Publications by authors named "Julian Adlard"

66 Publications

SDHC phaeochromocytoma and paraganglioma: A UK-wide case series.

Clin Endocrinol (Oxf) 2021 Sep 24. Epub 2021 Sep 24.

Department of Clinical Genetics, Birmingham Women's Hospital, Birmingham, UK.

Objective: Phaeochromocytomas and paragangliomas (PPGL) are rare, but strongly heritable tumours. Variants in succinate dehydrogenase (SDH) subunits are identified in approximately 25% of cases. However, clinical and genetic information of patients with SDHC variants are underreported.

Design: This retrospective case series collated data from 18 UK Genetics and Endocrinology departments.

Patients: Both asymptomatic and disease-affected patients with confirmed SDHC germline variants are included.

Measurements: Clinical data including tumour type and location, surveillance outcomes and interventions, SDHC genetic variant assessment, interpretation, and tumour risk calculation.

Results: We report 91 SDHC cases, 46 probands and 45 non-probands. Fifty-one cases were disease-affected. Median age at genetic diagnosis was 43 years (range: 11-79). Twenty-four SDHC germline variants were identified including six novel variants. Head and neck paraganglioma (HNPGL, n = 30, 65.2%), extra-adrenal paraganglioma (EAPGL, n = 13, 28.2%) and phaeochromocytomas (PCC) (n = 3, 6.5%) were present. One case had multiple PPGLs. Malignant disease was reported in 19.6% (9/46). Eight cases had non-PPGL SDHC-associated tumours, six gastrointestinal stromal tumours (GIST) and two renal cell cancers (RCC). Cumulative tumour risk (95% CI) at age 60 years was 0.94 (CI: 0.79-0.99) in probands, and 0.16 (CI: 0-0.31) in non-probands, respectively.

Conclusions: This study describes the largest cohort of 91 SDHC patients worldwide. We confirm disease-affected SDHC variant cases develop isolated HNPGL disease in nearly 2/3 of patients, EAPGL and PCC in 1/3, with an increased risk of GIST and RCC. One fifth developed malignant disease, requiring comprehensive lifelong tumour screening and surveillance.
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http://dx.doi.org/10.1111/cen.14594DOI Listing
September 2021

Breast and Prostate Cancer Risks for Male BRCA1 and BRCA2 Pathogenic Variant Carriers Using Polygenic Risk Scores.

J Natl Cancer Inst 2022 Jan;114(1):109-122

Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy.

Background: Recent population-based female breast cancer and prostate cancer polygenic risk scores (PRS) have been developed. We assessed the associations of these PRS with breast and prostate cancer risks for male BRCA1 and BRCA2 pathogenic variant carriers.

Methods: 483 BRCA1 and 1318 BRCA2 European ancestry male carriers were available from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). A 147-single nucleotide polymorphism (SNP) prostate cancer PRS (PRSPC) and a 313-SNP breast cancer PRS were evaluated. There were 3 versions of the breast cancer PRS, optimized to predict overall (PRSBC), estrogen receptor (ER)-negative (PRSER-), or ER-positive (PRSER+) breast cancer risk.

Results: PRSER+ yielded the strongest association with breast cancer risk. The odds ratios (ORs) per PRSER+ standard deviation estimates were 1.40 (95% confidence interval [CI] =1.07 to 1.83) for BRCA1 and 1.33 (95% CI = 1.16 to 1.52) for BRCA2 carriers. PRSPC was associated with prostate cancer risk for BRCA1 (OR = 1.73, 95% CI = 1.28 to 2.33) and BRCA2 (OR = 1.60, 95% CI = 1.34 to 1.91) carriers. The estimated breast cancer odds ratios were larger after adjusting for female relative breast cancer family history. By age 85 years, for BRCA2 carriers, the breast cancer risk varied from 7.7% to 18.4% and prostate cancer risk from 34.1% to 87.6% between the 5th and 95th percentiles of the PRS distributions.

Conclusions: Population-based prostate and female breast cancer PRS are associated with a wide range of absolute breast and prostate cancer risks for male BRCA1 and BRCA2 carriers. These findings warrant further investigation aimed at providing personalized cancer risks for male carriers and informing clinical management.
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http://dx.doi.org/10.1093/jnci/djab147DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8755508PMC
January 2022

Long-read nanopore sequencing enables accurate confirmation of a recurrent PMS2 insertion-deletion variant located in a region of complex genomic architecture.

Cancer Genet 2021 08 28;256-257:122-126. Epub 2021 May 28.

Leeds Institute of Medical Research, University of Leeds, St. James's University Hospital, Leeds LS9 7TF, United Kingdom; The Clinical Genetics Department, Chapel Allerton Hospital, Leeds LS7 4SA, United Kingdom.

Targeted next generation sequencing (NGS) is the predominant methodology for the molecular genetic diagnosis of inherited conditions. In many laboratories, NGS-identified variants are routinely validated using a different method, to minimize the risk of a false-positive diagnosis. This can be particularly important when pathogenic variants are located in complex genomic regions. In this situation, new long-read sequencing technologies have potential advantages over existing alternatives. However, practical examples of their utility for diagnostic purposes remain scant. Here, we report the use of nanopore sequencing to validate a PMS2 mutation refractory to conventional methods. In a patient who presented with colorectal cancer and loss of PMS2 immunostaining, short-read NGS of Lynch syndrome-associated genes identified the recurrent PMS2 insertion-deletion variant, c.736_741delinsTGTGTGTGAAG (p.Pro246Cysfs*3). Confirmation of this variant using bidirectional Sanger sequencing was impeded by an upstream intron 6 poly(T) tract. Using a locus-specific amplicon template, we undertook nanopore long-read sequencing in order to assess the diagnostic accuracy of this platform. Pairwise comparison between a curated benchmark allele (derived from short-read NGS and unidirectional Sanger sequencing) and the consensus nanopore dataset revealed 100% sequence identity. Our experience provides insight into the robustness and ease of deployment of "third-generation" sequencing for accurate characterisation of pathogenic variants.
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http://dx.doi.org/10.1016/j.cancergen.2021.05.012DOI Listing
August 2021

The predictive ability of the 313 variant-based polygenic risk score for contralateral breast cancer risk prediction in women of European ancestry with a heterozygous BRCA1 or BRCA2 pathogenic variant.

Genet Med 2021 09 10;23(9):1726-1737. Epub 2021 Jun 10.

Department of Cancer Epidemiology and Genetics, Masaryk Memorial Cancer Institute, Brno, Czech Republic.

Purpose: To evaluate the association between a previously published 313 variant-based breast cancer (BC) polygenic risk score (PRS) and contralateral breast cancer (CBC) risk, in BRCA1 and BRCA2 pathogenic variant heterozygotes.

