intratumoral cytokine and chemokine expression. We found that B7-H4 was predominantly expressed by tumor cells in the epithelial ovarian tumor microenvironment. Surface expression of B7-H4 on tumor cells was correlated with higher levels of infiltrating mature antigen-presenting cells. Further, expression of CXCL17, a monocyte and dendritic cell chemoattractant, correlated strongly with B7-H4 expression. T cells expressed activation markers, but T cells expressing a combination of markers associated with T cell activation/exhaustion phenotype were not prevalent. Overall, our data suggest that B7-H4 is associated with a pro-inflammatory tumor microenvironment.
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http://dx.doi.org/10.1080/2162402X.2019.1665460DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6844312PMC
September 2019

HPV-independent Vulvar Squamous Cell Carcinoma is Associated With Significantly Worse Prognosis Compared With HPV-associated Tumors.

Int J Gynecol Pathol 2020 Jul;39(4):391-399

Department of Pathology and Laboratory Medicine, Henry Ford Health System, Detroit, Michigan (G.A.) Departments of Radiation Oncology (M.L.Y., J.C., M.M.) Obstetrics and Gynecology, Division of Gynecologic Oncology (S.F.) Medical Oncology (H.M.) Laboratory Medicine and Pathobiology (S.K.R., I.W., D.G., B.A.C.) Biostatistics (M.P.), Princess Margaret Cancer Centre/University Health Network, and University of Toronto, Toronto, ON, Canada.

Vulvar squamous cell carcinomas (VSCC) represent the most common carcinoma of the female external genitalia, with increasing incidence. Although high-risk human papillomavirus (HPV) infection has long been implicated in the majority of cervical and anal squamous cell carcinomas, there is uncertainty about its prevalence and prognostic impact in VSCC. In this study, we conducted a retrospective integrated morphologic and multimodal HPV analysis of a cohort of 114 VSCC cases treated at the Princess Margaret Cancer Centre/University Health Network, Toronto, Canada between 2000 and 2010. VSCC histology was reviewed. We analyzed the cohort for HPV using polymerase chain reaction based method, and tissue microarray DNA and RNA in situ hybridization (ISH), and p16 immunohistochemistry. Among the 114 cases (age 70±16 yr), 36.7% of cases were classified as having histomorphology of HPV infection. HPV was detected in 31.9% (polymerase chain reaction), 14.0% (DNA ISH), and 27.3% (RNA ISH) of cases. p16 immunohistochemistry was positive in 37.8% of cases. On univariate analysis, HPV morphology (P=0.009), p16+ (P=0.00013), DNA ISH+ (P=0.021), and RNA ISH+ (P=0.00061) were associated with better 5-yr progression-free survival. DNA ISH+ (P=0.049) was associated with better 5-yr overall survival. On multivariate analysis, HPV morphology (P=0.033), p16+ (P=0.01), and RNA ISH+ (P=0.035) were associated with better 5-yr progression-free survival. In conclusion, a subset of VSCC is associated with HPV, which correlates with better outcome. Relatively inexpensive tests such as histomorphologic evaluation, p16 immunohistochemistry, and HPV RNA ISH can be used to predict outcome in VSCC. Therefore, routine reporting of HPV status in VSCC is recommended.
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http://dx.doi.org/10.1097/PGP.0000000000000620DOI Listing
July 2020

Metastatic low-grade endometrial stromal sarcoma of uterus presenting as a primary pancreatic tumor: case presentation and literature review.

Diagn Pathol 2019 Apr 22;14(1):30. Epub 2019 Apr 22.

Department of Anatomical Pathology, Laboratory Medicine Program, University Health Network, Toronto General Hospital, 200 Elizabeth Street, 11th Floor, Eaton Wing, Toronto, Ontario, M5G 2C4, Canada.

Background: Metastatic tumors to the pancreas are uncommon, accounting for approximately 2% of pancreatic malignancies. The most common primary tumors to give rise to pancreatic metastases are carcinomas.

