Publications by authors named "Stanley K Liu"

53 Publications

Elective nodal ultra hypofractionated radiation for prostate cancer: safety and efficacy from four prospective clinical trials.

Radiother Oncol 2021 Sep 3. Epub 2021 Sep 3.

Odette Cancer Centre, Sunnybrook Health Sciences Centre; Department of Radiation Oncology, University of Toronto; Institute of Health Policy, Management and Evaluation. Electronic address:

Background And Purpose: The role of elective nodal irradiation (ENI) in localized prostate cancer (PCa) is controversial. With increasing use of SBRT to the prostate, data is needed regarding the safety and efficacy of ENI using ultra-hypofractionated radiation (UHRT).

Materials And Methods: Between 2013-2020, 4 prospective clinical trials of intermediate or high-risk PCa receiving dose-escalated RT to the prostate (via HDR brachytherapy or SBRT boost) and ENI using UHRT (25Gy in 5 weekly fractions) were conducted. Primary endpoints included acute genitourinary and gastrointestinal toxicities (CTCAE v3.0/4.0), and secondary endpoints included late genitourinary and gastrointestinal toxicities, patient-reported quality of life (EPIC) and biochemical failure (Phoenix definition).

Results: One-hundred sixty-five patients were enrolled, of whom 98 (59%) had high-risk disease. ADT was used in 141 (85%). Median follow-up was 38 months (IQR 10-63). The worst acute genitourinary and gastrointestinal toxicities respectively were 48% and 7.5% for grade 2, and 2.7% and 0% for grade 3. Cumulative incidence of late grade 2+ genitourinary and gastrointestinal toxicities at 36 months were 58% and 11.3% and for late grade 3+ toxicities were 1% and 0%, respectively. No grade 4+ acute or late toxicities were observed. Bowel and sexual toxicity significantly worsened up to 1-year compared to baseline. Over time, urinary (p<0.0001), bowel (p=0.0018) and sexual (p<0.0001) scores significantly improved. The 3-year biochemical recurrence-free survival was 98%.

Conclusion: ENI using UHRT is associated with low incidence of grade 3+ toxicity, while grade 1-2 acute genitourinary and gastrointestinal toxicity is common. Randomized phase 3 trials are needed.
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http://dx.doi.org/10.1016/j.radonc.2021.08.017DOI Listing
September 2021

Proteomic discovery of non-invasive biomarkers of localized prostate cancer using mass spectrometry.

Nat Rev Urol 2021 Aug 27. Epub 2021 Aug 27.

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

Prostate cancer is the second most frequently diagnosed non-skin cancer in men worldwide. Patient outcomes are remarkably heterogeneous and the best existing clinical prognostic tools such as International Society of Urological Pathology Grade Group, pretreatment serum PSA concentration and T-category, do not accurately predict disease outcome for individual patients. Thus, patients newly diagnosed with prostate cancer are often overtreated or undertreated, reducing quality of life and increasing disease-specific mortality. Biomarkers that can improve the risk stratification of these patients are, therefore, urgently needed. The ideal biomarker in this setting will be non-invasive and affordable, enabling longitudinal evaluation of disease status. Prostatic secretions, urine and blood can be sources of biomarker discovery, validation and clinical implementation, and mass spectrometry can be used to detect and quantify proteins in these fluids. Protein biomarkers currently in use for diagnosis, prognosis and relapse-monitoring of localized prostate cancer in fluids remain centred around PSA and its variants, and opportunities exist for clinically validating novel and complimentary candidate protein biomarkers and deploying them into the clinic.
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http://dx.doi.org/10.1038/s41585-021-00500-1DOI Listing
August 2021

Elective pelvic nodal irradiation with a simultaneous hypofractionated integrated prostate boost for localized high risk prostate cancer: Long term results from a prospective clinical trial.

Radiother Oncol 2021 Jul 26;163:21-31. Epub 2021 Jul 26.

Department of Radiation Oncology, University of Toronto, Canada; Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada. Electronic address:

Background: To report on long-term results of elective pelvic nodal irradiation (EPNI) and a simultaneous hypofractionated prostate boost for high-risk prostate cancer.

Materials And Methods: This was a prospective single-arm study. Patients with high-risk disease (cT3, PSA >20 ng/mL, or Gleason score 8-10) were eligible. Patients received 45 Gy in 25 fractions to the prostate and pelvic lymph nodes with a simultaneous intensity-modulated radiotherapy boost of 22.5 Gy to the prostate (total dose 67.5 Gy in 25 fractions), with androgen deprivation therapy (ADT) for 2-3 years. The primary endpoint was biochemical failure. Secondary endpoints included distant metastases and overall survival. Multivariable analysis was performed to look for predictive factors. Late toxicity was assessed using CTCAE v3.0.

Results: 230 patients enrolled. Median follow-up was 11.2 years (IQR 8.1-12.9). At 10 years, cumulative incidence of biochemical failure was 33.4%, distant metastasis was 16.5%, and overall survival was 76.3%. On multivariable analysis, PSA nadir ≥0.05 ng/mL was associated with biochemical failure (HR 6.8, 95% CI 4-11.8, p < 0.001) and distant metastases (HR 7.5, 95% CI 3.9-14.5, p < 0.0001). PSA nadir ≥0.1 ng/mL (HR 5.2, 95% 2.2-12, p = 0.0001) and ADT use ≤12 months (versus >24 months) (HR 2.3, 95% CI 1.3-3.9, p = 0.004) were associated with worse survival. The 5-year cumulative incidence of any late grade ≥3 gastrointestinal and genitourinary toxicity was 2.3% and 7.5%, respectively.

Conclusion: EPNI and a simultaneous hypofractionated prostate boost combined with long-term ADT for high-risk prostate cancer resulted in acceptable 10-year biochemical control and survival with low grade ≥3 toxicity.
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http://dx.doi.org/10.1016/j.radonc.2021.07.018DOI Listing
July 2021

A proteomic investigation of isogenic radiation resistant prostate cancer cell lines.

Proteomics Clin Appl 2021 Sep 30;15(5):e2100037. Epub 2021 Jun 30.