Methods: We included women of European ancestry with a prevalent first primary invasive BC (BRCA1 = 6,591 with 1,402 prevalent CBC cases; BRCA2 = 4,208 with 647 prevalent CBC cases) from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA), a large international retrospective series. Cox regression analysis was performed to assess the association between overall and ER-specific PRS and CBC risk.

Results: For BRCA1 heterozygotes the estrogen receptor (ER)-negative PRS showed the largest association with CBC risk, hazard ratio (HR) per SD = 1.12, 95% confidence interval (CI) (1.06-1.18), C-index = 0.53; for BRCA2 heterozygotes, this was the ER-positive PRS, HR = 1.15, 95% CI (1.07-1.25), C-index = 0.57. Adjusting for family history, age at diagnosis, treatment, or pathological characteristics for the first BC did not change association effect sizes. For women developing first BC < age 40 years, the cumulative PRS 5th and 95th percentile 10-year CBC risks were 22% and 32% for BRCA1 and 13% and 23% for BRCA2 heterozygotes, respectively.

Conclusion: The PRS can be used to refine individual CBC risks for BRCA1/2 heterozygotes of European ancestry, however the PRS needs to be considered in the context of a multifactorial risk model to evaluate whether it might influence clinical decision-making.
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http://dx.doi.org/10.1038/s41436-021-01198-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8460445PMC
September 2021

Oral contraceptive use and ovarian cancer risk for BRCA1/2 mutation carriers: an international cohort study.

Am J Obstet Gynecol 2021 07 22;225(1):51.e1-51.e17. Epub 2021 Jan 22.

Department of Cancer Epidemiology and Genetics, Masaryk Memorial Cancer Institute, Brno, Czech Republic.

Background: Ovarian cancer risk in BRCA1 and BRCA2 mutation carriers has been shown to decrease with longer duration of oral contraceptive use. Although the effects of using oral contraceptives in the general population are well established (approximately 50% risk reduction in ovarian cancer), the estimated risk reduction in mutation carriers is much less precise because of potential bias and small sample sizes. In addition, only a few studies on oral contraceptive use have examined the associations of duration of use, time since last use, starting age, and calendar year of start with risk of ovarian cancer.

Objective: This study aimed to investigate in more detail the associations of various characteristics of oral contraceptive use and risk of ovarian cancer, to provide healthcare providers and carriers with better risk estimates.

Study Design: In this international retrospective study, ovarian cancer risk associations were assessed using oral contraceptives data on 3989 BRCA1 and 2445 BRCA2 mutation carriers. Age-dependent-weighted Cox regression analyses were stratified by study and birth cohort and included breast cancer diagnosis as a covariate. To minimize survival bias, analyses were left truncated at 5 years before baseline questionnaire. Separate analyses were conducted for each aspect of oral contraceptive use and in a multivariate analysis, including all these aspects. In addition, the analysis of duration of oral contraceptive use was stratified by recency of use.

Results: Oral contraceptives were less often used by mutation carriers who were diagnosed with ovarian cancer (ever use: 58.6% for BRCA1 and 53.5% BRCA2) than by unaffected carriers (ever use: 88.9% for BRCA1 and 80.7% for BRCA2). The median duration of use was 7 years for both BRCA1 and BRCA2 carriers who developed ovarian cancer and 9 and 8 years for unaffected BRCA1 and BRCA2 carriers with ovarian cancer, respectively. For BRCA1 mutation carriers, univariate analyses have shown that both a longer duration of oral contraceptive use and more recent oral contraceptive use were associated with a reduction in the risk of ovarian cancer. However, in multivariate analyses, including duration of use, age at first use, and time since last use, duration of oral contraceptive use proved to be the prominent protective factor (compared with <5 years: 5-9 years [hazard ratio, 0.67; 95% confidence interval, 0.40-1.12]; >10 years [hazard ratio, 0.37; 95% confidence interval, 0.19-0.73]; P=.008). The inverse association between duration of use and ovarian cancer risk persisted for more than 15 years (duration of ≥10 years; BRCA1 <15 years since last use [hazard ratio, 0.24; 95% confidence interval, 0.14-0.43]; BRCA1 >15 years since last use [hazard ratio, 0.56; 95% confidence interval, 0.18-0.59]). Univariate results for BRCA2 mutation carriers were similar but were inconclusive because of limited sample size.

Conclusion: For BRCA1 mutation carriers, longer duration of oral contraceptive use is associated with a greater reduction in ovarian cancer risk, and the protection is long term.
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http://dx.doi.org/10.1016/j.ajog.2021.01.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8278569PMC
July 2021

Homozygosity for the pathogenic RET hotspot variant p.Cys634Trp: A consanguineous family with MEN2A.

Eur J Med Genet 2021 Feb 12;64(2):104141. Epub 2021 Jan 12.

Yorkshire Regional Genetics Service, Chapel Allerton Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK.

Multiple endocrine neoplasia type 2 (MEN2) is a dominantly inherited condition with defined correlations between the genetic variant and clinical presentations. The location of pathogenic variants in the RET gene is a significant determinant of disease presentation and is associated with variable gene activation. Heterozygous pathogenic variants in codon 634 result in earlier onset of medullary thyroid carcinoma and higher incidence of phaeochromocytoma. Here we describe a consanguineous family with MEN2A that includes two children homozygous for the established pathogenic variant p. Cys634Trp. Both parents and a sibling were confirmed to being heterozygotes. Previous reports of biallelic or multiple RET variants have been limited to weakly activating variants. We present the first report of individuals homozygous for the highly activating RET p. Cys634Trp pathogenic variant and discuss disease severity and onset in this rare occurrence.
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http://dx.doi.org/10.1016/j.ejmg.2021.104141DOI Listing
February 2021

Multiple primary cancers (renal papillary, lymphoma and teratoma) and hepatic cysts in association with a pathogenic germline mutation in the MET gene.

Authors:
Julian Adlard

Fam Cancer 2021 01 20;20(1):81-83. Epub 2020 Jul 20.

Yorkshire Regional Genetics Service, Chapel Allerton Hospital, LS7 4SA, Leeds, United Kingdom.

Activating germline mutations of the MET gene are associated with hereditary papillary renal cancer. This a very rare autosomal dominant condition, which is usually considered not to display a phenotype of multiple types of malignancy. However, this report describes the case of a man who has been affected with testicular teratoma, diffuse large B-cell lymphoma and multiple hepatic cysts, as well as multiple papillary renal cancers. There is good supporting evidence for roles of over-expression/activity of the HGF/MET ligand-receptor in development of these tumours, raising the possibility of other increased cancer risks associated with activating germline MET gene mutations.
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http://dx.doi.org/10.1007/s10689-020-00196-zDOI Listing
January 2021

Polygenic risk scores and breast and epithelial ovarian cancer risks for carriers of BRCA1 and BRCA2 pathogenic variants.