Case Presentation: A 50-year old female patient was investigated for a cause of abdominal discomfort. She had a 2-year history of menorrhagia and dysmenorrhea which was ascribed to a fibroid uterus. On imaging, she was found to have a large solid and cystic mass in the tail of the pancreas. Imaging also confirmed a fibroid uterus. A distal pancreatectomy and splenectomy showed a 9 cm circumscribed mass within, and grossly confined to, the parenchyma of the pancreatic tail. Microscopically, the pancreatic lesion was lobulated, and well-circumscribed, but focally infiltrative. It comprised sheets of uniform spindled to epithelioid cells with round to oval nuclei, coarse to vesicular chromatin, visible nucleoli, nuclear grooves and clear to eosinophilic cytoplasm. Prominent arterioles were identified. The stroma was collagenized in areas. Occasional hemosiderin-laden macrophages were seen, and focal cystic change was present. There was no evidence of nuclear pleomorphism, mitotic activity or necrosis, and there was no evidence of endometriosis despite multiple sections being taken. Immunohistochemistry showed that the tumor cells were positive for CD10, estrogen receptor (ER), progesterone receptor (PR), Wilms tumor-1 (WT-1) and smooth muscle actin (SMA). RNA sequencing detected a PHF1 rearrangement. The morphological, immunohistochemical and molecular features were of a low-grade endometrial stromal sarcoma (LG-ESS). Subsequent total hysterectomy and bilateral salpingo-oophorectomy 3 months later, showed uterine fibroids and a 5 cm low-grade endometrial stromal sarcoma confined to the uterus, with lymphatic invasion.

Conclusions: To the best of our knowledge, this is the first documented case of metastatic endometrial stromal sarcoma of uterus presenting as a primary pancreatic neoplasm. An unexpected extra-uterine location and unusual presentation of ESS may make the diagnosis challenging, despite classic histological features. Morphological, immunohistochemical and molecular findings must be combined to render the correct diagnosis.
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http://dx.doi.org/10.1186/s13000-019-0807-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6477712PMC
April 2019

CDK4/6 inhibitors target SMARCA4-determined cyclin D1 deficiency in hypercalcemic small cell carcinoma of the ovary.

Nat Commun 2019 02 4;10(1):558. Epub 2019 Feb 4.

Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90027, USA.

Inactivating mutations in SMARCA4 (BRG1), a key SWI/SNF chromatin remodelling gene, underlie small cell carcinoma of the ovary, hypercalcemic type (SCCOHT). To reveal its druggable vulnerabilities, we perform kinase-focused RNAi screens and uncover that SMARCA4-deficient SCCOHT cells are highly sensitive to the inhibition of cyclin-dependent kinase 4/6 (CDK4/6). SMARCA4 loss causes profound downregulation of cyclin D1, which limits CDK4/6 kinase activity in SCCOHT cells and leads to in vitro and in vivo susceptibility to CDK4/6 inhibitors. SCCOHT patient tumors are deficient in cyclin D1 yet retain the retinoblastoma-proficient/p16-deficient profile associated with positive responses to CDK4/6 inhibitors. Thus, our findings indicate that CDK4/6 inhibitors, approved for a breast cancer subtype addicted to CDK4/6 activation, could be repurposed to treat SCCOHT. Moreover, our study suggests a novel paradigm whereby critically low oncogene levels, caused by loss of a driver tumor suppressor, may also be exploited therapeutically.
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http://dx.doi.org/10.1038/s41467-018-06958-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6361890PMC
February 2019

Neoadjuvant therapy in gynaecological malignancies: What pathologists need to know.

J Clin Pathol 2019 Feb;72(2):102-111

Department of Anatomical Pathology, Laboratory Medicine Program, University Health Network, Toronto, Ontario, Canada.

