Pathogenic Variants In BRCA2 Research Articles

EPCO-56. INHERITED PREDISPOSITION TO ADULT GLIOMAS: OVERVIEW OF THE CURRENT CLINICAL PRACTICE AND FUTURE RECOMMENDATIONS

Abstract Gliomas are the most common adult primary malignant brain tumor and occur in ages 45-65 years old. While most gliomas are sporadic in nature, a small portion is related to cancer predisposition syndromes (CPS), such as Li Fraumeni or Lynch syndromes. Given that 5–10% of patients will have a family history of glioma, there is currently an effort in identifying germline variants associated with gliomas. Additionally, with the advent of somatic tumor testing, it is possible to pick up suspected germline mutations in genes that cause CPS. Our experience includes a 32-year-old patient diagnosed with astrocytoma IDH mutant, Grade 2 who was found to have a BRAC1 mutation on somatic brain tumor testing. 10 years later, the patient was found with metastatic ovarian cancer and a germline BRAC1 mutation. Early identification of CPS can lead to early detection or prevention of malignancies in affected patients and relatives. However, gliomas are rarely the primary or presenting tumor of CPS, and guidance of CPS screening for these individuals is still lacking. Due to the increasing interest and importance of CPS testing in patients with glioma we have developed a collaborative protocol between our neuro-oncologists and genetic counselors aso that patients have access to germline testing. We propose that all patients with glioma at age of 50 or under, patients with strong family history of cancer including gliomas, and patients with suspected germline mutations based on tumoral somatic mutational profile should be referred to the genetic counselors. Our preliminary findings include 8 patients who completed germline genetic testing. Of these, one patient tested positive for a BRCA1 pathogenic variant. We are planning to continue to collect this data to better inform clinical practice.

Pathogenic variants in cancer susceptibility genes predispose to Ductal Carcinoma In situ of the breast.

To determine the relationship between germline pathogenic variants (PVs) in cancer predisposition genes and the risk of ductal carcinoma in situ (DCIS). Germline PV frequencies in breast cancer predisposition genes (ATM, BARD1, BRCA1, BRCA2, CDH1, CHEK2, PALB2, RAD51C, and RAD51D) were compared between DCIS cases and unaffected controls, and between DCIS and infiltrating ductal carcinoma (IDC) cases from a clinical-testing cohort (n=9,887), a population-based cohort (n=3,876) and the UK Biobank (n=2421). The risk of contralateral breast cancer for DCIS cases with PVs was estimated in the population-based cohort. Germline PVs were observed in 6.5% and 4.6% of women with DCIS in the clinical-testing and population-based cohorts, respectively. BRCA1, BRCA2, and PALB2 PVs frequencies were significantly lower among women with DCIS than IDC (clinical cohort: 2.8% vs. 5.7%; population-based cohort: 1.7% vs. 3.7%), whereas the PV frequencies for ATM and CHEK2 were similar. ATM, BRCA1, BRCA2, CHEK2, and PALB2 PVs were significantly associated with an increased risk of DCIS (OR>2.0), but only BRCA2 PVs were associated with high-risk (OR>4) in both cohorts. The cumulative incidence of contralateral breast cancer among carriers of PVs in high penetrance genes with DCIS was 23% over 15 years. The enrichment of PVs in ATM, BRCA1, BRCA2, CHEK2 and PALB2 among women with DCIS suggests that multigene panel testing may be appropriate for women with DCIS. Elevated risks of contralateral breast cancer in carriers of PVs in high penetrance genes with DCIS confirmed the utility of testing for surgical decision-making.

Reduced penetrance BRCA1 and BRCA2 pathogenic variants in clinical germline genetic testing

Prior studies have suggested the existence of reduced penetrance pathogenic variants (RPPVs) in BRCA1 and BRCA2 (BRCA) which pose challenges for patient counseling and care. Here, we sought to establish RPPVs as a new category of variants. Candidate BRCA RPPVs provided by two large clinical diagnostic laboratories were compiled to identify those with the highest likelihood of being a RPPV, based on concordant interpretations. Sixteen concordant candidate BRCA RPPVs across both laboratories were systematically assessed. RPPVs included missense, splice site, and frameshift variants. Our study establishes RPPVs as a new class of variants imparting a moderately increased risk of breast cancer, which impacts risk-informed cancer prevention strategies, and provides a framework to standardize interpretation and reporting of BRCA RPPVs. Further work to define clinically meaningful risk thresholds and categories for reporting BRCA RPPVs is needed to personalize cancer risks in conjunction with other risk factors.

Characteristics of Chinese breast cancer patients with double heterozygosity for BRCA1 and BRCA2 germline pathogenic variants.