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

To model the problem of radiation resistance in prostate cancer, cell lines mimicking a clinical course of conventionally fractionated or hypofractionated radiotherapy have been generated. Proteomic analysis of radiation resistant and radiosensitive DU145 prostate cancer cells detected 4410 proteins. Over 400 proteins were differentially expressed across both radiation resistant cell lines and pathway analysis revealed enrichment in epithelial to mesenchymal transition, glycolysis and hypoxia. From the radiation resistant protein candidates, the cell surface protein CD44 was identified in the glycolysis and epithelial to mesenchymal transition pathways and may serve as a potential therapeutic target.
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http://dx.doi.org/10.1002/prca.202100037DOI Listing
September 2021

Stereotactic body radiotherapy versus conventional external beam radiotherapy in patients with painful spinal metastases: an open-label, multicentre, randomised, controlled, phase 2/3 trial.

Lancet Oncol 2021 07 11;22(7):1023-1033. Epub 2021 Jun 11.

Canadian Clinical Trials Group, Queens's University, Kingston, ON, Canada.

Background: Conventional external beam radiotherapy is the standard palliative treatment for spinal metastases; however, complete response rates for pain are as low as 10-20%. Stereotactic body radiotherapy delivers high-dose, ablative radiotherapy. We aimed to compare complete response rates for pain after stereotactic body radiotherapy or conventional external beam radiotherapy in patients with painful spinal metastasis.

Methods: This open-label, multicentre, randomised, controlled, phase 2/3 trial was done at 13 hospitals in Canada and five hospitals in Australia. Patients were eligible if they were aged 18 years and older, and had painful (defined as ≥2 points with the Brief Pain Inventory) MRI-confirmed spinal metastasis, no more than three consecutive vertebral segments to be included in the treatment volume, an Eastern Cooperative Oncology Group performance status of 0-2, a Spinal Instability Neoplasia Score of less than 12, and no neurologically symptomatic spinal cord or cauda equina compression. Patients were randomly assigned (1:1) with a web-based, computer-generated allocation sequence to receive either stereotactic body radiotherapy at a dose of 24 Gy in two daily fractions or conventional external beam radiotherapy at a dose of 20 Gy in five daily fractions using standard techniques. Treatment assignment was done centrally by use of a minimisation method to achieve balance for the stratification factors of radiosensitivity, the presence or absence of mass-type tumour (extraosseous or epidural disease extension, or both) on imaging, and centre. The primary endpoint was the proportion of patients with a complete response for pain at 3 months after radiotherapy. The primary endpoint was analysed in the intention-to-treat population and all safety and quality assurance analyses were done in the as-treated population (ie, all patients who received at least one fraction of radiotherapy). The trial is registered with ClinicalTrials.gov, NCT02512965.

Findings: Between Jan 4, 2016, and Sept 27, 2019, 229 patients were enrolled and randomly assigned to receive conventional external beam radiotherapy (n=115) or stereotactic body radiotherapy (n=114). All 229 patients were included in the intention-to-treat analysis. The median follow-up was 6·7 months (IQR 6·3-6·9). At 3 months, 40 (35%) of 114 patients in the stereotactic body radiotherapy group, and 16 (14%) of 115 patients in the conventional external beam radiotherapy group had a complete response for pain (risk ratio 1·33, 95% CI 1·14-1·55; p=0·0002). This significant difference was maintained in multivariable-adjusted analyses (odds ratio 3·47, 95% CI 1·77-6·80; p=0·0003). The most common grade 3-4 adverse event was grade 3 pain (five [4%] of 115 patients in the conventional external beam radiotherapy group vs five (5%) of 110 patients in the stereotactic body radiotherapy group). No treatment-related deaths were observed.

Interpretation: Stereotactic body radiotherapy at a dose of 24 Gy in two daily fractions was superior to conventional external beam radiotherapy at a dose of 20 Gy in five daily fractions in improving the complete response rate for pain. These results suggest that use of conformal, image-guided, stereotactically dose-escalated radiotherapy is appropriate in the palliative setting for symptom control for selected patients with painful spinal metastases, and an increased awareness of the need for specialised and multidisciplinary involvement in the delivery of end-of-life care is needed.

Funding: Canadian Cancer Society and the Australian National Health and Medical Research Council.
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http://dx.doi.org/10.1016/S1470-2045(21)00196-0DOI Listing
July 2021

Three-antibody classifier for muscle invasive urothelial carcinoma and its correlation with p53 expression.

J Clin Pathol 2021 Jun 8. Epub 2021 Jun 8.

Division of Anatomic Pathology, Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

Aims: To assess the utility of a three-antibody immunohistochemistry panel to classify muscle invasive bladder cancers (MIBCs) in correlation with morphological features and p53 status.

Methods: A retrospective review of 243 chemotherapy naïve MIBC cystectomy specimens was performed to assess morphological features. A tissue microarray was sequentially stained with CK5/6, GATA-3 and p16. Subgroups were assigned as basal-like (CK5/6+, GATA3-) and luminal (CK5/6-, GATA3+), with the latter subdivided into genomically unstable (GU, p16+) and urothelial like (Uro, p16-) subgroups. p53 staining was assessed as abnormal/wild type. Cases from the The Cancer Genome Atlas (TCGA) portal were assessed as external validation.

Results: We identified 78.8% luminal, 21.2% basal cases within our cohort and 63.4% luminal, 36.6% basal in the TCGA dataset. Divergent differentiation (p<0.001) was significantly associated with basal-subtype cases in both cohorts. Within the luminal subgroup (n=186), 81 cases were classified as GU and 105 as Uro. Abnormal p53 staining was noted in 48.0% of basal, 80.2% GU and 38.1% Uro cases. Further, basal-subtype tumours significantly correlated with disease-specific death compared with Uro cases in multivariate survival analysis.

Conclusions: This retrospective study demonstrates the potential utility of a three-antibody immunohistochemistry panel to differentiate luminal and basal MIBC.
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http://dx.doi.org/10.1136/jclinpath-2021-207573DOI Listing
June 2021

Stereotactic pelvic radiotherapy with HDR boost for dose escalation in intermediate and high-risk prostate cancer (SPARE): Efficacy, toxicity and quality of life.

Radiother Oncol 2021 08 3;161:40-46. Epub 2021 Jun 3.

Odette Cancer Centre, Sunnybrook Health Sciences Centre, Canada; Department of Radiation Oncology, University of Toronto, Canada; Institute of Health Policy, Management and Evaluation, Canada. Electronic address:

Background: The ASCO/CCO guidelines recommend brachytherapy (BT) boost for eligible intermediate- (IR) or high-risk (HR) prostate cancer (PCa) patients. We present efficacy, toxicity and quality-of-life (QoL) outcomes in patients treated on a prospective protocol of MRI dose-painted high-dose-rate BT boost (HDR-BT) followed by 5-fraction pelvic radiotherapy (RT) and 6-18 months of androgen deprivation therapy (ADT).

