BRCA2 Polymorphic Stop Codon K3326X and the Risk of Breast, Prostate, and Ovarian Cancers

Germline Pathogenic Variants in Patients With Pancreatic and Periampullary Cancers

PURPOSE

Inherited cancer susceptibility is often not suspected in the absence of a significant cancer family history. Pathogenic germline variants in pancreatic cancer are well-studied, and routine genetic testing is recommended in the guidelines. However, data on rare periampullary cancers other than pancreatic cancer are insufficient. We compared the prevalence of germline susceptibility variants in patients with pancreatic cancer and nonpancreatic periampullary cancers.

MATERIALS AND METHODS

Six hundred and eight patients who had undergone pancreaticoduodenal resection at a tertiary referral hospital were studied, including 213 with pancreatic ductal adenocarcinoma, 172 with ampullary cancer, 154 with distal common bile duct cancer, and 69 with duodenal adenocarcinoma. Twenty cancer susceptibility and candidate susceptibility genes were sequenced, and variant interpretation was assessed by interrogating ClinVar and PubMed.

RESULTS

Pathogenic or likely pathogenic, moderate- to high-penetrant germline variants were identified in 46 patients (7.7%), including a similar percentage of patients with pancreatic (8.5%) and nonpancreatic periampullary cancer (7.1%). Low-penetrant variants were identified in an additional 11 patients (1.8%). Eighty-nine percent of the moderate- to high-penetrant variants involved the major cancer susceptibility genes BRCA2, ATM, BRCA1, CDKN2A, MSH2/MLH1, and PALB2; the remaining 11% involved other cancer susceptibility genes such as BRIP1, BAP1, and MSH6. Almost all pathogenic variant carriers had a family history of cancer.

CONCLUSION

Patients with pancreatic and nonpancreatic periampullary cancer have a similar prevalence of pathogenic cancer susceptibility variants. Germline susceptibility testing should be considered for patients with any periampullary cancer.

Genetic Basis of Breast and Ovarian Cancer: Approaches and Lessons Learnt from Three Decades of Inherited Predisposition Testing

Germline variants occurring in BRCA1 and BRCA2 give rise to hereditary breast and ovarian cancer (HBOC) syndrome, predisposing to breast, ovarian, fallopian tube, and peritoneal cancers marked by elevated incidences of genomic aberrations that correspond to poor prognoses. These genes are in fact involved in genetic integrity, particularly in the process of homologous recombination (HR) DNA repair, a high-fidelity repair system for mending DNA double-strand breaks. In addition to its implication in HBOC pathogenesis, the impairment of HR has become a prime target for therapeutic intervention utilizing poly (ADP-ribose) polymerase (PARP) inhibitors. In the present review, we introduce the molecular roles of HR orchestrated by BRCA1 and BRCA2 within the framework of sensitivity to PARP inhibitors. We examine the genetic architecture underneath breast and ovarian cancer ranging from high- and mid- to low-penetrant predisposing genes and taking into account both germline and somatic variations. Finally, we consider higher levels of complexity of the genomic landscape such as polygenic risk scores and other approaches aiming to optimize therapeutic and preventive strategies for breast and ovarian cancer.

Prevalence of BRCA1 and BRCA2 germline variants in an unselected pancreatic cancer patient cohort in Pakistan

BACKGROUND

BRCA1 and BRCA2 (BRCA1/2) are the most frequently investigated genes among Caucasian pancreatic cancer patients, whereas limited reports are available among Asians. We aimed to investigate the prevalence of BRCA1/2 germline variants in Pakistani pancreatic cancer patients.

METHODS

One hundred and fifty unselected and prospectively enrolled pancreatic cancer patients were comprehensively screened for BRCA1/2 germline variants using denaturing high-performance liquid chromatography and high-resolution melting analyses, followed by DNA sequencing of the variant fragments. The novel variants were analyzed for their pathogenic effect using in-silico tools. Potentially functional variants were further screened in 200 cancer-free controls.

RESULTS

Protein truncating variant was detected in BRCA2 only, with a prevalence of 0.7% (1/150). A frameshift BRCA2 variant (p.Asp946Ilefs*14) was identified in a 71-year-old male patient of Pathan ethnicity, with a family history of abdominal cancer. Additionally, we found a novel variant in BRCA2 (p.Glu2650Gln), two previously reported variants in BRCA1 (p.Thr293Ser) and BRCA2 (p.Ile2296Leu) and a recurrent nonsense variant in BRCA2 (p.Lys3326Ter). These variants were classified as variants of uncertain significance (VUS). It is noteworthy that none of these VUS carriers had a family history of pancreatic or other cancers.

CONCLUSIONS

In this first study, BRCA1/2 pathogenic variant is identified with a low frequency in pancreatic cancer patients from Pakistan. Comprehensive multigene panel testing is recommended in the Pakistani pancreatic cancer patients to enhance genetic understanding in this population.

A Single nucleotide polymorphism in the ALDH2 gene modifies the risk of esophageal squamous cell carcinoma in BRCA2 p.K3326* carriers

Esophageal squamous cell carcinoma (ESCC) has a very high incidence rate in northeastern Iran. Our team previously reported the BReast CAncer gene 2 (BRCA2) p.K3326* mutation as a moderately penetrant ESCC susceptibility variant in northern Iran (odds ratio (OR) = 3.64, 95% confidence interval (CI) = 1.74-7.59, P = 0.0003). Recently, it has been reported that aldehydes can induce BRCA2 haploinsufficiency in cells with a heterozygous pathogenic BRCA2 mutation and predispose them to carcinogenic effects. Based on this observation, we speculate that dysfunctional variants in Aldehyde Dehydrogenase 2 Family Member (ALDH2) may result in aldehyde-induced BRCA2 haploinsufficiency and increase cancer risk in BRCA2 mutation carriers. In support of this hypothesis, our team recently reported the breast cancer risk modifying effect of an ALDH2 common polymorphism, rs10744777, among Polish carriers of the BRCA2 p.K3326* mutation. In the current case-control study, we aimed to investigate the ESCC risk modifying effect of this ALDH2 polymorphism among BRCA2 p.K3326* mutation carriers. We assessed the interaction between the ALDH2 rs10744777 polymorphism and BRCA2 p.K3326* mutation in ESCC risk by genotyping this ALDH2 variant in the germline DNA of 746 ESCC cases and 1,373 controls from northern Iran who were previously genotyped for the BRCA2 p.K3326* mutation. Among a total of 464 individuals with TT genotype of the ALDH2 rs10744777 polymorphism, which is associated with lower ALDH2 expression, we found 9 of 164 cases versus 3 of 300 controls who carried the BRCA2 p.K3326* variant (OR = 5.66, 95% CI = 1.22-26.2, P = 0.018). This finding supports our hypothesis that the ALDH2-rs10744777 TT genotype may be a significant risk modifier of ESCC in individuals with a BRCA2 p.K3326* mutation.

Breast cancer polygenic risk scores derived in White European populations are not calibrated for women of Ashkenazi Jewish descent

PURPOSE

Polygenic risk scores (PRSs) are a major component of accurate breast cancer (BC) risk prediction but require ethnicity-specific calibration. Ashkenazi Jewish (AJ) population is assumed to be of White European (WE) origin in some commercially available PRSs despite differing effect allele frequencies (EAFs). We conducted a case-control study of WE and AJ women from the Predicting Risk of Cancer at Screening Study. The Breast Cancer in Northern Israel Study provided a separate AJ population-based case-control validation series.

METHODS

All women underwent Illumina OncoArray single-nucleotide variation (SNV; formerly single-nucleotide polymorphism [SNP]) analysis. Two PRSs were assessed, SNV142 and SNV78. A total of 221 of 2243 WE women (discovery: cases = 111; controls = 110; validation: cases = 651; controls = 1772) and 221 AJ women (cases = 121; controls = 110) were included from the UK study; the Israeli series consisted of 2045 AJ women (cases = 1331; controls = 714). EAFs were obtained from the Genome Aggregation Database.

RESULTS

In the UK study, the mean SNV142 PRS demonstrated good calibration and discrimination in WE population, with mean PRS of 1.33 (95% CI 1.18-1.48) in cases and 1.01 (95% CI 0.89-1.13) in controls. In AJ women from Manchester, the mean PRS of 1.54 (1.38-1.70) in cases and 1.20 (1.08-1.32) in controls demonstrated good discrimination but overestimation of BC relative risk. After adjusting for EAFs for the AJ population, mean risk was corrected (mean SNV142 PRS cases = 1.30 [95% CI 1.16-1.44] and controls = 1.02 [95% CI 0.92-1.12]). This was recapitulated in the larger Israeli data set with good discrimination (area under the curve = 0.632 [95% CI 0.607-0.657] for SNV142).

CONCLUSION

AJ women should not be given BC relative risk predictions based on PRSs calibrated to EAFs from the WE population. PRSs need to be recalibrated using AJ-derived EAFs. A simple recalibration using the mean PRS adjustment ratio likely performs well.

Stratifying the risk of ovarian cancer incidence by histologic subtypes in the Korean Epithelial Ovarian Cancer Study (Ko-EVE)

INTRODUCTION

This study aimed to verify the association between ovarian cancer (OC) and reproductive- and lifestyle-related risk factors stratified by the subtype of OC.

METHODS

In this matched case-control study derived from the Korean epithelial ovarian cancer study (Ko-EVE), we calculated the risk of OC subtypes using odds ratios (ORs) and 95% confidence intervals (95% CIs) in a logistic regression model.

