Pathology of breast and ovarian cancers among BRCA1 and BRCA2 mutation carriers: results from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA)

Genetic landscapes of breast tumors by next-generation sequencing with focus on less common types and genotype-phenotype correlations

Next-generation sequencing (NGS) has transformed our understanding of oncogenic pathways and mutational processes underlying many breast tumors. Although large-scale NGS studies included mostly common invasive breast carcinomas, the genetic landscapes of several less common or rare special histologic types and other breast tumors have now also been elucidated. Many of these lesions harbor highly specific types of mutations or rearrangements/gene fusions, including invasive lobular carcinoma, tall cell carcinoma with reversed polarity, most salivary gland-like neoplasms, fibroepithelial neoplasms, and mesenchymal tumors such as fibromatosis, nodular fasciitis, and dermatofibrosarcoma protuberans. In some cases, surrogate immunohistochemical or RNA in situ hybridization markers evaluable by light microscopy have been shown to correlate with the underlying genetic alterations. Angiosarcomas and other special breast cancer subtypes, such as triple negative apocrine carcinomas, metaplastic carcinomas, and a subset of ER-positive carcinomas (mucinous and micropapillary carcinomas, neuroendocrine neoplasms) have not been associated with specific genetic underpinnings but are enriched for certain genetic features and oncogenic pathways. The identification of characteristic genetic alterations or their molecular surrogates can be useful to establish an accurate diagnosis, and in some cases, may point to potentially actionable therapeutic targets. This review aims to summarize the genetic landscapes of less common benign and malignant breast tumors, with special attention to genotype-phenotype correlations and to the diagnostic utility of genetics and surrogate markers when applicable. BRCA1/2-associated breast carcinomas will also be discussed due to the association of so-called BRCAness with basal-like histology.

Identifying the germline variation spectrum and predisposition genes in Chinese ovarian cancer using whole exome sequencing

BACKGROUND

Next-generation sequencing (NGS) allows for the simultaneous sequencing of multiple cancer predisposition genes. We assessed the frequency and spectrum of germline variations in individuals with ovarian cancer (OC), using whole exome sequencing (WES).

METHODS

A total of 92 patients with OC, with or without a family history of cancer, were consecutively recruited between May 2020 and September 2023. Germline DNA was sequenced using WES.

RESULTS

Among the 12 canonical OC predisposition genes recommended by the National Comprehensive Cancer Network (NCCN) guidelines, 26 patients (28.26%) were found to have 28 pathogenic or likely pathogenic variations in 5 genes, including BRCA1 (n = 13), BRCA2 (n = 8), RAD51D (n = 4), BRIP1 (n = 2), and MSH2 (n = 1). Additionally, 24 patients (26.08%) harbored variants of uncertain significance (VUS) in canonical OC predisposition genes or other putative OC predisposition genes, including 3 loss of function variation: NM_001142548.1(RAD54L): c.1825C > T (p.Arg609Ter), NM_002907.3(RECQL): c.796C > T (p.Gln266Ter), and NM_001114132.2 (NBEAL1): c.5837dup (p.Tyr1946Ter). Moreover, we found that the detection rate of predisposition genes was correlated with a family history of malignancies and a personal history of other malignancies.

CONCLUSIONS

Using WES, we found that 28.26% of patients with OC had germline cancer-predisposing variations. WES substantially improved the detection rates of a wide spectrum of variations in OC patients and uncovered putative predisposition genes.

Impact of germline BRCA1/2 mutations on response to neoadjuvant systemic therapy and prognosis in breast cancer: a propensity score matched cohort study

BACKGROUND

We investigated whether germline BRCA1/2 pathogenic variants (PVs) influence treatment response and survival outcomes in breast cancer patients treated with neoadjuvant chemotherapy (NCT). Using propensity score matching (PSM) to control for variations in treatment and clinicopathological characteristics, this study aimed to evaluate the influence of BRCA1/2 mutations on prognosis and treatment efficacy, providing insights for optimizing therapeutic strategies and improving patient outcomes.

METHODS

We conducted a retrospective cohort study using data from two institutions. The study analyzed breast cancer patients who underwent germline BRCA1/2 testing and received NCT followed by curative resection and standard adjuvant therapy from January 2001 to January 2019. PSM was used to balance confounding variables.

RESULTS

Among 411 patients included, 86 have BRCA1/2 mutations. After matching, BRCA1/2 PV carriers had a higher pCR rate (40.0%) compared to wild-type patients (26.5%, OR = 1.85, 95% CI: 1.07-3.22, P = 0.029). They also exhibited a significantly lower 5-year DM rate (4.7% vs. 18.2%, OR = 0.22, 95% CI: 0.08-0.65, P = 0.006). Among pCR patients, outcomes were excellent regardless of BRCA1/2 status. For non-pCR patients, BRCA1/2 PV carriers had better DMFS (hazard ratio (HR) = 0.27, 95% confidence interval (CI) = 0.09-0.81, P = 0.02), though overall survival differences were not significant (HR = 0.47, 95% CI = 0.15-1.47, P = 0.197).

CONCLUSIONS AND RELEVANCE

Germline BRCA1/2 mutations are associated with higher pCR rates and improved DMFS in breast cancer patients treated with NCT. These findings emphasize the enhanced chemosensitivity of BRCA-associated tumors and the importance of genetic testing in treatment planning. Further research is needed to validate these findings and optimize treatment strategies.

Parity, breastfeeding, and the risk of early-onset breast cancer in women with a BRCA1 pathogenic variant

BACKGROUND

It is not clear if breastfeeding and/or parity are associated with the risk of breast cancer among women with a germline pathogenic variant in BRCA1. We sought to evaluate the associations of these two factors with early-onset breast cancer in the BRCA1 pathogenic variant.

METHODS

This case-control study included individuals with a BRCA1 pathogenic variant enroled in a longitudinal study using reproductive and disease histories ascertained at the time of enrolment. Cases had invasive breast cancer prior to age 45, and controls had no breast cancer prior to age 45. Logistic regression was used to evaluate the associations of parity and breastfeeding with cancer risk.

RESULTS

Parity per se was not associated with breast cancer risk (OR = 1.09; 95%CI 0.95-1.25); however, among women who never breastfed, the OR for parous vs. nulliparous women was 1.45 (95%CI 1.20-1.75). After matching for parity, ever breastfeeding was associated with 25% lower odds of breast cancer (95%CI 0.61-0.91), and the odds ratio was 0.53 (95%CI 0.40-0.72) for those who breastfed for 20 or more months.

DISCUSSION

Our findings suggest a potential role for breastfeeding in the prevention of young-onset breast cancer among individuals with a BRCA1 pathogenic variant and provide insight into possible prevention targets.

Population-based study of recurrent DNA damage response gene variants in breast cancer cases

PURPOSE

Several variants in DNA damage response (DDR) genes increase the probability to develop breast cancer and show enrichment in Northern Finland. Here, the population prevalence and risk estimations were refined for sixteen recurrent pathogenic/likely pathogenic DDR gene variants.

METHODS

Variant genotyping was performed in 2343 unselected Northern Finnish breast cancer cases and 4607 cancer-free controls, and tumor features and family history of cancer for the carriers were examined.