Genet Med 2020 10 15;22(10):1653-1666. Epub 2020 Jul 15.

Royal Devon & Exeter Hospital, Department of Clinical Genetics, Exeter, UK.

Purpose: We assessed the associations between population-based polygenic risk scores (PRS) for breast (BC) or epithelial ovarian cancer (EOC) with cancer risks for BRCA1 and BRCA2 pathogenic variant carriers.

Methods: Retrospective cohort data on 18,935 BRCA1 and 12,339 BRCA2 female pathogenic variant carriers of European ancestry were available. Three versions of a 313 single-nucleotide polymorphism (SNP) BC PRS were evaluated based on whether they predict overall, estrogen receptor (ER)-negative, or ER-positive BC, and two PRS for overall or high-grade serous EOC. Associations were validated in a prospective cohort.

Results: The ER-negative PRS showed the strongest association with BC risk for BRCA1 carriers (hazard ratio [HR] per standard deviation = 1.29 [95% CI 1.25-1.33], P = 3×10). For BRCA2, the strongest association was with overall BC PRS (HR = 1.31 [95% CI 1.27-1.36], P = 7×10). HR estimates decreased significantly with age and there was evidence for differences in associations by predicted variant effects on protein expression. The HR estimates were smaller than general population estimates. The high-grade serous PRS yielded the strongest associations with EOC risk for BRCA1 (HR = 1.32 [95% CI 1.25-1.40], P = 3×10) and BRCA2 (HR = 1.44 [95% CI 1.30-1.60], P = 4×10) carriers. The associations in the prospective cohort were similar.

Conclusion: Population-based PRS are strongly associated with BC and EOC risks for BRCA1/2 carriers and predict substantial absolute risk differences for women at PRS distribution extremes.
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http://dx.doi.org/10.1038/s41436-020-0862-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7521995PMC
October 2020

Prostate Cancer Risk by BRCA2 Genomic Regions.

Eur Urol 2020 10 10;78(4):494-497. Epub 2020 Jun 10.

Department of Medical Genetics, National Institute for Health Research Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, UK.

A BRCA2 prostate cancer cluster region (PCCR) was recently proposed (c.7914 to 3') wherein pathogenic variants (PVs) are associated with higher prostate cancer (PCa) risk than PVs elsewhere in the BRCA2 gene. Using a prospective cohort study of 447 male BRCA2 PV carriers recruited in the UK and Ireland from 1998 to 2016, we estimated standardised incidence ratios (SIRs) compared with population incidences and assessed variation in risk by PV location. Carriers of PVs in the PCCR had a PCa SIR of 8.33 (95% confidence interval [CI] 4.46-15.6) and were at a higher risk of PCa than carriers of other BRCA2 PVs (SIR = 3.31, 95% CI 1.97-5.57; hazard ratio = 2.34, 95% CI 1.09-5.03). PCCR PV carriers had an estimated cumulative PCa risk of 44% (95% CI 23-72%) by the age of 75 yr and 78% (95% CI 54-94%) by the age of 85 yr. Our results corroborate the existence of a PCCR in BRCA2 in a prospective cohort. PATIENT SUMMARY: In this report, we investigated whether the risk of prostate cancer for men with a harmful mutation in the BRCA2 gene differs based on where in the gene the mutation is located. We found that men with mutations in one region of BRCA2 had a higher risk of prostate cancer than men with mutations elsewhere in the gene.
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http://dx.doi.org/10.1016/j.eururo.2020.05.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7532700PMC
October 2020

Risk-reducing salpingo-oophorectomy, natural menopause, and breast cancer risk: an international prospective cohort of BRCA1 and BRCA2 mutation carriers.

Breast Cancer Res 2020 01 16;22(1). Epub 2020 Jan 16.

Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, 3010, Australia.

Background: The effect of risk-reducing salpingo-oophorectomy (RRSO) on breast cancer risk for BRCA1 and BRCA2 mutation carriers is uncertain. Retrospective analyses have suggested a protective effect but may be substantially biased. Prospective studies have had limited power, particularly for BRCA2 mutation carriers. Further, previous studies have not considered the effect of RRSO in the context of natural menopause.

Methods: A multi-centre prospective cohort of 2272 BRCA1 and 1605 BRCA2 mutation carriers was followed for a mean of 5.4 and 4.9 years, respectively; 426 women developed incident breast cancer. RRSO was modelled as a time-dependent covariate in Cox regression, and its effect assessed in premenopausal and postmenopausal women.

Results: There was no association between RRSO and breast cancer for BRCA1 (HR = 1.23; 95% CI 0.94-1.61) or BRCA2 (HR = 0.88; 95% CI 0.62-1.24) mutation carriers. For BRCA2 mutation carriers, HRs were 0.68 (95% CI 0.40-1.15) and 1.07 (95% CI 0.69-1.64) for RRSO carried out before or after age 45 years, respectively. The HR for BRCA2 mutation carriers decreased with increasing time since RRSO (HR = 0.51; 95% CI 0.26-0.99 for 5 years or longer after RRSO). Estimates for premenopausal women were similar.

Conclusion: We found no evidence that RRSO reduces breast cancer risk for BRCA1 mutation carriers. A potentially beneficial effect for BRCA2 mutation carriers was observed, particularly after 5 years following RRSO. These results may inform counselling and management of carriers with respect to RRSO.
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http://dx.doi.org/10.1186/s13058-020-1247-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6966793PMC
January 2020

Cancer Risks Associated With Germline Pathogenic Variants: An International Study of 524 Families.

J Clin Oncol 2020 03 16;38(7):674-685. Epub 2019 Dec 16.

Biopathologie, Centre Léon Bérard, Lyon, France.

Purpose: To estimate age-specific relative and absolute cancer risks of breast cancer and to estimate risks of ovarian, pancreatic, male breast, prostate, and colorectal cancers associated with germline pathogenic variants (PVs) because these risks have not been extensively characterized.

Methods: We analyzed data from 524 families with PVs from 21 countries. Complex segregation analysis was used to estimate relative risks (RRs; relative to country-specific population incidences) and absolute risks of cancers. The models allowed for residual familial aggregation of breast and ovarian cancer and were adjusted for the family-specific ascertainment schemes.

