BRCA1-associated Tumors Research Articles

Abstract PO4-16-01: EZH2 is Overexpressed in Invasive Carcinoma and DCIS in both BRCA1 and BRCA2 Mutation Carriers

Abstract Background The transcriptional repressor EZH2 (Polycomb Group Protein Enhancer of Zeste Homologue 2) is overexpressed in multiple neoplasms including breast cancer where it associates with high proliferation, aggressive features and poor prognosis and is of interest as a potential therapeutic target. EZH2 nuclear expression in breast cancer has been shown to correlate specifically with high tumor grade and basal-like histologic features but has not been well studied in cancers from BRCA carriers. Here we evaluate the expression of EZH2 protein in BRCA-associated invasive breast carcinomas and precursor lesions. Methods Eighteen cases of invasive breast cancer in consented BRCA carriers (8 BRCA1 and 10 BRCA2) treated at Dana Farber Cancer Institute from 2001-2019 were reviewed by two pathologists (TAD and RBPP). Histopathologic features (histologic subtype, nuclear grade, mitotic score) and presence of precursor lesions were recorded. Immunohistochemistry for EZH2 was performed on freshly cut formalin-fixed paraffin-embedded tissue sections (1-3 sections/case) using a monoclonal antibody against EZH2 (D2C9, Cell Signaling). Nuclear EZH2 expression was scored as negative (score=1, no staining); weak (score 2, < 25%); moderate (score=3, 25–75%); and strong (score=4, >75%), of any intensity following published criteria. EZH2 overexpression was defined as scores 3 and 4. Results The majority of the invasive carcinomas showed grade III histology (13/18, 72%), as expected. Of 8 BRCA1 cases, 6 were classified as grade III (75%), 1 as grade II, and 1 as grade I (7 cases of invasive ductal carcinoma and 1 case of invasive tubular carcinoma). Of 10 BRCA2 cases, 7 were classified as grade III (70%) and 3 as grade II (30%) (5 cases of invasive ductal carcinoma and 5 cases of invasive carcinoma with ductal and lobular features). The majority of cases (13 of 18, 72%) showed high expression of EZH2 in the invasive carcinoma (6 BRCA1 and 7 BRCA2 cases; 2 grade II and 11 grade III). Of 13 cases with EZH2 overexpression, 6 were ER+/PR+/HER2- and 7 were triple negative, with 9 invasive ductal carcinomas and 4 invasive carcinomas with ductal and lobular features. Of 5 cases with no/low EZH2 overexpression, 1 was ER+/PR+/HER2-, 3 were ER+/PR-/HER2- and 1 was triple negative, with 3 invasive ductal carcinomas, 1 invasive carcinoma with ductal and lobular features and 1 invasive tubular carcinoma. In all cases with adjacent ductal carcinoma in situ (DCIS) (n=14), the pattern of EZH2 expression in the DCIS was identical to that seen in the invasive carcinoma (11 high and 3 low expression). Overexpression of EZH2 was not observed in any other precursor lesions (LCIS, ADH, ALH) or in normal tissue. Conclusion EZH2 protein overexpression is seen in the majority of invasive carcinomas in BRCA carriers, both in BRCA1 and in BRCA2. In all cases, the associated DCIS shows the same pattern of expression as the invasive carcinoma, suggesting that overexpression occurs early in tumorigenesis, while tumor cells are still confined within the ducts. The high rate of overexpression of EZH2 in BRCA1- and BRCA2-associated tumors suggests a potential role for EZH2 as a target and/or a biomarker in these cancers. Citation Format: Tabata Alves Domingos, Roberto Bonfim Pimenta Peixoto, Rodrigo Fonseca Abreu, Ashka Patel, Krishan Taneja, McKenna Moore, Celina Kleer, Deborah Dillon. EZH2 is Overexpressed in Invasive Carcinoma and DCIS in both BRCA1 and BRCA2 Mutation Carriers [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-16-01.