Despite of very rare, breast cancer patients with double heterozygosity (DH) variants in BRCA1 and BRCA2 genes have been identified in other ethnic groups and seem to be associated with distinctive phenotypes. However, little is known about the frequency and clinical characteristics of Chinese breast cancer patients with BRCA1/2 DH variants. Four hundred and eleven unrelated patients with BRCA1 or BRCA2 pathogenic variants (PVs) were identified in a large series of unselected breast cancer patients. Another two siblings with metachronous bilateral breast cancer were referred for genetic counseling, after which BRCA1/2 DH variants were detected. Four unrelated breast cancer patients with BRCA1/2 DH were identified in the cohort of 411 patients with BRCA1 or BRCA2 PVs, the frequency of BRCA1/2 DH was 0.97%. In total, six BRCA1/2 DH patients from five families were found in this study. In two families, the hereditary pattern of DH was speculated to have originated from both sides of the family. BRCA1/2 DH patients were more likely to have a family history of breast cancer than patients with a BRCA1 (100% vs. 29.2%, P = 0.004) or BRCA2 (100% vs. 29.6%, P = 0.004) single PV. BRCA1/2 DH patients were more likely to be triple-negative breast tumors than patients with single BRCA2 PVs (66.7% vs. 14.1%, P = 0.020), which was comparable to the findings in patients with single BRCA1 PVs (66.7% vs. 56.9%, P = 1.00). Chinese patients with BRCA1/2 DH exhibit a high percentage of family history of breast cancer. The tumor pathological features of BRCA1/2 DH carriers are similar to those of BRCA1 PV carriers.

Germline Genetic Susceptibility Testing Among Emirati Nationals at Risk for Hereditary Breast and Ovarian Cancer Syndrome

PURPOSE Breast cancer among Emirati patients is characterized by early-onset disease and later stages at presentation. Little is known about the germline genetic variants that may contribute to these observations. The goal of this study is to characterize the rate and implications of germline genetic variants among a cohort of Emirati patients at risk for hereditary breast and ovarian cancer syndrome. MATERIALS AND METHODS A retrospective study was performed to analyze the results of clinical germline genetic testing (March 2020-January 2023) among a cohort of consecutive Emirati patients at risk for hereditary breast and ovarian cancer syndrome: group A: patients with personal history of breast or ovarian cancer (n = 135); group B: unaffected patients with family history of breast or ovarian cancer (n = 37); and group C: patients presenting for cascade testing (n = 20). Management of patients identified to have pathogenic/likely pathogenic (P/LP) variants was analyzed. RESULTS The rate of P/LP germline variants for each group was: group A: 17.3%, group B: 16.6%, group C: 57.9%. BRCA1 gene was the most commonly identified gene harboring P/LP variants, followed by BRCA2 , among this cohort. Four unrelated patients had a recurrent BRCA1 pathogenic variant: c.4065_4068del (p.Asn1355Lysfs*10). Only two patients in this series elected risk-reducing mastectomy and four patients elected risk-reducing bilateral salpingo-oophorectomy. CONCLUSION A higher rate of P/LP variants is seen among Emirati patients at risk for hereditary breast and ovarian cancer syndrome compared with reports of similar patients from Western populations. Efforts to increase utilization and awareness of germline genetic testing are warranted among Emirati patients.

Second Primary Cancer Risks After Breast Cancer in BRCA1 and BRCA2 Pathogenic Variant Carriers.