RESULTS

Based on their prevalence and carrier family history, the studied BRCA1 and BRCA2 variants, PALB2 c.1592delT, and ATM c.7570G > C were confirmed as high-risk alleles, whereas CHEK2 c.1100delC, MCPH1 c.909_921del, and RAD50 c.687delT were moderate-risk alleles. FANCM c.5101C > T and c.5791C > T did not associate with overall breast cancer risk. Double carriers were significantly more common in cases (0.5%, 11/2343) than controls (0.07%, 3/4601, OR 7.2). The BRCA1/2 and PALB2 c.1592delT carrier tumors all had high proliferation rates, PALB2 c.1592delT associating also with grade 3 tumors (p = 0.002). Progesterone receptor (p < 0.05) and estrogen receptor positive tumors were enriched in ATM c.7570G > C and CHEK2 c.1100delC carriers, whereas MCPH1 c.904_916del carriers had a significantly high percentage of multifocal tumors (38%, p = 0.001). Moreover, one FANCM c.5101C > T homozygote case suffered severe side effects from chemotherapy.

CONCLUSION

The studied DDR gene variants were present in 9% of the unselected cases. As the presence of germline pathogenic variants can provide additional value for surgical decision-making and affect the choice of oncological treatments, the results promote the benefits of genetic testing as a part of breast cancer diagnostics.

Association of gene variant type and location with breast cancer risk in the general population

BACKGROUND

Pathogenic variants (PVs) in ATM, BRCA1, BRCA2, CHEK2, and PALB2 are associated with increased breast cancer risk. It is unknown, however, whether this risk differs by PV type or location in carriers ascertained from the general population.

PATIENTS AND METHODS

To evaluate breast cancer risks associated with PV type and location in ATM, BRCA1, BRCA2, CHEK2, and PALB2, we carried out age-adjusted case-control association analysis in 32 247 women with and 32 544 age-matched women without breast cancer from the CARRIERS Consortium. PVs were grouped by type and location within genes and assessed for risks of breast cancer [odds ratios (OR), 95% confidence intervals (CI), and P values] using logistic regression.

RESULTS

Compared with women carrying BRCA2 exon 11 protein truncating variants (PTVs) in the CARRIERS population-based study, women with BRCA2 ex1-10 PTVs (OR = 13.5, 95% CI 6.0-38.7, P < 0.001) and ex13-27 PTVs (OR = 9.0, 95% CI 4.9-18.5, P < 0.001) had higher breast cancer risks, lower rates of estrogen receptor (ER)-negative breast cancer (ex13-27 OR = 0.5, 95% CI 0.2-0.9, P = 0.035; ex1-10 OR = 0.5, 95% CI 0.1-1.0, P = 0.065), and earlier age at breast cancer diagnosis (ex13-27 5.5 years, P < 0.001; ex1-10 2.4 years, P = 0.169). These associations with ER-negative breast cancer and age were replicated in a high-risk clinical cohort from Ambry Genetics and the population-based UK Biobank cohort. No differences in risk by gene region were observed for PTVs in other predisposition genes.

CONCLUSIONS

Population-based and clinical high-risk cohorts establish that PTVs in exon 11 of BRCA2 are associated with reduced breast cancer risk, later age at diagnosis, and greater risk of ER-negative disease. These differential risks may improve individualized risk prediction and clinical management for women carrying BRCA2 PTVs.

Germline Testing in Breast Cancer: A Single-Center Analysis Comparing Strengths and Challenges of Different Approaches

BACKGROUND/OBJECTIVES

Compared to single gene testing (SGT), multigene panel testing (MGPT) improves pathogenic variants (PVs) detection. However, MGPT yields complex results, including secondary findings, heterozygous PVs in recessive genes, low-penetrance PVs, and variants of uncertain significance. We reported our mono-institutional experience of germline testing in breast cancer (BC), comparing SGT and MGPT.

METHODS

We retrospectively analyzed clinical and molecular data from 1084 BC patients: 308 underwent SGT (BRCA1/BRCA2) and 776 MGPT (for 28 cancer-related genes). We compared these approaches regarding the genetic classification of the findings (positive, uncertain, uninformative) and their impact on clinical management (primary findings (PFs); complex and inconclusive results). Additionally, we described clinical features supporting one approach over the other and focused on copy number variation (CNV) frequency in non-BRCA genes.

RESULTS

We found ≥1 PV in 165 patients (165/1084 = 15.2%), including 91 in BRCA1/BRCA2 (91/1084 = 8.4%), with 42 identified by SGT (42/308 = 13.6%) and 49 by MGPT (49/776 = 6.3%). MGPT detected PVs in non-BRCA genes in 74 patients (74/776 = 9.5%), including 40 PFs. Overall, MGPT identified 89 PFs (89/776 = 11.5%). We observed complex results in 21 patients (21/308 = 6.8%) with SGT and in 300 (300/776 = 38.7%) with MGPT. Compared to MGPT, SGT detected a similar percentage of PFs (13.6% vs. 11.5%) but a significantly reduced percentage of complex results (6.8% vs. 38.7%) (p < 0.001). Triple-negative BCs prevailed in BRCA1 carriers, while ER-positive BCs were more prevalent in ATM/CHEK2 carriers. Concerning non-BRCA genes, MGPT detected CNVs in PALB2, representing 20% of PVs in this gene.

CONCLUSIONS

Although MGPT increases hereditary BC detection, its complexity requires clear guidelines for optimal clinical management and strategies for merging the benefits of SGT and MGPT.

Chemotherapy receipt in affected BRCA1/2 and PALB2 carriers with operable breast cancer: the impact of early detection and pre-diagnostic awareness on clinical outcomes and treatment

PURPOSE

While enhanced breast screening of germline pathogenic variant (GPV) carriers results in earlier stage at diagnosis, the impact of tumour biology and GPV on chemotherapy receipt in early-stage disease remains understudied.

METHODS

We retrospectively reviewed treatment administered following a first diagnosis of BRCA1/2- and PALB2-associated breast cancer between 2002 and 2022. Chemotherapy receipt was compared according to tumor size, biologic subtype, and GPV. Subgroup analyses were performed in women with T1N0 disease and in those with pre-diagnostic awareness of their GPV.

RESULTS

Overall, 309 affected BRCA1/2 and PALB2 carriers with a median age of 43 years at breast cancer diagnosis (range, 19-80 years) were included; 160 (51.8%) BRCA1, 130 (42.1%) BRCA2, and 19 (6.1%) PALB2 carriers. Chemotherapy was administered in 70.9% of index breast cancer cases and was significantly associated with younger age, tumor size, histologic grade, nodal status, and biologic subtype (all p < 0.05). Chemotherapy receipt was 80.6% in BRCA1-associated breast cancers compared to 56.9% in BRCA2 and 84.2% in PALB2 associated breast cancers (p < 0.001). In subgroup analysis of early stage, T1N0 disease, chemotherapy was administered in 78.9% BRCA1 and 59.5% BRCA2/PALB2 patients (p = 0.04). Pre-diagnostic awareness of a GPV in BRCA1/2 or PALB2 was associated with smaller invasive tumors (%T1, 50% vs. 32.9%; p = 0.002) and node-negative invasive disease (87.1% vs. 72.2%), as well as a reduced likelihood of chemotherapy (59.7% vs. 74.3%, p = 0.02).

CONCLUSION

Chemotherapy receipt is high in BRCA1/2 and PALB2-associated breast cancers including in early stage, node-negative disease. Pre-diagnostic awareness is associated with a lower likelihood of requiring chemotherapy for a breast cancer diagnosis.