Abstract 3019: Dissecting in vivo functions of R-Loops in Brca1-associated DNA replication stress and mammary tumorigenesis

Abstract Germ-line BRCA1 mutations are associated with a significantly increased incidence of breast cancer in women. Although BRCA1-associated breast tumors are basal-like and estrogen receptor α negative (ERα−), they originate from luminal progenitor cells. At the molecular level, BRCA1 is best known for its roles in resolution of DNA replication stress and promotion of homologous recombination (HR)-based double strand break (DSB) repair. In addition, BRCA1 is implicated in reduction of R-loops, a DNA-RNA hybrid structure and transcriptional byproduct associated with genome instability and transcriptional regulation. Our published findings suggest that BRCA1-dependent R-loop mitigation contributes to luminal cell-specific transcription and differentiation (Zhang et al, 2017, Nature Communications, 8:15908), which could in turn suppress Brca1-associated tumorigenesis. Using cell type-specific mouse genetics, we investigate a direct impact of R-loop removal on Brca1-associated mammary epithelial tumor formation. R-loop formation in mammary epithelial cells is efficiently reduced by over-expression of RNase H1, an R-loop-specific ribonuclease. R-loop removal does not affect mammary duct development or function. However, it drastically increases ɣH2AX foci in proliferating BRCA1-deficient epithelial cells without external DNA damage. This suggests a role of R-loops in attenuating elevated DNA replication stress caused by the loss of Brca1. While R-loop removal does not appear to affect the overall Brca1-associated mammary tumor incidence, it promotes cell differentiation from ERα− luminal progenitor cells to ERα+ mature luminal cells. Accordingly, unlike their counterparts, a significant percentage of Brca1-associated mammary tumors with RNase H1 overexpression tend to be ERα+. Thus, our findings provide in vivo evidence for a previously unappreciated role of R-loop dynamics on Brca1-associated DNA replication stress and tumor development in mammary epithelium. Citation Format: Huai-Chin Chiang, Leilei Qi, Yanfen Hu, Rong Li. Dissecting in vivo functions of R-Loops in Brca1-associated DNA replication stress and mammary tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3019.

Reversion mutations in germline BRCA1/2-mutant tumors reveal a BRCA-mediated phenotype in non-canonical histologies

The association between loss of BRCA1/2 and a homologous recombination deficiency phenotype is lineage dependent. In BRCA-associated cancers such as breast, ovarian, pancreas and prostate, this phenotype confers sensitivity to PARP inhibitors and platinum-therapies. Somatic reversion mutations restoring BRCA1/2 function mediate resistance, and have exclusively been reported in BRCA-associated tumors. In this study, we analyze matched tumor and normal sequencing from 31,927 patients and identify 846 (2.7%) patients with germline BRCA1/2 variants across 43 different cancer types, including 11 with somatic reversion mutations. While nine are in BRCA-associated tumors, we find two reversion mutations in non-BRCA-associated histologies, namely lung and esophagogastric adenocarcinomas. Both were detected following platinum therapy. Whole exome sequencing confirms the homologous recombination deficiency phenotype of these tumors. While reversion mutations arise in all BRCA-associated cancer types, here we show that reversion mutations arising post-platinum in non-BRCA associated histologies, while rare, may indicate BRCA1/2 mediated tumorigenesis.

193P Experience with olaparib in the treatment of BRCA-associated tumors in real clinical practice: Experience of re-challenge mode of olaparib usage

The PARP inhibitor olaparib has shown promising results in the treatment of patients with BRCA-associated tumors. By revealing more and more tumors, the development of which is caused by disorders in the BRCA gene, PARP inhibitors are also expanding their indications. Olaparib shows statistical improvement in ovarian cancer, breast cancer, prostate cancer and pancreatic cancer over standard options while showing a moderate toxic profile. All this makes olaparib a significant option in the planning of patient treatment tactics.

BRCA1-associated protein 1 c.368delG mutation leads to the development of multiple BAPomas and cutaneous melanomas: a novel pathogenic variant in BRCA1-associated protein tumor predisposition syndrome.

BRCA1-associated protein 1 c.368delG mutation leads to the development of multiple BAPomas and cutaneous melanomas: a novel pathogenic variant in BRCA1-associated protein tumor predisposition syndrome.