Methods: In this phase I/II study, IR or HR PCa patients received HDR-BT 15 Gy × 1 to prostate and up to 22.5 Gy to MRI nodule, followed by 25 Gy in 5, weekly fractions to pelvis. Toxicity was assessed using CTCAEv3.0, and QoL was captured using EPIC questionnaire. Biochemical failure (BF; nadir + 2.0), and proportion of patients with PSA < 0.4 ng/ml at 4-years (4yPSARR) were evaluated. A minimally clinically important change (MCIC) was recorded if QoL score decreased >0.5 standard deviation of baseline scores.

Results: Thirty-one patients (NCCN 3.2% favorable IR, 48.4% unfavorable IR and 48.4% HR) completed treatment with a median follow-up of 61 months. Median D90 to MR nodule was 19.0 Gy and median prostate V100% was 96.5%. The actuarial 5-year BF rate was 18.2%, and the 4yPSARR was 71%. One patient died of PCa. Acute grade 2 and 3 toxicities: GU: 50%, 7%, and GI: 3%, none, respectively. Late grade 2 and 3 toxicities were: GU: 23%, 3%, and GI: 7%, none, respectively. Proportion of patients with MCIC was 7.7% for urinary domain and 32.0% for bowel domain.

Conclusions: This novel treatment protocol incorporating MRI dose-painted HDR-BT boost and 5-fraction pelvic RT with ADT is well tolerated.
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http://dx.doi.org/10.1016/j.radonc.2021.05.024DOI Listing
August 2021

Reciprocal interactions between tumour cell populations enhance growth and reduce radiation sensitivity in prostate cancer.

Commun Biol 2021 01 4;4(1). Epub 2021 Jan 4.

CRUK and MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK.

Intratumoural heterogeneity (ITH) contributes to local recurrence following radiotherapy in prostate cancer. Recent studies also show that ecological interactions between heterogeneous tumour cell populations can lead to resistance in chemotherapy. Here, we evaluated whether interactions between heterogenous populations could impact growth and response to radiotherapy in prostate cancer. Using mixed 3D cultures of parental and radioresistant populations from two prostate cancer cell lines and a predator-prey mathematical model to investigate various types of ecological interactions, we show that reciprocal interactions between heterogeneous populations enhance overall growth and reduce radiation sensitivity. The type of interaction influences the time of regrowth after radiation, and, at the population level, alters the survival and cell cycle of each population without eliminating either one. These interactions can arise from oxygen constraints and from cellular cross-talk that alter the tumour microenvironment. These findings suggest that ecological-type interactions are important in radiation response and could be targeted to reduce local recurrence.
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http://dx.doi.org/10.1038/s42003-020-01529-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7782740PMC
January 2021

Saturation transfer properties of tumour xenografts derived from prostate cancer cell lines 22Rv1 and DU145.

Sci Rep 2020 12 4;10(1):21315. Epub 2020 Dec 4.

Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada.

Histopathology is currently the most reliable tool in assessing the aggressiveness and prognosis of solid tumours. However, developing non-invasive modalities for tumour evaluation remains crucial due to the side effects and complications caused by biopsy procedures. In this study, saturation transfer MRI was used to investigate the microstructural and metabolic properties of tumour xenografts in mice derived from the prostate cancer cell lines 22Rv1 and DU145, which express different aggressiveness. The magnetization transfer (MT) and chemical exchange saturation transfer (CEST) effects, which are associated with the microstructural and metabolic properties in biological tissue, respectively, were analyzed quantitatively and compared amongst different tumour types and regions. Histopathological staining was performed as a reference. Higher cellular density and metabolism expressed in more aggressive tumours (22Rv1) were associated with larger MT and CEST effects. High collagen content in the necrotic regions might explain their higher MT effects compared to tumour regions.
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http://dx.doi.org/10.1038/s41598-020-78353-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7718243PMC
December 2020

Can immune markers help identify fast relapse in patients with muscle invasive bladder cancer?

Pathol Res Pract 2020 Nov 5;216(11):153200. Epub 2020 Sep 5.

Division of Anatomic Pathology, Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada. Electronic address:

The aim of this pilot study was to assess the role of immune markers in fast relapse (<2 years) of high-grade muscle invasive urothelial carcinomas of the bladder (HGUC) treated by cystectomy. A series of 40 such cases was investigated for immune protein (CD3, CD4, CD8, CD20, CD68, CD163, FOXP3 and PD-1) status by immunohistochemistry. Decreased expression of all immune cell markers was observed in tumors of patients who relapsed quickly. In Kaplan-Meier (log-rank test) analysis, low CD3, CD4 and CD8 expression was associated with fast relapse (P = 0.005, 0.028, 0.036 respectively). Additional evaluation of the immune transcriptome by NanoString Human PanCancer Immune Panel v.1.1 has identified 5 differentially expressed genes significantly associated with fast relapse. Among these, KLRB1 and HLA-DQA1 were also significant on Kaplan-Meier analysis (log-rank test P = 0.007 and 0.006, respectively). These findings strengthen the potential clinical utility and, hence, the need for further evaluation of immune markers in HGUC prognostication.
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http://dx.doi.org/10.1016/j.prp.2020.153200DOI Listing
November 2020

Necessity and Challenges of Sample Preconcentration in Analysis of Multiple MicroRNAs by Capillary Electrophoresis.

Anal Chem 2020 10 2;92(20):14251-14258. Epub 2020 Oct 2.

Department of Chemistry and Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada.