Risk of lymphoid malignancy associated with cancer predisposition genes

We investigated the prevalence of rare inherited pathogenic variants (PV) in 19 cancer predisposition genes regularly included on multi-gene panel testing based on NCCN guidelines and their association with the risk of lymphoid malignancies (LM) overall and by common lymphoma subtypes and multiple myeloma. The study population included newly diagnosed LM cases (N = 6990) and unrelated controls (N = 42,632), excluding individuals with a history of hematologic malignancy. Whole exome sequencing was performed on DNA from whole blood. PV were defined as loss-of-function (i.e., nonsense, frameshift, consensus splice sites) or identified as "pathogenic" or "likely pathogenic" in the ClinVar database. A total of 1816 (3.7%) individuals had a PV across the 19 genes, higher in cases (4.7%) than controls (3.5%). In controls, CHEK2 (1.0%), ATM (0.4%), BRCA2 (0.4%), and BRCA1 (0.3%) had the highest prevalence. ATM (odds ratio [OR] = 1.86, 95% confidence interval [CI]: 1.36-2.49), CHEK2 (OR = 1.74, 95% CI: 1.42-2.13) and TP53 (OR = 9.07, 95% CI: 4.51-18.87) were associated with increased risk of LM overall and were further validated in the UK Biobank. We observed heterogeneity in associations by LM subtype. These results demonstrate that several commonly tested cancer predisposition genes are associated with an increased risk of LM.

Current controversies in the use of Oncotype DX in early breast cancer

Multigene prognostic genomic assays have become essential tools in the management of early breast cancer (BC), providing information that help in risk-stratification, to provide risk-adapted decision-making of adjuvant treatments. Clinical practice guidelines recommend refining the prognostic information provided by clinical and pathology features with the use of genomic tests, such as Oncotype DX®, to classify cancers into risk groups and inform adjuvant treatment strategies. However, the clinical value (i.e., prognostic and/or predictive) and applicability of these assays vary due to differences in the clinical setting, especially in those populations that were underrepresented in pivotal clinical trials. Oncotype DX® is a broadly utilized genomic test for breast cancer, having the highest level of supporting evidence to inform clinical practice. Our manuscript provides a comprehensive overview on this recurrence score assay, evaluates supporting evidence across patient populations, and discusses their impact on treatment decisions in those groups of patients underrepresented in pivotal clinical trials, where evidence is limited with the use of Oncotype DX.

Constitutional Epimutations: From Rare Events Toward Major Cancer Risk Factors?

Constitutional epimutations are epigenetic aberrations that arise in normal cells prenatally. Two major forms exist: secondary constitutional epimutations (SCEs), associated with cis-acting genetic aberrations, and primary constitutional epimutations (PCEs), for which no associated genetic aberrations were identified. Some SCEs have been associated with risk of cancer (MLH1 and MSH2 with colon or endometrial cancers, BRCA1 with familial breast and ovarian cancers), although such epimutations are rare, with a total of <100 cases reported. This contrasts recent findings for PCE, where low-level mosaic BRCA1 epimutations are recorded in 5%-10% of healthy females across all age groups, including newborns. BRCA1 PCEs predict an elevated risk of high-grade serous ovarian cancer and triple-negative breast cancer (TNBC) and are estimated to account for about 20% of all TNBCs. A similarly high population frequency is observed for mosaic constitutional epimutations in MGMT, occurring as PCE or SCE, but not in MLH1. Contrasting BRCA1 and MLH1, a potential association with cancer risk for MGMT epimutations is yet unclear. In this review, we provide a summary of findings linking constitutional epimutations to cancer risk with emphasis on PCE. We also highlight challenges in detection of PCE exemplified by low-level mosaic epimutations in BRCA1 and indicate the need for further studies, hypothesizing that improved knowledge about PCE may add significantly to our understanding of cancer risk, carcinogenesis, and potentially development of other diseases as well.

Beyond failure of endocrine-based therapies in HR+/HER2 negative advanced breast cancer: What before chemotherapy? A glimpse into the future

Despite the impressive improvements achieved by endocrine therapy and CDK4/6 inhibitors (CDK4/6i) and the forthcoming availability of alternative endocrine manipulations and targeted therapies, hormone-receptor positive/HER2 negative (HR+/HER2-) advanced breast cancer (ABC) is almost inevitably destined to become endocrine- refractory. At this time chemotherapy has been recently challenged and partly replaced by new targeted options as antibody-drug conjugated (ADCs). Trastuzumab-deruxtecan has been proven meaningfully superior to chemotherapy either in 1st and later lines after progression to CDK4/6i in HER2-low ABC and results with other ADCs as Sacituzumab Govitecan and Datopotamab-deruxtecan are promising, but the definition of cross-resistance between these drugs sharing either antibody or payload is crucial before implementing them in a useful sequence. While PARP inhibitors are the standard 2nd line in patients with gBRCA mutation, it is not still known whether patients with mutations of PALB2 or of other homologous recombinant defect (HRD)-related genes will benefit of the same treatment. On the other hand, the results obtained with immune checkpoint inhibitors (ICIs) in HR+ /HER2-ABC contrarily to the early setting are disappointing up to now, but investigations of ICIs in combination with other targeted drugs which may increase immune response and the search for better markers of activity are under way. Moreover the anticipation in upfront treatment of ADCs or PARPi in patients with features of putative endocrine resistance and/or of less sensitiviy to CDK4/6i and the choice of therapy in patients recurring during or soon after adjuvant CDK4/6i and olaparib represent further challenges for the future.

The patterns and spectrum of BRCA1 and BRCA2 mutations in Iranian breast and ovarian cancer patients

Women with inherited BRCA1/2 mutations are at increased risk of breast and ovarian cancer. The reports on the prevalence and spectrum of these mutations have been primarily focused on individuals with European ancestry. A previous study on Iranian breast cancer patients reported no BRCA1/2 mutation in early-onset breast cancer with no other criteria, which is contrary to other populations. The purpose of this study was to characterize the patterns of these mutations in Iranian breast and ovarian cancer patients and evaluate the predictive efficacy of the Manchester scoring system in patients and their unaffected family members. We retrospectively reviewed the genetic testing performed for breast and ovarian cancer patients and unaffected individuals with a positive family history. The study participants were selected based on the NCCN (National Comprehensive Cancer Network) criteria (version 2.2024). A total of 376 female breast cancer patients, 49 ovarian cancer patients, and 74 unaffected individuals were enrolled in this study. In breast cancer patients, 24 (6.4%) BRCA1 and 23 (6.1%) BRCA2 mutations were detected. In ovarian cancer patients, 9 (18.5%) BRCA1 and 1 (2%) BRCA2 mutations were identified. Three (4.1%) BRCA2 mutations were identified in unaffected individuals. Seven breast cancer patients with age of cancer diagnosis ≤ 40 and no other criteria (including family history) had an underlying mutation: Four BRCA2, and three BRCA1 mutations. The Manchester score performed well, with a sensitivity of 81% and a specificity of 70%. More research is needed to clarify the hereditary component of breast and ovarian cancer in Iranian patients.