Experience with olaparib in the treatment of BRCA-associated tumors in real clinical practice. Observational study

Background. PARP inhibitor olaparib shows encouraging results in the treatment of patients with BRCA-associated tumors. The detection of new tumors associated with abnormalities of the BRCA gene, also can lead to the expansion of PARP inhibitors application. The application of PARP inhibitors improved treatment outcomes for ovarian, breast, prostate and pancreatic cancers in comparison with standard drug therapy regimens, demonstrating the moderate toxicity profile. All this makes olaparib the significant option in planning the tactics of treatment of this category of patients.
 Aim. Assess the efficacy of olaparib in real clinical practice conditions in our region and to demonstrate the clinical experience accumulated in the regional clinical oncology dispensary.
 Materials and methods. We analyzed the cases of the treatment with olaparib in the Republican Clinical Oncological Dispensary of the Ministry of Health of the Republic of Bashkortostan. The study included 79 patients.
 Results. Median progression-free survival reached 12 months and the best response was the stabilization of the disease among patients receiving olaparib. Median progression-free survival was 6 months and the best response was the stabilization of the disease among the patients treated with olaparib during Re-Challenge regimen.
 Conclusion. Olaparib applying in real clinical practice demonstrated satisfactory results.

Experience with olaparib in a patient with luminal HER2-positive metastatic breast cancer

Hereditary breast cancer (BC) accounts for about 5-10% of cases. BRCA-associated tumors have been identified as a separate group of malignant neoplasms with distinctive clinical manifestations and specific treatment features. Understanding of biological mechanisms leading to cancer in BRCA1/2 mutation carriers and discovery of potential molecular targets, such as poly (ADP-ribose) polymerase (PARP), involved in base excision repair mechanisms, led to the development of a new class of targeted drugs belonging to the PARP inhibitors group. PARP inhibition leads to the preservation of single-stranded DNA breaks, the arrest of the replication fork, and the realization of the “synthetic lethality” phenomenon due to the inability to repair double-stranded DNA breaks by homologous recombination in cells with mutations in the BRCA1/2 genes. Two randomized trials OlympiAD and EMBRACA evaluated and proved the effectiveness of PARP inhibitors in patients with metastatic BRCA-mutated HER2-negative breast cancer in comparison with standard chemotherapy. At the same time, data on the potential use of PARP inhibitors for the treatment of BRCA-mutated HER2-positive breast cancer patients are extremely limited. This article presents a clinical example of the use of olaparib in a patient with BRCA-mutated HER2-positive metastatic breast cancer.

G-Quadruplex Matters in Tissue-Specific Tumorigenesis by BRCA1 Deficiency.

How and why distinct genetic alterations, such as BRCA1 mutation, promote tumorigenesis in certain tissues, but not others, remain an important issue in cancer research. The underlying mechanisms may reveal tissue-specific therapeutic vulnerabilities. Although the roles of BRCA1, such as DNA damage repair and stalled fork stabilization, obviously contribute to tumor suppression, these ubiquitously important functions cannot explain tissue-specific tumorigenesis by BRCA1 mutations. Recent advances in our understanding of the cancer genome and fundamental cellular processes on DNA, such as transcription and DNA replication, have provided new insights regarding BRCA1-associated tumorigenesis, suggesting that G-quadruplex (G4) plays a critical role. In this review, we summarize the importance of G4 structures in mutagenesis of the cancer genome and cell type-specific gene regulation, and discuss a recently revealed molecular mechanism of G4/base excision repair (BER)-mediated transcriptional activation. The latter adequately explains the correlation between the accumulation of unresolved transcriptional regulatory G4s and multi-level genomic alterations observed in BRCA1-associated tumors. In summary, tissue-specific tumorigenesis by BRCA1 deficiency can be explained by cell type-specific levels of transcriptional regulatory G4s and the role of BRCA1 in resolving it. This mechanism would provide an integrated understanding of the initiation and development of BRCA1-associated tumors.