Results: We found associations between PVs and risk of female breast cancer (RR, 7.18; 95% CI, 5.82 to 8.85; = 6.5 × 10), ovarian cancer (RR, 2.91; 95% CI, 1.40 to 6.04; = 4.1 × 10), pancreatic cancer (RR, 2.37; 95% CI, 1.24 to 4.50; = 8.7 × 10), and male breast cancer (RR, 7.34; 95% CI, 1.28 to 42.18; = 2.6 × 10). There was no evidence for increased risks of prostate or colorectal cancer. The breast cancer RRs declined with age ( for trend = 2.0 × 10). After adjusting for family ascertainment, breast cancer risk estimates on the basis of multiple case families were similar to the estimates from families ascertained through population-based studies ( for difference = .41). On the basis of the combined data, the estimated risks to age 80 years were 53% (95% CI, 44% to 63%) for female breast cancer, 5% (95% CI, 2% to 10%) for ovarian cancer, 2%-3% (95% CI females, 1% to 4%; 95% CI males, 2% to 5%) for pancreatic cancer, and 1% (95% CI, 0.2% to 5%) for male breast cancer.

Conclusion: These results confirm as a major breast cancer susceptibility gene and establish substantial associations between germline PVs and ovarian, pancreatic, and male breast cancers. These findings will facilitate incorporation of into risk prediction models and optimize the clinical cancer risk management of PV carriers.
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http://dx.doi.org/10.1200/JCO.19.01907DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7049229PMC
March 2020

Association of Genomic Domains in and with Prostate Cancer Risk and Aggressiveness.

Cancer Res 2020 02 13;80(3):624-638. Epub 2019 Nov 13.

Unité de Prévention et d'Epidémiologie Génétique, Centre Léon Bérard, Lyon, France.

Pathogenic sequence variants (PSV) in or () are associated with increased risk and severity of prostate cancer. We evaluated whether PSVs in were associated with risk of overall prostate cancer or high grade (Gleason 8+) prostate cancer using an international sample of 65 and 171 male PSV carriers with prostate cancer, and 3,388 and 2,880 male PSV carriers without prostate cancer. PSVs in the 3' region of (c.7914+) were significantly associated with elevated risk of prostate cancer compared with reference bin c.1001-c.7913 [HR = 1.78; 95% confidence interval (CI), 1.25-2.52; = 0.001], as well as elevated risk of Gleason 8+ prostate cancer (HR = 3.11; 95% CI, 1.63-5.95; = 0.001). c.756-c.1000 was also associated with elevated prostate cancer risk (HR = 2.83; 95% CI, 1.71-4.68; = 0.00004) and elevated risk of Gleason 8+ prostate cancer (HR = 4.95; 95% CI, 2.12-11.54; = 0.0002). No genotype-phenotype associations were detected for PSVs in . These results demonstrate that specific PSVs may be associated with elevated risk of developing aggressive prostate cancer. SIGNIFICANCE: Aggressive prostate cancer risk in BRCA2 mutation carriers may vary according to the specific BRCA2 mutation inherited by the at-risk individual.
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http://dx.doi.org/10.1158/0008-5472.CAN-19-1840DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7553241PMC
February 2020

The :p.Arg658* truncating variant is associated with risk of triple-negative breast cancer.

NPJ Breast Cancer 2019 1;5:38. Epub 2019 Nov 1.

25University of Texas MD Anderson Cancer Center, Department of Breast Medical Oncology, Houston, TX USA.

Breast cancer is a common disease partially caused by genetic risk factors. Germline pathogenic variants in DNA repair genes , , , , and are associated with breast cancer risk. , which encodes for a DNA translocase, has been proposed as a breast cancer predisposition gene, with greater effects for the ER-negative and triple-negative breast cancer (TNBC) subtypes. We tested the three recurrent protein-truncating variants :p.Arg658*, p.Gln1701*, and p.Arg1931* for association with breast cancer risk in 67,112 cases, 53,766 controls, and 26,662 carriers of pathogenic variants of or . These three variants were also studied functionally by measuring survival and chromosome fragility in patient-derived immortalized fibroblasts treated with diepoxybutane or olaparib. We observed that :p.Arg658* was associated with increased risk of ER-negative disease and TNBC (OR = 2.44,  = 0.034 and OR = 3.79;  = 0.009, respectively). In a country-restricted analysis, we confirmed the associations detected for :p.Arg658* and found that also :p.Arg1931* was associated with ER-negative breast cancer risk (OR = 1.96;  = 0.006). The functional results indicated that all three variants were deleterious affecting cell survival and chromosome stability with :p.Arg658* causing more severe phenotypes. In conclusion, we confirmed that the two rare deleterious variants p.Arg658* and p.Arg1931* are risk factors for ER-negative and TNBC subtypes. Overall our data suggest that the effect of truncating variants on breast cancer risk may depend on their position in the gene. Cell sensitivity to olaparib exposure, identifies a possible therapeutic option to treat -associated tumors.
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http://dx.doi.org/10.1038/s41523-019-0127-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6825205PMC
November 2019

Prostate Cancer Risks for Male BRCA1 and BRCA2 Mutation Carriers: A Prospective Cohort Study.

Eur Urol 2020 01 6;77(1):24-35. Epub 2019 Sep 6.

Oncogenetics Team, Division of Genetics and Epidemiology, The Institute of Cancer Research, London, UK; Cancer Genetics Unit, Royal Marsden NHS Foundation Trust, London, UK.

Background: BRCA1 and BRCA2 mutations have been associated with prostate cancer (PCa) risk but a wide range of risk estimates have been reported that are based on retrospective studies.

Objective: To estimate relative and absolute PCa risks associated with BRCA1/2 mutations and to assess risk modification by age, family history, and mutation location.

Design, Setting, And Participants: This was a prospective cohort study of male BRCA1 (n = 376) and BRCA2 carriers (n = 447) identified in clinical genetics centres in the UK and Ireland (median follow-up 5.9 and 5.3 yr, respectively).

Outcome Measurements And Statistical Analysis: Standardised incidence/mortality ratios (SIRs/SMRs) relative to population incidences or mortality rates, absolute risks, and hazard ratios (HRs) were estimated using cohort and survival analysis methods.

Results And Limitations: Sixteen BRCA1 and 26 BRCA2 carriers were diagnosed with PCa during follow-up. BRCA2 carriers had an SIR of 4.45 (95% confidence interval [CI] 2.99-6.61) and absolute PCa risk of 27% (95% CI 17-41%) and 60% (95% CI 43-78%) by ages 75 and 85 yr, respectively. For BRCA1 carriers, the overall SIR was 2.35 (95% CI 1.43-3.88); the corresponding SIR at age <65 yr was 3.57 (95% CI 1.68-7.58). However, the BRCA1 SIR varied between 0.74 and 2.83 in sensitivity analyses to assess potential screening effects. PCa risk for BRCA2 carriers increased with family history (HR per affected relative 1.68, 95% CI 0.99-2.85). BRCA2 mutations in the region bounded by positions c.2831 and c.6401 were associated with an SIR of 2.46 (95% CI 1.07-5.64) compared to population incidences, corresponding to lower PCa risk (HR 0.37, 95% CI 0.14-0.96) than for mutations outside the region. BRCA2 carriers had a stronger association with Gleason score ≥7 (SIR 5.07, 95% CI 3.20-8.02) than Gleason score ≤6 PCa (SIR 3.03, 95% CI 1.24-7.44), and a higher risk of death from PCa (SMR 3.85, 95% CI 1.44-10.3). Limitations include potential screening effects for these known mutation carriers; however, the BRCA2 results were robust to multiple sensitivity analyses.