Second primary cancer (SPC) risks after breast cancer (BC) in BRCA1/BRCA2 pathogenic variant (PV) carriers are uncertain. We estimated relative and absolute risks using a novel linkage of genetic testing data to population-scale National Disease Registration Service and Hospital Episode Statistics electronic health records. We followed 25,811 females and 480 males diagnosed with BC and tested for germline BRCA1/BRCA2 PVs in NHS Clinical Genetics centers in England between 1995 and 2019 until SPC diagnosis, death, migration, contralateral breast/ovarian surgery plus 1 year, or the 31st of December 2020. We estimated standardized incidence ratios (SIRs) using English population incidences, hazard ratios (HRs) comparing carriers to noncarriers using Cox regression, and Kaplan-Meier 10-year cumulative risks. There were 1,840 BRCA1 and 1,750 BRCA2 female PV carriers. Compared with population incidences, BRCA1 carriers had elevated contralateral BC (CBC; SIR, 15.6 [95% CI, 11.8 to 20.2]), ovarian (SIR, 44.0 [95% CI, 31.4 to 59.9]), combined nonbreast/ovarian (SIR, 2.18 [95% CI, 1.59 to 2.92]), colorectal (SIR, 4.80 [95% CI, 2.62 to 8.05]), and endometrial (SIR, 2.92 [95% CI, 1.07 to 6.35]) SPC risks. BRCA2 carriers had elevated CBC (SIR, 7.70 [95% CI, 5.45 to 10.6]), ovarian (SIR, 16.8 [95% CI, 10.3 to 26.0]), pancreatic (SIR, 5.42 [95% CI, 2.09 to 12.5]), and combined nonbreast/ovarian (SIR, 1.68 [95% CI, 1.24 to 2.23]) SPC risks. Compared with females without BRCA1/BRCA2 PVs on testing, BRCA1 carriers had elevated CBC (HR, 3.60 [95% CI, 2.65 to 4.90]), ovarian (HR, 33.0 [95% CI, 19.1 to 57.1]), combined nonbreast/ovarian (HR, 1.45 [95% CI, 1.05 to 2.01]), and colorectal (HR, 2.93 [95% CI, 1.53 to 5.62]) SPC risks. BRCA2 carriers had elevated CBC (HR, 2.40 [95% CI, 1.70 to 3.40]), ovarian (HR, 12.0 [95% CI, 6.70 to 21.5]), and pancreatic (HR, 3.56 [95% CI, 1.34 to 9.48]) SPC risks. Ten-year cumulative CBC, ovarian, and combined nonbreast/ovarian cancer risks were 16%/6.3%/7.8% (BRCA1 carriers), 12%/3.0%/6.2% (BRCA2 carriers), and 3.6%/0.4%/4.9% (noncarriers). Male BRCA2 carriers had higher CBC (HR, 13.1 [95% CI, 1.19 to 146]) and prostate (HR, 5.61 [95% CI, 1.96 to 16.0]) SPC risks than noncarriers. Survivors of BC carrying BRCA1 and BRCA2 PVs are at high SPC risk. They may benefit from enhanced surveillance and risk-reduction measures.

The discrepancy of somatic BRCA1/2 pathogenic variants from two different platforms in epithelial ovarian, fallopian tube, and peritoneal cancer

The somatic BRCA1 or BRCA2 Pathogenic Variant (PV)/Likely PV (LPV) from Next Generation Sequencing (NGS) is the most important biomarker for PARP inhibitor use and maintenance-targeted therapies. A discrepancy in the detection rates of BRCA1 and BRCA2 PV/LPV was identified among the NGS platforms. The objective of this study was to compare the somatic BRCA results from two distinct platforms using the same cohort and to identify the causes of these differences. Patients with epithelial ovarian cancer who concurrently underwent tumor NGS using two different platforms between January 2022 and June 2023 were included in this study. The two platforms used were in-house tumor NGS (Illumina NextSeq 550Dx, SureSelectXT library kit, and datasets from 1000 Genomes, ESP6500, ExAC, and ClinVar) and GreenPlan homologous recombination deficiency (HRD) test (Illumina NextSeq 550Dx, customized Twist Bioscience library kit, and datasets from COSMIC and OncoKB). The results of somatic mutations in BRCA1 and BRCA2 were compared between the two platforms. Of the 118 patients, 11.9% (n = 14) exhibited a discordant interpretation of BRCA1 or BRCA2 between the two platforms. Eleven patients (9.3%) exhibited negative results in the in-house platform but positive results (eight seven as PV of BRCA1, one as PV of BRCA2, one as LPV of BRCA1, and two as LPV of BRCA2) in the GreenPlan HRD test, while three patients (2.6%) had positive BRCA pathogenic variants (two as PV of BRCA1 [c.3340G > T, c.5152 + 3 A > C], one as LPV of BRCA2 [c.8174G > T], and one as LPV of BRCA1 [c.5017_5019delCAC]) in the in-house platform but a negative result in the GreenPlan HRD test. The discordance rate of somatic BRCA1 or BRCA2 mutations from different platforms was approximately 12%. In the case of the strong implication of BRCA PV/LPV with a negative result with one genetic test, different platforms could be considered in limited cases. Careful interpretation and further studies for the cross-validation of gene analysis platforms are needed.

Clinical characteristics of male patients with breast cancer in the Latino population.

Breast cancer is the most prevalent cancer type in Mexico, with male breast cancer accounting for only 1% of all breast cancer cases. A limited number of studies have described the clinical-pathological profiles of males with breast cancer in low- and middle-income countries. This study presents an analysis of patients with breast cancer seen at three different institutions in México. A retrospective review of the medical records was performed to analyze the clinical and pathological characteristics of 49 men diagnosed with breast cancer and their overall survival. The mean age at diagnosis was 64.65years. A significant proportion of patients presented at diagnosis with stage IV disease (n = 11, 22.45%), had triple-negative subtype (n = 6, 12.24%), and nuclear grade III (n = 20, 40.8%). Primary endocrine resistance was observed in 10 patients (31.25%). Genetic analysis was performed on 24 patients (48.9%), revealing a germline BRCA pathogenic variant in 8.33%. Our findings described the clinical and pathological profile of breast cancer in a male cohort in Mexico, with a significantly high proportion of advanced disease, triple-negative subtype, nuclear grade III, and endocrine resistance. Further comprehensive studies, including research into somatic mutations, are needed.