RESULTS

As a result of matching, 531 cases and 2,124 controls were selected. Smoking had positive association with high-grade serous (HGS) OC (OR = 2.69, 95% CI = 1.15-6.30), whereas alcohol consumption had positive association with mucinous type (MUC) (OR = 3.63, 95% CI = 1.39-9.49). Obesity (≥30 kg/m² ) was associated with clear cell type (CLC) (OR = 4.57, 95% CI = 1.06-19.77). Spontaneous abortion was negatively associated with CLC (OR = 0.34, 95% CI = 0.13-0.90), in contrast to HGS (OR = 1.43, 95% CI = 0.96-2.15). Tubal ligation, hysterectomy, and oophorectomy were associated with decreased risk of HGS (OR = 0.14, 95% CI = 0.05-0.39; OR = 0.23, 95% CI = 0.07-0.73; OR = 0.28, 95% CI = 0.08-0.97, respectively). Early menarche was strongly associated with increased risk of CLC, but not MUC (OR = 6.11, 95% CI = 1.53-24.42; OR = 3.23, 95% CI = 0.98-10.86). Further, childbirth (≥2 times) was negatively associated with endometrioid type OC and CLC (OR = 0.11, 95% CI = 0.04-0.35; OR = 0.12, 95% CI = 0.02-0.37, respectively). Oral contraceptives and hormone replacement therapy were negatively associated with OC (OR = 0.61, 95% CI = 0.40-0.93; OR = 0.51, 95% CI = 0.32-0.80, respectively), and similar negative associations were also observed in HGS (OR = 0.69; OR = 0.60, respectively). Associations between family history of breast cancer and OC, regular exercise (≥5/week), and artificial abortion and OC were similar across all subtypes (OR = 3.92; OR = 0.41; OR = 0.72, respectively).

CONCLUSION

A heterogeneous association between some risk factors and the incidence of each subtype of epithelial OC was observed, suggesting that the carcinogenic mechanisms of each subtype may be partly different.

Genome-Wide Analysis of Rare Haplotypes Associated with Breast Cancer Risk

Numerous common genetic variants have been linked to breast cancer risk, but they only partially explain the total breast cancer heritability. Inference from Nordic population-based twin data indicates rare high-risk loci as the chief determinant of breast cancer risk. Here, we use haplotypes, rather than single variants, to identify rare high-risk loci for breast cancer. With computationally phased genotypes from 181,034 white British women in the UK Biobank, a genome-wide haplotype-breast cancer association analysis was conducted using sliding windows of 5 to 500 consecutive array-genotyped variants. In the discovery stage, haplotype-breast cancer associations were evaluated retrospectively in the prestudy-enrollment data including 5,487 breast cancer cases. Breast cancer hazard ratios (HR) for additive haplotypic effects were estimated using Cox regression. The replication analysis included a prospective cohort of women free of breast cancer at enrollment, of whom 3,524 later developed breast cancer. This two-stage analysis detected 13 rare loci (frequency <1%), each associated with an appreciable breast cancer-risk increase (discovery: HRs = 2.84-6.10, P < 5 × 10-8; replication: HRs = 2.08-5.61, P < 0.01). In contrast, the variants that formed these rare haplotypes individually exhibited much smaller effects. Functional annotation revealed extensive cis-regulatory DNA elements in breast cancer-related cells underlying the replicated rare haplotypes. Using phased, imputed genotypes from 30,064 cases and 25,282 controls in the DRIVE OncoArray case-control study, 6 of the 13 rare-loci associations were found generalizable (odds ratio estimates: 1.48-7.67, P < 0.05). This study demonstrates the complementary advantage of utilizing rare haplotypes to capture novel risk loci and suggests the potential for the discovery of more genetic elements contributing to cancer heritability as large data sets of germline whole-genome sequencing become available.

SIGNIFICANCE

A genome-wide two-stage haplotype analysis identifies rare haplotypes associated with breast cancer risk and suggests that the rare risk haplotypes represent long-range interactions with regulatory consequences influencing cancer risk.

Clonal hematopoiesis and risk of prostate cancer in large samples of European ancestry men

Little is known regarding the potential relationship between clonal hematopoiesis (CH) of indeterminate potential (CHIP), which is the expansion of hematopoietic stem cells with somatic mutations, and risk of prostate cancer, the fifth leading cause of cancer death of men worldwide. We evaluated the association of age-related CHIP with overall and aggressive prostate cancer risk in two large whole-exome sequencing studies of 75 047 European ancestry men, including 7663 prostate cancer cases, 2770 of which had aggressive disease, and 3266 men carrying CHIP variants. We found that CHIP, defined by over 50 CHIP genes individually and in aggregate, was not significantly associated with overall (aggregate HR = 0.93, 95% CI = 0.76-1.13, P = 0.46) or aggressive (aggregate OR = 1.14, 95% CI = 0.92-1.41, P = 0.22) prostate cancer risk. CHIP was weakly associated with genetic risk of overall prostate cancer, measured using a polygenic risk score (OR = 1.05 per unit increase, 95% CI = 1.01-1.10, P = 0.01). CHIP was not significantly associated with carrying pathogenic/likely pathogenic/deleterious variants in DNA repair genes, which have previously been found to be associated with aggressive prostate cancer. While findings from this study suggest that CHIP is likely not a risk factor for prostate cancer, it will be important to investigate other types of CH in association with prostate cancer risk.

Common Variant in ALDH2 Modifies the Risk of Breast Cancer Among Carriers of the p.K3326* Variant in BRCA2

PURPOSE

The BRCA2 p.K3326* variant is considered a low-penetrance variant for breast cancer. Aldehydes that accumulate in cells under insufficient aldehyde oxidation were most recently shown to trigger carcinogenesis by promoting depletion of BRCA2 protein. Allele T of the common variant rs10744777 in the ALDH2 gene was associated with reduced expression of aldehyde dehydrogenase, the main enzyme in aldehyde oxidation. We hypothesized that this allele could modify breast cancer risk in women with the BRCA2 p.K3326* low-penetrance variant through reduced function of ALDH2, increased accumulation of cellular aldehydes, and depletion of BRCA2 protein.

MATERIALS AND METHODS

We genotyped 11,873 Polish women diagnosed with breast cancer and 7,615 ethnically matched controls for these two variants. Next, we extended our analysis of rs10744777 to 231 carriers of pathogenic BRCA2 mutations.

RESULTS

BRCA2 p.K3326* variant was associated with significant increase in breast cancer risk only in those who were homozygous for the T allele of the ALDH2 rs10744777 variant (odds ratio = 1.72; 95% CI, 1.19 to 2.48; P = .003). The BRCA2 p.K3326* variant did not increase the risk of breast cancer among those who were heterozygous or homozygous for the C allele of the ALDH2 rs10744777 variant (odds ratio = 1.05; 95% CI, 0.73 to 1.51; P = .81). In the carriers of high-risk BRCA2 mutations, the TT genotype of rs10744777 conferred a modest (18%) and not significant increase in breast cancer risk.

CONCLUSION

Our results suggest that BRCA2 p.K3326* variant, which is low-penetrance by itself, confers increased breast cancer risk on the background of the TT genotype of the ALDH2 rs10744777 variant in the Polish population.

Common variants in breast cancer risk loci predispose to distinct tumor subtypes

BACKGROUND

Genome-wide association studies (GWAS) have identified multiple common breast cancer susceptibility variants. Many of these variants have differential associations by estrogen receptor (ER) status, but how these variants relate with other tumor features and intrinsic molecular subtypes is unclear.

METHODS

Among 106,571 invasive breast cancer cases and 95,762 controls of European ancestry with data on 173 breast cancer variants identified in previous GWAS, we used novel two-stage polytomous logistic regression models to evaluate variants in relation to multiple tumor features (ER, progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and grade) adjusting for each other, and to intrinsic-like subtypes.

RESULTS

Eighty-five of 173 variants were associated with at least one tumor feature (false discovery rate < 5%), most commonly ER and grade, followed by PR and HER2. Models for intrinsic-like subtypes found nearly all of these variants (83 of 85) associated at p < 0.05 with risk for at least one luminal-like subtype, and approximately half (41 of 85) of the variants were associated with risk of at least one non-luminal subtype, including 32 variants associated with triple-negative (TN) disease. Ten variants were associated with risk of all subtypes in different magnitude. Five variants were associated with risk of luminal A-like and TN subtypes in opposite directions.

CONCLUSION

This report demonstrates a high level of complexity in the etiology heterogeneity of breast cancer susceptibility variants and can inform investigations of subtype-specific risk prediction.

Lung cancer is also a hereditary disease

Pathogenic genetic variants (formerly called mutations) present in the germline of some individuals are associated with a clinically relevant increased risk of developing lung cancer. These germline pathogenic variants are hereditary and are transmitted in an autosomal dominant fashion. There are two major lung cancer susceptibility syndromes, and both seem to be specifically associated with the adenocarcinoma subtype. Li-Fraumeni syndrome is caused by variants in the TP53 tumour-suppressor gene. Carriers are mainly at risk of early-onset breast cancer, sarcoma, glioma, leukaemia, adrenal cortical carcinoma and lung cancer. EGFR variants, T790M in particular, cause the EGFR susceptibility syndrome. Risk seems limited to lung cancer. Emerging data suggest that variants in ATM, the breast and pancreatic cancer susceptibility gene, also increase lung adenocarcinoma risk. As for inherited lung disease, cancer risk is increased in SFTPA1 and SFTPA2 variant carriers independently of the underlying fibrosis. In this review, we provide criteria warranting the referral of a lung cancer patient to the cancer genetics clinic. Pathogenic variants are first identified in patients with cancer, and then in a subset of their relatives. Lung cancer screening should be offered to asymptomatic carriers, with thoracic magnetic resonance imaging at its core.