Conclusions: The results substantiate PCa risk patterns indicated by retrospective analyses for BRCA2 carriers, including further evidence of association with aggressive PCa, and give some support for a weaker association in BRCA1 carriers.

Patient Summary: In this study we followed unaffected men known to carry mutations in the BRCA1 and BRCA2 genes to investigate whether they are at higher risk of developing prostate cancer compared to the general population. We found that carriers of BRCA2 mutations have a high risk of developing prostate cancer, particularly more aggressive prostate cancer, and that this risk varies by family history of prostate cancer and the location of the mutation within the gene.
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http://dx.doi.org/10.1016/j.eururo.2019.08.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6926480PMC
January 2020

Increasing Evidence for the Association of Breast Implant-Associated Anaplastic Large Cell Lymphoma and Li Fraumeni Syndrome.

Case Rep Genet 2019 16;2019:5647940. Epub 2019 Jul 16.

Department of Breast and Endocrine Surgery, St James's University Hospital, Leeds, LS9 7TF, UK.

We report a case of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) occurring in a 53-year-old female with Li Fraumeni syndrome (LFS) with a prior history of breast cancer. We present the clinical features, investigation, and management of this patient and potential mechanisms that could explain the increasing association of BIA-ALCL and LFS.
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http://dx.doi.org/10.1155/2019/5647940DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6662482PMC
July 2019

Oral Contraceptive Use and Breast Cancer Risk: Retrospective and Prospective Analyses From a BRCA1 and BRCA2 Mutation Carrier Cohort Study.

JNCI Cancer Spectr 2018 Apr 28;2(2):pky023. Epub 2018 Jun 28.

Department of Pathology and Molecular Medicine, Juravinski Hospital and Cancer Centre, McMaster University, Hamilton, Ontario, Canada.

Background: For BRCA1 and BRCA2 mutation carriers, the association between oral contraceptive preparation (OCP) use and breast cancer (BC) risk is still unclear.

Methods: Breast camcer risk associations were estimated from OCP data on 6030 BRCA1 and 3809 BRCA2 mutation carriers using age-dependent Cox regression, stratified by study and birth cohort. Prospective, left-truncated retrospective and full-cohort retrospective analyses were performed.

Results: For BRCA1 mutation carriers, OCP use was not associated with BC risk in prospective analyses (hazard ratio [HR] = 1.08, 95% confidence interval [CI] = 0.75 to 1.56), but in the left-truncated and full-cohort retrospective analyses, risks were increased by 26% (95% CI = 6% to 51%) and 39% (95% CI = 23% to 58%), respectively. For BRCA2 mutation carriers, OCP use was associated with BC risk in prospective analyses (HR = 1.75, 95% CI = 1.03 to 2.97), but retrospective analyses were inconsistent (left-truncated: HR = 1.06, 95% CI = 0.85 to 1.33; full cohort: HR = 1.52, 95% CI = 1.28 to 1.81). There was evidence of increasing risk with duration of use, especially before the first full-term pregnancy (BRCA1: both retrospective analyses, < .001 and = .001, respectively; BRCA2: full retrospective analysis, = .002).

Conclusions: Prospective analyses did not show that past use of OCP is associated with an increased BC risk for BRCA1 mutation carriers in young middle-aged women (40-50 years). For BRCA2 mutation carriers, a causal association is also not likely at those ages. Findings between retrospective and prospective analyses were inconsistent and could be due to survival bias or a true association for younger women who were underrepresented in the prospective cohort. Given the uncertain safety of long-term OCP use for BRCA1/2 mutation carriers, indications other than contraception should be avoided and nonhormonal contraceptive methods should be discussed.
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http://dx.doi.org/10.1093/jncics/pky023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6649757PMC
April 2018

Cas9-based enrichment and single-molecule sequencing for precise characterization of genomic duplications.

Lab Invest 2020 01 4;100(1):135-146. Epub 2019 Jul 4.

Yorkshire Regional Genetics Service, St. James's University Hospital, Leeds, LS9 7TF, UK.

The widespread use of genome-wide diagnostic screening methods has greatly increased the frequency with which incidental (but possibly pathogenic) copy number changes affecting single genes are detected. These findings require validation to allow appropriate clinical management. Deletion variants can usually be readily validated using a range of short-read next-generation sequencing (NGS) strategies, but the characterization of duplication variants at nucleotide resolution remains challenging. This presents diagnostic problems, since pathogenicity cannot generally be assessed without knowing the structure of the variant. We have used a novel Cas9 enrichment strategy, in combination with long-read single-molecule nanopore sequencing, to address this need. We describe the nucleotide-level resolution of two problematic cases, both of whom presented with neurodevelopmental problems and were initially investigated by array CGH. In the first case, an incidental 1.7-kb imbalance involving a partial duplication of VHL exon 3 was detected. This variant was inherited from the patient's father, who had a history of renal cancer at 38 years. In the second case, an incidental ~200-kb de novo duplication that included DMD exons 30-44 was resolved. In both cases, the long-read data yielded sufficient information to enable Sanger sequencing to define the rearrangement breakpoints, and creation of breakpoint-spanning PCR assays suitable for testing of relatives. Our Cas9 enrichment and nanopore sequencing approach can be readily adopted by molecular diagnostic laboratories for cost-effective and rapid characterization of challenging duplication-containing alleles. We also anticipate that in future this method may prove useful for characterizing acquired translocations in tumor cells, and for precisely identifying transgene integration sites in mouse models.
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http://dx.doi.org/10.1038/s41374-019-0283-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6923135PMC
January 2020

Mendelian randomisation study of height and body mass index as modifiers of ovarian cancer risk in 22,588 BRCA1 and BRCA2 mutation carriers.

Br J Cancer 2019 07 19;121(2):180-192. Epub 2019 Jun 19.

Department of Gynaecological Oncology, Chris O'Brien Lifehouse and The University of Sydney, Camperdown, NSW, Australia.

Background: Height and body mass index (BMI) are associated with higher ovarian cancer risk in the general population, but whether such associations exist among BRCA1/2 mutation carriers is unknown.