Selective progesterone receptor blockade prevents BRCA1-associated mouse mammary tumors through modulation of epithelial and stromal genes

Pharmacological approaches to breast cancer risk-reduction for BRCA1 mutation carriers would provide an alternative to mastectomy. BRCA1-deficiency dysregulates progesterone signaling, promoting tumorigenesis. Selective progesterone receptor (PR) modulators (SPRMs) are therefore candidate prevention agents. However, their efficacy varies in different BRCA1-deficient mouse models. We examined chemopreventive efficacy of telapristone acetate (TPA), ulipristal acetate (UPA) and mifepristone (MFP) in mice with a conditional knockout of the Brca1 C-terminal domain. The SPRMs displayed a spectrum of efficacy: UPA was most effective, TPA less, and MFP ineffective. Compared to no-treatment controls, UPA reduced tumorigenesis (p=0.04), and increased tumor latency (p=0.03). In benign mammary glands, UPA decreased Ki67 (p<0.001) and increased PR expression (p<0.0001). RNA sequencing analysis revealed distinct gene expression in response to UPA and MFP. UPA downregulated glycolysis and extracellular matrix-inflammation genes (Fn1, Ptgs2, Tgfb2, Tgfb3) whereas MFP downregulated claudin genes and upregulated amino acid metabolism and inflammation genes. The anti-glucocorticoid effects of MFP appeared not to be tumor-protective, while altering estrogen receptor signaling and NF-kB activation. Our study points to an important role of epithelial PR and its paracrine action on the microenvironment in BRCA1-deficient mammary tumorigenesis, and prevention.

166P Hereditary breast, ovarian and pancreatic cancers: Looking beyond the BRCA1/2 genes

Hereditary breast (BC), ovarian (OC) and pancreatic (PC) cancers are the major BRCA-associated tumours. However, some BRCA1/2-non informative patients with a strong cancer personal and/or family history need a further genetic testing through a multi-gene panel including other high- and moderate-risk susceptibility genes. In recent years, Next-Generation Sequencing has allowed to study multiple genes simultaneously, reducing analysis costs, increasing genetic data, and offering more information to patients.

Prevalence study of BRCA1/2 mutations in Portuguese patients diagnosed with non-mucinous ovarian cancer, fallopian tube invasive neoplasia or peritoneal primary cancer (PADOC)

<h3>Objectives:</h3> Family history is a representative risk factor for ovary cancer (OC), frequently associated with <i>BRCA1/2</i> mutations. The primary objective was to determine the prevalence of <i>BRCA1/2</i> mutations (somatic and germline) in patients with non-mucinous ovarian cancer (NMOC), invasive fallopian tube neoplasia (IFTN) or primary peritoneal carcinoma (PPC). <h3>Methods:</h3> National, interventional, retrospective and analytical study, with an estimated sample size of 261 women aged ≥18 years, diagnosed with NMOC, IFTN or PPC between 01/01/2014 and 31/12/2016 in the nine selected centers. <h3>Results:</h3> From 165 women eligible for analysis, the prevalence of <i>BRCA1/2</i> mutation was 20% (24.2% somatic, 75.8% germline). For patients with a mutation, 54.5% had a mutation in <i>BRCA1</i> (27.8% somatic, 72.2% germline), while 45.5% in <i>BRCA2</i> (20.0% somatic, 80.0% germline). Mean age of the sample was 61.1 years (mutated 60.3 years, non-mutated 61.3 years For patients with a mutation, the ages of the subgroups with somatic and germline were 70.5 and 57.0 years, respectively, with statistically significant difference. Furthermore, patients with somatic mutation were 68.1 years at diagnosis, whereas those with germline were 54.6 years, with statistically significant difference. In addition, 56.4% of patients with a mutation had disease in stage III and 18.8% in stage IV. Regarding family history, 20.6% of the total had confirmed family history of <i>BRCA</i> associated cancer, being that information unknown by 29.1%. In patients with <i>BRCA1/2</i> germline mutation, 48.0% confirmed family history of BRCA-associated tumors, in opposition to 15.2% in the non-mutated group. From the patients with mutation who reported familial history, 75.0% reported breast cancer, 33.3% ovarian cancer and 15.0% other tumors. <h3>Conclusions:</h3> PADOC study evaluated for the first time the nationwide prevalence of <i>BRCA1/2</i> germline and somatic mutations in ovarian cancer in Portugal, and the results suggest an estimated prevalence of 20.0%. These results highlight the importance of raising awareness for the disease in Portugal and the recommendation of broad genetic testing also bearing in mind the percentage of patients that have no information of <i>BRCA</i>-related cancers in family.