A proportion of lung cancers are hereditary. This includes patients with Li-Fraumeni syndrome and patients with EGFR-associated genetic susceptibility. They are mainly young patients with adenocarcinoma regardless of smoking history.https://bit.ly/2QAfjnB

Synchronous detection of pancreatic adenocarcinoma and paraganglioma in a Whipple resection specimen

We report a case of a pancreatic ductal adenocarcinoma (PDAC) presenting synchronously with a paraganglioma (PGL) in a Whipple reaction specimen. The patient was a 72-year-old female with a history of breast and vulvar cancer. The simultaneous occurrence of two synchronous tumours in the pancreas was striking. Due to the presence of PGL and multiple meta- and synchronous tumours, the patient was referred to genetic counselling. Tumour tissue from the vulvar carcinoma, the PDAC and the PGL was analysed by targeted next-generation sequencing (NGS) of 161 cancer-related genes and by whole exome sequencing (WES). Peripheral blood was also examined by NGS and WES. These genetic analyses revealed germline polymorphisms in AXIN2 (NM_004655.4:c 0.2272 G>A; p.Ala758Thr), BRCA2 (NM_000059.3:c.9976 A>T; p.Lys3326Ter), NCOR1 (NM_006311.4:c 0.6544 G>A; p.Ala2182Thr) and SPTA1 (NM_003126.3:c 0.373 G>A; p.Ala125Thr) and somatic mutations of KRAS (NM_033360.3;c 0.35 G>A; p.Gly12Asp) and TP53 (NM_000546.5; c.602delT; p.Leu201CysfsTer46) in the PDAC and of TP53 (NM_000546.5; c 0.733 G>A; p.Gly245Ser) and TERT (NM_198253.2; c.-124 C>T; promotor region) in the vulvar carcinoma. Breast carcinoma tissue was not available for genetic analysis. The results of the genetic analyses did not explain the presence of multiple tumours in this patient, despite a slightly increased risk of breast cancer associated with the identified BRCA2 polymorphism. To our knowledge, this is the first report of the synchronous occurrence of PDAC and PGL. This case emphasizes the importance of thorough macroscopic examination of pancreatic resection specimens, as coexisting neoplasms may otherwise be missed.

Actionable genomic variants in 6045 participants from the Qatar Genome Program

In a clinical setting, DNA sequencing can uncover findings unrelated to the purpose of genetic evaluation. The American College of Medical Genetics and Genomics (ACMG) recommends the evaluation and reporting of 59 genes from clinic genomic sequencing. While the prevalence of secondary findings is available from large population studies, these data lack Arab and other Middle Eastern populations. The Qatar Genome Program (QGP) generates whole-genome sequencing (WGS) data and combines it with phenotypic information to create a comprehensive database for studying the Qatari and wider Arab and Middle Eastern populations at the molecular level. This study identified and analyzed medically actionable variants in the 59 ACMG genes using WGS data from 6045 QGP participants. Our results identified a total of 60 pathogenic and likely pathogenic variants in 25 ACMG genes in 141 unique individuals. Overall, 2.3% of the QGP sequenced participants carried a pathogenic or likely pathogenic variant in one of the 59 ACMG genes. We evaluated the QGP phenotype-genotype association of additional nonpathogenic ACMG variants. These variants were found in patients from the Hamad Medical Corporation or reported incidental findings data in Qatar. We found a significant phenotype association for two variants, c.313+3A>C in LDLR, and c.58C>T (p.Gln20*) in the TPM1.

Risks and Function of Breast Cancer Susceptibility Alleles

Family history remains one of the strongest risk factors for breast cancer. It is well established that women with a first-degree relative affected by breast cancer are twice as likely to develop the disease themselves. Twins studies indicate that this is most likely due to shared genetics rather than shared epidemiological/lifestyle risk factors. Linkage and targeted sequencing studies have shown that rare high- and moderate-penetrance germline variants in genes involved in the DNA damage response (DDR) including BRCA1, BRCA2, PALB2, ATM, and TP53 are responsible for a proportion of breast cancer cases. However, breast cancer is a heterogeneous disease, and there is now strong evidence that different risk alleles can predispose to different subtypes of breast cancer. Here, we review the associations between the different genes and subtype-specificity of breast cancer based on the most comprehensive genetic studies published. Genome-wide association studies (GWAS) have also been used to identify an additional hereditary component of breast cancer, and have identified hundreds of common, low-penetrance susceptibility alleles. The combination of these low penetrance risk variants, summed as a polygenic risk score (PRS), can identify individuals across the spectrum of disease risk. However, there remains a substantial bottleneck between the discovery of GWAS-risk variants and their contribution to tumorigenesis mainly because the majority of these variants map to the non-protein coding genome. A range of functional genomic approaches are needed to identify the causal risk variants and target susceptibility genes and establish their underlying role in disease biology. We discuss how the application of these multidisciplinary approaches to understand genetic risk for breast cancer can be used to identify individuals in the population that may benefit from clinical interventions including screening for early detection and prevention, and treatment strategies to reduce breast cancer-related mortalities.

Differences in Ovarian and Other Cancers Risks by Population and BRCA Mutation Location

Hereditary breast and ovarian cancer is caused by a germline mutation in BRCA1 or BRCA2 genes. The frequency of germline BRCA1/2 gene mutation carriers and the ratio of germline BRCA1 to BRCA2 mutations in BRCA-related cancer patients vary depending on the population. Genotype and phenotype correlations have been reported in BRCA mutant families, however, the correlations are rarely used for individual risk assessment and management. BRCA genetic testing has become a companion diagnostic for PARP inhibitors, and the number of families with germline BRCA mutation identified is growing rapidly. Therefore, it is expected that analysis of the risk of developing cancer will be possible in a large number of BRCA mutant carriers, and there is a possibility that personal and precision medicine for the carriers with specific common founder mutations will be realized. In this review, we investigated the association of ovarian cancer risk and BRCA mutation location, and differences of other BRCA-related cancer risks by BRCA1/2 mutation, and furthermore, we discussed the difference in the prevalence of germline BRCA mutation in ovarian cancer patients. As a result, although there are various discussions, there appear to be differences in ovarian cancer risk by population and BRCA mutation location. If it becomes possible to estimate the risk of developing BRCA-related cancer for each BRCA mutation type, the age at risk-reducing salpingo-oophorectomy can be determined individually. The decision would bring great benefits to young women with germline BRCA mutations.

The Genetic Analyses of French Canadians of Quebec Facilitate the Characterization of New Cancer Predisposing Genes Implicated in Hereditary Breast and/or Ovarian Cancer Syndrome Families

The French Canadian population of the province of Quebec has been recognized for its contribution to research in medical genetics, especially in defining the role of heritable pathogenic variants in cancer predisposing genes. Multiple carriers of a limited number of pathogenic variants in BRCA1 and BRCA2, the major risk genes for hereditary breast and/or ovarian cancer syndrome families, have been identified in French Canadians, which is in stark contrast to the array of over 2000 different pathogenic variants reported in each of these genes in other populations. As not all such cancer syndrome families are explained by BRCA1 and BRCA2, newly proposed gene candidates identified in other populations have been investigated for their role in conferring risk in French Canadian cancer families. For example, multiple carriers of distinct variants were identified in PALB2 and RAD51D. The unique genetic architecture of French Canadians has been attributed to shared ancestry due to common ancestors of early settlers of this population with origins mainly from France. In this review, we discuss the merits of genetically characterizing cancer predisposing genes in French Canadians of Quebec. We focused on genes that have been implicated in hereditary breast and/or ovarian cancer syndrome families as they have been the most thoroughly characterized cancer syndromes in this population. We describe how genetic analyses of French Canadians have facilitated: (i) the classification of variants in BRCA1 and BRCA2; (ii) the identification and classification of variants in newly proposed breast and/or ovarian cancer predisposing genes; and (iii) the identification of a new breast cancer predisposing gene candidate, RECQL. The genetic architecture of French Canadians provides a unique opportunity to evaluate new candidate cancer predisposing genes regardless of the population in which they were identified.

Whole Exome Sequencing reveals NOTCH1 mutations in anaplastic large cell lymphoma and points to Notch both as a key pathway and a potential therapeutic target

Patients diagnosed with Anaplastic Large Cell Lymphoma (ALCL) are still treated with toxic multi-agent chemotherapy and as many as 25-50% of patients relapse. To understand disease pathology and to uncover novel targets for therapy, Whole-Exome Sequencing (WES) of Anaplastic Lymphoma Kinase (ALK)+ ALCL was performed as well as Gene-Set Enrichment Analysis. This revealed that the T-cell receptor (TCR) and Notch pathways were the most enriched in mutations. In particular, variant T349P of NOTCH1, which confers a growth advantage to cells in which it is expressed, was detected in 12% of ALK+ and ALK- ALCL patient samples. Furthermore, we demonstrate that NPM-ALK promotes NOTCH1 expression through binding of STAT3 upstream of NOTCH1. Moreover, inhibition of NOTCH1 with γ-secretase inhibitors (GSIs) or silencing by shRNA leads to apoptosis; co-treatment in vitro with the ALK inhibitor Crizotinib led to additive/synergistic anti-tumour activity suggesting this may be an appropriate combination therapy for future use in the circumvention of ALK inhibitor resistance. Indeed, Crizotinib-resistant and sensitive ALCL were equally sensitive to GSIs. In conclusion, we show a variant in the extracellular domain of NOTCH1 that provides a growth advantage to cells and confirm the suitability of the Notch pathway as a second-line druggable target in ALK+ ALCL.

Novel and recurrent BRCA1/BRCA2 germline mutations in patients with breast/ovarian cancer: a series from the south of Tunisia

Background

The incidence of breast cancer (BC) and/or ovarian cancer (OC) is increasing in Tunisia especially in young women and mostly those with family history. However, the spectrum of BRCA mutations remains little explored in Tunisian patients in particular in the southern region.

Methods

We sequenced the entire coding regions of BRCA1and BRCA2 genes using next generation sequencing (NGS) in 134 selected patients with BC and/or OC.