Thousands of putative microRNA (miRNA)-based cancer biomarkers have been reported, but none has been validated for approval by the Food and Drug Administration. One of the reasons for this alarming discrepancy is the lack of a method that is sufficiently robust for carrying out validation studies, which may require analysis of samples from hundreds of patients across multiple institutions and pooling the results together. The capillary electrophoresis (CE)-based hybridization assay proved to be more robust than reversed transcription polymerase chain reaction (the current standard), but its limit of quantification (LOQ) exceeds 10 pM while miRNA concentrations in cell lysates are below 1 pM. Thus, CE-based separation must be preceded by on-column sample preconcentration. Here, we explain the challenges of sample preconcentration for CE-based miRNA analyses and introduce a preconcentration method that can suit CE-based miRNA analysis utilizing peptide nucleic acid (PNA) hybridization probes. The method combines field-amplified sample stacking (FASS) with isotachophoresis (ITP). We proved that FASS-ITP could retain and concentrate both near-neutral PNA with highly negatively charged PNA-miRNA hybrids. We demonstrated that preconcentration by FASS-ITP could be combined with the CE-based separation of the unreacted PNA probes from the PNA-miRNA hybrids and facilitate improvement in LOQ by a factor of 140, down to 0.1 pM. Finally, we applied FASS-ITP-CE for the simultaneous detection of two miRNAs in crude cell lysates and proved that the method was robust when used in complex biological matrices. The 140-fold improvement in LOQ and the robustness to biological matrices will significantly expand the applicability of CE-based miRNA analysis, bringing it closer to becoming a practical tool for validation of miRNA biomarkers.
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http://dx.doi.org/10.1021/acs.analchem.0c03605DOI Listing
October 2020

Reassessment of p53 immunohistochemistry thresholds in invasive high grade bladder cancer shows a better correlation with TP53 and FGFR3 mutations.

Pathol Res Pract 2020 Nov 23;216(11):153186. Epub 2020 Aug 23.

Division of Anatomic Pathology, Department of Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada. Electronic address:

FGFR3 mutations are frequently mutually exclusive of TP53 mutations in invasive high grade urothelial carcinoma (HGUC) and p53 immunohistochemistry is often used as a surrogate for TP53 mutations. A 10 % staining cut off has been used in HGUC for designation as p53 positive or negative however, a novel contemporary method we have previously proposed (0% or >50 % - abnormal vs. 1-49 % - wild type) has shown significant correlation with oncologic outcome as well. We aimed to compare how a ≥10 % vs. 0 % and ≥ 50 % cut off p53 assessment method correlates with TP53 and FGFR3 mutation status. Tissue microarrays created from three retrospective cohorts (two cystectomy cohorts (cohort A, n = 206 and cohort B, n = 91; one T1 transurethral resection cohort (cohort C, n = 47)) were stained with p53 and scored by two blinded reviewers using both p53 scoring schemes. 50 cases from cohort A were assessed for TP53 and FGFR3 mutation status using next generation sequencing and FGFR3 mutation status was separately assessed in cohorts B and C using SNaPshot methodology. 202 (58.7 %) and 142 (41.3 %) cases showed abnormal and wild type p53 staining, respectively. Using the 10 % cut off, 254 cases were positive (73.8 %) and 90 cases were negative (26.2 %). 27 (14.4 %) and 15 (30 %) assessed cases demonstrated FGFR3 and TP53 mutations, respectively; 19/27 FGFR3 mutated showed a wild type pattern of p53 expression while 15/15 TP53 mutated tumours showed an abnormal pattern of p53 expression. There was a significant correlation between the contemporary p53 scoring scheme and TP53 and FGFR3 mutations (p < 0.0001 and p = 0.002, respectively). Improved sensitivity, specificity, positive predictive value, and negative predictive value for TP53 mutation was also seen compared to the 10 % cut off; specifically, the sensitivity and negative predictive value were 100 %. These findings might be of clinical relevance in the era of precision medicine.
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http://dx.doi.org/10.1016/j.prp.2020.153186DOI Listing
November 2020

Immune gene expression profiles in high-grade urothelial carcinoma of the bladder: a NanoString study.

J Clin Pathol 2021 Jan 29;74(1):53-57. Epub 2020 May 29.

Pathology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

Aims: The advent of immune checkpoint inhibitor therapy has proven beneficial in a subset of high-grade urothelial carcinomas (HGUC) of the bladder. Although treatment selection is currently largely determined by programmed death-ligand 1 (PD-L1) status, multiple factors in the immune system may modulate the host immune response to HGUC and immunotherapy. In this pilot study, we used a transcriptomic approach to identify the immune milieu associated with PD-L1 expression to enhance our understanding of the HGUC immune evasion network.

Methods: The immune transcriptome of 40 HGUC cystectomy cases was profiled using the NanoString nCounter Human V.1.1 PanCancer Panel. All cases were assessed for associated PD-L1 status (SP263) using whole tissue sections. PD-L1 status was determined as high or low using 25% tumour and/or immune cell staining.

Results: The most significantly differentially expressed gene was PD-L1 messenger RNA (), which strongly correlated with protein expression (r=0.720, p<0.001). The sensitivity, specificity, positive and negative predictive values of for PD-L1 expression were 85%, 96%, 92% and 93%, respectively. The PD-L1 associated gene signature also included complement components and and (innate immune system), proinflammatory cytokines and along with the immune response mediator among others. Pathway analysis determined enrichment of these genes in interleukin-10 production, lymphocyte chemotaxis and aberrant IFNγ, NF-κB and ERK signalling networks.

Conclusions: We report key genes and pathways in the immune transcriptome and their association with PD-L1 status, which may be involved in immune evasion of HGUC and warrants further investigation.
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http://dx.doi.org/10.1136/jclinpath-2020-206631DOI Listing
January 2021

Urinary biomarkers in prostate cancer: to the miRnome and beyond.

Transl Androl Urol 2020 Apr;9(2):843-845

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

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http://dx.doi.org/10.21037/tau.2019.11.25DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7214960PMC
April 2020

An Automated Segmentation Pipeline for Intratumoural Regions in Animal Xenografts Using Machine Learning and Saturation Transfer MRI.

Sci Rep 2020 05 15;10(1):8063. Epub 2020 May 15.

Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada.