Impact of deleterious variants in other genes beyond BRCA1/2 detected in breast/ovarian and pancreatic cancer patients by NGS-based multi-gene panel testing: looking over the hedge

BackgroundHereditary breast cancer (BC), ovarian cancer (OC), and pancreatic cancer (PC) are the major BRCA-associated tumours. However, some BRCA1/2-wild-type (wt) patients with a strong personal and/or family history of cancer need a further genetic testing through a multi-gene panel containing other high- and moderate-risk susceptibility genes.Patients and methodsOur study was aimed to assess if some BC, OC, or PC patients should be offered multi-gene panel testing, based on well-defined criteria concerning their personal and/or family history of cancer, such as earliness of cancer onset, occurrence of multiple tumours, or presence of at least two or more affected first-degree relatives. For this purpose, 205 out of 915 BC, OC, or PC patients, resulted negative for BRCA1/2 and with significant personal and/or family history of cancer, were genetically tested for germline pathogenic or likely pathogenic variants (PVs/LPVs) in genes different from BRCA1/2.ResultsOur investigation revealed that 31 (15.1%) out of 205 patients harboured germline PVs/LPVs in no-BRCA genes, including PALB2, CHEK2, ATM, MUTYH, MSH2, and RAD51C. Interestingly, in the absence of an analysis conducted through multi-gene panel, a considerable percentage (15.1%) of PVs/LPVs would have been lost.ConclusionsProviding a multi-gene panel testing to BRCA1/2-wt BC/OC/PC patients with a strong personal and/or family history of cancer could significantly increase the detection rates of germline PVs/LPVs in other cancer predisposition genes beyond BRCA1/2. The use of a multi-gene panel testing could improve the inherited cancer risk estimation and clinical management of patients and unaffected family members.

Increased gene expression variability in BRCA1-associated and basal-like breast tumours

PurposeInherited variants in the cancer susceptibility genes, BRCA1 and BRCA2 account for up to 5% of breast cancers. Multiple gene expression studies have analysed gene expression patterns that maybe associated with BRCA12 pathogenic variant status; however, results from these studies lack consensus. These studies have focused on the differences in population means to identified genes associated with BRCA1/2-carriers with little consideration for gene expression variability, which is also under genetic control and is a feature of cellular function.MethodsWe measured differential gene expression variability in three of the largest familial breast cancer datasets and a 2116 breast cancer meta-cohort. Additionally, we used RNA in situ hybridisation to confirm expression variability of EN1 in an independent cohort of more than 500 breast tumours.ResultsBRCA1-associated breast tumours exhibited a 22.8% (95% CI 22.3–23.2) increase in transcriptome-wide gene expression variability compared to BRCAx tumours. Additionally, 40 genes were associated with BRCA1-related breast cancers that had ChIP-seq data suggestive of enriched EZH2 binding. Of these, two genes (EN1 and IGF2BP3) were significantly variable in both BRCA1-associated and basal-like breast tumours. RNA in situ analysis of EN1 supported a significant (p = 6.3 × 10−04) increase in expression variability in BRCA1-associated breast tumours.ConclusionOur novel results describe a state of increased gene expression variability in BRCA1-related and basal-like breast tumours. Furthermore, genes with increased variability may be driven by changes in DNA occupancy of epigenetic effectors. The variation in gene expression is replicable and led to the identification of novel associations between genes and disease phenotypes.

Post hoc analyses of GOG 9923: Does BRCA status affect toxicities?: An NRG oncology study

ObjectiveTo evaluate how women with epithelial ovarian cancer (EOC), dichotomized by BRCA status, tolerate intravenous (IV) or intraperitoneal (IP) chemotherapy given with veliparib and bevacizumab (bev) on a GOG phase I study (GOG 9923, NCT00989651). MethodsThis is an unplanned, post hoc analysis of an IRB approved, multi-institutional, prospective study (GOG 9923). Clinical characteristics and toxicity data based on BRCA status were evaluated and descriptive statistics were used to summarize baseline patient characteristics and toxicities. The Kaplan Meier method was used to generate survival estimates. ResultsFour hundred twenty-four patients were evaluable. Patients were treated with IV carboplatin, paclitaxel, and bev every 21 days (regimen 1), weekly IV paclitaxel with carboplatin and bev (regimen 2) or IV paclitaxel and bev with IP cisplatin (regimen 3). Bev was continued as maintenance in all arms. Within each of these regimens, veliparib was given either twice daily for the entirety of each cycle (continuous) or on days −2 to 5 (intermittent). Ten percent of patients treated on regimen 1, 12% on regimen 2, and 19.8% on regimen 3 had BRCA-associated tumors. Patients with BRCA-associated tumors, when compared to wild type, experienced similar rates of anemia, febrile neutropenia (, abdominal pain, colonic perforation, nausea, vomiting, and peripheral sensory neuropathy. Median progression free survival (PFS) was not significantly different between BRCA-associated and wild type cancers (HR 0.96, CI 0.65–1.42), though this study's primary aim was not to evaluate outcomes. ConclusionsGermline BRCA mutations positively affect chemosensitivity in EOC, but whether differences in toxicities among BRCA-associated and BRCA wild type tumors existed was previously not reported. In this population with newly diagnosed ovarian cancer no differences in reported toxicity between the two groups was observed.