Dual targeting of Aurora Kinase A and poly (ADP-ribose) polymerase as a therapeutic option for patients with ovarian cancer: preclinical evaluations

PURPOSE

Epithelial ovarian cancers (EOCs) are often diagnosed at an advanced stage, leading to poor survival outcomes despite chemotherapeutic and surgical advances. Precision oncology strategies have been developed to treat EOCs characterized by BRCA1 and BRCA2 inactivation with consequent homologous recombination (HR) repair defects. HR deficiency enhances tumor sensitivity to poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis), approved for EOCs as maintenance therapy, although they have been discontinued as recurrent EOC monotherapy. However, combination treatment with PARPis may be a viable alternate strategy for EOCs. Moreover, EOC patients with wild-type BRCA are ineligible for PARPs, necessitating novel approaches. We previously discovered that inhibiting Aurora kinase A (AURKA) downregulates PARP and BRCA1/2 expression in EOCs and may constitute a viable approach for EOCs.

METHODS

Herein, we evaluated combined PARPi olaparib with the selective AURKA inhibitor (AURKAi) VIC-1911 in six different patient-derived xenograft (PDX) EOC models, including two with mutant BRCA1, two with mutant BRCA2, one with mutant BRCA1/2, and one with wild-type BRCA1/2.

RESULTS

We found that combined olaparib + VIC-1911 treatment reduced tumor volumes and weights by up 90% in some PDX models, with synergistic effect compared to olaparib and VIC-1911 monotherapy. Additionally, combined olaparib + VIC-1911 treatment improved survival of mice harboring both mutant BRCA1 and wild-type BRCA1/2 PDXs. Generally, mice tolerated the drug combinations well during treatment, though loss of body weight was observed at higher drug dosages and with intensive treatment regimens.

CONCLUSION

Our studies indicate a synergistic benefit from combined PARPi and AURKAi in mutant and wild-type BRCA EOC tumors.

Prognostic Significance and Molecular Classification of Triple Negative Breast Cancer: A Systematic Review

Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer defined by the absence of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression. Despite accounting for 15-20% of all breast cancer cases, TNBC is associated with poor prognosis and a high likelihood of recurrence and metastasis. Understanding the molecular subtypes of TNBC is important for developing targeted therapies and improving patient outcomes. This systematic review aimed to assess the prognostic significance of molecular subtypes of TNBC and the implications for therapeutic management. A comprehensive literature search was conducted across multiple databases, including PubMed, Scopus, and Web of Science, to identify studies focusing on the molecular classification of TNBC and its prognostic relevance. Studies were included based on specific inclusion criteria, including original research evaluating clinical outcomes and survival data in molecularly classified TNBC cohorts. Data were extracted, synthesized, and analyzed to determine the prognostic implications of different TNBC subtypes. The review identified several distinct molecular subtypes of TNBC, including basal-like, mesenchymal, immune-modulatory, and luminal androgen receptor (LAR) subtypes. Basal-like TNBC was associated with poor prognosis and high rates of recurrence, while immune-modulatory TNBC exhibited better survival outcomes, particularly in patients with high levels of tumor-infiltrating lymphocytes. Mesenchymal and LAR subtypes exhibited diverse clinical behavior and varying therapeutic responses. Furthermore, key prognostic biomarkers, such as BRCA1/2 mutations and programmed death-ligand 1 expression, were highlighted which have therapeutic implications. Molecular classification of TNBC provides valuable prognostic information and guides therapeutic strategies. Integrating molecular subtyping into clinical decision-making will be essential for the development of personalized treatments and improved outcomes for TNBC patients. However, further research is needed to refine classification systems and address existing therapeutic gaps in TNBC management.

Signaling pathway dysregulation in breast cancer

This article provides a comprehensive analysis of the signaling pathways implicated in breast cancer (BC), the most prevalent malignancy among women and a leading cause of cancer-related mortality globally. Special emphasis is placed on the structural dynamics of protein complexes that are integral to the regulation of these signaling cascades. Dysregulation of cellular signaling is a fundamental aspect of BC pathophysiology, with both upstream and downstream signaling cascade activation contributing to cellular process aberrations that not only drive tumor growth, but also contribute to resistance against current treatments. The review explores alterations within these pathways across different BC subtypes and highlights potential therapeutic strategies targeting these pathways. Additionally, the influence of specific mutations on therapeutic decision-making is examined, underscoring their relevance to particular BC subtypes. The article also discusses both approved therapeutic modalities and ongoing clinical trials targeting disrupted signaling pathways. However, further investigation is necessary to fully elucidate the underlying mechanisms and optimize personalized treatment approaches.

[Risk-reducing bilateral salpingo-oophorectomy: For whom, how and what results?]

Currently, the main means of diagnosing ovarian cancer at an early stage involve risk prediction, prevention and screening in patients identified as being at genetic risk. Our aim is to identify patients who may benefit from bilateral salpingo-oophorectomy for risk reduction purposes, as well as the modalities for its realization. We list the genes associated with ovarian cancer predisposition, their frequency in the general population, the risk of patients carrying these genes developing ovarian cancer, and the risk-reducing surgical procedures associated with each gene.

The prognostic significance of fragile X mental retardation syndrome-related protein 1 (FXR1) in breast cancer

Background

Breast cancer (BC) is a highly heterogeneous disease with variable histological appearance, biological features, clinical outcomes, and treatment responses. The number of BC cases in Saudi Arabia has more than tripled during the last 17 years to constitute 30% of all cancer cases in women. Therefore, greater efforts are needed to evaluate prognostic factors for BC in Saudi Arabia to improve prognostication and provide more personalized therapy. Recently, fragile X mental retardation syndrome-related protein 1 (FXR1) was identified as a novel biomarker that contributes to oncogenesis; however, its role in BC has not been well studied. This study aims to evaluate the clinicopathological significance of FXR1 in women with primary BC.

Methods

The protein levels of FXR1 in BC tissue samples (n=100) were determined immunohistochemically. The associations between FXR1 levels and clinicopathological parameters and outcomes were evaluated, and significant associations were validated by assessing FXR1 mRNA levels in publicly available cohorts in the BC Gene-Expression Miner database (version 5).

Results

High protein levels of FXR1 were significantly associated with tumor aggressiveness, including stage IIB and IIIC and hormone receptor negativity, the triple-negative BC (TNBC) subtype, and poor outcomes. Consistent with the protein results, high mRNA levels of FXR1 were significantly associated with hormone receptor negativity and the TNBC subtype.

Conclusions

This study revealed that FXR1 is a prognostic factor for poor prognosis in women with BC. Further functional studies are needed to confirm its role in aggressive BC and its value as a therapeutic target.

Germinal mutations among patients with breast cancer in Colombia: is BRCA3 coming?

Purpose

Breast cancer is the most common type of cancer in women and accounts for 25% of all cancers worldwide. The mechanisms by which it develops include germline (generally inherited) and somatic mutations. There are six mutations with the highest incidence in the Colombian population, called the Colombia profile, which is associated with the BRCA1 and BRCA2 genes. The aim of this study is to identify germline mutations in individuals with breast cancer, such as BRCA and other genes.

Methods

This study describes the frequency and type of variants in hereditary cancer genes associated with breast cancer detected by the next-generation sequencing of a panel of 111 hereditary cancer genes, including BRCA1 and BRCA2.

Results

This analysis allowed the identification of variants associated with breast cancer in 307 patients from a population in southwestern Colombia, of which 19% had pathogenic and probably pathogenic mutations associated with hereditary cancer. According to the variant classification, it was found that the mutation frequency in BRCA1 was 17%, in BRCA2 was 14% and in the ATM gene was 12%; nevertheless, 57% of mutations were attributed to other genes such as MUTYH, FANCM, FANCA and TP53. Four patients were found to have the mutation c.3450delCAAG in the BRCA1 gene, which is included in the Colombia profile.