Results

Among the 134 patients, 19 (14.17%) carried pathogenic mutations (10 are BRCA1 mutation carriers and 9 are BRCA2 mutation carriers) that are mainly frameshift index (76.9%). Interestingly, 5 out of the 13 variants (38.46%) were found at least twice in unrelated patients, as the c.1310-1313 delAAGA in BRCA2 and the c.5030_5033 delCTAA that has been identified in 4/98 BC patients and in 3/15 OC patients from unrelated families with strong history of cancer. Besides recurrent mutations, 6 variant (4 in BRCA1 and 2 in BRCA2) were not reported previously. Furthermore, 3 unrelated patients carried the VUS c.9976A > T, (K3326*) in BRCA2 exon 27. BRCA carriers correlated significantly with tumor site (p = 0.029) and TNBC cases (p = 0.008). In the groups of patients aged between 31 and 40, and 41–50 years, BRCA1 mutations occurred more frequently in patients with OC than those with BC, and conversely BRCA2 carriers are mostly affected with BC (p = 0.001, and p = 0.044 respectively).

Conclusions

The overall frequency of the BRCA germline mutations was 14.17% in patients with high risk of breast/ovarian cancer. We identified recurrent mutations as the c.1310_1313 delAAGA in BRCA2 gene and the c.5030_5033 delCTAA in BRCA1 gene that were found in 4% and 20% of familial BC and OC respectively. Our data will contribute in the implementation of genetic counseling and testing for families with high-risk of BC and/or OC.

Application of Multilayer Evidence for Annotation of C-Terminal BRCA2 Variants

Simple Summary

The potential pathogenic role of germline BRCA2 c.9976A>T and c.10095delinsGAATTATATCT was evaluated in hereditary breast and ovarian cancer (HBOC) patients by investigating 2491 probands and verified in an independent cohort of 122,209 patients. Although the c.10095delinsGAATTATATCT variant was more prevalent among patients compared to control populations, no increased risk for cancer was found. No association between c.9976A>T and clinicopathological parameters or elevated risk for HBOC cases was detected. However, lung cancer was more prevalent in families carrying c.9976A>T compared to pathogenic BRCA1/BRCA2 carrier families. An increased frequency of pancreatic cancer was found in families where c.9976A>T occurred together with other pathogenic BRCA1 variants. The C-terminal stop codon variants showed no association with other pathogenic BRCA2 variants. No loss of heterozygosity (LOH) in tumor tissue and no allelic imbalance in RNA level were confirmed. The c.9976A>T variant may be considered as a potential risk for lung cancer, and a potential modifying factor in pancreatic cancer when it occurs along with the pathogenic BRCA1 variant, although this observation should be validated in a larger sample cohort.

Abstract

The clinical relevance of the BRCA2 C-terminal stop codon variants is controversial. The pathogenic role of the germline BRCA2 c.9976A>T and c.10095delinsGAATTATATCT variants in hereditary breast and ovarian cancer (HBOC) patients was evaluated. An association with clinicopathological parameters was performed in 2491 independent probands diagnosed with HBOC and in 122,209 cancer patients reported earlier. Loss-of-heterozygosity (LOH) in tumor samples and allelic imbalance in RNA extracted from peripheral blood cells were investigated. Neither c.10095delinsGAATTATATCT or c.9976A>T variants showed significant association with clinicopathological parameters or elevated risk for HBOC-associated tumors. Lung cancer was more prevalent in families carrying the c.9976A>T variant compared to pathogenic BRCA1 or BRCA2 carrier families. An increased prevalence of pancreatic cancer was found in families where c.9976A>T occurred together with other pathogenic BRCA1 variants. An increased risk for familial pancreatic, lung and upper aero-digestive tract cancers was confirmed in the validation set. Regarding BRCA2 C-terminal variants, no linkage with other pathogenic BRCA2 variants, no LOH in tumor tissue and no allelic imbalance in RNA level were confirmed. The c.9976A>T variant may be considered as a potential risk for lung cancer, and a potential modifying factor in pancreatic cancer when it occurs along with the pathogenic BRCA1 variant, although this observation should be validated in a larger sample cohort.

K3326X and Other C-Terminal BRCA2 Variants Implicated in Hereditary Cancer Syndromes: A Review

Simple Summary

The cancer associated protein BRCA2 is the subject of intense continual study. Because of this, new insights into the relation of specific variants of this gene and cancer are regularly generated. These discoveries shed light on cancer risk and management for patients carrying these mutations. Additionally, new techniques for variant discovery and investigation are developed and tested, further enhancing scientific and clinical understanding of this key protein. In this review we will investigate the recent literature associated with variants in the C-terminus of BRCA2 and their effect on health and cancer predisposition.

Abstract

Whole genome analysis and the search for mutations in germline and tumor DNAs is becoming a major tool in the evaluation of risk as well as the management of hereditary cancer syndromes. Because of the identification of cancer predisposition gene panels, thousands of such variants have been catalogued yet many remain unclassified, presenting a clinical challenge for the management of hereditary cancer syndromes. Although algorithms exist to estimate the likelihood of a variant being deleterious, these tools are rarely used for clinical decision-making. Here, we review the progress in classifying K3326X, a rare truncating variant on the C-terminus of BRCA2 and review recent literature on other novel single nucleotide polymorphisms, SNPs, on the C-terminus of the protein, defined in this review as the portion after the final BRC repeat (amino acids 2058–3418).

Gene panel screening for insight towards breast cancer susceptibility in different ethnicities

African American breast cancer genetics is less understood compared to European American breast cancer susceptibility. Despite the many advantages of gene panel screening, studies investigating African American inherited breast cancer risk and comparing variant contributions between ethnicities are infrequent. Thus, 97 breast cancer-affected individuals of African and European descent from the Alabama Hereditary Cancer Cohort were screened using the research-based gene-panel, B.O.P. (Breast, Ovarian, and Prostate cancer). Upon sequencing and bioinformatic processing, rare coding variants in 14 cancer susceptibility genes were categorized according to the American College of Medical Genetics guidelines and compared between ethnicities. Overall, 107 different variants were identified, the majority of which were benign/likely benign. A pathogenic/likely pathogenic variant was detected in 8.6% and 6.5% of African American and European American cases, respectively, which was not statistically significant. However, African Americans were more likely to have at least one variant of uncertain significance (VUS; p-value 0.006); they also had significantly more VUSs in BRCA1/2 compared to European Americans (p-value 0.015). Additionally, 51.4% of African Americans and 32.3% of European Americans harbored multiple rare variants, and African Americans were more likely to have at least one VUS and one benign/likely benign variant (p-value 0.032), as well as multiple benign/likely benign variants (p-value 0.089). Moreover, of the 15 variants detected in multiple breast cancer cases, ATM c.2289T>C (p.F763L), a VUS, along with two likely benign variants, BRCA2 c.2926_2927delinsAT (p.S976I) and RAD51D c.251T>A (p.L84H), were determined to be associated with African American breast cancer risk when compared to ethnic-specific controls. Ultimately, B.O.P. screening provides essential insight towards the variant contributions in clinically relevant cancer susceptibility genes and differences between ethnicities, stressing the need for future research to elucidate inherited breast cancer risk.

Germline Sequencing DNA Repair Genes in 5545 Men With Aggressive and Nonaggressive Prostate Cancer

BACKGROUND

There is an urgent need to identify factors specifically associated with aggressive prostate cancer (PCa) risk. We investigated whether rare pathogenic, likely pathogenic, or deleterious (P/LP/D) germline variants in DNA repair genes are associated with aggressive PCa risk in a case-case study of aggressive vs nonaggressive disease.

METHODS

Participants were 5545 European-ancestry men, including 2775 nonaggressive and 2770 aggressive PCa cases, which included 467 metastatic cases (16.9%). Samples were assembled from 12 international studies and germline sequenced together. Rare (minor allele frequency < 0.01) P/LP/D variants were analyzed for 155 DNA repair genes. We compared single variant, gene-based, and DNA repair pathway-based burdens by disease aggressiveness. All statistical tests are 2-sided.

RESULTS

BRCA2 and PALB2 had the most statistically significant gene-based associations, with 2.5% of aggressive and 0.8% of nonaggressive cases carrying P/LP/D BRCA2 alleles (odds ratio [OR] = 3.19, 95% confidence interval [CI] = 1.94 to 5.25, P = 8.58 × 10-7) and 0.65% of aggressive and 0.11% of nonaggressive cases carrying P/LP/D PALB2 alleles (OR = 6.31, 95% CI = 1.83 to 21.68, P = 4.79 × 10-4). ATM had a nominal association, with 1.6% of aggressive and 0.8% of nonaggressive cases carrying P/LP/D ATM alleles (OR = 1.88, 95% CI = 1.10 to 3.22, P = .02). In aggregate, P/LP/D alleles within 24 literature-curated candidate PCa DNA repair genes were more common in aggressive than nonaggressive cases (carrier frequencies = 14.2% vs 10.6%, respectively; P = 5.56 × 10-5). However, this difference was non-statistically significant (P = .18) on excluding BRCA2, PALB2, and ATM. Among these 24 genes, P/LP/D carriers had a 1.06-year younger diagnosis age (95% CI = -1.65 to 0.48, P = 3.71 × 10-4).

CONCLUSIONS

Risk conveyed by DNA repair genes is largely driven by rare P/LP/D alleles within BRCA2, PALB2, and ATM. These findings support the importance of these genes in both screening and disease management considerations.

Literature Review of BARD1 as a Cancer Predisposing Gene with a Focus on Breast and Ovarian Cancers

Soon after the discovery of BRCA1 and BRCA2 over 20 years ago, it became apparent that not all hereditary breast and/or ovarian cancer syndrome families were explained by germline variants in these cancer predisposing genes, suggesting that other such genes have yet to be discovered. BRCA1-associated ring domain (BARD1), a direct interacting partner of BRCA1, was one of the earliest candidates investigated. Sequencing analyses revealed that potentially pathogenic BARD1 variants likely conferred a low-moderate risk to hereditary breast cancer, but this association is inconsistent. Here, we review studies of BARD1 as a cancer predisposing gene and illustrate the challenge of discovering additional cancer risk genes for hereditary breast and/or ovarian cancer. We selected peer reviewed research articles that focused on three themes: (i) sequence analyses of BARD1 to identify potentially pathogenic germline variants in adult hereditary cancer syndromes; (ii) biological assays of BARD1 variants to assess their effect on protein function; and (iii) association studies of BARD1 variants in family-based and case-control study groups to assess cancer risk. In conclusion, BARD1 is likely to be a low-moderate penetrance breast cancer risk gene.