An interpretable deep learning model for detecting BRCA pathogenic variants of breast cancer from hematoxylin and eosin-stained pathological images.

Determining the status of breast cancer susceptibility genes (BRCA) is crucial for guiding breast cancer treatment. Nevertheless, the need for BRCA genetic testing among breast cancer patients remains unmet due to high costs and limited resources. This study aimed to develop a Bi-directional Self-Attention Multiple Instance Learning (BiAMIL) algorithm to detect BRCA status from hematoxylin and eosin (H&E) pathological images. A total of 319 histopathological slides from 254 breast cancer patients were included, comprising two dependent cohorts. Following image pre-processing, 633,484 tumor tiles from the training dataset were employed to train the self-developed deep-learning model. The performance of the network was evaluated in the internal and external test sets. BiAMIL achieved AUC values of 0.819 (95% CI [0.673-0.965]) in the internal test set, and 0.817 (95% CI [0.712-0.923]) in the external test set. To explore the relationship between BRCA status and interpretable morphological features in pathological images, we utilized Class Activation Mapping (CAM) technique and cluster analysis to investigate the connections between BRCA gene mutation status and tissue and cell features. Significantly, we observed that tumor-infiltrating lymphocytes and the morphological characteristics of tumor cells appeared to be potential features associated with BRCA status. An interpretable deep neural network model based on the attention mechanism was developed to predict the BRCA status in breast cancer. Keywords: Breast cancer, BRCA, deep learning, self-attention, interpretability.

Establishment of a clinical cancer genetics program for breast cancer in a resource-limited country; challenges and opportunities.

Breast cancer is the most common cancer among women worldwide, and its incidence rate is still increasing, especially among younger women. Nationally, it constitutes one-fifth of all cancer cases and almost 40% of all female cancers. With a median age of 51 years, breast cancer is diagnosed at least a decade earlier, and at more advanced stages compared to Western societies. Hereditary cancers account for 10% or more of all cancer burden worldwide. With expanded indications, increased number of genes tested, and significant decline in cost of testing, such proportion will probably increase. Individuals with pathogenic variants of BRCA1 and BRCA2 are at higher risk of breast, ovarian, pancreatic and many other cancers. Over the past two decades, several highly penetrant cancer-susceptibility genes were identified across almost all tumor sites, thus increasing the need for comprehensive cancer genetic programs that address the testing process, counselling patients and at-risk family members, and then deal with all testing results and its consequences. In addition to its important role in preventing more cancers in index patients themselves and among their close relatives, identification of pathogenic or likely pathogenic variants, mostly in BRCA1 or BRCA2, may inform therapeutic decisions in common cancers including breast, ovarian, prostate and pancreatic cancers. In this manuscript, we describe the experience of a comprehensive cancer center, in a resource-limited country in establishing a comprehensive clinical cancer genetics program that can serve as an example for others who share similar demographic and financial restrains.

Two founder variants account for over 90% of pathogenic BRCA alleles in theOrkney and Shetland Isles in Scotland.

For breast and ovarian cancer risk assessment in the isolated populations of the Northern Isles of Orkney and Shetland (in Scotland, UK) and their diasporas, quantifying genetically drifted BRCA1 and BRCA2 pathogenic variants is important. Two actionable variants in these genes have reached much higher frequencies than in cosmopolitan UK populations. Here, we report a BRCA2 splice acceptor variant, c.517-2A>G, found in breast and ovarian cancer families from Shetland. We investigated the frequency and origin of this variant in a population-based research cohort of people of Shetland ancestry, VIKING I. The variant segregates with female breast and ovarian cancer in diagnosed cases and is classified as pathogenic. Exome sequence data from 2108 VIKING I participants with three or more Shetlandic grandparents was used to estimate the population prevalence of c.517-2A>G in Shetlanders. Nine VIKING I research volunteers carry this variant, on a shared haplotype (carrier frequency 0.4%). This frequency is ~130-fold higher than in UK Biobank, where the small group of carriers has a different haplotype. Records of birth, marriage and death indicate genealogical linkage of VIKING I carriers to a founder from the Isle of Whalsay, Shetland, similar to our observations for the BRCA1 founder variant c.5207T>C from Westray, Orkney. In total, 93.5% of pathogenic BRCA variant carriers in Northern Isles exomes are accounted for by these two drifted variants. We thus provide the scientific evidence of an opportunity for screening people of Orcadian and Shetlandic origins for each drifted pathogenic variant, particularly women with Westray or Whalsay ancestry.