Conclusion

In summary, in the Colombian population, there is a great diversity of germline mutations in genes other than BRCA1 and BRCA2 that are associated with breast cancer. Studying mutations and variants of uncertain significance in ATM could improve understanding of how mutations in these genes contribute to cancer and whether ATM should be considered as BRCA3.

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

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

Survivors of BC carrying BRCA1 and BRCA2 PVs are at high SPC risk. They may benefit from enhanced surveillance and risk-reduction measures.

Long Intergenic Non-Coding RNAs and BRCA1 in Breast Cancer Pathogenesis: Neighboring Companions or Nemeses?

Breast cancer is one of the leading causes of mortality among women, primarily due to its complex molecular landscape and heterogeneous nature. The tendency of breast cancer patients to develop metastases poses significant challenges in clinical management. Notably, mutations in the breast cancer gene 1 (BRCA1) significantly elevate breast cancer risk. The current research endeavors employ diverse molecular approaches, including RNA, DNA, and protein studies, to explore avenues for the early diagnosis and treatment of breast cancer. Recent attention has shifted towards long non-coding RNAs (lncRNAs) as promising diagnostic, prognostic, and therapeutic targets in the multifaceted progression of breast cancer. Among these, long intergenic non-coding RNAs (lincRNAs), a specific class of lncRNAs, play critical roles in regulating various aspects of tumorigenesis, including cell proliferation, apoptosis, epigenetic modulation, tumor invasion, and metastasis. Their distinctive expression patterns in cellular and tissue contexts underscore their importance in breast cancer development and progression. Harnessing lincRNAs' sensitivity and precision as diagnostic, therapeutic, and prognostic markers holds significant promise for the clinical management of breast cancer. However, the potential of lincRNAs remains relatively underexplored, particularly in the context of BRCA1-mutated breast cancer and other clinicopathological parameters such as receptor status and patient survival. Consequently, there is an urgent need for comprehensive investigations into novel diagnostic and prognostic breast cancer biomarkers. This review examines the roles of lincRNAs associated with BRCA1 in the landscape of breast cancer, highlighting the potential avenues for future research and clinical applications.

Germline BRCA testing in Denmark following invasive breast cancer: Progress since 2000

BACKGROUND AND PURPOSE

Despite advancements in genetic testing and expanded eligibility criteria, underutilisation of germline testing for pathogenic variants in BRCA1 and BRCA2 (BRCA) remains evident among breast cancer (BC) patients. This observational cohort study presents real-world data on BRCA testing within the context of clinical practice challenges, including incomplete family history and under-referral.

MATERIAL AND METHODS

From the Danish Breast Cancer Group (DBCG) clinical database, we included 65,117 females with unilateral stage I-III BC diagnosed in 2000-2017, of whom 9,125 (14%) were BRCA tested. Test results spanned from 1999 to 2021. We evaluated test rates overall and in three diagnosis periods. In logistic regression models, we examined the correlation between a BRCA test and patients' age, residency region, receptor status, and diagnosis period.

RESULTS

Test rates rose most significantly among patients aged under 40 years, increasing from 47% (2000-2005) to 88% (2012-2017), albeit with regional discrepancies. Test timing shifted in recent years, with most results within 6 months of BC diagnosis, primarily among the youngest patients. BRCA test rates were higher for oestrogen receptor-negative/human epidermal growth factor receptor 2-negative BC (25% in 2000-2005 vs. 38% in 2012-2017), and these findings were confirmed in multivariate regression models.

INTERPRETATION

Our results indicate a critical need for an intensified focus on BRCA testing among BC patients older than 40, where a mainstreamed testing approach might overcome delayed or missed testing. Current DBCG guidelines recommend BRCA testing of all BC patients younger than 50 years, while a general recommendation for older patients is still missing.

BRCA1 and BRCA2: from cancer susceptibility to synthetic lethality

The discovery of BRCA1 and BRCA2 as tumor susceptibility genes and their role in genome maintenance has transformed our understanding of hereditary breast and ovarian cancer. This review traces the evolution of BRCA1/2 research over the past 30 years, highlighting key discoveries in the field and their contributions to tumor development. Additionally, we discuss current preventive measures for BRCA1/2 mutation carriers and targeted treatment options based on the concept of synthetic lethality. Finally, we explore the challenges of acquired therapy resistance and discuss potential alternative avenues for targeting BRCA1/2 mutant tumors.

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

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Breast Cancer Susceptibility Gene Sequence Variations and Development of Contralateral Breast Cancer

Importance

Heterogeneity in development of estrogen receptor (ER)-specific first primary breast cancer exists due to deleterious germline variants in moderate- to high-penetrance breast cancer susceptibility genes, but it is unknown if these associations occur in ER-specific CBC.

Objective

To determine the association of deleterious germline variants in breast cancer susceptibility genes with ER-specific CBC development and whether ER status of the first primary breast cancer modifies these associations.

Design, Setting, and Participants

This case-control study included CBC cases and matched unilateral breast cancer controls from The Women's Environment, Cancer, and Radiation Epidemiology (WECARE) Study, a population-based case-control study. Eligible women were diagnosed between 1985 and 2000 with data and biospecimens collected from 2001 to 2004. Eligible participants were women younger than 55 years at first invasive breast cancer diagnosis. Participants were matched on age, diagnosis year, cancer registry region, and race and ethnicity, and countermatched on radiation treatment. For cases, CBC occurred 1 year or more following first breast cancer diagnosis. Analyses were performed from May to October 2024.

Exposures

CHEK2 1100delC and deleterious variants in ATM, BRCA1, and BRCA2.

Main Outcome and Measure

Development of CBC, measured as a rate ratio (RR).

Results

A total of 1290 women were included in analysis (median [IQR] age at first diagnosis, 47 [42-51] years). The ER-positive CBC rate for women with deleterious ATM variants was 4 times higher than for women without deleterious ATM variants (RR, 4.84; 95% CI, 1.11-21.08; P = .04); no women with ER-negative CBC carried deleterious ATM variants. The ER-positive CBC rates for women with deleterious variants in BRCA2 or CHEK2 1100delC were 5 to 6 times higher than for women without deleterious variants in BRCA2 or CHEK2 1100delC, respectively (BRCA2: RR, 5.88; 95% CI, 2.61-13.26, P < .001; CHEK2 1100delC: RR, 6.06; 95% CI, 1.26-29.04; P = .02). The ER-negative CBC rate for women with deleterious BRCA1 variants was 26 times higher than for women without deleterious BRCA1 variants (RR, 26.16; 95% CI, 8.01-85.44; P < .001). First primary breast cancer ER status did not modify associations between deleterious variants and ER-specific CBC development.

Conclusions and Relevance

In this case-control study of CBC, deleterious variants in breast cancer susceptibility genes were differentially associated with ER-specific CBC development. Germline variation profile may inform estimates of outcomes for ER-specific CBC subtypes.