Criteria of the German Consortium for Hereditary Breast and Ovarian Cancer for the Classification of Germline Sequence Variants in Risk Genes for Hereditary Breast and Ovarian Cancer

More than ten years ago, the German Consortium for Hereditary Breast and Ovarian Cancer (GC-HBOC) set up a panel of experts (VUS Task Force) which was tasked with reviewing the classifications of genetic variants reported by individual centres of the GC-HBOC to the central database in Leipzig and reclassifying them, where necessary, based on the most recent data. When it evaluates variants, the VUS Task Force must arrive at a consensus. The resulting classifications are recorded in a central database where they serve as a basis for ensuring the consistent evaluation of previously known and newly identified variants in the different centres of the GC-HBOC. The standardised VUS evaluation by the VUS Task Force is a key element of the recall system which has also been set up by the GC-HBOC. The system will be used to pass on information to families monitored and managed by GC-HBOC centres in the event that previously classified variants are reclassified based on new information. The evaluation algorithm of the VUS Task Force was compiled using internationally established assessment methods (IARC, ACMG, ENIGMA) and is presented here together with the underlying evaluation criteria used to arrive at the classification decision using a flow chart. In addition, the characteristics and special features of specific individual risk genes associated with breast and/or ovarian cancer are discussed in separate subsections. The URLs of relevant databases have also been included together with extensive literature references to provide additional information and cover the scope and dynamism of the current state of knowledge on the evaluation of genetic variants. In future, if criteria are updated based on new information, the update will be published on the website of the GC-HBOC ( https://www.konsortium-familiaerer-brustkrebs.de/ ).

Pathogenic Germline DNA Repair Gene and HOXB13 Mutations in Men With Metastatic Prostate Cancer

PURPOSE

Germline mutations in DNA repair (DR) genes and susceptibility genes CDKN2A and HOXB13 have previously been associated with prostate cancer (PC) incidence and/or progression. However, the role and prevalence of this class of mutations in metastatic PC (mPC) are not fully understood.

PATIENTS AND METHODS

To evaluate the frequency of pathogenic/likely pathogenic germline variants (PVs/LPVs) in men with mPC, this study sequenced 38 DR genes, CDKN2A, and HOXB13 in a predominantly white cohort of 317 patients with mPC. A PC registry at the University of Utah was used for patient sample acquisition and retrospective clinical data collection. Deep target sequencing allowed for germline and copy number variant analyses. Validated PVs/LPVs were integrated with clinical and demographic data for statistical correlation analyses.

RESULTS

All pathogenic variants were found in men self-reported as white, with a carrier frequency of 8.5% (DR genes, 7.3%; CDKN2A/HOXB13, 1.2%). Consistent with previous reports, mutations were most frequently identified in the breast cancer susceptibility gene BRCA2. It was also found that 50% of identified PVs/LPVs were categorized as founder mutations with European origins. Correlation analyses did not support a trend toward more advanced or earlier-onset disease in comparisons between carriers and noncarriers of deleterious DR or HOXB13 G84E mutations.

CONCLUSION

These findings demonstrate a lower prevalence of germline PVs/LPVs in an unselected, predominantly white mPC cohort than previously reported, which may have implications for the design of clinical trials testing targeted therapies. Larger studies in broad and diverse populations are needed to more accurately define the prevalence of germline mutations in men with mPC.

Skipping Nonsense to Maintain Function: The Paradigm of BRCA2 Exon 12

Germline nonsense and canonical splice site variants identified in disease-causing genes are generally considered as loss-of-function (LoF) alleles and classified as pathogenic. However, a fraction of such variants could maintain function through their impact on RNA splicing. To test this hypothesis, we used the alternatively spliced BRCA2 exon 12 (E12) as a model system because its in-frame skipping leads to a potentially functional protein. All E12 variants corresponding to putative LoF variants or predicted to alter splicing (n = 40) were selected from human variation databases and characterized for their impact on splicing in minigene assays and, when available, in patient lymphoblastoid cell lines. Moreover, a selection of variants was analyzed in a mouse embryonic stem cell-based functional assay. Using these complementary approaches, we demonstrate that a subset of variants, including nonsense variants, induced in-frame E12 skipping through the modification of splice sites or regulatory elements and, consequently, led to an internally deleted but partially functional protein. These data provide evidence, for the first time in a cancer-predisposition gene, that certain presumed null variants can retain function due to their impact on splicing. Further studies are required to estimate cancer risk associated with these hypomorphic variants. More generally, our findings highlight the need to exercise caution in the interpretation of putative LoF variants susceptible to induce in-frame splicing modifications. SIGNIFICANCE: This study presents evidence that certain presumed loss-of-function variants in a cancer predisposition gene can retain function due to their direct impact on RNA splicing.

Olaparib in patients with metastatic castration-resistant prostate cancer with DNA repair gene aberrations (TOPARP-B): a multicentre, open-label, randomised, phase 2 trial

BACKGROUND

Metastatic castration-resistant prostate cancer is enriched in DNA damage response (DDR) gene aberrations. The TOPARP-B trial aims to prospectively validate the association between DDR gene aberrations and response to olaparib in metastatic castration-resistant prostate cancer.

METHODS

In this open-label, investigator-initiated, randomised phase 2 trial following a selection (or pick-the-winner) design, we recruited participants from 17 UK hospitals. Men aged 18 years or older with progressing metastatic castration-resistant prostate cancer previously treated with one or two taxane chemotherapy regimens and with an Eastern Cooperative Oncology Group performance status of 2 or less had tumour biopsies tested with targeted sequencing. Patients with DDR gene aberrations were randomly assigned (1:1) by a computer-generated minimisation method, with balancing for circulating tumour cell count at screening, to receive 400 mg or 300 mg olaparib twice daily, given continuously in 4-week cycles until disease progression or unacceptable toxicity. Neither participants nor investigators were masked to dose allocation. The primary endpoint of confirmed response was defined as a composite of all patients presenting with any of the following outcomes: radiological objective response (as assessed by Response Evaluation Criteria in Solid Tumors 1.1), a decrease in prostate-specific antigen (PSA) of 50% or more (PSA50) from baseline, or conversion of circulating tumour cell count (from ≥5 cells per 7·5 mL blood at baseline to <5 cells per 7·5 mL blood). A confirmed response in a consecutive assessment after at least 4 weeks was required for each component. The primary analysis was done in the evaluable population. If at least 19 (43%) of 44 evaluable patients in a dose cohort responded, then the dose cohort would be considered successful. Safety was assessed in all patients who received at least one dose of olaparib. This trial is registered at ClinicalTrials.gov, NCT01682772. Recruitment for the trial has completed and follow-up is ongoing.

FINDINGS

711 patients consented for targeted screening between April 1, 2015, and Aug 30, 2018. 161 patients had DDR gene aberrations, 98 of whom were randomly assigned and treated (49 patients for each olaparib dose), with 92 evaluable for the primary endpoint (46 patients for each olaparib dose). Median follow-up was 24·8 months (IQR 16·7-35·9). Confirmed composite response was achieved in 25 (54·3%; 95% CI 39·0-69·1) of 46 evaluable patients in the 400 mg cohort, and 18 (39·1%; 25·1-54·6) of 46 evaluable patients in the 300 mg cohort. Radiological response was achieved in eight (24·2%; 11·1-42·3) of 33 evaluable patients in the 400 mg cohort and six (16·2%; 6·2-32·0) of 37 in the 300 mg cohort; PSA50 response was achieved in 17 (37·0%; 23·2-52·5) of 46 and 13 (30·2%; 17·2-46·1) of 43; and circulating tumour cell count conversion was achieved in 15 (53·6%; 33·9-72·5) of 28 and 13 (48·1%; 28·7-68·1) of 27. The most common grade 3-4 adverse event in both cohorts was anaemia (15 [31%] of 49 patients in the 300 mg cohort and 18 [37%] of 49 in the 400 mg cohort). 19 serious adverse reactions were reported in 13 patients. One death possibly related to treatment (myocardial infarction) occurred after 11 days of treatment in the 300 mg cohort.

INTERPRETATION

Olaparib has antitumour activity against metastatic castration-resistant prostate cancer with DDR gene aberrations, supporting the implementation of genomic stratification of metastatic castration-resistant prostate cancer in clinical practice.

FUNDING

Cancer Research UK, AstraZeneca, Prostate Cancer UK, the Prostate Cancer Foundation, the Experimental Cancer Medicine Centres Network, and the National Institute for Health Research Biomedical Research Centres.

Fine-mapping of 150 breast cancer risk regions identifies 191 likely target genes

Genome-wide association studies have identified breast cancer risk variants in over 150 genomic regions, but the mechanisms underlying risk remain largely unknown. These regions were explored by combining association analysis with in silico genomic feature annotations. We defined 205 independent risk-associated signals with the set of credible causal variants in each one. In parallel, we used a Bayesian approach (PAINTOR) that combines genetic association, linkage disequilibrium and enriched genomic features to determine variants with high posterior probabilities of being causal. Potentially causal variants were significantly over-represented in active gene regulatory regions and transcription factor binding sites. We applied our INQUSIT pipeline for prioritizing genes as targets of those potentially causal variants, using gene expression (expression quantitative trait loci), chromatin interaction and functional annotations. Known cancer drivers, transcription factors and genes in the developmental, apoptosis, immune system and DNA integrity checkpoint gene ontology pathways were over-represented among the highest-confidence target genes.