In recent times, there has been a growing tendency to treat advanced gynaecological malignancies with neoadjuvant chemotherapy (NACT), with the goal of reducing tumour volume and enhancing operability resulting in optimal cytoreduction. This approach is used in particular for patients with advanced high-grade serous carcinoma of the ovary, fallopian tube or peritoneum. Pathology plays a crucial role in the management of these patients, both before and after NACT. Prior to initiation of NACT, a biopsy should be performed, usually of the omental cake, to confirm that a malignancy is present, to identify the site of origin of the tumour and to type and grade the tumour. Histopathologists must be aware of the resultant morphological effects of NACT when examining specimens following interval cytoreduction surgery. Tumour typing and grading, and even the identification of residual neoplasia, are particular challenges. Immunohistochemistry, when used judiciously, can be a useful adjunct in certain scenarios. A pathological assessment of the response to chemotherapy, and the pathological stage should be provided in the pathology report, as these may inform prognosis and subsequent management. We present a comprehensive overview of the relevant clinical and pathological aspects pertaining to NACT for gynaecological malignancies for the practicing surgical pathologist.
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http://dx.doi.org/10.1136/jclinpath-2018-205634DOI Listing
February 2019

Landscape of genomic alterations in high-grade serous ovarian cancer from exceptional long- and short-term survivors.

Genome Med 2018 10 31;10(1):81. Epub 2018 Oct 31.

Princess Margaret Cancer Centre, University Health Network, 610 University Avenue, Toronto, Ontario, M5G 2M9, Canada.

Background: Patients diagnosed with high-grade serous ovarian cancer (HGSOC) who received initial debulking surgery followed by platinum-based chemotherapy can experience highly variable clinical responses. A small percentage of women experience exceptional long-term survival (long term (LT), 10+ years), while others develop primary resistance to therapy and succumb to disease in less than 2 years (short term (ST)). To improve clinical management of HGSOC, there is a need to better characterize clinical and molecular profiles to identify factors that underpin these disparate survival responses.

Methods: To identify clinical and tumor molecular biomarkers associated with exceptional clinical response or resistance, we conducted an integrated clinical, exome, and transcriptome analysis of 41 primary tumors from LT (n = 20) and ST (n = 21) HGSOC patients.

Results: Younger age at diagnosis, no residual disease post debulking surgery and low CA125 levels following surgery and chemotherapy were clinical characteristics of LT. Tumors from LT survivors had increased somatic mutation burden (median 1.62 vs. 1.22 non-synonymous mutations/Mbp), frequent BRCA1/2 biallelic inactivation through mutation and loss of heterozygosity, and enrichment of activated CD4+, CD8+ T cells, and effector memory CD4+ T cells. Characteristics of ST survival included focal copy number gain of CCNE1, lack of BRCA mutation signature, low homologous recombination deficiency scores, and the presence of ESR1-CCDC170 gene fusion.

Conclusions: Our findings suggest that exceptional long- or short-term survival is determined by a concert of clinical, molecular, and microenvironment factors.
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http://dx.doi.org/10.1186/s13073-018-0590-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6208125PMC
October 2018

Expanding the morphological spectrum of ovarian microcystic stromal tumour.

Histopathology 2019 Feb 5;74(3):443-451. Epub 2018 Dec 5.

Cancer Research Program, Research Institute, McGill University Health Centre, Montreal, QC, Canada.

Aims: To expand the morphological spectrum of ovarian microcystic stromal tumour, a rare neoplasm considered to have a relatively constant morphology with microcysts, solid cellular regions and hyalinised fibrous stroma.

Methods And Results: We report four ovarian neoplasms in patients aged 45, 56, 61 and 71 years with the characteristic immunophenotype of microcystic stromal tumour (diffuse nuclear positivity with beta-catenin, cyclin D1 and WT1; diffuse cytoplasmic positivity with CD10; negative inhibin, calretinin, oestrogen receptor and progesterone receptor). The tumours had variant morphology (diffuse, nested and corded arrangements in three cases, including one with spindle cell elements; nested, corded and tubular in the other). A CTNNB1 point mutation in exon 3 (c.98C>G,p.S33C; c.100G>A,p.G34R; c.97T>G,p.S33A) was present in the three cases with material available for testing.