The Role of BRCA1/2-Mutated Tumor Microenvironment in Breast Cancer.

Simple SummaryThe link between BRCA1/2 mutations and high susceptibility to breast cancer development has been well-established for years. However, the potential impact of BRCA1/2 mutations on the individual cell populations within the unique tumor microenvironment and their relation to breast cancer has been understudied. This review aims to provide significant insights into up-to-date knowledge about the role of BRCA1/2-mutated tumor microenvironment and possible mechanisms by which it interacts with and promotes breast cancer development and progression. Uncovering and exposing these mechanisms of the aberrant microenvironment might provide more effective strategies for treatment of germline mutation-carrying breast cancer patients.Taking into account the factors of high incidence rate, prevalence and mortality, breast cancer represents a crucial social and economic burden. Most cases of breast cancer develop as a consequence of somatic mutations accumulating in mammary epithelial cells throughout lifetime and approximately 5–10% can be ascribed to monogenic predispositions. Even though the role of genetic predispositions in breast cancer is well described in the context of genetics, very little is known about the role of the microenvironment carrying the same aberrant cells impaired by the germline mutation in the breast cancer development and progression. Based on the clinical observations, carcinomas carrying mutations in hereditary tumor-suppressor genes involved in maintaining genome integrity such as BRCA1/2 have worse prognosis and aggressive behavior. One of the mechanisms clarifying the aggressive nature of BRCA-associated tumors implies alterations within the surrounding adipose tissue itself. The objective of this review is to look at the role of BRCA1/2 mutations in the context of breast tumor microenvironment and plausible mechanisms by which it contributes to the aggressive behavior of the tumor cells.

Molecular biological subtypes of breast cancer in BRCA1 mutation carriers

Background. According to the literature, BRCA1-associated breast cancer (BC) most often belongs to the triple negative (TNBC) molecular subtype. The data on the contribution of other molecular subtypes to this group of patients differ among different studies.The study objective is to evaluate the frequency of different tumor molecular subtypes in BC patients with BRCA1 gene mutation treated in N. N. Blokhin National Medical Research Center of Oncology in the period from 2017 to 2020.Materials and methods. The study included BC patients with a mutation in the BRCA1 gene (n = 209) identified as a result BRCA1 mutation screening of patients with BC. DNA diagnostics was carried out on blood samples of patients using the real-time polymerase chain reaction method. After analyzing the patients primary documentation clinical and morphological data were taken into account: the age of diagnosis, the stage of the disease, the results of immunohistochemical studies (estrogen receptor status, progesterone receptor status, HER2 expression, Ki-67 proliferation index). The assignment to the particular molecular tumour subtypes was performed according to estrogen receptor status, progesterone receptor status, HER2 status and Ki67 value.Results. Clinical and pathomorphological data of 209 patients with BRCA1-associated BC were analyzed. The age at diagnosis ranged from 23 to 72 years, the median age was 40 years, the mean age was 41.46 ± 9.82 years. BC associated with BRCA1 was found to be TNBC in 71.3 % and luminal B, HER2 negative (LumB–) in 19.1 % of the cases. Other tumour subtypes were much less common: luminal B, HER2 positive (LumB+) in 7.2 %, luminal A (LumA) in 1 % and HER2-positive (HER2+) in 1.4 % of the cases. The frequency of subtypes was estimated in different age groups (1st – patients 23–34 (n = 53), 2nd – 35–49 (n = 111), and 3rd – 50–72 (n = 45) years old). TNBC frequency was 81.1 % in the 1st group, 73.9 % in the 2nd and 53.4 % in the 3rd group; LumB– frequency was 15.1, 15.3 and 33.3 % respectively. Using the Fisher test it was shown that the differences in frequencies were statistically significant between groups 1st and 3 rd, as well as between groups 2 nd and 3 rd (p &lt;0.05).Conclusion. TNBC was the main molecular subtype in all age groups of BC patients with BRCA1 germinal mutation, TNBC frequency was lower in the older age group. LumB– subtype was also common in BRCA1-associated tumors especially in older women.