Saturation transfer MRI can be useful in the characterization of different tumour types. It is sensitive to tumour metabolism, microstructure, and microenvironment. This study aimed to use saturation transfer to differentiate between intratumoural regions, demarcate tumour boundaries, and reduce data acquisition times by identifying the imaging scheme with the most impact on segmentation accuracy. Saturation transfer-weighted images were acquired over a wide range of saturation amplitudes and frequency offsets along with T and T maps for 34 tumour xenografts in mice. Independent component analysis and Gaussian mixture modelling were used to segment the images and identify intratumoural regions. Comparison between the segmented regions and histopathology indicated five distinct clusters: three corresponding to intratumoural regions (active tumour, necrosis/apoptosis, and blood/edema) and two extratumoural (muscle and a mix of muscle and connective tissue). The fraction of tumour voxels segmented as necrosis/apoptosis quantitatively matched those calculated from TUNEL histopathological assays. An optimal protocol was identified providing reasonable qualitative agreement between MRI and histopathology and consisting of T and T maps and 22 magnetization transfer (MT)-weighted images. A three-image subset was identified that resulted in a greater than 90% match in positive and negative predictive value of tumour voxels compared to those found using the entire 24-image dataset. The proposed algorithm can potentially be used to develop a robust intratumoural segmentation method.
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http://dx.doi.org/10.1038/s41598-020-64912-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7228927PMC
May 2020

microRNAs identified in prostate cancer: Correlative studies on response to ionizing radiation.

Mol Cancer 2020 03 23;19(1):63. Epub 2020 Mar 23.

CRCINA, INSERM, Université d'Angers, Université de Nantes, Nantes, France.

As the most frequently diagnosed non-skin cancer in men and a leading cause of cancer-related death, understanding the molecular mechanisms that drive treatment resistance in prostate cancer poses a significant clinical need. Radiotherapy is one of the most widely used treatments for prostate cancer, along with surgery, hormone therapy, and chemotherapy. However, inherent radioresistance of tumor cells can reduce local control and ultimately lead to poor patient outcomes, such as recurrence, metastasis and death. The underlying mechanisms of radioresistance have not been fully elucidated, but it has been suggested that miRNAs play a critical role. miRNAs are small non-coding RNAs that regulate gene expression in every signaling pathway of the cell, with one miRNA often having multiple targets. By fine-tuning gene expression, miRNAs are important players in modulating DNA damage response, cell death, tumor aggression and the tumor microenvironment, and can ultimately affect a tumor's response to radiotherapy. Furthermore, much interest has focused on miRNAs found in biofluids and their potential utility in various clinical applications. In this review, we summarize the current knowledge on miRNA deregulation after irradiation and the associated functional outcomes, with a focus on prostate cancer. In addition, we discuss the utility of circulating miRNAs as non-invasive biomarkers to diagnose, predict response to treatment, and prognosticate patient outcomes.
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http://dx.doi.org/10.1186/s12943-020-01186-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7087366PMC
March 2020

Correlation of mismatch repair protein deficiency, PD-L1 and CD8 expression in high-grade urothelial carcinoma of the bladder.

J Clin Pathol 2020 Aug 9;73(8):519-522. Epub 2020 Jan 9.

Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

Mismatch repair-deficient (d-MMR) tumours have been reported to show susceptibility to immune checkpoint inhibitors targeting programmed death-1/PD ligand-1 (PD-1/PD-L1). In this study, we sought to correlate the association of d-MMR, PD-L1 and CD8 expression in muscle invasive, high-grade urothelial carcinoma (HGUC) of bladder. A tissue microarray (TMA) was constructed from 201 cases and sequentially stained with PD-L1, CD8, MSH2, MSH6, MLH1 and PMS2. PD-L1 was assessed in tumour and immune cells. CD8 was assessed in a hotspot fashion with results averaged across cores. Loss of nuclear MMR expression on TMA sections was further assessed using corresponding whole tissue sections. d-MMR was identified in four cases (2%). The mean CD8 count was significantly higher in d-MMR tumours (10 vs 35, p=0.007) as was the proportion of PD-L1 positivity (75% vs 20%, p=0.031). d-MMR is uncommon in HGUC of bladder but shows strong correlation with cytotoxic T lymphocyte infiltration and PD-L1 tissue expression.
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http://dx.doi.org/10.1136/jclinpath-2019-206256DOI Listing
August 2020

miR-191 promotes radiation resistance of prostate cancer through interaction with RXRA.

Cancer Lett 2020 03 23;473:107-117. Epub 2019 Dec 23.

Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Medical Biophysics, University of Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada. Electronic address:

Radiation therapy is a common treatment for prostate cancer, however recurrence remains a problem. MicroRNA expression is altered in prostate cancer and may promote therapy resistance. Through bioinformatic analyses of TCGA and CPC-GENE patient cohorts, we identified higher miR-191 expression in tumor versus normal tissue, and increased expression in higher Gleason scores. In vitro and in vivo experiments demonstrated that miR-191 overexpression promotes radiation survival, and contributes to a more aggressive phenotype. Retinoid X receptor alpha, RXRA, was discovered to be a novel target of miR-191, and knockdown recapitulated radioresistance. Furthermore, treatment of prostate cancer cells with the RXRA agonist 9-cis-retinoic acid restored radiosensitivity. Supporting this relationship, patients with high miR-191 and low RXRA abundance experienced quicker biochemical recurrence. Reduced RXRA translated to a higher risk of distant failure after radiotherapy. Notably, this miR-191/RXRA interaction was conserved in a novel primary cell line derived from radiorecurrent prostate cancer. Together, our findings demonstrate that miR-191 promotes prostate cancer survival after radiotherapy, and highlights retinoids as a potential option to improve radiotherapy response.
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http://dx.doi.org/10.1016/j.canlet.2019.12.025DOI Listing
March 2020

Dosimetric predictors of toxicity and quality of life following prostate stereotactic ablative radiotherapy.

Radiother Oncol 2020 03 3;144:135-140. Epub 2019 Dec 3.

Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Canada; Institute of Health Policy Management and Evaluation, University of Toronto, Canada. Electronic address:

Purpose: SABR offers an effective treatment option for clinically localized prostate cancer. Here we report the dosimetric predictors of late toxicity and quality of life (QOL) in a pooled cohort of patients from four phase II trials.

Methods: The combined cohort included all three prostate cancer risk groups. The prescription dose was 35-40 Gy in 5 fractions. Toxicity (CTCAE) and QOL (EPIC) were collected. Multiple dosimetric parameters for the bladder, rectum and penile bulb were collected. Univariate (UVA) followed by multivariate (MVA) logistic regression analysis was conducted to search for significant dosimetric predictors of late GI/GU toxicity, or minimal clinically important change in the relevant QOL domain.

Results: 258 patients were included with median follow up of 6.1 years. For QOL, bladder Dmax, V38, D1cc, D2cc, D5cc and rectal V35 were predictors of urinary and bowel MCIC on UVA. On MVA, only bladder V38 remained significant. For late toxicity, various parameters were significant on UVA but only rectal Dmax, V38 and bladder D2cc were significant predictors on MVA.