Conclusions: We feel that the cases we report are related to microcystic stromal tumour but with variant morphology; as such, the morphological spectrum of ovarian microcystic stromal tumour is broader than hitherto reported.
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http://dx.doi.org/10.1111/his.13755DOI Listing
February 2019

Regulatory T Cells in Ovarian Cancer Are Characterized by a Highly Activated Phenotype Distinct from that in Melanoma.

Clin Cancer Res 2018 11 31;24(22):5685-5696. Epub 2018 Jul 31.

The Campbell Family Institute for Breast Cancer Research, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.

Regulatory T (Treg) cells expressing the transcription factor FOXP3 are essential for the maintenance of immunologic self-tolerance but play a detrimental role in most cancers due to their ability to suppress antitumor immunity. The phenotype of human circulating Treg cells has been extensively studied, but less is known about tumor-infiltrating Treg cells. We studied the phenotype and function of tumor-infiltrating Treg cells in ovarian cancer and melanoma to identify potential Treg cell-associated molecules that can be targeted by tumor immunotherapies. The phenotype of intratumoral and circulating Treg cells was analyzed by multicolor flow cytometry, mass cytometry, RNA-seq, and functional assays. Treg cells isolated from ovarian tumors displayed a distinct cell surface phenotype with increased expression of a number of receptors associated with TCR engagement, including PD-1, 4-1BB, and ICOS. Higher PD-1 and 4-1BB expression was associated with increased responsiveness to further TCR stimulation and increased suppressive capacity, respectively. Transcriptomic and mass cytometry analyses revealed the presence of Treg cell subpopulations and further supported a highly activated state specifically in ovarian tumors. In comparison, Treg cells infiltrating melanomas displayed lower FOXP3, PD-1, 4-1BB, and ICOS expression and were less potent suppressors of CD8 T-cell proliferation. The highly activated phenotype of ovarian tumor-infiltrating Treg cells may be a key component of an immunosuppressive tumor microenvironment. Receptors that are expressed by tumor-infiltrating Treg cells could be exploited for the design of novel combination tumor immunotherapies. .
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http://dx.doi.org/10.1158/1078-0432.CCR-18-0554DOI Listing
November 2018

Inhibitory Projections in the Mouse Auditory Tectothalamic System.

Brain Sci 2018 Jun 9;8(6). Epub 2018 Jun 9.

Department of Comparative Biomedical Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA 70803, USA.

The medial geniculate body (MGB) is the target of excitatory and inhibitory inputs from several neural sources. Among these, the inferior colliculus (IC) is an important nucleus in the midbrain that acts as a nexus for auditory projections, ascending and descending, throughout the rest of the central auditory system and provides both excitatory and inhibitory inputs to the MGB. In our study, we assessed the relative contribution from presumed excitatory and inhibitory IC neurons to the MGB in mice. Using retrograde tract tracing with cholera toxin beta subunit (CTβ)-Alexa Fluor 594 injected into the MGB of transgenic, vesicular GABA transporter (VGAT)-Venus mice, we quantitatively analyzed the projections from both the ipsilateral and contralateral IC to the MGB. Our results demonstrate inhibitory projections from both ICs to the MGB that likely play a significant role in shaping auditory processing. These results complement prior studies in other species, which suggest that the inhibitory tectothalamic pathway is important in the regulation of neuronal activity in the auditory forebrain.
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http://dx.doi.org/10.3390/brainsci8060103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6025108PMC
June 2018

Genomic profiling identifies amplification in association with sarcomatous transformation in a subset of uterine carcinosarcomas.

J Pathol Clin Res 2018 Jan 24;4(1):69-78. Epub 2018 Jan 24.

Department of PathologyUniversity Health Network, University of TorontoTorontoCanada.