Impact of graphical display on the intention to undergo risk-reducing salpingo-oophorectomy and mastectomy in individuals positive for BRCA pathogenic variant

The BRCA1/2 pathogenic variant (PV) increases the risk of breast and ovarian cancer; thus, risk-reducing salpingo-oophorectomy (RRSO) and mastectomy (RRM) are recommended. We evaluated the effects of the graphical display of cancer risk compared with those of numerical presentation on the decision-making for risk-reducing (RR) surgery. A total of 471 women representing the Korean population were recruited. The lifetime risk of breast/ovarian cancer were given numerically followed by graphically in hypothetical BRCA1/2 PV-positive cases. Subsequently, the study participants were asked for their willingness to undergo RRSO/RRM. When the ovarian cancer risk was shown as 44.0%, the percentage of study participants who chose RRSO was 41.0% after numerical presentation versus 39.9% after graphical display, of which the difference was not significant. When the breast cancer risk was presented as 72.0%, 30.4% of the participants opted for RRM under numerical presentation, whereas this increased to 38.6% under graphical display, of which the difference was significant (p < 0.0075). The average levels of the cancer risk which study participants consider RR surgery were 57.1% for ovarian cancer and 60.6% for breast cancer. This suggests that the impacts of different formats of risk communication on decision about RRSO or RRM may be different by the absolute levels of ovarian or breast cancer.

12488 Exome Sequencing Unravels New Susceptibility Genes For Pheochromocytomas And Paragangliomas

Abstract Disclosure: G.F. Fagundes: None. F.F. Castro: None. L.S. Santana: None. A.F. Afonso: None. A.W. Maciel: None. F.L. Ledesma: None. C.A. Pereira: None. I.C. Soares: None. D.M. Lourenço Junior: None. M.A. Pereira: None. V. Srougi: None. F.Y. Tanno: None. J.L. Chambo: None. M.C. Fragoso: None. A.O. Hoff: None. B.B. Mendonca: None. A. Latronico: None. M.Q. Almeida: None. Background: Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors with a high association with hereditary disease, affecting 40% of the cases. PPGL susceptibility genes are categorized into three clusters based on their pathophysiological and metabolomic mechanisms. Somatic oncogenic variants are identified in 30% of the tumors. Most of the germline and somatic drivers are mutually exclusive in PPGLs. Thus, 30% of the PPGLs remain without known genetic causes. Aim: To investigate new susceptibility genes for PPGLs using whole exome sequencing. Methods: We included 145 index patients with PPGLs (93 female and 52 male) with 91 pheochromocytomas (PHEO) and 60 paragangliomas, of which 43 (29.65%) were metastatic. A target next-generation sequencing panel for susceptibility genes was initially performed. Whole exome sequencing was performed in 56 patients with PPGLs (38 were paired with tumor DNA). Results:SDHB was the most frequently affected gene in 29 of 145 patients (20%). Germline SDHB exon 1 deletion was identified in 14 patients (48.27%). Germline variants were identified as follow: RET 22 (15.17%), VHL 13 (8.96%), SDHA 6 (4.14%), SDHD 5 (3.45%), NF1 5 (3.45%), FH 2 (1.38%), MAX 2 (1.38%), DLST 1 (0.69%), TMEM127 1 (0.69%), SDHC 1 (0.69%) and H3F3A 1 (0.69%) case. Somatic variants were identified in 21 tumors: NF1 6 (4.14%), HRAS 5 (3.45%), VHL 2 (1.38%), FGFR1 2 (1.38%), and RET 1 (0.69%). Six variants (five germline and one somatic) were identified in 3 new candidate genes: 1) Three very rare germline CHEK2 likely pathogenic or pathogenic variants (c.475T&amp;gt;C/ p.Tyr159His; c.362G&amp;gt;A/ p.Cys121Tyr; c.319+2T&amp;gt;A) in one metastatic PHEO and two PGLs (one metastatic). The metastatic PGL did not harbor any somatic oncogenic variant, while exome sequencing of a metastatic lesion from the PHEO had a somatic likely oncogenic HRAS variant; 2) Two very rare germline BRCA2 pathogenic variants (c.3680_3681delTG/ p.Leu1227fs; c.7806-2A&amp;gt;C) in a 33-year-old man with non-metastatic PHEO and in a 25-year-old man with metastatic PGL. All germline variants have not been reported in the Brazilian genomic variant repository. Exome sequencing did not reveal any somatic oncogenic driver in both tumors; 3) The somatic GNAS likely oncogenic variant c.601C&amp;gt;T/ p.Arg201Cys in a pheochromocytoma. The prevalence of CHEK2 and BRCA2 pathogenic or likely pathogenic variants in our cohort were significantly higher compared with those in the gnomAD population database (p &amp;lt; 0.0001 and p = 0.0004, respectively). Co-occurrence of germline and somatic drivers were found in 3 cases: FH and FGFR1, DLST and NF1, and CHEK2 and HRAS. In summary, germline and somatic diagnosis were reached in 63.45% and 15.18% of the PPGLs in our cohort, respectively. Conclusion: Our findings support CHEK2, BRCA2 and GNAS as novel susceptibility genes for PPGLs. Support: Sao Paulo Research Foundation (FAPESP) grant 2019/15873-6. Presentation: 6/2/2024