A therapeutic algorithm guiding subsequent therapy selection after CDK4/6 inhibitors' failure: A review of current and investigational treatment for HR+/Her2- breast cancer

The first-line combination therapies utilizing cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) with endocrine therapy (ET) have significantly impacted the course of hormone receptor positive (HR+)/Human Epidermal Growth Factor Receptor 2 negative (HER2-) advanced breast cancer (ABC). However, resistance often emerges, leading to a molecularly different disease. Estrogen receptor one (ESR1) gene mutations, driving resistance to aromatase inhibitors (AIs), may guide the use of fulvestrant or emerging oral selective estrogen receptor degraders (SERDs) like elacestrant. The dynamic nature of ESR1 mutations suggests potential guidance for continuing CDK4/6i therapy beyond progression. Targeting mutations like breast cancer gene 1 and 2 (BRCA 1/2) with Poly (ADP-ribose) polymerase (PARP) inhibitors or the PI3K/AKT/mTOR pathway provides therapeutic options. The advent of antibody-drug conjugates (ADCs) like trastuzumab deruxtecan (T-DXd) and novel agents targeting Trophoblast cell surface antigen-2 (Trop-2) introduces further complexity, underscoring the need for early intervention targeting specific genomic alterations in metastatic BC.

The Tumour Microenvironment and Epigenetic Regulation in BRCA1 Pathogenic Variant-Associated Breast Cancers

Background/Objectives: BRCA1 pathogenic variant (PV)-associated breast cancers are most commonly seen in hereditary genetic conditions such as the autosomal-dominant Hereditary Breast and Ovarian Cancer (HBOC) syndrome, and rarely in sporadic breast cancer. Such breast cancers tend to exhibit greater aggressiveness and poorer prognoses due to the influence of BRCA1 pathogenic variants (PVs) on the tumour microenvironment. Additionally, while the genetic basis of BRCA1 PV breast cancer is well-studied, the role of epigenetic mediators in the tumourigenesis of these hereditary breast cancers is also worth exploring. Results: PVs in the BRCA1 gene interact with stromal cells and immune cells, promoting epithelial-mesenchymal transition, angiogenesis, and affecting oestrogen levels. Additionally, BRCA1 PVs contribute to breast cancer development through epigenetic effects on cells, including DNA methylation and histone acetylation, leading to the suppression of proto-oncogenes and dysregulation of cytokines. In terms of epigenetics, lysine-specific demethylase 1 (LSD-1) is considered a master epigenetic regulator, governing both transcriptional repression and activation. It exerts epigenetic control over BRCA1 and, to a lesser extent, BRCA2 genes. The upregulation of LSD-1 is generally associated with a poorer prognosis in cancer patients. In the context of breast cancer in BRCA1/2 PV carriers, LSD-1 contributes to tumour development through various mechanisms. These include the maintenance of a hypoxic environment and direct suppression of BRCA1 gene expression. Conclusions: While LSD-1 itself does not directly cause mutations in BRCA1 or BRCA2 genes, its epigenetic influence sheds light on the potential role of LSD-1 inhibitors as a therapeutic approach in managing breast cancer, particularly in individuals with BRCA1/2 PVs. Targeting LSD-1 may help counteract its detrimental effects and provide a promising avenue for therapy in this specific subgroup of breast cancer.

Mutations Matter: Unravelling the Genetic Blueprint of Invasive Lobular Carcinoma for Progression Insights and Treatment Strategies

Invasive Lobular Carcinoma (ILC) presents a distinct subtype of breast cancer, representing 10-15% of cases, with unique clinical and molecular features. Characterized by a non-cohesive, single-file invasion pattern, ILC is typically estrogen receptor (ER)- and progesterone receptor (PR)-positive but human epidermal growth factor receptor 2 (HER2)-negative. Despite favorable prognostic features, its highly metastatic nature and predilection for atypical sites contribute to lower long-term survival compared to invasive breast carcinoma of no special type (NST). ILC's genetic landscape includes mutations in various genes (CDH1, BRCA2, ATM, etc.) and signaling pathways that impact treatment responses, especially in endocrine treatment. Furthermore, the diverse ILC subtypes complicate its management. Current challenges in chemotherapy, along with the targeted therapies, are also discussed. The present article aims to comprehensively review the recent literature, focusing on the pathological and molecular aspects of ILC, including associated genetic mutations influencing disease progression and drug resistance.

Poly (adenosine diphosphate-ribose) polymerase inhibitors in the treatment of triple-negative breast cancer with homologous repair deficiency

Breast cancer (BC) is a highly heterogeneous disease, and the presence of germline breast cancer gene mutation (gBRCAm) is associated with a poor prognosis. Triple-negative breast cancer (TNBC) is a BC subtype, characterized by the absence of hormone and growth factor receptor expression, making therapeutic decisions difficult. Defects in the DNA damage response pathway due to mutation in breast cancer genes (BRCA 1/2) lead to homologous recombination deficiency (HRD). However, in HRD conditions, poly (adenosine diphosphate-ribose) polymerase (PARP) proteins repair DNA damage and lead to tumor cell survival. Biological understanding of HRD leads to the development of PARP inhibitors (PARPi), which trap PARP proteins and cause genomic instability and tumor cell lysis. HRD assessment can be an important biomarker in identifying gBRCAm patients with BC who could benefit from PARPi therapy. HRD can be identified by homologous recombination repair (HRR) gene-based assays, genomic-scarring assays and mutational signatures, transcription and protein expression profiles, and functional assays. However, gold standard methodologies that are robust and reliable to assess HRD are not available currently. Hence, there is a pressing need to develop accurate biomarkers identifying HRD tumors to guide targeted therapies such as PARPi in patients with BC. HRD assessment has shown fruitful outcomes in chemotherapy studies and preliminary evidence on PARPi intervention as monotherapy and combination therapy in HRD-stratified patients. Furthermore, ongoing trials are exploring the potential of PARPi in BC and clinically complex TNBC settings, where HRD testing is used as an adjunct to stratify patients based on BRCA mutations.

From fallopian tube epithelium to high-grade serous ovarian cancer: A single-cell resolution review of sex steroid hormone signaling

High-grade serous ovarian cancer (HGSOC) represents the most lethal subtype of ovarian cancer, largely due to being commonly diagnosed at advanced stages. The early molecular mechanisms underlying ovarian carcinogenesis remain poorly defined, posing challenges to the development of prevention and early detection strategies. Here we dissect the molecular mechanisms of sex steroid hormone signaling throughout the decades-long evolution of HGSOC precursor lesions, which predominantly originate from secretory epithelial cells of fallopian tubes (FT). We also discuss the prognostic significance of sex steroid receptor isoforms and steroid metabolizing enzymes in HGSOCs. Finally, we provide a comprehensive gene expression atlases of sex steroid receptors, steroidogenic, and steroid-metabolizing enzymes across different cell populations in pre- and postmenopausal FTs, and HGSOCs, using published single-cell RNA sequencing datasets. These atlases reveal that secretory epithelial cells and stromal populations in FTs express sex steroid receptors and enzymes responsible for the formation and inactivation of genotoxic estrogen metabolites. In HGSOC, epithelial cells express various HSD17B isoforms and steroid conjugating enzymes, suggesting an enhanced ability to finely regulate the levels of bioactive sex steroids.

Association of Gene Variant Type and Location with Breast Cancer Risk in the General Population

Importance

Pathogenic variants (PVs) in ATM, BRCA1, BRCA2, CHEK2 , and PALB2 are associated with increased breast cancer risk. However, it is unknown whether breast cancer risk differs by PV type or location in carriers ascertained from the general population.