Methods: We applied a Mendelian randomisation approach to examine height/BMI with ovarian cancer risk using the Consortium of Investigators for the Modifiers of BRCA1/2 (CIMBA) data set, comprising 14,676 BRCA1 and 7912 BRCA2 mutation carriers, with 2923 ovarian cancer cases. We created a height genetic score (height-GS) using 586 height-associated variants and a BMI genetic score (BMI-GS) using 93 BMI-associated variants. Associations were assessed using weighted Cox models.

Results: Observed height was not associated with ovarian cancer risk (hazard ratio [HR]: 1.07 per 10-cm increase in height, 95% confidence interval [CI]: 0.94-1.23). Height-GS showed similar results (HR = 1.02, 95% CI: 0.85-1.23). Higher BMI was significantly associated with increased risk in premenopausal women with HR = 1.25 (95% CI: 1.06-1.48) and HR = 1.59 (95% CI: 1.08-2.33) per 5-kg/m increase in observed and genetically determined BMI, respectively. No association was found for postmenopausal women. Interaction between menopausal status and BMI was significant (P < 0.05).

Conclusion: Our observation of a positive association between BMI and ovarian cancer risk in premenopausal BRCA1/2 mutation carriers is consistent with findings in the general population.
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http://dx.doi.org/10.1038/s41416-019-0492-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6738050PMC
July 2019

Mutational Signature Analysis Reveals NTHL1 Deficiency to Cause a Multi-tumor Phenotype.

Cancer Cell 2019 02;35(2):256-266.e5

Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands.

Biallelic germline mutations affecting NTHL1 predispose carriers to adenomatous polyposis and colorectal cancer, but the complete phenotype is unknown. We describe 29 individuals carrying biallelic germline NTHL1 mutations from 17 families, of which 26 developed one (n = 10) or multiple (n = 16) malignancies in 14 different tissues. An unexpected high breast cancer incidence was observed in female carriers (60%). Mutational signature analysis of 14 tumors from 7 organs revealed that NTHL1 deficiency underlies the main mutational process in all but one of the tumors (93%). These results reveal NTHL1 as a multi-tumor predisposition gene with a high lifetime risk for extracolonic cancers and a typical mutational signature observed across tumor types, which can assist in the recognition of this syndrome.
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http://dx.doi.org/10.1016/j.ccell.2018.12.011DOI Listing
February 2019

Additional loss of MSH2 and MSH6 expression in sporadic deficient mismatch repair colorectal cancer due to MLH1 promoter hypermethylation.

J Clin Pathol 2019 Jun 5;72(6):443-447. Epub 2019 Feb 5.

Pathology, University of Leeds, Leeds, UK

Colorectal cancer (CRC) is common with 3% of cases associated with germline mutations in the mismatch repair pathway characteristic of Lynch syndrome (LS). The UK National Institute for Health and Care Excellence recommends screening for LS in all patients newly diagnosed with CRC, irrespective of age. The Yorkshire Cancer Research Bowel Cancer Improvement Programme includes a regional LS screening service for all new diagnoses of CRC. In the first 829 cases screened, 80 cases showed deficient mismatch repair (dMMR) including four cases showing areas with loss of expression of all four mismatch repair proteins by immunohistochemistry. The cases demonstrated diffuse MLH1 loss associated with BRAF mutations and MLH1 promoter hypermethylation in keeping with sporadic dMMR, with presumed additional double hit mutations in MSH2+/-MSH6 rather than underlying LS. Recognition and accurate interpretation of this unusual phenotype is important to prevent unnecessary referrals to clinical genetics and associated patient anxiety.
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http://dx.doi.org/10.1136/jclinpath-2018-205687DOI Listing
June 2019

Comprehensive Study of the Clinical Phenotype of Germline BAP1 Variant-Carrying Families Worldwide.

J Natl Cancer Inst 2018 12;110(12):1328-1341

Medical Oncology Unit, Ospedale Policlinico San Martino, Genoa, Italy.

Background: The BRCA1-associated protein-1 (BAP1) tumor predisposition syndrome (BAP1-TPDS) is a hereditary tumor syndrome caused by germline pathogenic variants in BAP1 encoding a tumor suppressor associated with uveal melanoma, mesothelioma, cutaneous melanoma, renal cell carcinoma, and cutaneous BAP1-inactivated melanocytic tumors. However, the full spectrum of tumors associated with the syndrome is yet to be determined. Improved understanding of the BAP1-TPDS is crucial for appropriate clinical management of BAP1 germline variant carriers and their families, including genetic counseling and surveillance for new tumors.

Methods: We collated germline variant status, tumor diagnoses, and information on BAP1 immunohistochemistry or loss of somatic heterozygosity on 106 published and 75 unpublished BAP1 germline variant-positive families worldwide to better characterize the genotypes and phenotypes associated with the BAP1-TPDS. Tumor spectrum and ages of onset were compared between missense and null variants. All statistical tests were two-sided.

Results: The 181 families carried 140 unique BAP1 germline variants. The collated data confirmed the core tumor spectrum associated with the BAP1-TPDS and showed that some families carrying missense variants can exhibit this phenotype. A variety of noncore BAP1-TPDS -associated tumors were found in families of variant carriers. Median ages of onset of core tumor types were lower in null than missense variant carriers for all tumors combined (P < .001), mesothelioma (P < .001), cutaneous melanoma (P < .001), and nonmelanoma skin cancer (P < .001).

Conclusions: This analysis substantially increases the number of pathogenic BAP1 germline variants and refines the phenotype. It highlights the need for a curated registry of germline variant carriers for proper assessment of the clinical phenotype of the BAP1-TPDS and pathogenicity of new variants, thus guiding management of patients and informing areas requiring further research.
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http://dx.doi.org/10.1093/jnci/djy171DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6292796PMC
December 2018

Height and Body Mass Index as Modifiers of Breast Cancer Risk in BRCA1/2 Mutation Carriers: A Mendelian Randomization Study.

J Natl Cancer Inst 2019 04;111(4):350-364

Department of Medicine, Huntsman Cancer Institute at the University of Utah, Salt Lake City, UT.

Background: BRCA1/2 mutations confer high lifetime risk of breast cancer, although other factors may modify this risk. Whether height or body mass index (BMI) modifies breast cancer risk in BRCA1/2 mutation carriers remains unclear.

Methods: We used Mendelian randomization approaches to evaluate the association of height and BMI on breast cancer risk, using data from the Consortium of Investigators of Modifiers of BRCA1/2 with 14 676 BRCA1 and 7912 BRCA2 mutation carriers, including 11 451 cases of breast cancer. We created a height genetic score using 586 height-associated variants and a BMI genetic score using 93 BMI-associated variants. We examined both observed and genetically determined height and BMI with breast cancer risk using weighted Cox models. All statistical tests were two-sided.