Conclusions: This report confirms that the high-dose regions in the bladder and rectum are more significant predictors of late toxicity and QOL after prostate SABR compared to low-dose regions. Caution must be taken to avoid high doses and hotspots in those organs.
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http://dx.doi.org/10.1016/j.radonc.2019.11.017DOI Listing
March 2020

MicroRNA‑198 suppresses prostate tumorigenesis by targeting MIB1.

Oncol Rep 2019 Sep 15;42(3):1047-1056. Epub 2019 Jul 15.

Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada.

MicroRNAs are small non‑coding RNA molecules which act as modulators of gene function, and have been identified as playing important roles in cancer as both tumor suppressors and oncogenes. The present study aimed to examine the role of miR‑198 in prostate cancer aggression by analyzing how it influences several hallmarks of cancer. Abundance of miR‑198 in prostate cancer and association with clinical characteristics was analyzed using a CPC‑Gene prostate cancer dataset. Overexpression of miR‑198 was performed using transient transfection of miR‑198 mimic prior to assaying proliferation, cell cycle, and colony formation in LNCaP and DU145 cell lines using standard protocols. In vivo tumor formation in athymic nude mice was examined using LNCaP xenografts with stable overexpression conferred using lentiviral miR‑198 transduction. Protein and mRNA abundance of MIB1 was determined using western blotting and RT‑qPCR respectively, while miR‑198 binding to MIB1 was validated using a luciferase reporter assay. miR‑198 abundance was lower in high Gleason grade prostate cancer relative to intermediate and low‑grade cancer. Overexpression of miR‑198 diminished proliferation of prostate cancer cell lines, increased G0/G1 cell cycle arrest, and significantly impaired colony formation. Elevated miR‑198 abundance was also demonstrated to impair tumor formation in vivo using LNCaP xenografts. Mindbomb E3 ubiquitin protein ligase 1 (MIB1) was demonstrated to be directly targeted by miR‑198, and knockdown of MIB1 recapitulated the effects of miR‑198 on proliferation and colony formation. The present evidence supports miR‑198 as an important tumor suppressor in prostate cancer, and demonstrates for the first time that it acts by targeting MIB1. The present study reinforces the importance and complexity of miRNA in regulating prostate cancer aggression.
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http://dx.doi.org/10.3892/or.2019.7234DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6667842PMC
September 2019

RSPO3 is a prognostic biomarker and mediator of invasiveness in prostate cancer.

J Transl Med 2019 04 15;17(1):125. Epub 2019 Apr 15.

Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.

Background: While prostate cancer can often manifest as an indolent disease, the development of locally-advanced or metastatic disease can cause significant morbidity or mortality. Elucidation of molecular mechanisms contributing to disease progression is crucial for more accurate prognostication and effective treatments. R-Spondin 3 (RSPO3) is a protein previously implicated in the progression of colorectal and lung cancers. However, a role for RSPO3 in prostate cancer prognosis and behaviour has not been explored.

Methods: We compare the relative levels of RSPO3 expression between normal prostate tissue and prostate cancer in two independent patient cohorts (Taylor and GSE70768-Cambridge). We also examine the association of biochemical relapse with RSPO3 levels in these cohorts. For elucidation of the biological effect of RSPO3, we use siRNA technology to reduce the levels of RSPO3 in established prostate cancer cell lines, and perform in vitro proliferation, invasion, western blotting for EMT markers and clonogenic survival assays for radiation resistance. Furthermore, we show consequences of RSPO3 knockdown in an established chick chorioallantoic membrane (CAM) assay model of metastasis.

Results: RSPO3 levels are lower in prostate cancer than normal prostate, with a tendency for further loss in metastatic disease. Patients with lower RSPO3 expression have lower rates of biochemical relapse-free survival. SiRNA-mediated loss of RSPO3 results in no change to clonogenic survival and a lower proliferative rate, but increased invasiveness in vitro with induction of epithelial-mesenchymal transition (EMT) markers. Consistent with these results, lower RSPO3 expression translates to greater metastatic capacity in the CAM assay. Together, our preclinical findings identify a role of RSPO3 downregulation in prostate cancer invasiveness, and provide a potential explanation for how RSPO3 functions as a positive prognostic marker in prostate cancer.
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http://dx.doi.org/10.1186/s12967-019-1878-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6466739PMC
April 2019

Circulating blood miRNAs for prostate cancer risk stratification: miRroring the underlying tumor biology with liquid biopsies.

Res Rep Urol 2019 27;11:29-42. Epub 2019 Feb 27.

Biological Sciences, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada,

Current risk stratification methods for prostate cancer - although they have seen marked improvements over the past decades - are far from perfect. Despite the significant utility of prostate-specific antigen as a biomarker to monitor for disease recurrence, it cannot predict which tumors will recur or recommend the best treatment for patients. Similarly, although biopsies are imperative for diagnosis and staging, they are saddled with limitations and risks. We must move toward a noninvasive biomarker that has predictive and prognostic efficacy. We therefore review the current literature on circulating miRNA biomarkers, apply their use to two significant clinical problems (ie, how limitations of prostate biopsies can impact diagnosis and treatment management, and the need to tailor treatment for a clinically heterogeneous disease), and evaluate how circulating miRNAs have inherent properties that make them ideal liquid biomarkers. We also outline current gaps in knowledge that must be addressed before they can be implemented into routine clinical practice. With further research on their function and validation of their biomarker utility in large prospective cohorts, circulating miRNAs will likely prove to be the liquid biopsies of tomorrow.
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http://dx.doi.org/10.2147/RRU.S165625DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6398395PMC
February 2019

Combining urinary DNA methylation and cell-free microRNA biomarkers for improved monitoring of prostate cancer patients on active surveillance.

Urol Oncol 2019 05 16;37(5):297.e9-297.e17. Epub 2019 Feb 16.

Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada; Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada. Electronic address:

Purpose: Prostate cancer (CaP) patients with low-grade tumors are enrolled in active surveillance (AS) programs and monitored with digital rectal exams (DREs), prostate-specific antigen (PSA) tests, and periodic invasive biopsies. Patients are "reclassified" with higher-risk disease if they show signs of disease progression. However, AS patients who will reclassify cannot be easily identified upfront and suffer morbidities associated with biopsy. Biomarkers derived from noninvasively obtained specimens such as serum or urine samples are promising alternatives to monitor patients with clinically insignificant cancer. Previously, we have characterized and validated a urinary DNA methylation panel and a serum miRNA panel for the prediction of patient reclassification in 2 independent AS cohorts. In this exploratory study, we have investigated cell-free miRNAs in the urinary supernatant combined with urinary DNA methylation markers to form an integrative panel for prediction of AS patient reclassification.