Objective

To evaluate breast cancer risks associated with PV type and location in ATM, BRCA1, BRCA2, CHEK2 , and PALB2 .

Design

Age adjusted case-control association analysis for all participants, subsets of PV carriers, and women with no breast cancer family history in population-based and clinical testing cohorts.

Setting

Twelve US population-based studies within the Cancer Risk Estimates Related to Susceptibility (CARRIERS) Consortium, and breast cancer cases from the UK-Biobank and an Ambry Genetics clinical testing cohort.

Participants

32,247 women with and 32,544 age-matched women without a breast cancer diagnosis from CARRIERS; 237 and 1351 women with BRCA2 PVs and breast cancer from the UKBB and Ambry Genetics, respectively.

Exposures

PVs in ATM, BRCA1, BRCA2, CHEK2, and PALB2.

Main Outcomes and Measures

PVs were grouped by type and location within genes and assessed for risks of breast cancer (odds ratios (OR), 95% confidence intervals (CI), and p-values) using logistic regression. Mean ages at diagnosis were compared using linear regression.

Results

Compared to women carrying BRCA2 exon 11 protein truncating variants (PTVs) in the CARRIERS population-based study, women with BRCA2 ex13-27 PTVs (OR=2.7, 95%CI 1.1-7.9) and ex1-10 PTVs (OR=1.6, 95%CI 0.8-3.5) had higher breast cancer risks, lower rates of ER-negative breast cancer (ex13-27 OR=0.5, 95%CI 0.2-0.9; ex1-10 OR=0.5, 95%CI 0.1-1.0), and earlier age of breast cancer diagnosis (ex13-27 5.5 years, p<0.001; ex1-10 2.4 years, p=0.17). These associations with ER-negative breast cancer and age replicated in a high-risk clinical cohort and the population-based UK Biobank cohort. No differences in risk or age at diagnosis by gene region were observed for PTVs in other predisposition genes.

Conclusions and Relevance

Population-based and clinical high-risk cohorts establish that PTVs in exon 11 of BRCA2 are associated with reduced risk of breast cancer, later age at diagnosis, and greater risk of ER-negative disease. These differential risks may improve individualized risk prediction and clinical management for women carrying BRCA2 PTVs.

Key Points

Question: Does ATM , BRCA1 , BRCA2 , CHEK2 and PALB2 pathogenic variant type and location influence breast cancer risk in population-based studies? Findings: Breast cancer risk and estrogen receptor status differ based on the type and location of pathogenic variants in BRCA2 . Women carrying protein truncating variants in exon 11 have a lower breast cancer risk in the population-based cohorts, older age at diagnosis and higher rates of estrogen receptor negative breast cancer than women with exon 1-10 or exon 13-27 truncation variants in population-based and clinical testing cohorts. Meaning: Incorporating pathogenic variant type and location in cancer risk models may improve individualized risk prediction.

Characteristics and clinical outcomes of breast cancer in young BRCA carriers according to tumor histology

BACKGROUND

Young women with breast cancer (BC) have an increased chance of carrying germline BRCA pathogenic variants (PVs). Limited data exist on the prognostic impact of tumor histology (i.e. ductal versus lobular) in hereditary breast cancer.

METHODS

This multicenter retrospective cohort study included women aged ≤40 years with early-stage breast cancer diagnosed between January 2000 and December 2020 and known to carry germline PVs in BRCA1/2. Histology was locally assessed in each center. The Kaplan-Meier method and Cox regression analysis were used to assess disease-free survival and overall survival.

RESULTS

Of 4628 patients included from 78 centers worldwide, 3969 (86%) had pure ductal, 135 (3%) pure lobular, and 524 (11%) other histologies. Compared with ductal tumors, lobular tumors were more often grade 1/2 (57.7% versus 22.1%), stage III (29.6% versus 18.5%), and luminal A-like (42.2% versus 12.2%). Lobular tumors were more often associated with BRCA2 PVs (71.1% BRCA2), while ductal tumors were more often associated with BRCA1 PVs (65.7% BRCA1). Patients with lobular tumors more often had mastectomy (68.9% versus 58.3%), and less often received chemotherapy (83.7% versus 92.9%). With a median follow-up of 7.8 years, no significant differences were observed in disease-free survival (adjusted hazard ratio 1.01, 95% confidence interval 0.74-1.37) or overall survival (hazard ratio 0.96, 95% confidence interval 0.62-1.50) between patients with ductal versus lobular tumors. No significant survival differences were observed according to specific BRCA gene, breast cancer subtype, or body mass index.

CONCLUSIONS

In this large global cohort of young BRCA carriers with breast cancer, the incidence of pure lobular histology was low and associated with higher disease stage at diagnosis, luminal-like disease and BRCA2 PVs. Histology did not appear to impact prognosis.

Olaparib plus trastuzumab in HER2-positive advanced breast cancer patients with germline BRCA1/2 mutations: The OPHELIA phase 2 study

PURPOSE

To evaluate the efficacy and safety of the combination of olaparib plus trastuzumab in patients with HER2-positive advanced breast cancer (ABC) and germinal BRCA mutations (gBRCAm).

METHODS

OPHELIA (NCT03931551) was a single-arm, open-label, phase 2 clinical trial. Patients aged ≥18 years diagnosed with HER2-positive ABC with germinal deleterious mutations in BRCA1 or BRCA2 who had received at least one prior systemic regimen for advanced disease were enrolled. Patients received olaparib plus trastuzumab until disease progression, unacceptable toxicity, or consent withdrawal. The primary endpoint was investigator-assessed clinical benefit rate for at least 24 weeks as per RECIST v.1.1. Key secondary endpoints included overall response rate (ORR) and safety profile.

RESULTS

A total of 68 pre-treated HER2-positive ABC patients were screened. Due to slow accrual the trial was stopped after enrolling 5 patients instead of the planned sample size of 20. Four patients achieved clinical benefit (80.0 %, 95 % CI; 28.4-99.5, p < 0.001) and the primary endpoint was met. The ORR was 60.0 % (95 % CI; 14.7-94.7), including one complete response. Four (80.0 %) patients experienced at least one treatment-related treatment-emergent adverse event (TEAE). Most TEAEs were grade 1 or 2. There were no treatment-related deaths and no new safety signals were identified.

CONCLUSIONS

This study suggests that the combination of olaparib plus trastuzumab may be effective and safe in pre-treated patients with HER2-positive gBRCAm ABC. This ABC patient population should be further studied and not be pre-emptively excluded from clinical trials of targeted therapy for BRCA1/2-driven cancers.