Results: Observed height was positively associated with breast cancer risk (HR = 1.09 per 10 cm increase, 95% confidence interval [CI] = 1.0 to 1.17; P = 1.17). Height genetic score was positively associated with breast cancer, although this was not statistically significant (per 10 cm increase in genetically predicted height, HR = 1.04, 95% CI = 0.93 to 1.17; P = .47). Observed BMI was inversely associated with breast cancer risk (per 5 kg/m2 increase, HR = 0.94, 95% CI = 0.90 to 0.98; P = .007). BMI genetic score was also inversely associated with breast cancer risk (per 5 kg/m2 increase in genetically predicted BMI, HR = 0.87, 95% CI = 0.76 to 0.98; P = .02). BMI was primarily associated with premenopausal breast cancer.

Conclusion: Height is associated with overall breast cancer and BMI is associated with premenopausal breast cancer in BRCA1/2 mutation carriers. Incorporating height and BMI, particularly genetic score, into risk assessment may improve cancer management.
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http://dx.doi.org/10.1093/jnci/djy132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6449171PMC
April 2019

Comprehensive Cancer-Predisposition Gene Testing in an Adult Multiple Primary Tumor Series Shows a Broad Range of Deleterious Variants and Atypical Tumor Phenotypes.

Am J Hum Genet 2018 07 14;103(1):3-18. Epub 2018 Jun 14.

North East Thames Regional Genetics Service, Great Ormond Street Hospital for Children, London WC1N 3JH, UK.

Multiple primary tumors (MPTs) affect a substantial proportion of cancer survivors and can result from various causes, including inherited predisposition. Currently, germline genetic testing of MPT-affected individuals for variants in cancer-predisposition genes (CPGs) is mostly targeted by tumor type. We ascertained pre-assessed MPT individuals (with at least two primary tumors by age 60 years or at least three by 70 years) from genetics centers and performed whole-genome sequencing (WGS) on 460 individuals from 440 families. Despite previous negative genetic assessment and molecular investigations, pathogenic variants in moderate- and high-risk CPGs were detected in 67/440 (15.2%) probands. WGS detected variants that would not be (or were not) detected by targeted resequencing strategies, including low-frequency structural variants (6/440 [1.4%] probands). In most individuals with a germline variant assessed as pathogenic or likely pathogenic (P/LP), at least one of their tumor types was characteristic of variants in the relevant CPG. However, in 29 probands (42.2% of those with a P/LP variant), the tumor phenotype appeared discordant. The frequency of individuals with truncating or splice-site CPG variants and at least one discordant tumor type was significantly higher than in a control population (χ = 43.642; p ≤ 0.0001). 2/67 (3%) probands with P/LP variants had evidence of multiple inherited neoplasia allele syndrome (MINAS) with deleterious variants in two CPGs. Together with variant detection rates from a previous series of similarly ascertained MPT-affected individuals, the present results suggest that first-line comprehensive CPG analysis in an MPT cohort referred to clinical genetics services would detect a deleterious variant in about a third of individuals.
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http://dx.doi.org/10.1016/j.ajhg.2018.04.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6037202PMC
July 2018

Risks of breast or ovarian cancer in BRCA1 or BRCA2 predictive test negatives: findings from the EMBRACE study.

Genet Med 2018 12 22;20(12):1575-1582. Epub 2018 Mar 22.

Oncogenetics Team, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, UK.

Purpose: BRCA1/BRCA2 predictive test negatives are proven noncarriers of a BRCA1/BRCA2 mutation that is carried by their relatives. The risk of developing breast cancer (BC) or epithelial ovarian cancer (EOC) in these women is uncertain. The study aimed to estimate risks of invasive BC and EOC in a large cohort of BRCA1/BRCA2 predictive test negatives.

Methods: We used cohort analysis to estimate incidences, cumulative risks, and standardized incidence ratios (SIRs).

Results: A total of 1,895 unaffected women were eligible for inclusion in the BC risk analysis and 1,736 in the EOC risk analysis. There were 23 incident invasive BCs and 2 EOCs. The cumulative risk of invasive BC was 9.4% (95% confidence interval (CI) 5.9-15%) by age 85 years and the corresponding risk of EOC was 0.6% (95% CI 0.2-2.6%). The SIR for invasive BC was 0.93 (95% CI 0.62-1.40) in the overall cohort, 0.85 (95% CI 0.48-1.50) in noncarriers from BRCA1 families, and 1.03 (95% CI 0.57-1.87) in noncarriers from BRCA2 families. The SIR for EOC was 0.79 (95% CI 0.20-3.17) in the overall cohort.

Conclusion: Our results did not provide evidence for elevated risks of invasive BC or EOC in BRCA1/BRCA2 predictive test negatives.
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http://dx.doi.org/10.1038/gim.2018.44DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6033314PMC
December 2018

Mutational spectrum in a worldwide study of 29,700 families with BRCA1 or BRCA2 mutations.

Hum Mutat 2018 05 12;39(5):593-620. Epub 2018 Mar 12.

Lunenfeld-Tanenbaum Research Institute, Toronto, Canada.

The prevalence and spectrum of germline mutations in BRCA1 and BRCA2 have been reported in single populations, with the majority of reports focused on White in Europe and North America. The Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) has assembled data on 18,435 families with BRCA1 mutations and 11,351 families with BRCA2 mutations ascertained from 69 centers in 49 countries on six continents. This study comprehensively describes the characteristics of the 1,650 unique BRCA1 and 1,731 unique BRCA2 deleterious (disease-associated) mutations identified in the CIMBA database. We observed substantial variation in mutation type and frequency by geographical region and race/ethnicity. In addition to known founder mutations, mutations of relatively high frequency were identified in specific racial/ethnic or geographic groups that may reflect founder mutations and which could be used in targeted (panel) first pass genotyping for specific populations. Knowledge of the population-specific mutational spectrum in BRCA1 and BRCA2 could inform efficient strategies for genetic testing and may justify a more broad-based oncogenetic testing in some populations.
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http://dx.doi.org/10.1002/humu.23406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5903938PMC
May 2018

Tumour risks and genotype-phenotype correlations associated with germline variants in succinate dehydrogenase subunit genes , and .

J Med Genet 2018 06 31;55(6):384-394. Epub 2018 Jan 31.

West Midlands Regional Genetics service, Birmingham Women's Hospital, Birmingham, UK.

Background: Germline pathogenic variants in / are the most frequent causes of inherited phaeochromocytomas/paragangliomas. Insufficient information regarding penetrance and phenotypic variability hinders optimum management of mutation carriers. We estimate penetrance for symptomatic tumours and elucidate genotype-phenotype correlations in a large cohort of / mutation carriers.