Methods: Post-DRE urine was collected from 103 CaP patients on active surveillance. Urinary sediment DNA methylation levels of selected genes were previously analyzed using qPCR-based MethyLight assay. Using qRT-PCR, we analyzed the urinary supernatants for relative quantities of 10 miRNAs previously shown to be associated with AS reclassification. Logistic regression and Receiver Operating Characteristics curve analyses were performed to assess the predictive ability of miRNAs and DNA methylation biomarkers.

Results: We identified a 3-marker panel, consisting of miR-24, miR-30c and CRIP3 methylation, that was significant for prediction of patient reclassification (Odds ratio = 2.166, 95% confidence interval = 1.22-3.847) with a negative predictive value of 90.9%. Our 3-marker panel also demonstrated additive value to PSA for prediction of patient reclassification (c-statistic = 0.717, ROC bootstrapped 1000 iteration P = 0.041).

Conclusion: A urinary integrated panel of methylation and miRNA markers is a promising approach to identify AS patients at risk for reclassification. Our 3-marker panel, with its high negative predictive value, would be beneficial to identify and preclude AS patients with truly indolent cancer and to personalize monitoring strategies for AS patients.
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http://dx.doi.org/10.1016/j.urolonc.2019.01.031DOI Listing
May 2019

Molecular landmarks of tumor hypoxia across cancer types.

Nat Genet 2019 02 14;51(2):308-318. Epub 2019 Jan 14.

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

Many primary-tumor subregions have low levels of molecular oxygen, termed hypoxia. Hypoxic tumors are at elevated risk for local failure and distant metastasis, but the molecular hallmarks of tumor hypoxia remain poorly defined. To fill this gap, we quantified hypoxia in 8,006 tumors across 19 tumor types. In ten tumor types, hypoxia was associated with elevated genomic instability. In all 19 tumor types, hypoxic tumors exhibited characteristic driver-mutation signatures. We observed widespread hypoxia-associated dysregulation of microRNAs (miRNAs) across cancers and functionally validated miR-133a-3p as a hypoxia-modulated miRNA. In localized prostate cancer, hypoxia was associated with elevated rates of chromothripsis, allelic loss of PTEN and shorter telomeres. These associations are particularly enriched in polyclonal tumors, representing a constellation of features resembling tumor nimbosus, an aggressive cellular phenotype. Overall, this work establishes that tumor hypoxia may drive aggressive molecular features across cancers and shape the clinical trajectory of individual tumors.
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http://dx.doi.org/10.1038/s41588-018-0318-2DOI Listing
February 2019

Spurious elevation of Prostate-specific antigen associated with shingles in a prostate cancer patient undergoing active surveillance.

Clin Case Rep 2018 Dec 22;6(12):2338-2340. Epub 2018 Oct 22.

Department of Radiation Oncology, Odette Cancer Institute, Sunnybrook Hospital University of Toronto Ontario Canada.

Spurious PSA increase in prostate cancer associated with shingles reactivation should be considered under the right clinical scenario to avoid unnecessary investigations or treatment.
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http://dx.doi.org/10.1002/ccr3.1838DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6293149PMC
December 2018

Direct Quantitative Analysis of Multiple microRNAs (DQAMmiR) with Peptide Nucleic Acid Hybridization Probes.

Anal Chem 2018 12 4;90(24):14610-14615. Epub 2018 Dec 4.

Department of Chemistry and Centre for Research on Biomolecular Interactions , York University , Toronto , Ontario M3J 1P3 , Canada.

Direct quantitative analysis of multiple miRNAs (DQAMmiR) is a hybridization-based assay, in which the excess of the DNA hybridization probes is separated from the miRNA-probe hybrids, and the hybrids are separated from each other in gel-free capillary electrophoresis (CE) using two types of mobility shifters: single-strand DNA binding protein (SSB) added to the CE running buffer and peptide drag tags conjugated with the probes. Here we introduce the second-generation DQAMmiR, which utilizes peptide nucleic acid (PNA) rather than DNA hybridization probes and requires no SSB in the CE running buffer. PNA probes are electrically neutral, while PNA-miRNA hybrids are negatively charged, and this difference in charge can be a basis for separation of the hybrids from the probes. In this proof-of-principle work, we first experimentally confirmed that the PNA-RNA hybrid was separable from the excess of the PNA probe without SSB in the running buffer, resulting in a near 10 min time window, which would allow, theoretically, separation of up to 30 hybrids. Then, we adapted to PNA-RNA hybrids our previously developed theoretical model for predicting hybrid mobilities. The calculation performed with the modified theoretical model indicated that PNA-RNA hybrids of slightly different lengths could be separated from each other without drag tags. Accordingly, we designed a simple experimental model capable of confirming: (i) separation of tag-free hybrids of different lengths and (ii) separation of same-length hybrids due to a drag tag on the PNA probe. The experimental model included three miRNAs: 20-nt miR-147a, 20-nt miR-378g, and 22-nt miR-21. The three complementary PNA probes had lengths matching those of the corresponding target miRNAs. The probe for miR-147a had a short five-amino-acid drag tag; the other two had no drag tags. We were able to achieve baseline separation of the three hybrids from each other. The LOQ of 14 pM along with the high accuracy (recovery >90%) and precision (RSD ≈ 10%) of the assay at picomolar target concentrations suggest that PNA-facilitated DQAMmiR could potentially support practical miRNA analysis of clinical samples.
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http://dx.doi.org/10.1021/acs.analchem.8b04793DOI Listing
December 2018

Immune infiltrates and PD-L1 expression in treatment-naïve acinar prostatic adenocarcinoma: an exploratory analysis.

J Clin Pathol 2018 Nov 26;71(11):1023-1027. Epub 2018 Sep 26.