Germinal BRCA1-2 pathogenic variants (gBRCA1-2pv) and pancreatic cancer: epidemiology of an Italian patient cohort

ObjectiveGermline BRCA1-2 pathogenic variants (gBRCApv) increase the risk of pancreatic cancer and predict for response to platinating agents and poly(ADP-ribose) polymerase inhibitors. Data on worldwide gBRCApv incidence among pancreatic ductal adenocarcinoma (PDAC) patients are sparse and describe a remarkable geographic heterogeneity. The aim of this study is to analyze the epidemiology of gBRCApv in Italian patients.Materials and methodsPatients of any age with pancreatic adenocarcinoma, screened within 3 months from diagnosis for gBRCApv in Italian oncologic centers systematically performing tests without any selection. For the purposes of our analysis, breast, ovarian, pancreas, and prostate cancer in a patient's family history was considered as potentially BRCA-associated. Patients or disease characteristics were examined using the χ2 test or Fisher's exact test for qualitative variables and the Student's t-test or Mann–Whitney test for continuous variables, as appropriate.ResultsBetween June 2015 and May 2020, 939 patients were tested by 14 Italian centers; 492 (52%) males, median age 62 years (range 28-87), 569 (61%) metastatic, 273 (29%) with a family history of potentially BRCA-associated cancers. gBRCA1-2pv were found in 76 patients (8.1%; 9.1% in metastatic; 6.4% in non-metastatic). The gBRCA2/gBRCA1 ratio was 5.4 : 1. Patients with gBRCApv were younger compared with wild-type (59 versus 62 years, P = 0.01). The gBRCApv rate was 17.1% among patients <40 years old, 10.4% among patients 41-50 years old, 9.2% among patients 51-60 years old, 6.7% among patients aged 61-70 years, and 6.2% among patients >70 years old (none out of 94 patients >73 years old). gBRCApv frequency in 845 patients <74 years old was 9%. Patients with/without a family history of potentially BRCA-associated tumors had 14%/6% mutations.ConclusionBased on our findings of a gBRCApv incidence higher than expected in a real-life series of Italian patients with incident PDAC, we recommend screening all PDAC patients <74 years old, regardless of family history and stage, due to the therapeutic implications and cancer risk prevention in patients' relatives.

Preclinical evaluation of radiation therapy of BRCA1-associated mammary tumors using a mouse model.

Although germline mutations in BRCA1 highly predispose women towards breast and ovarian cancer, few substantial improvements in preventing or treating such cancers have been made. Importantly, BRCA1 function is closely associated with DNA damage repair, which is required for genetic stability. Here, we examined the efficacy of radiotherapy, assessing the accumulation of genetic instabilities, in the treatment of BRCA1-associated breast cancer using a Brca1-mutant mouse model. Treatment of Brca1-mutant tumor-engrafted mice with X-rays reduced tumor progression by 27.9% compared with untreated controls. A correlation analysis of irradiation responses and biomarker profiles in tumors at baseline identified differences between responders and non-responders at the protein level (pERα, pCHK2, p53, and EpCAM) and at the SOX2 target expression level. We further demonstrated that combined treatment of Brca1-mutant mammary tumors with irradiation and AZD2281, which inhibits PARP, significantly reduced tumor progression and extended survival. Our findings enhance the understanding of DNA damage and biomarker responses in BRCA1-associated mammary tumors and provide preclinical evidence that radiotherapy with synthetic DNA damage is a potential strategy for the therapeutic management of BRCA1-associated breast cancer.

Genome-Wide Gene Expression Analyses of BRCA1- and BRCA2-Associated Breast and Ovarian Tumours.