Treatment of Pediatric Glioblastoma with Combination Olaparib and Temozolomide Demonstrates 2-Year Durable Response

For pediatric patients with high-grade gliomas, standard-of-care treatment includes surgery, chemotherapy, and radiation therapy; however, most patients ultimately succumb to their disease. With advances in genomic characterization of pediatric high-grade gliomas, the use of targeted therapies in combination with current treatment modalities offer the potential to improve survival in this patient population. In this report, we present the case of a 3-year-old girl with glioblastoma who continues to experience an exceptional and durable response (>2 years) to the poly (ADP-ribose) polymerase (PARP) inhibitor olaparib. Our patient presented with persistent and progressive seizure activity that upon workup was the result of a large heterogeneously enhancing, mixed cystic and solid mass in the left frontal-parietal-temporal region. Histopathologic analysis of resected tumor tissue confirmed the diagnosis of glioblastoma, and comprehensive genomic profiling demonstrated absence of any BRAF or H3F3A mutations. Genomic profiling, however, did reveal a probable germline heterozygous BRCA2 Lys3326Ter (K3226*) nonsense variant. After debulking surgery, the patient received standard-of-care treatment with radiation and temozolomide. Nine months later the PARP inhibitor olaparib was administered in combination with temozolomide for 16 cycles. This regimen was well tolerated by the patient and serial imaging showed reduction in tumor size. Since completion of the regimen, the patient remains neurologically intact with no evidence of tumor recurrence. To our knowledge, this represents the first case of a pediatric glioblastoma that maintains a durable response to a therapeutic strategy that included the PARP inhibitor olaparib and more generally highlights the potential clinical utility of incorporating these agents into the treatment of pediatric high-grade gliomas. KEY POINTS: Germline mutations detected in pediatric gliomas may represent a cancer predisposition syndrome. Integrating molecular testing into routine clinical care for pediatric patients with glioma is critical to identify therapeutic targets and patients with a cancer predisposition syndrome. Patients with glioma with defects in DNA repair pathway components (e.g., BRCA1/2) may show increased responsiveness to poly (ADP-ribose) polymerase (PARP) inhibitors. Combining PARP inhibitors with temozolomide (standard-of-care treatment) revealed no adverse events or toxicities over the course of 18 months.

Towards controlled terminology for reporting germline cancer susceptibility variants: an ENIGMA report

The vocabulary currently used to describe genetic variants and their consequences reflects many years of studying and discovering monogenic disease with high penetrance. With the recent rapid expansion of genetic testing brought about by wide availability of high-throughput massively parallel sequencing platforms, accurate variant interpretation has become a major issue. The vocabulary used to describe single genetic variants in silico, in vitro, in vivo and as a contributor to human disease uses terms in common, but the meaning is not necessarily shared across all these contexts. In the setting of cancer genetic tests, the added dimension of using data from genetic sequencing of tumour DNA to direct treatment is an additional source of confusion to those who are not experienced in cancer genetics. The language used to describe variants identified in cancer susceptibility genetic testing typically still reflects an outdated paradigm of Mendelian inheritance with dichotomous outcomes. Cancer is a common disease with complex genetic architecture; an improved lexicon is required to better communicate among scientists, clinicians and patients, the risks and implications of genetic variants detected. This review arises from a recognition of, and discussion about, inconsistencies in vocabulary usage by members of the ENIGMA international multidisciplinary consortium focused on variant classification in breast-ovarian cancer susceptibility genes. It sets out the vocabulary commonly used in genetic variant interpretation and reporting, and suggests a framework for a common vocabulary that may facilitate understanding and clarity in clinical reporting of germline genetic tests for cancer susceptibility.

Insights into BRCA Cancer Predisposition from Integrated Germline and Somatic Analyses in 7632 Cancers

Background

It is often assumed any cancer in a germline BRCA1 or BRCA2 (collectively termed BRCA) mutation carrier was caused by that mutation. It is also often assumed the occurrence of breast or ovarian cancer in an individual with a variant of uncertain significance (VUS) suggests the VUS is pathogenic. These assumptions have profound management implications for cancer patients and healthy individuals.

Methods

We compared the frequency of BRCA mutations, allele loss, and Signature 3 in 7632 individuals with 28 cancers and 1000 population controls. Because only increased frequency was the focus of the study, all statistical tests were one-sided.

Results

Individuals with breast or ovarian cancer had increased germline BRCA pathogenic mutation frequencies compared to controls (P = 1.0x10⁻¹⁰ and P = 1.4x10⁻³⁴, respectively). There was no increase in other cancer types. Wild-type allele loss and Signature 3 were statistically significantly higher in breast and ovarian cancers with BRCA mutations compared with other cancers with BRCA mutations (P = 5.1x10⁻¹⁰ and P = 3.7x10⁻⁹) and cancers without BRCA mutations (P = 2.8x10⁻⁵³ and P = 1.0x10⁻¹³⁴). There was no difference between non-breast and non-ovarian cancers with BRCA mutations and cancers without BRCA mutations. Allele loss and Signature 3 were statistically significantly higher in breast and ovarian cancers in individuals with BRCA pathogenic mutations compared to those with VUS (P = 3.8x10⁻¹⁷ and P = 1.6x10⁻⁸) or benign variants (P = 1.2x10⁻²⁸ and P = 2.2x10⁻¹⁰). There was no difference between individuals with BRCA VUS and those with benign variants.

Conclusions

These data show that non-breast and non-ovarian cancers in individuals with germline BRCA pathogenic mutations are often not causally related to the mutation and that BRCA VUS are highly unlikely to be pathogenic. These results should reduce inappropriate management of germline BRCA information.

Selecting variants of unknown significance through network-based gene-association significantly improves risk prediction for disease-control cohorts

Variants of unknown/uncertain significance (VUS) pose a huge dilemma in current genetic variation screening methods and genetic counselling. Driven by methods of next generation sequencing (NGS) such as whole exome sequencing (WES), a plethora of VUS are being detected in research laboratories as well as in the health sector. Motivated by this overabundance of VUS, we propose a novel computational methodology, termed VariantClassifier (VarClass), which utilizes gene-association networks and polygenic risk prediction models to shed light into this grey area of genetic variation in association with disease. VarClass has been evaluated using numerous validation steps and proves to be very successful in assigning significance to VUS in association with specific diseases of interest. Notably, using VUS that are deemed significant by VarClass, we improved risk prediction accuracy in four large case-studies involving disease-control cohorts from GWAS as well as WES, when compared to traditional odds ratio analysis. Biological interpretation of selected high scoring VUS revealed interesting biological themes relevant to the diseases under investigation. VarClass is available as a standalone tool for large-scale data analyses, as well as a web-server with additional functionalities through a user-friendly graphical interface.

Genetic Testing to Guide Risk-Stratified Screens for Breast Cancer

Breast cancer screening modalities and guidelines continue to evolve and are increasingly based on risk factors, including genetic risk and a personal or family history of cancer. Here, we review genetic testing of high-penetrance hereditary breast and ovarian cancer genes, including BRCA1 and BRCA2, for the purpose of identifying high-risk individuals who would benefit from earlier screening and more sensitive methods such as magnetic resonance imaging. We also consider risk-based screening in the general population, including whether every woman should be genetically tested for high-risk genes and the potential use of polygenic risk scores. In addition to enabling early detection, the results of genetic screens of breast cancer susceptibility genes can be utilized to guide decision-making about when to elect prophylactic surgeries that reduce cancer risk and the choice of therapeutic options. Variants of uncertain significance, especially missense variants, are being identified during panel testing for hereditary breast and ovarian cancer. A finding of a variant of uncertain significance does not provide a basis for increased cancer surveillance or prophylactic procedures. Given that variant classification is often challenging, we also consider the role of multifactorial statistical analyses by large consortia and functional tests for this purpose.

BRCA Challenge: BRCA Exchange as a global resource for variants in BRCA1 and BRCA2

The BRCA Challenge is a long-term data-sharing project initiated within the Global Alliance for Genomics and Health (GA4GH) to aggregate BRCA1 and BRCA2 data to support highly collaborative research activities. Its goal is to generate an informed and current understanding of the impact of genetic variation on cancer risk across the iconic cancer predisposition genes, BRCA1 and BRCA2. Initially, reported variants in BRCA1 and BRCA2 available from public databases were integrated into a single, newly created site, www.brcaexchange.org. The purpose of the BRCA Exchange is to provide the community with a reliable and easily accessible record of variants interpreted for a high-penetrance phenotype. More than 20,000 variants have been aggregated, three times the number found in the next-largest public database at the project’s outset, of which approximately 7,250 have expert classifications. The data set is based on shared information from existing clinical databases—Breast Cancer Information Core (BIC), ClinVar, and the Leiden Open Variation Database (LOVD)—as well as population databases, all linked to a single point of access. The BRCA Challenge has brought together the existing international Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA) consortium expert panel, along with expert clinicians, diagnosticians, researchers, and database providers, all with a common goal of advancing our understanding of BRCA1 and BRCA2 variation. Ongoing work includes direct contact with national centers with access to BRCA1 and BRCA2 diagnostic data to encourage data sharing, development of methods suitable for extraction of genetic variation at the level of individual laboratory reports, and engagement with participant communities to enable a more comprehensive understanding of the clinical significance of genetic variation in BRCA1 and BRCA2.

The goal of this study and paper has been to develop an international resource to generate an informed and current understanding of the impact of genetic variation on cancer risk across the cancer predisposition genes, BRCA1 and BRCA2. Reported variants in BRCA1 and BRCA2 available from public databases were integrated into a single, newly created site, www.brcaexchange.org, to provide a reliable and easily accessible record of variants interpreted for a high-penetrance phenotype.

Germline BRCA1 and BRCA2 deleterious mutations and variants of unknown clinical significance associated with breast/ovarian cancer: a report from North India

Background

The spectrum of BRCA mutations that predispose to development of breast/ovarian cancer in Indian population remains unexplored. We report incidence and various types of pathogenic, likely pathogenic and variants of unknown significance (VUS) mutations in BRCA1 and BRCA2 genes observed at a tertiary cancer center in North India.