Uterine carcinosarcoma, also known as Malignant Mixed Müllerian Tumour, is a high-grade biphasic neoplasm composed of sarcomatous elements thought to originate via transdifferentiation from high-grade endometrial carcinoma. To identify molecular factors contributing to the histogenesis of this tumour, we analyzed DNA extracted from matched carcinoma and sarcoma components from 12 cases of carcinosarcoma by a molecular inversion probe microarray to assess genomic copy number alterations (CNAs) and allelic imbalances. Widespread CNAs were identified in tumours with serous histology in the carcinoma component (9/12), while the remaining three cases with endometrioid carcinoma were near-diploid. Quantification of the extent of genomic aberrations revealed a significant increase in sarcoma relative to carcinoma in tumours with well-delineated histologic components. Focal amplification of 13q31.3 was identified in 6/12 profiled tumours, of which four harboured the aberration exclusively in the sarcoma component. This result was verified by fluorescence hybridization against , the only gene situated within the minimal region of amplification. In a validation cohort composed of 97 carcinosarcomas and other uterine sarcomas, amplification of (/ ratio ≥ 2.2) was identified in 11/97 (11.3%) cases (9/64 carcinosarcoma, 1/3 rhabdomyosarcoma, 1/21 leiomyosarcoma, 0/8 adenosarcoma, 0/1 undifferentiated endometrial sarcoma) and an additional 4 (2.8%) cases had low level gains ( ratio ≥1.5 but <2.2). The functional relevance of Glypican-5, the gene product of , in regulating differentiation and lineage commitment was demonstrated in an endometrial carcinoma cell line . In conclusion, we identified amplification as a molecular event mediating epithelial-mesenchymal transdifferentiation in a subset of uterine carcinosarcomas.
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http://dx.doi.org/10.1002/cjp2.89DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5783974PMC
January 2018

Novel combinations of PI3K-mTOR inhibitors with dacomitinib or chemotherapy in PTEN-deficient patient-derived tumor xenografts.

Oncotarget 2017 Oct 8;8(49):84659-84670. Epub 2017 Jul 8.

Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, Ontario, Canada.

PTEN inactivation occurs commonly in human cancers and putatively activates the PI3K/AKT/ mTOR pathway. Activation of this pathway has been involved in resistance to chemotherapy or anti-EGFR/HER2 therapies. We evaluated the combination of PI3K-mTOR inhibitors with chemotherapy or the pan-HER inhibitor dacomitinib in PTEN-deficient patient-derived tumor xenografts (PDX). Three PDXs were selected for their lack of PTEN expression by immunohistochemistry: a triple-negative breast cancer (TNBC), a G12R low-grade serous ovarian cancer (LGSOC), and G12C and R181P lung adenocarcinoma (LADC). Two dual PI3K-mTOR inhibitors were evaluated-PF-04691502 and PF-05212384-in combination with cisplatin, paclitaxel, or dacomitinib. The addition of PI3K-mTOR inhibitors to cisplatin or paclitaxel increased the activity of chemotherapy in the TNBC and LGSOC models; whereas no added activity was observed in the LADC model. Pharmacodynamic modulation of pS6 and pAKT was observed in the group treated with PI3K-mTOR inhibitor. Our research suggests that the addition of a PI3K-mTOR inhibitor may enhance tumor growth inhibition when compared to chemotherapy alone in certain PTEN-deficient PDXs. However, this benefit was absent in the and mutant LADC model. The role of PTEN deficiency in the antitumor activity of these combinations should be further investigated in the clinic.
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http://dx.doi.org/10.18632/oncotarget.19109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5689564PMC
October 2017

DICER1 Mutations Are Consistently Present in Moderately and Poorly Differentiated Sertoli-Leydig Cell Tumors.

Am J Surg Pathol 2017 Sep;41(9):1178-1187

*Department of Human Genetics, McGill University †Segal Cancer Centre, Lady Davis Institute, Jewish General Hospital ¶Research Institute of the McGill University Health Centre, Montréal, QC, Canada ‡Department of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Toronto, ON, Canada §Department of Pathology, Belfast Health and Social Care Trust, Royal Group of Hospitals Trust, Belfast, United Kingdom ∥School for Women's and Infants' Health, University of Western Australia, Perth, WA, Australia.