Development of a novel prediction model for carriage of BRCA1/2 pathogenic variant in Japanese patients with breast cancer based on Japanese organization of hereditary breast and ovarian cancer registry data.

With the increasing demand for BRCA genetic testing, most existing prediction models were developed using data from individuals of European descent. This study aimed to identify clinicopathological factors of hereditary breast and ovarian cancer (HBOC) syndrome and develop the first Japanese-specific prediction model for BRCA pathogenic variant carriers in Japan. We utilized data from 3072 Japanese patients with breast cancer aggregated by the Japanese Organization of Hereditary Breast and Ovarian Cancer registry. Prediction models were developed using 70% of the overall dataset and validated using the remaining 30%. Factors associated with the BRCA pathogenic variant status were identified using logistic univariate analysis, and significant factors were further analyzed using logistic multivariate analysis to develop prediction models for BRCA1/2 (BRCA1 and/or BRCA2), BRCA1, and BRCA2 pathogenic variants. BRCA1 showed associations with aggressive clinicopathological factors such as triple-negative breast cancer and nuclear grade 3. Moreover, the prediction model showed a high area under the curve (AUC) of 0.879. By contrast, BRCA2 exhibited fewer characteristic associated factors, and the AUC of the model was 0.669. Common factors shared by BRCA1/2, BRCA1, and BRCA2 were the age at diagnosis of breast cancer and the youngest age of relatives with breast cancer. Consistent with previous research, early-onset breast cancer appeared to be strongly associated with HBOC. We successfully developed prediction models for BRCA1/2, BRCA1, and BRCA2 pathogenic variants. By accurately stratifying patients' risk and guiding targeted screening and preventative interventions, these models will contribute to improved management and outcomes of HBOC.

The implementation and outcome of a breast cancer genetic counselling service at Potchefstroom Hospital: a model for outreach

Aim Breast cancer is the most prevalent cancer in South African females, making up 27.1% of all histologically diagnosed cancers in 2020. Although genetic technology and awareness of genetic counselling have improved, genetic counselling services in South Africa remain largely inaccessible. Clinical genetic services are only formally available in four South African provinces and few outreach programmes exist for small towns and cities. Until 2019, genetic counselling services were unavailable in the North West province; however, since then, genetic counsellors from the National Health Laboratory Service and the University of the Witwatersrand have provided genetic counselling services to patients at the Breast Clinic at Potchefstroom Hospital regularly each year. Method The aim of this pilot study was to perform a retrospective file review and report on the implementation and outcomes of the genetic counselling service at the Breast Clinic at Potchefstroom Hospital, from its inception in 2019, until November 2022. Fifty-two patients attended a genetic counselling consultation during that period. Results The majority of patients (83.7%) were diagnosed with an invasive ductal carcinoma, and 57.7% of the patients had a family history of cancer. A total of 62.8% of patients had a histologic grade 3 tumour. A total of 25.5% (12/47) of patients tested positive for a pathogenic variant in BRCA1 or BRCA2. A total of 45 at-risk first-degree relatives were identified who could benefit from predictive testing. Conclusions This study highlights the benefit of offering clinical genetics services through outreach clinics. Being able to offer this service is not only beneficial for the management of the affected individuals, but also for their at-risk relatives. The initiative serves as a positive example of how limited resources can be extended to benefit patients.

Pathogenic Germline Variants in Uveal Melanoma Driver and BAP1-Associated Genes in Finnish Patients with Uveal Melanoma.

Uveal melanoma (UM) is a rare yet aggressive eye cancer causing over 50% mortality from metastasis. Familial UM, amounting to 1%-6% of patients in Finland and the United States, mostly lack identified genetic cause, while 8% show associations with other cancer syndromes. We searched novel genetic associations for predisposition to UM, additional to already studied BAP1 and MBD4, by using targeted amplicon sequencing of 19 genes associated with UM, BAP1, or renal cell carcinoma in 270 consecutively enrolled Finnish patients with UM. Key UM drivers GNAQ, GNA11, CYSLTR2, PLCB4, EIF1AX, and SF3B1 lacked pathogenic germline variants. One patient carried the pathogenic BRCA1 variant c.3626del p.(Leu1209*), and one harbored a novel truncating MET variant c.252C > G p.(Tyr84*), classified as likely pathogenic. FLCN and BRCA2, previously identified with pathogenic variants in patients with UM, did not have such variants in our cohort. Two patients were heterozygous for a pathogenic recessive BLM variant c.2824-2A > T. None of the carriers of identified variants had familial UM. We identified BRCA1 and MET as genes with pathogenic germline variants in Finnish UM patients, each with a frequency of 0.4% (95% confidence interval, 0-2).