Simple SummaryVariants in the breast cancer susceptibility genes BRCA1 and BRCA2 increase the risk of developing breast and ovarian cancers. Over the past two decades researchers have aimed to identify gene expression changes associated with high-risk BRCA1 and BRCA2 variants. In this review we explore the replicability of BRCA1- and BRCA2-associated gene expression profiles in diseased and normal tissue. We highlight the impact of experimental factors and study designs on the comparability and utility of gene expression profiles associated with high-risk BRCA1 and BRCA2 variants. Additionally, we emphasise the importance of controlling for confounding molecular features that may influence the design of study cohort groups.Germline pathogenic variants in BRCA1 and BRCA2 increase cumulative lifetime risk up to 75% for breast cancer and 76% for ovarian cancer. Genetic testing for BRCA1 and BRCA2 pathogenic variants has become an important part of clinical practice for cancer risk assessment and for reducing individual risk of developing cancer. Genetic testing can produce three outcomes: positive (a pathogenic variant), uninformative (no pathogenic variant) and uncertain significance (a variant of unknown clinical significance). More than one third of BRCA1 and BRCA2 variants identified have been classified as variants of uncertain significance, presenting a challenge for clinicians. To address this important clinical challenge, a number of studies have been undertaken to establish a gene expression phenotype for pathogenic BRCA1 and BRCA2 variant carriers in several diseased and normal tissues. However, the consistency of gene expression phenotypes described in studies has been poor. To determine if gene expression analysis has been a successful approach for variant classification, we describe the design and comparability of 23 published gene expression studies that have profiled cells from BRCA1 and BRCA2 pathogenic variant carriers. We show the impact of advancements in expression-based technologies, the importance of developing larger study cohorts and the necessity to better understand variables affecting gene expression profiles across different tissue types.

Clinical characteristics and prognostic implications of BRCA-associated tumors in males: a pan-tumor survey

BackgroundThe BRCA mutation (BRCAm) in males has been reported to confer a higher risk for the development of various tumors. However, little is known about its clinicopathologic features and prognostic implications.DesignWe conducted a retrospective pan-tumor survey on 346 cases of BRCA-associated tumors in males. Comparative analyses were conducted among male and female patients with BRCAm (n = 349), as well as in male patients without BRCAm (n = 4577).ResultsSimilar incidences of BRCAm (6.0 vs. 6.6%) and age at diagnosis of tumor (median, 65 vs. 60 years) were observed in male and female patients. Carcinomas of the lung, bladder, stomach, and cutaneous melanoma were the frequent tumors demonstrating BRCAm in males, of which the majority were stage II or III diseases with a higher frequency of BRCA2 mutations. Compared to that in the non-BRCAm group, cutaneous melanoma (16.3 vs. 5.0%), lung cancer (19.4 vs. 11.8%), bladder cancer (15.6 vs. 5.6%), and stomach cancer (11.9 vs. 5.5%) accounted for a higher proportion in the BRCAm group. Advanced disease and more mutation counts (median, 322 vs. 63 mutations) were also found in the BRCAm group. A total of 127 BRCA1 and 311 BRCA2 mutations were identified, of which 21.8 and 28.6% were deleterious, respectively. Frequent deleterious variants were identified in carcinomas of the breast (100.0%), colorectum (62.2%), prostate (43.3%), and stomach (42.9%). BRCA1 fusions with NF1, FAM134C, BECN1, or LSM12 and recurrent BRCA2 mutations at P606L/S, E832K/G, and T3033Lfs*29 were detected. Frameshift mutations in BRCA2 at N1784 (N1784Kfs*3, N1784Tfs*3) were frequently observed in both male and female patients. Compared with those in females, BRCA mutations in males were associated with decreased overall survival (OS) and progression-free survival (PFS). Male patients with deleterious BRCAm displayed increased OS compared with non-BRCAm carriers. The subgroup analysis demonstrated that BRCAm was associated with increased OS in gastric and bladder cancers, decreased PFS in prostate, esophageal, and head and neck cancers, and decreased OS in glioma/glioblastoma in males.ConclusionThese findings provide an overview of the distinct characteristics and clinical outcomes of male patients with BRCA-associated tumors, suggesting the importance of further genetic BRCA testing in males.