Materials and methods

A total of 206 unrelated breast and/or ovarian cancer patients, who met the National Comprehensive Cancer Network (NCCN) guidelines for genetic testing, were screened for germline BRCA1/BRCA 2 mutations on high-throughput sequencing platform; large genomic rearrangements were assessed by multiple ligation probe assay. Mutations were mined in mutational databases, PubMed, and discerned into classes. Furthermore, the clinicopathological correlation of BRCA mutation status with prognostic markers in breast cancer and tumor histology in ovarian cancer was performed.

Results

In total, 45/206 and 17/206 cases showed positivity for BRCA1 and BRCA2 mutations, respectively, whereas 1/206 was positive for a mutation in both the genes. Altogether, 33 distinct BRCA1 mutations were observed, among which 27 were deleterious (12 frameshifts, 8 nonsense, 1 missense, 3 splice-site variants, 2 big deletions and 1 large duplication) and 6 were VUS. Five novel BRCA1 mutations (c.541G>T, c.1681delT, c.2295delG, c.4915C>T and exon 23 deletion) were identified. Seven mutations (c.2214_2215insT, c.2295delG, c.3607C>T,c.4158_4162delCTCTC, c.4571C>A, splicesite_3 (C>T) and exon 21–23 duplication) occurred more than once, whereas 16 distinct BRCA2 mutations were noted – 9 were lethal (6 frameshifts, 2 nonsense and 1 big deletion) and 7 VUS. One unique pathogenic BRCA2 mutation (c.932_933insT) was recognized. Two mutations (c.9976A>T and c.10089A>G) recurred twice. No significant difference in hormone receptor status was observed among BRCA1 carriers, BRCA2 carriers and noncarriers.

Conclusion

We have documented various pathogenic and VUS mutations in BRCA1 and BRCA2 genes observed in the cohort. Six novel mutations were identified. The knowledge shared would assist genetic testing in enabling more focused site-specific screening for mutations in biological relatives.

Derivation of Breast Cancer Cell Lines Under Physiological (5%) Oxygen Concentrations

Background: Most human breast cancer cell lines currently in use were developed and are cultured under ambient (21%) oxygen conditions. While this is convenient in practical terms, higher ambient oxygen could increase oxygen radical production, potentially modulating signaling pathways. We have derived and grown a series of four human breast cancer cell lines under 5% oxygen, and have compared their properties to those of established breast cancer lines growing under ambient oxygen.

Methods: Cell lines were characterized in terms of appearance, cellular DNA content, mutation spectrum, hormone receptor status, pathway utilization and drug sensitivity.

Results: Three of the four lines (NZBR1, NZBR2, and NZBR4) were triple negative (ER-, PR-, HER2-), with NZBR1 also over-expressing EGFR. NZBR3 was HER2+ and ER+ and also over-expressed EGFR. Cell lines grown in 5% oxygen showed increased expression of the hypoxia-inducible factor 1 (HIF-1) target gene carbonic anhydrase 9 (CA9) and decreased levels of ROS. As determined by protein phosphorylation, NZBR1 showed low AKT pathway utilization while NZBR2 and NZBR4 showed low p70S6K and rpS6 pathway utilization. The lines were characterized for sensitivity to 7-hydroxytamoxifen, doxorubicin, paclitaxel, the PI3K inhibitor BEZ235 and the HER inhibitors lapatinib, afatinib, dacomitinib, and ARRY-380. In some cases they were compared to established breast cancer lines. Of particular note was the high sensitivity of NZBR3 to HER inhibitors. The spectrum of mutations in the NZBR lines was generally similar to that found in commonly used breast cancer cell lines but TP53 mutations were absent and mutations in EVI2B, LRP1B, and PMS2, which have not been reported in other breast cancer lines, were detected. The results suggest that the properties of cell lines developed under low oxygen conditions (5% O₂) are similar to those of commonly used breast cancer cell lines. Although reduced ROS production and increased HIF-1 activity under 5% oxygen can potentially influence experimental outcomes, no difference in sensitivity to estrogen or doxorubicin was observed between cell lines cultured in 5 vs. 21% oxygen.

Rare Variants in Known Susceptibility Loci and Their Contribution to Risk of Lung Cancer

BACKGROUND

Genome-wide association studies are widely used to map genomic regions contributing to lung cancer (LC) susceptibility, but they typically do not identify the precise disease-causing genes/variants. To unveil the inherited genetic variants that cause LC, we performed focused exome-sequencing analyses on genes located in 121 genome-wide association study-identified loci previously implicated in the risk of LC, chronic obstructive pulmonary disease, pulmonary function level, and smoking behavior.

METHODS

Germline DNA from 260 case patients with LC and 318 controls were sequenced by utilizing VCRome 2.1 exome capture. Filtering was based on enrichment of rare and potential deleterious variants in cases (risk alleles) or controls (protective alleles). Allelic association analyses of single-variant and gene-based burden tests of multiple variants were performed. Promising candidates were tested in two independent validation studies with a total of 1773 case patients and 1123 controls.

RESULTS

We identified 48 rare variants with deleterious effects in the discovery analysis and validated 12 of the 43 candidates that were covered in the validation platforms. The top validated candidates included one well-established truncating variant, namely, BRCA2, DNA repair associated gene (BRCA2) K3326X (OR = 2.36, 95% confidence interval [CI]: 1.38-3.99), and three newly identified variations, namely, lymphotoxin beta gene (LTB) p.Leu87Phe (OR = 7.52, 95% CI: 1.01-16.56), prolyl 3-hydroxylase 2 gene (P3H2) p.Gln185His (OR = 5.39, 95% CI: 0.75-15.43), and dishevelled associated activator of morphogenesis 2 gene (DAAM2) p.Asp762Gly (OR = 0.25, 95% CI: 0.10-0.79). Burden tests revealed strong associations between zinc finger protein 93 gene (ZNF93), DAAM2, bromodomain containing 9 gene (BRD9), and the gene LTB and LC susceptibility.

CONCLUSION

Our results extend the catalogue of regions associated with LC and highlight the importance of germline rare coding variants in LC susceptibility.

Association of BRCA2 K3326* With Small Cell Lung Cancer and Squamous Cell Cancer of the Skin

Background

Most pathogenic mutations in the BRCA2 gene carry a high risk of hereditary breast and ovarian cancer (HBOC). However, a stop-gain mutation, K3326* (rs11571833), confers risk of lung cancer and cancers of the upper-aero-digestive tract but only a modest risk of breast or ovarian cancer. The Icelandic population provides an opportunity for comprehensive characterization of the cancer risk profiles of K3326* and HBOC mutations because a single mutation, BRCA2 999del5, is responsible for almost all BRCA2-related HBOC in the population.

Methods

Genotype information on 43 641 cancer patients and 370 971 control subjects from Iceland, the Netherlands, and the United States was used to assess the cancer risk profiles of K3326* and BRCA2 999del5. BRCA2 expression was assessed using RNAseq data from blood (n = 2233), as well as 52 tissues reported in the GTEx database.

Results

The cancer risks associated with K3326* are fundamentally different from those associated with 999del5. We report for the first time an association between K3326* and small cell lung cancer (odds ratio [OR] = 2.06, 95% confidence interval [CI] = 1.35 to 3.16) and squamous cell carcinoma of the skin (OR = 1.69, 95% CI = 1.26 to 2.26). Individuals homozygous for K3326* reach old age and have children. Unlike BRCA2 999del5, the K3326* allele does not affect the level of BRCA2 transcripts, and the allele is expressed to the same extent as the wild-type allele.

Conclusions

K3326* associates primarily with cancers that have strong environmental genotoxic risk factors. Expression of the K3326* allele suggests that a variant protein may be made that retains the DNA repair capabilities important to hormone-responsive tissues but may be less efficient in responding to genotoxic stress.

Whole Exome Sequencing Uncovers Germline Variants of Cancer-Related Genes in Sporadic Pheochromocytoma

Background

Pheochromocytomas (PCCs) show the highest degree of heritability in human neoplasms. However, despite the wide number of alterations until now reported in PCCs, it is likely that other susceptibility genes remain still unknown, especially for those PCCs not clearly syndromic.

Methods

Whole exome sequencing of tumor DNA was performed on a set of twelve PCCs clinically defined as sporadic.

Results

About 50% of PCCs examined had somatic mutations on the known susceptibility VHL, NF1, and RET genes. In addition to these driver events, mutations on SYNE1, ABCC10, and RAD54B genes were also detected. Moreover, extremely rare germline variants were present in half of the sporadic PCC samples analyzed, in particular variants of MAX and SAMD9L were detected in the germline of cases wild-type for mutations in the known susceptibility genes.

Conclusions

Additional somatic passenger mutations can be associated with known susceptibility VHL, NF1, and RET genes in PCCs, and a wide number of germline variants with still unknown clinical significance can be detected in these patients. Therefore, many efforts should be aimed to better define the pathogenetic role of all these germline variants for discovering novel potential therapeutic targets for this disease still orphan of effective treatments.