The Pivotal Role of Germline BRCA2 Pathogenic Variants in "Apparently Sporadic" Pancreatic Cancer.

In 1996, Goggins and colleagues demonstrated the importance of germline BRCA2 pathogenic variants in the development of apparently sporadic pancreatic ductal adenocarcinoma (PDAC). Previously, the group identified homozygous deletion of the 13q region in PDACs, enabling the identification of the BRCA2 gene. This 1996 article first revealed loss of BRCA2, both germline and somatic, as a key driver of PDAC at a time when there was still doubt if PDAC even had an inherited component. Contrary to the prevailing wisdom, not all individuals with inherited pathogenic BRCA2 variants had a family history of cancer. The innovative bedside-to-bench nature of this work revealed that individuals with these variants would be missed if genetic testing was limited only to those meeting the family history criteria. Therefore, Goggins and colleagues advocated that universal genetic testing may be indicated for pancreatic cancer at a time when genetic testing was in its infancy. Twenty-three years later, in 2019, universal testing for pancreatic cancer became standard of care in the United States. Additionally, this work and future-related publications by the Kern Laboratory set the stage for targeting BRCA2 and related DNA repair mutations in pancreatic cancer via a synthetic lethal therapeutic approach. The provocative discussion initiated by this team in this publication is still inspiring the field today. In this seminal publication, Goggins and colleagues profoundly impacted the direction of pancreatic cancer research, leading to a more sophisticated approach to designing earlier detection and precision treatment strategies for pancreatic cancer. See related article by Goggins and colleagues, Cancer Res 1996;56:5360-4.

Abstract PR-04: Phase 2 Trial Testing The PARP Inhibitor Niraparib In Patients With Advanced Pancreatic Cancer with Pathogenic Variants In BRCA 1, BRCA2, PALB2, ATM and CHEK2

Abstract Background: Poly-(adenosine diphosphate ribose) polymerase (PARP) inhibitors have demonstrated efficacy in patients with platinum-sensitive pancreatic cancer who harbor germline BRCA 1/2 pathogenic variants (PVs). Whether PARP inhibitors are effective in a broader population of pancreatic cancer patients is still under investigation. Methods: This was a multicenter, single arm, open-label phase II trial (NCT03601923) investigating the use of the PARP inhibitor niraparib in patients with advanced pancreatic cancer. Eligible patients were required to have germline or somatic mutations in BRCA1, BRCA2, PALB2, ATM and/or CHEK2. Prior treatment with PARP inhibitors and prior progression on a platinum chemotherapy were not allowed, though patients could be included if they had progression on non-platinum based therapy. Patients were treated with weight-adjusted niraparib (200 mg or 300 mg) once daily on a 28-day cycle. The primary endpoint was 6-month progression free survival (PFS) rate (binary). Secondary endpoints were PFS, overall survival (OS), objective response rate (ORR) by RECIST v1.1, and safety. Serial plasma samples were collected for circulating tumor DNA analyses. Results: Thirty-two patients (10 females [31%]; median age 67) were evaluable for the primary endpoint. Patients had a germline or somatic alteration in one or more of the following genes: ATM (n=14), BRCA2 (n=10), PALB2 (n=3), CHEK2 (n=4), or BRCA1 (n=2). There were 10 patients who received niraparib as maintenance therapy and 12 patients whose tumors previously progressed on a non-platinum-based chemotherapy. The 6-month PFS rate was 25% (90% CI: 13-41), rejecting the null hypothesis of a 17% 6-month PFS rate. The median PFS for the entire population was 2.0 months (90% CI: 1.7-3.7) and median OS was 10.2 months (90% CI: 8.2-13.2). The objective response rate was 14% (90% CI: 5-30%); 2 patients had a complete response, 2 patients had a partial response. Patients who never previously progressed on chemotherapy had a significantly longer median PFS (p=0.02) and OS (p=0.003) than patients who previously progressed on chemotherapy. Three patients with biallelic inactivation of ATM, who never progressed on prior lines of chemotherapy, were on niraparib for over 1 year (range 1 – 4 years). Reversion mutations restoring the reading frame in BRCA2 were identified in cell-free DNA in 3 patients with BRCA2 pathogenic frameshift variants. Additional putative resistance mutations in other DNA repair genes were identified and will be reported. Conclusions: Niraparib demonstrated a promising 6-month PFS rate and provided clinically meaningful benefit in patients with pancreatic cancer. The observation of prolonged benefit of three patients with biallelic ATM inactivation warrants further investigation. Acknowledgment: Funding for this study was provided by GSK. GSK was provided the opportunity to review a preliminary version of this abstract for factual accuracy. The authors are solely responsible for final content and interpretation. Citation Format: Brandon M. Huffman, Jett Crowdis, Matthew B. Yurgelun, Nora Horick, Yvonne Li, Huy Nguyen, Kalindi Parmar, Bose S. Kochupurakkal, Andrea Enzinger, Marios Giannakis, Nadine McCleary, Kimmie Ng, Anuj K. Patel, Kimberly J. Perez, Douglas A. Rubinson, Benjamin L. Schlechter, Harshabad Singh, Helen Lam, Kaitlyn Ramsey, Elizabeth Andrews, Leigh Culnane, Andrea Bullock, Ahmed Rattani, Jeffrey Clark, Mary Linton Peters, Brian M. Wolpin, Alan D. D'Andrea, Geoffrey I. Shapiro, Andrew J. Aguirre, James M. Cleary. Phase 2 Trial Testing The PARP Inhibitor Niraparib In Patients With Advanced Pancreatic Cancer with Pathogenic Variants In BRCA 1, BRCA2, PALB2, ATM and CHEK2 [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr PR-04.