Ovarian Sertoli-Leydig cell tumors (SLCTs) are uncommon sex cord-stromal tumors associated with both germ-line and somatic DICER1 mutations, the frequency of which has varied widely in different studies (0% to 62.5%). The current World Health Organization Classification includes 3 histologic types of SLCTs (well-differentiated, moderately differentiated, and poorly differentiated); heterologous elements and/or retiform patterns may be present in moderately and poorly differentiated neoplasms. We investigated the frequency of DICER1 mutations in a series of 38 ovarian tumors initially diagnosed as SLCTs, and explored whether identified mutations were associated with specific morphologic features. Specialist pathology review performed blinded to molecular results confirmed 34 tumors to be SLCTs (22 moderately differentiated, 8 poorly differentiated; 4 well-differentiated), while the remaining 4 neoplasms were considered not to represent SLCTs. Of the 34 cases diagnosed as SLCTs, 30 (88%) harbored ≥1 DICER1 mutation. All 30 moderately differentiated/poorly differentiated SLCTs contained mutations, but we did not find deleterious DICER1 mutations in the 4 well-differentiated SLCTs. Our study reports the highest DICER1 mutation frequency to date in SLCTs, with 100% of moderately differentiated and poorly differentiated tumors being DICER1-mutated. This suggests that DICER1 mutation may be a defining feature of these neoplasms. Although the number of cases is limited, well-differentiated SLCTs appear to be DICER1-independent. Moderately differentiated and poorly differentiated SLCT components often coexist with each other and form part of a spectrum, while well-differentiated SLCTs usually occur in pure form, suggesting that fundamentally, these represent 2 separate and independent tumor types with a different pathogenesis. We suggest that all patients with ovarian SLCTs undergo germ-line DICER1 mutation testing.
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http://dx.doi.org/10.1097/PAS.0000000000000895DOI Listing
September 2017

Ovarian carcinoma histotype in Lynch syndrome.

Gynecol Oncol Rep 2017 May 16;20:140-141. Epub 2017 Mar 16.

Dept of Human Genetics, McGill University, Montreal, QC, Canada.

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http://dx.doi.org/10.1016/j.gore.2017.03.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5993521PMC
May 2017

Somatic BRCA1/2 Recovery as a Resistance Mechanism After Exceptional Response to Poly (ADP-ribose) Polymerase Inhibition.

J Clin Oncol 2017 Apr 21;35(11):1240-1249. Epub 2017 Feb 21.

Stephanie Lheureux, Jeff P. Bruce, Julia V. Burnier, Katherine Karakasis, S.Y. Cindy Yang, Rene Quevedo, Tiantian Li, Mark Dowar, Valerie Bowering, Trevor J. Pugh, and Amit M. Oza, Princess Margaret Cancer Centre; Stephanie Lheureux, Patricia A. Shaw, Blaise A. Clarke, S.Y. Cindy Yang, Rene Quevedo, Trevor J. Pugh, and Amit M. Oza, University of Toronto; Patricia A. Shaw and Blaise A. Clarke, University Health Network, Toronto, Canada.

Purpose Durable and long-term responses to the poly (ADP-ribose) polymerase inhibitor olaparib are observed in patients without BRCA1/2 mutations. However, beyond BRCA1/2 mutations, there are no approved biomarkers for olaparib in high-grade serous ovarian cancer (HGSOC). To determine mechanisms of durable response and resistance to olaparib therapy, we performed an analysis of HGSOC tumors from three patients without germline BRCA1/2 mutations who experienced exceptional responses to olaparib. Patients and Methods We performed integrated exome, low-pass genome, and RNA sequence analysis of tumors at diagnosis and upon relapse from patients with platinum-sensitive HGSOC recurrence who were treated > 5 years with olaparib therapy as a single agent. Results We observed somatic disruption of BRCA1/2 in all three patients at diagnosis, followed by subsequent BRCA recovery upon progression by copy number gain and/or upregulation of the remaining functional allele in two patients. The third patient with ongoing response (> 7 years) had a tumor at diagnosis with biallelic somatic deletion and loss-of-function mutation, thereby lacking a functional allele for recovery of BRCA1 activity and indicating a potential cure. Conclusion Olaparib has durable benefit for patients with ovarian cancer beyond germline BRCA1/2 carriers. These data suggest that biallelic loss of BRCA1/2 in cancer cells may be a potential marker of long-term response to poly (ADP-ribose) polymerase inhibition and that restoration of homologous repair function may be a mechanism of disease resistance.
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http://dx.doi.org/10.1200/JCO.2016.71.3677DOI Listing
April 2017