BRCA1 founder mutations and beyond in the Polish population: A single-institution BRCA1/2 next-generation sequencing study

Hereditary mutations in BRCA1/2 genes increase the risk of breast cancer by 60–80% and ovarian cancer by about 20–40% in female carriers. Detection of inherited mutations in asymptomatic carriers allows for the implementation of appropriate preventive measures. BRCA1/2 genotyping is also important for poly(adenosine diphosphate)-ribose polymerase (PARP) inhibitor administration. This work addresses the need for next-generation sequencing (NGS) technology for the detection of BRCA1/2 mutations in Poland where until recently mostly founder mutations have been tested, and whether BRCA diagnostics should be extended beyond the panel of founder mutations in this population. The study comprises 2931 patients who were referred for genetic counseling and tested for founder and recurrent mutations in BRCA1 (5382insC (c.5266dupC; p.Gln1756Profs), c.5370C>T (c.5251C>T; p.R1751*), 300T>G (c.181T>G; p.Cys61Gly), 185delAG (c.68_69delAG; p.Glu23Valfs), and 4153delA (c.4035delA; p.Glu1346Lysfs)) by high-resolution melting/Sanger sequencing. A total of 103 (3.5%) mutations were detected, including 53 (51%) in healthy subjects and 50 (49%) in cancer patients. Then, based on more stringent clinical and pedigree criteria, sequencing of all BRCA1/2 exons was performed in 454 (16%) patients without founder mutations by NGS, which detected 58 mutations (12.8%), 40 (8.8%) of which were pathogenic. In 14 (3.1%) subjects, variants of uncertain significance (VUS) were detected, and in four (0.9%) subjects, the detected mutations were benign. In total, 161 mutations were detected using our two-step algorithm (founder test and NGS), of which 64% were founder mutations, 25% were NGS-detected pathogenic mutations, 9% were VUS, and 2% were benign. In addition, 38 mutations not yet reported in the Polish population were detected. In total, founder mutations accounted for only 64% of all detected mutations, and the remaining mutations (36%) were dispersed across the BRCA1/2 gene sequences. Thus, in Poland, testing for constitutional mutations in BRCA1/2 should be carried out in two stages, where NGS is performed in qualifying subjects if founder mutations are not identified.

A Population of Heterogeneous Breast Cancer Patient-Derived Xenografts Demonstrate Broad Activity of PARP Inhibitor in BRCA1/2 Wild-Type Tumors

Background: Breast cancer patients who do not respond to neoadjuvant therapy have a poor prognosis. There is a pressing need for novel targets and models for preclinical testing. Here we report characterization of breast cancer patient-derived xenografts (PDX) largely generated from residual tumors following neoadjuvant chemotherapy.Experimental Design: PDXs were derived from surgical samples of primary or locally recurrent tumors. Normal and tumor DNA sequencing, RNASeq, and reverse phase protein arrays (RPPA) were performed. Phenotypic profiling was performed by determining efficacy of a panel of standard and investigational agents.Results: Twenty-six PDXs were developed from 25 patients. Twenty-two were generated from residual disease following neoadjuvant chemotherapy, and 24 were from triple-negative breast cancer (TNBC). These PDXs harbored a heterogeneous set of genomic alterations and represented all TNBC molecular subtypes. On RPPA, PDXs varied in extent of PI3K and MAPK activation. PDXs also varied in their sensitivity to chemotherapeutic agents. PI3K, mTOR, and MEK inhibitors repressed growth but did not cause tumor regression. The PARP inhibitor talazoparib caused dramatic regression in five of 12 PDXs. Notably, four of five talazoparib-sensitive models did not harbor germline BRCA1/2 mutations, but several had somatic alterations in homologous repair pathways, including ATM deletion and BRCA2 alterations.Conclusions: PDXs capture the molecular and phenotypic heterogeneity of TNBC. Here we show that PARP inhibition can have activity beyond germline BRCA1/2 altered tumors, causing regression in a variety of molecular subtypes. These models represent an opportunity for the discovery of rational combinations with targeted therapies and predictive biomarkers. Clin Cancer Res; 23(21); 6468-77. ©2017 AACR.

Association between the BRCA2 rs144848 polymorphism and cancer susceptibility: a meta-analysis

The BRCA2 gene plays an important role in cancer carcinogenesis, and polymorphisms in this gene have been associated with cancer risk. The BRCA2 rs144848 polymorphism has been associated with several cancers, but results have been inconsistent. In the present study, a meta-analysis was performed to assess the association between the rs144848 polymorphism and cancer risk. Literature was searched from the databases of PubMed, Embase and Google Scholar before April 2016. The fixed or random effects model was used to calculate pooled odd ratios on the basis of heterogeneity. Meta-regression, sensitivity analysis, subgroup analysis and publication bias assessment were also performed using STATA 11.0 software according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009. A total of 40 relevant studies from 30 publications including 34,911 cases and 48,329 controls were included in the final meta-analysis. Among them, 22 studies focused on breast cancer, seven on ovarian cancer, five on non-Hodgkin lymphoma, and the remaining six studies examined various other cancers. The meta-analysis results showed that there were significant associations between the rs144848 polymorphism and cancer risk in all genetic models. Stratified by cancer type, the rs144848 polymorphism was associated with non-Hodgkin lymphoma. Stratified by study design, the allele model was associated with breast cancer risk in population-based studies. The meta-analysis suggests that the BRCA2 rs144848 polymorphism may play a role in cancer risk. Further well-designed studies are warranted to confirm these results.

No Evidence for the Pathogenicity of the BRCA2 c.6937 + 594T>G Deep Intronic Variant: A Case-Control Analysis

BACKGROUND

The role of deep intronic variants in hereditary cancer susceptibility has been largely understudied. Previously, the BRCA2 c.6937 + 594T>G variant has been shown to preferentially promote the inclusion of a 95 nucleotide cryptic exon and to introduce a premature termination codon. Our objective was to further assess the pathogenicity of the BRCA2 c.6937 + 594T>G deep intronic variant.

PATIENTS AND METHODS

We examined the association between BRCA2 c.6937 + 594T>G and breast cancer (BC) risk in 464 BC cases and 497 noncancer controls from Puerto Rico.

RESULTS

The overall frequency of the G allele was 2.1% in this population. There was no association between the TG/GG genotypes and BC risk in the uncorrected model and after correcting for confounders. There was only one carrier of the GG genotype. This individual did not have personal or family history of cancer and did not meet the National Comprehensive Cancer Network criteria for hereditary cancer genetic testing.

CONCLUSIONS

Although previous work has demonstrated that the BRCA2 c.6937 + 594T>G variant affects splicing, this association study does not support a pathogenic role for the BRCA2 c.6937 + 594T>G intronic variant in breast and ovarian cancer syndrome susceptibility. Furthermore, it emphasizes the need to take into account multiple diverse populations in association studies for the assessment of variant pathogenicity.

Double Heterozygosity for BRCA1 Pathogenic Variant and BRCA2 Polymorphic Stop Codon K3326X: A Case Report in a Southern Italian Family

Here, we describe a patient with bilateral breast cancer and melanoma, and with a concomitant double variant, namely p.Gln563Ter in BRCA1 and p.Lys3326Ter in BRCA2. The BRCA2 p.Lys3326Ter (K3326X) (rs11571833) mutation identified in our patient is a debated substitution of thymidine for adenine which is currently regarded as benign polymorphism in main gene databases. Recent studies, however, describe this variant as associated with breast and ovarian tumors. Based on the observation of the cancer’s earliest age of onset in this subject, our purpose was to reevaluate this variant according to recent papers indicating a role of powerful modifier of the genetic penetrance. Genetic testing was performed in all consenting patient’s relatives, and in the collection of the clinical data particular attention was paid to the age of onset of the neoplasia. Following our observation that the our patient with double heterozygosis had an early age of onset for cancer similar to a few rare cases of double mutation for BRCA1 and BRCA2, we also performed an extensive review of the literature relative to patients carrying a double heterozygosity for both genes. In line with previous studies relative to the rare double heterozygosity in both BRCA1/2 genes, we found the earlier onset of breast cancer in our patient with both BRCA1/2 mutations with respect to other relatives carrying the single BRCA1 mutation. The presence of the second K3326X variant in our case induces a phenotype characterized by early onset of the neoplasia in a manner similar to the other cases of double heterozygosity previously described. Therefore, we suggest that during the genetic counseling, it should be recommendable to evaluate the presence of the K3326X variant in association with other pathogenic mutations.

A possible role of FANCM mutations in male breast cancer susceptibility: Results from a multicenter study in Italy

INTRODUCTION

Breast cancer (BC) in men is a rare disease, whose etiology appears to be associated with genetic factors. Inherited mutations in BRCA1/2 genes account for about 10-15% of all cases. FANCM, functionally linked to BRCA1/2, has been suggested as a novel BC susceptibility gene. Our aim was to test if FANCM germline mutations could further explain male BC (MBC) susceptibility.

METHODS

We screened the entire coding region of FANCM in 286 MBCs by a multi-gene panel analysis, and compared these data with available whole exome sequencing data from 415 men used as population controls. Moreover, we genotyped the two most frequent FANCM mutations (c.5101C>T and c.5791C>T) in 506 MBCs and 854 healthy male controls.

RESULTS

Two FANCM truncating mutations, the c.1432C>T (p.Arg478Ter) and c.1972C>T (p.Arg658Ter), were identified in two MBC cases (0.7%). When specifically considering cases at increased genetic risk for BC, FANCM mutation frequency raises up to 1%. One mutation, the c.2201_2202delCT (p.Ser734Terfs), was found among controls (0.24%). Mutation frequency in cases was higher than in controls, however this difference was not statistically significant. FANCM c.5101C>T was not present in any of the cases and controls analyzed, whereas FANCM c.5791C>T was found in two controls (0.23%).

CONCLUSION

Rare FANCM truncating mutations, other than c.5101C>T and c.5791C>T, may have a role in MBC susceptibility. The inclusion of FANCM in gene panels for research purpose would allow for the identification of a higher number of mutation carriers, thus helping estimate BC risk associated with FANCM mutations.

Immunotherapy for Prostate Cancer: Where We Are Headed

Prostate cancer is one of the most common malignant neoplasms in men worldwide, and is the fifth cause of cancer-related death. In recent years, a new generation of therapies have been approved for the management of metastatic disease. Moreover, the development of new immunotherapeutic drugs has become a novel frontier for the treatment of several tumor types; to date, numerous studies have investigated their potential activity, including in prostate cancer. In this article, we discuss the role of emerging immunotherapeutic drugs in prostate cancer patients.