Germline BRCA pathogenic variants in patients with ovarian cancer and post-poly (ADP-ribose) polymerase inhibitor myeloid neoplasms

Among patients with advanced high-grade ovarian carcinoma (aHGOC) treated with poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis), the presence of a germline BRCA pathogenic variant (gBRCA-PV) may increase the risk of bone marrow mutagenesis resulting in postcytotoxic therapy myelodysplastic neoplasms (MDS-pCT) or acute myeloid leukemia (AML-pCT), as it is expressed in heterozygosity also by hematopoietic progenitors. We aimed to investigate the occurrence of post-PARPi MDSs/AMLs-pCTs according to gBRCA-PV status. We conducted a retrospective single-center study to evaluate MDS/AML-pCT in patients with aHGOC and a known gBRCA-PV status receiving at least 8 weeks of maintenance PARPi, in any line of therapy, from February 2017 to December 2022. The endpoint was the proportion of patients who experienced MDSs-pCT and AMLs-pCT during and after treatment with PARPi, in gBRCA-PV carriers and non-carriers. A total of 166 patients were included: 95 (57%) had a gBRCA-PV and 72% received PARPi for recurrent disease. The number of lines of chemotherapies before and after PARPi, median overall survival, and median follow-up were comparable between gBRCA-PV carriers and non-carriers. After a median follow-up of 40.0 (95% confidence interval: 35.7-44.3) months, 10 (6%) patients were diagnosed with an MDS-pCT and 4 (2%) with an AML-pCT. A higher proportion of MDSs/AMLs-pCT (10% versus 2%; P= 0.16) and, in particular, of MDSs-pCT (9% versus 1%; P= 0.04) was observed among gBRCA-PV carriers. The presence of a gBRCA-PV is associated with a higher risk of MDS-pCT and possibly of myeloid neoplasms after PARPi in patients with aHGOC who received PARPi, especially in the setting of recurrent disease.

Assessing the acceptability and appropriateness of a psychoeducational graphic novel about inherited cancer risk designed for men.

Men with germline pathogenic variants in BRCA1 or BRCA2 genes are at an increased lifetime risk for developing breast cancer, prostate cancer, and pancreatic cancer. Men report that managing clinical care is challenging because they are under-informed about their cancer risks. As the demand for genetic testing has increased, so too has the need to relay accurate and relatable genetic health information. This research developed and assessed the acceptability and appropriateness of a psychoeducational graphic novel designed for men to improve their cancer risk knowledge, manage their cancer-related uncertainty, and increase their intent to disclose their BRCA1/2 risks to family members and healthcare providers. Through purposive and snowball sampling, men (n = 20) and certified genetic counselors (CGCs; n = 15) participated in semi-structured interviews assessing the acceptability and appropriateness of the graphic novel. Interviews were audio-recorded, transcribed, and thematically analyzed. Both reported that the graphic novel confirmed risk information provided helpful resources, included relatable storylines, and had a unique visual appeal. Some men remained unsure about how to perform recommended screenings and how to talk to family members, particularly children, about BRCA1/2 test results after assessing the graphic novel. CGCs also discussed the helpfulness of the graphic novel for their practice. Given that this psychoeducational graphic novel was appealing to men and CGCs, it shows promise as an acceptable approach that may assist men in managing their cancer risks and communicating their genetic risk information to family members and healthcare providers.