A distinct innate lymphoid cell population regulates tumor-associated T cells.

Nat Med 2017 Mar 6;23(3):368-375. Epub 2017 Feb 6.

Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.

Antitumor T cells are subject to multiple mechanisms of negative regulation. Recent findings that innate lymphoid cells (ILCs) regulate adaptive T cell responses led us to examine the regulatory potential of ILCs in the context of cancer. We identified a unique ILC population that inhibits tumor-infiltrating lymphocytes (TILs) from high-grade serous tumors, defined their suppressive capacity in vitro, and performed a comprehensive analysis of their phenotype. Notably, the presence of this CD56CD3 population in TIL cultures was associated with reduced T cell numbers, and further functional studies demonstrated that this population suppressed TIL expansion and altered TIL cytokine production. Transcriptome analysis and phenotypic characterization determined that regulatory CD56CD3 cells exhibit low cytotoxic activity, produce IL-22, and have an expression profile that overlaps with those of natural killer (NK) cells and other ILCs. NKp46 was highly expressed by these cells, and addition of anti-NKp46 antibodies to TIL cultures abrogated the ability of these regulatory ILCs to suppress T cell expansion. Notably, the presence of these regulatory ILCs in TIL cultures corresponded with a striking reduction in the time to disease recurrence. These studies demonstrate that a previously uncharacterized ILC population regulates the activity and expansion of tumor-associated T cells.
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http://dx.doi.org/10.1038/nm.4278DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5497996PMC
March 2017

Clinical, morphological and immunohistochemical evidence that small-cell carcinoma of the ovary of hypercalcaemic type (SCCOHT) may be a primitive germ-cell neoplasm.

Histopathology 2017 Jun 20;70(7):1147-1154. Epub 2017 Mar 20.

Department of Human Genetics, McGill University, Montreal, Quebec, Canada.

Aims: The histogenesis and cell lineage of small-cell carcinoma of the ovary of hypercalcaemic type (SCCOHT) is unknown. We aim to provide evidence that this may be a primitive germ-cell neoplasm arising from a teratoma.

Methods And Results: Following the identification of two cases of SCCOHT associated with germ-cell tumours (one dermoid cyst, one immature teratoma with a focus of yolk sac tumour), we undertook a literature review to look for any prior reports of SCCOHT in association with other neoplasms or elements. This revealed two cases associated with immature teratomas, one arising in an ovary where a cystectomy had been undertaken previously for a teratoma and another in association with a mucinous borderline tumour. Mucinous elements have also been reported in SCCOHT, this type of epithelium potentially being of teratomatous derivation. We stained whole tissue sections of nine cases of SCCOHT and a tissue microarray (TMA) containing 34 different SCCOHT with germ-cell markers SALL4, OCT3/4, alpha fetoprotein (AFP) and glypican 3. All except one of the whole tissue sections and approximately half the TMA cases were positive with SALL4, while all cases were OCT3/4-, AFP- and glypican 3-negative, except for focal glypican 3 staining in an occasional case.

Conclusions: Our findings provide additional evidence to that proposed by others that SCCOHT is a primitive germ-cell neoplasm arising from a teratoma.
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http://dx.doi.org/10.1111/his.13177DOI Listing
June 2017
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