Methods: A retrospective survey of 1832 individuals referred for genetic testing due to a personal or family history of phaeochromocytoma/paraganglioma. 876 patients (401 previously reported) had a germline mutation in / (n=673/43/160). Tumour risks were correlated with in silico structural prediction analyses.

Results: Tumour risks analysis provided novel penetrance estimates and genotype-phenotype correlations. In addition to tumour type susceptibility differences for individual genes, we confirmed that the p.Pro81Leu mutation has a distinct phenotype and identified increased age-related tumour risks with highly destabilising missense mutations. By Kaplan-Meier analysis, the penetrance (cumulative risk of clinically apparent tumours) in and (paternally inherited) mutation-positive non-probands (n=371/67 with detailed clinical information) by age 60 years was 21.8% (95% CI 15.2% to 27.9%) and 43.2% (95% CI 25.4% to 56.7%), respectively. Risk of malignant disease at age 60 years in non-proband mutation carriers was 4.2%(95% CI 1.1% to 7.2%). With retrospective cohort analysis to adjust for ascertainment, cumulative tumour risks for mutation carriers at ages 60 years and 80 years were 23.9% (95% CI 20.9% to 27.4%) and 30.6% (95% CI 26.8% to 34.7%).

Conclusions: Overall risks of clinically apparent tumours for mutation carriers are substantially lower than initially estimated and will improve counselling of affected families. Specific genotype-tumour risk associations provides a basis for novel investigative strategies into succinate dehydrogenase-related mechanisms of tumourigenesis and the development of personalised management for / mutation carriers.
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http://dx.doi.org/10.1136/jmedgenet-2017-105127DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5992372PMC
June 2018

Identification of ten variants associated with risk of estrogen-receptor-negative breast cancer.

Nat Genet 2017 Dec 23;49(12):1767-1778. Epub 2017 Oct 23.

Department of Epidemiology, University of California, Irvine, Irvine, California, USA.

Most common breast cancer susceptibility variants have been identified through genome-wide association studies (GWAS) of predominantly estrogen receptor (ER)-positive disease. We conducted a GWAS using 21,468 ER-negative cases and 100,594 controls combined with 18,908 BRCA1 mutation carriers (9,414 with breast cancer), all of European origin. We identified independent associations at P < 5 × 10 with ten variants at nine new loci. At P < 0.05, we replicated associations with 10 of 11 variants previously reported in ER-negative disease or BRCA1 mutation carrier GWAS and observed consistent associations with ER-negative disease for 105 susceptibility variants identified by other studies. These 125 variants explain approximately 16% of the familial risk of this breast cancer subtype. There was high genetic correlation (0.72) between risk of ER-negative breast cancer and breast cancer risk for BRCA1 mutation carriers. These findings may lead to improved risk prediction and inform further fine-mapping and functional work to better understand the biological basis of ER-negative breast cancer.
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http://dx.doi.org/10.1038/ng.3785DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5808456PMC
December 2017

Increased Sensitivity of Diagnostic Mutation Detection by Re-analysis Incorporating Local Reassembly of Sequence Reads.

Mol Diagn Ther 2017 12;21(6):685-692

Yorkshire Regional Genetics Service, St. James's University Hospital, 6.2 Clinical Sciences Building, Leeds, LS9 7TF, United Kingdom.

Background: Diagnostic genetic testing programmes based on next-generation DNA sequencing have resulted in the accrual of large datasets of targeted raw sequence data. Most diagnostic laboratories process these data through an automated variant-calling pipeline. Validation of the chosen analytical methods typically depends on confirming the detection of known sequence variants. Despite improvements in short-read alignment methods, current pipelines are known to be comparatively poor at detecting large insertion/deletion mutations.

Methods: We performed clinical validation of a local reassembly tool, ABRA (assembly-based realigner), through retrospective reanalysis of a cohort of more than 2000 hereditary cancer cases.

Results: ABRA enabled detection of a 96-bp deletion, 4-bp insertion mutation in PMS2 that had been initially identified using a comparative read-depth approach. We applied an updated pipeline incorporating ABRA to the entire cohort of 2000 cases and identified one previously undetected pathogenic variant, a 23-bp duplication in PTEN. We demonstrate the effect of read length on the ability to detect insertion/deletion variants by comparing HiSeq2500 (2 × 101-bp) and NextSeq500 (2 × 151-bp) sequence data for a range of variants and thereby show that the limitations of shorter read lengths can be mitigated using appropriate informatics tools.

Conclusions: This work highlights the need for ongoing development of diagnostic pipelines to maximize test sensitivity. We also draw attention to the large differences in computational infrastructure required to perform day-to-day versus large-scale reprocessing tasks.
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http://dx.doi.org/10.1007/s40291-017-0304-xDOI Listing
December 2017

Characterization and Genomic Localization of a SMAD4 Processed Pseudogene.

J Mol Diagn 2017 11 1;19(6):933-940. Epub 2017 Sep 1.

Yorkshire Regional Genetics Service, St. James's University Hospital, Leeds, United Kingdom; MRC Medical Bioinformatics Centre, Leeds Institute for Data Analytics, St. James's University Hospital, Leeds, United Kingdom; MRC Single Cell Functional Genomics Centre, University of Leeds, St. James's University Hospital, Leeds, United Kingdom.

Like many clinical diagnostic laboratories, the Yorkshire Regional Genetics Service undertakes routine investigation of cancer-predisposed individuals by high-throughput sequencing of patient DNA that has been target-enriched for genes associated with hereditary cancer. Accurate diagnosis using such reagents requires alertness regarding rare nonpathogenic variants that may interfere with variant calling. In a cohort of 2042 such cases, we identified 5 that initially appeared to be carriers of a 95-bp deletion of SMAD4 intron 6. More detailed analysis indicated that these individuals all carried one copy of a SMAD4 processed gene. Because of its interference with diagnostic analysis, we characterized this processed gene in detail. Whole-genome sequencing and confirmatory Sanger sequencing of junction PCR products were used to show that in each of the 5 cases, the SMAD4 processed gene was integrated at the same position on chromosome 9, located within the last intron of the SCAI gene. This rare polymorphic processed gene therefore reflects the occurrence of a single ancestral retrotransposition event. Compared to the reference SMAD4 mRNA sequence NM_005359.5 (https://www.ncbi.nlm.nih.gov/nucleotide), the 5' and 3' untranslated regions of the processed gene are both truncated, but its open reading frame is unaltered. Our experience leads us to advocate the use of an RNA-seq aligner as part of diagnostic assay quality assurance, since this allows recognition of processed pseudogenes in a comparatively facile automated fashion.
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http://dx.doi.org/10.1016/j.jmoldx.2017.08.002DOI Listing
November 2017
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