Anatomic Pathology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

Tumour-induced immunosuppression plays a role in the development and progression of cancer. Of interest is the interaction between programmed death-1 and programmed death ligand-1 (PD-L1) which can be targeted through immune checkpoint blockade; however, there are limited data surrounding the composition of the immune milieu in prostate cancer. We preliminarily assessed 21 radical prostatectomies in therapy-naïve patients for immune markers and PD-L1 expression. The immune infiltrates were higher in adenocarcinoma than benign prostate (lymphocytes p<0.001, macrophages p=0.010) with 5% of cases being PD-L1 high (≥5% expression). Increased peritumoural CD68 and CD163 expression correlated with lower grade group (GG) (p=0.024 and p=0.014, respectively) with a trend towards increased CD68 expression in lower stage cases (p=0.086). There was also increased CD45 expression in lower GGs (p=0.063). We found the immune infiltrate in acinar prostate cancer to be extremely heterogeneous with an overall immunophenotype unlikely to respond to immune checkpoint blockade.
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http://dx.doi.org/10.1136/jclinpath-2018-205404DOI Listing
November 2018

Reproducibility of PD-L1 immunohistochemistry interpretation across various types of genitourinary and head/neck carcinomas, antibody clones, and tissue types.

Hum Pathol 2018 12 1;82:131-139. Epub 2018 Aug 1.

Department of Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, ON, M4N 3M5, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M4N 3M5, Canada. Electronic address:

Programmed death-ligand 1 (PD-L1) expression by tumor cells is a mechanism for down-regulation of antitumor T-cell responses and is a target for immunotherapy in various cancers. PD-L1 status as a predictor of treatment response has led to the development of multiple platforms with different reference cutoffs. We studied 128 cases of genitourinary and head/neck carcinomas, aiming to assess the frequency of PD-L1 positivity, interobserver reliability of PD-L1 interpretation, and the concordance of PD-L1 scoring between small samples from tissue microarray and whole sections using SP263 and SP142 clones. No prostatic carcinoma (0/21) was PD-L1 positive compared with 15% to 24% PD-L1 positivity in urothelial carcinoma (UC), hypopharyngeal squamous cell carcinoma (HP-SCC), and high-grade salivary gland carcinoma. There was substantial interobserver agreement in determining overall PD-L1 positivity in UC and HP-SCC using SP263 (κ = 0.702) and SP142 (κ = 0.757) antibodies. Subgroup analysis for both antibodies showed excellent agreement in UC (κ = 0.812 and 0.827) and moderate agreement in HP-SCC (κ = 0.469 and 0.591). Moderate to substantial agreement between tissue microarray and whole sections was achieved using SP263 (overall, κ = 0.573; UC, κ = 0.424; and HP-SCC, κ = 0.667) and SP142 (UC, κ = 0.493). PD-L1 interpretation in genitourinary and head/neck carcinomas is reliable and reproducible among pathologists and across different tissue preparations. Tumor PD-L1 staining heterogeneity may lead to discrepant PD-L1 results between small biopsies and large sections from surgical resection in a subset of tumors (19% of UC and 15% of HP-SCC). Retesting in such cases may be required to determine patient suitability for anti-PD-1/PD-L1 therapy.
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http://dx.doi.org/10.1016/j.humpath.2018.07.024DOI Listing
December 2018

Differentiation of Normal and Radioresistant Prostate Cancer Xenografts Using Magnetization Transfer-Prepared MRI.

Sci Rep 2018 Jul 11;8(1):10447. Epub 2018 Jul 11.

Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.

The ability of MRI to differentiate between normal and radioresistant cancer was investigated in prostate tumour xenografts in mice. Specifically, the process of magnetization exchange between water and other molecules was studied. It was found that magnetization transfer from semisolid macromolecules (MT) and chemical exchange saturation transfer (CEST) combined were significantly different between groups (p < 0.01). Further, the T relaxation of the semisolid macromolecular pool (T), a parameter specific to MT, was found to be significantly different (p < 0.01). Also significantly different were the rNOE contributions associated with methine groups at -0.9 ppm with a saturation B of 0.5 µT (p < 0.01) and with other aliphatic groups at -3.3 ppm with 0.5 and 2 µT (both p < 0.05). Independently, using a live-cell metabolic assay, normal cells were found to have a greater metabolic rate than radioresistant ones. Thus, MRI provides a novel, in vivo method to quantify the metabolic rate of tumours and predict their radiosensitivity.
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http://dx.doi.org/10.1038/s41598-018-28731-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6041323PMC
July 2018

Basal-subtype bladder tumours show a 'hot' immunophenotype.

Histopathology 2018 Nov 14;73(5):748-757. Epub 2018 Aug 14.

Department of Anatomic Pathology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.

Aims: Basal and luminal molecular subgroups of muscle-invasive urothelial carcinoma (UC) can be recognised by the use of immunohistochemical markers. Studies have shown that responses to chemotherapy and outcomes differ among these subtypes. High-grade UC of the bladder is an immunogenic neoplasm that induces a substantial intratumoral and peritumoral immune response; the phenotype of infiltrating immune cells may yield prognostic information and predict response to therapy. In this study, we aimed to correlate the immunohistochemical phenotype of high-grade UC with immune microenvironment composition.

Methods And Results: Two hundred and thirty-five cases of high-grade UC treated with cystectomy were reviewed. Clinicopathological variables for each case were recorded, and disease-free survival at last follow-up was calculated. Invasive front inflammation and tumour-infiltrating lymphocytes were scored for each case. Two hundred and seven cases were used to construct a triplicate-core tissue microarray (TMA), with sections stained for cytokeratin (CK) 5/6 and GATA3. Of the evaluable cases, 167 were designated as luminal (CK5/6- and GATA3+) and 29 as basal (CK5/6+ and GATA3-). Additional sequential TMA sections were stained for CD3, CD4, CD8, CD20, CD68, CD163, FOXP3, programmed cell death protein 1 (PD-1), and programmed death-ligand 1 (PD-L1) (SP263). Basal-subtype tumours showed a trend towards worse disease-specific survival (P = 0.078). There were statistically significant associations between basal subtype and CD8 expression (P = 0.008), PD-1 expression (P = 0.001), and PD-L1 expression (P = 0.014). Lower CD4/CD8 and increased CD8/FOXP3 ratios (P = 0.047 and P = 0.031, respectively) were also identified in the basal-subtype group.

Conclusions: Basal-subtype high-grade UC has an abundance of CD8+ T cells with increased expression of inhibitory markers, indicative of a 'hot' immunophenotype.
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http://dx.doi.org/10.1111/his.13696DOI Listing
November 2018
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