Constitutional BRCA1 Epimutations: A Key for Understanding Basal-Like Breast and High-Grade Serous Ovarian Cancer

Germline pathogenic genetic variants in the BRCA1 and BRCA2 genes are the most frequent causes of familial breast and ovarian cancer. Contrasting BRCA2, epimutations in the BRCA1 gene are frequently detected in tissue from triple-negative breast (TNBC) and high-grade serous ovarian cancers (HGSOC). While studies over the last decade have reported BRCA1 epimutations in white blood cells (WBC) from breast and ovarian cancer patients, the potential hazard ratio for incident TNBC and HGSOC was not formally assessed until recently. Conducting a prospective nested case-control study on women participating in the American Women's Health Initiative Study, we provided firm evidence that mosaic WBC BRCA1 epimutations, even at allele frequencies < 0.1%, are associated with a significantly increased risk of both incident HGSOC and TNBC > 5 years after WBC collection. In a second study assessing BRCA1 epimutations in WBC and matched tumor samples from TNBC, our results indicated such epimutations to be the underlying cause of around 20% of TNBC, far exceeding the percentage of cases carrying BRCA1 germline pathogenic genetic variants. We detected primary constitutional BRCA1 epimutations in tissues derived from all three germ layers. They occur independently of BRCA1 promoter haplotypes but are present on the same allele in all WBC within affected individuals. Moreover, epimutations are consistently found on the same allele in normal and tumor breast tissue as well as in WBC. This finding, together with BRCA1 epimutations detected in WBC from newborns, strongly indicates an early embryonic event with clonal expansion affecting all germ layers. Future work in the field must lead to an understanding of exactly when and how the BRCA1 epimutations occur and, most importantly, whether primary constitutional epimutations in genes other than BRCA1 may cause an elevated risk of other cancer types.

iKNOW-Supporting the counseling of women with hereditary risk of breast and ovarian cancer with digital technologies: A randomized controlled trial

Purpose

We developed the online-based counseling tool iKNOW for women with a pathogenic germline variant in BRCA1/2 to improve risk understanding and quality of life.

Methods

With a randomized controlled trial, we investigated the efficacy of iKNOW with regard to risk understanding (primary endpoint), quality of life, risk perception, and anxiety (secondary endpoints). Self-report questionnaires were administered to N = 217 women with a pathogenic variant in BRCA1/2 before counseling (T0), immediately after (T1), 4 weeks after (T2), and 6 months after (T3).

Result

Deviations between self-assessed and calculated cancer risks tended to be smaller in the intervention group than in the control group but no longer significantly after adjustment for multiple testing. In the intervention group, the proportion of women with a correct understanding of breast cancer risk at T3 was higher (30.7% vs 14.7%; P = .032). There were no differences in secondary endpoints.

Conclusion

iKNOW tends to positively influence the understanding of familial cancer risk. At the same time, it does not negatively influence any of the secondary endpoints. However, converging evidence suggests that iKNOW seems to affect the quality of counseling processes and can thus be used as a paradigm for reinventing the notion of efficient, digital care.

Large-scale copy number alterations are enriched for synthetic viability in BRCA1/BRCA2 tumors

BACKGROUND

Pathogenic BRCA1 or BRCA2 germline mutations contribute to hereditary breast, ovarian, prostate, and pancreatic cancer. Paradoxically, bi-allelic inactivation of BRCA1 or BRCA2 (bBRCA1/2) is embryonically lethal and decreases cellular proliferation. The compensatory mechanisms that facilitate oncogenesis in bBRCA1/2 tumors remain unclear.

METHODS

We identified recurrent genetic alterations enriched in human bBRCA1/2 tumors and experimentally validated if these improved proliferation in cellular models. We analyzed mutations and copy number alterations (CNAs) in bBRCA1/2 breast and ovarian cancer from the TCGA and ICGC. We used Fisher's exact test to identify CNAs enriched in bBRCA1/2 tumors compared to control tumors that lacked evidence of homologous recombination deficiency. Genes located in CNA regions enriched in bBRCA1/2 tumors were further screened by gene expression and their effects on proliferation in genome-wide CRISPR/Cas9 screens. A set of candidate genes was functionally validated with in vitro clonogenic survival and functional assays to validate their influence on proliferation in the setting of bBRCA1/2 mutations.

RESULTS

We found that bBRCA1/2 tumors harbor recurrent large-scale genomic deletions significantly more frequently than histologically matched controls (n = 238 cytobands in breast and ovarian cancers). Within the deleted regions, we identified 277 BRCA1-related genes and 218 BRCA2-related genes that had reduced expression and increased proliferation in bBRCA1/2 but not in wild-type cells in genome-wide CRISPR screens. In vitro validation of 20 candidate genes with clonogenic proliferation assays validated 9 genes, including RIC8A and ATMIN (ATM-Interacting protein). We identified loss of RIC8A, which occurs frequently in both bBRCA1/2 tumors and is synthetically viable with loss of both BRCA1 and BRCA2. Furthermore, we found that metastatic homologous recombination deficient cancers acquire loss-of-function mutations in RIC8A. Lastly, we identified that RIC8A does not rescue homologous recombination deficiency but may influence mitosis in bBRCA1/2 tumors, potentially leading to increased micronuclei formation.

CONCLUSIONS

This study provides a means to solve the tumor suppressor paradox by identifying synthetic viability interactions and causal driver genes affected by large-scale CNAs in human cancers.

Triple-Negative Breast Cancer: Molecular Particularities Still a Challenge

Worldwide, breast cancer (BC) is one of the most common cancers in women and is responsible for the highest number of cancer-related deaths among women, with a special clinical behavior and therapy response. Triple-negative breast cancer (TNBC) is seen as a highly invasive BC, characterized by a short survival, higher mortality, recurrence, and metastasis when it is compared to the other BC subtypes. The molecular subtyping of TNBC based on mRNA expression levels does not accurately reflect protein expression levels, which impacts targeted therapy effectiveness and prognostic predictions. Most TNBC cases exhibit a high frequency of homologous recombination (HR) DNA repair deficiency (HRD) signatures and are associated with a complex genomic profile. Biomarker research in TNBC includes investigating genetic mutations, gene expression patterns, immune system-related markers, and other factors that can provide valuable information for diagnosis, treatment selection, and patient outcomes. Additionally, these biomarkers are often crucial in the development of personalized and precision medicine approaches, where treatments are customized to each patient's unique characteristics. This ongoing research is essential for improving the management and outcomes of TNBC, which is a challenging and heterogeneous form of breast cancer. The findings of this research have practical implications for refining treatment strategies, particularly in selecting appropriate systemic therapies and integrating traditional treatment modalities like surgery and radiotherapy into comprehensive care plans for TNBC patients.

Triple-Negative Pleomorphic Lobular Carcinoma in a BRCA1 Mutation Carrier: A Case of Complete Pathological Response

BACKGROUND Hereditary breast cancer arising in BRCA1-deficient patients is commonly diagnosed as invasive carcinoma of no special type (NST) with medullary features, while invasive lobular carcinoma (ILC) appears to be significantly under-represented in BRCA1 mutation carriers. We report a case of pleomorphic ILC arising in a 28-year-old woman harboring a germline BRCA1 c.3756_3759delGTCT p.(Ser1253Argfs*10) pathogenic variant. CASE REPORT A nulliparous 28-year-old woman with a family history of BRCA1 mutation presented to the symptomatic breast clinic with a several-week history of a left 80-mm breast lump. Core biopsy established a diagnosis of a poorly differentiated triple-negative breast cancer (TNBC) of pleomorphic lobular phenotype. Her clinical diagnosis was cT3, N0, M0, cStageIIB. The MDT recommended CT staging, MRI breast imaging and neoadjuvant chemotherapy (NACT). PET CT imaging showed no evidence of distant metastatic disease. The patient had a good radiological response to NACT with a FEC-T carboplatin regimen. Post-NACT imaging showed a residual cystic mass and the patient underwent a mastectomy and sentinel lymph node biopsy with plans for a delayed latissimus dorsi reconstruction following her adjuvant radiotherapy treatment. A complete pathological response was subsequently demonstrated without any evidence of metastatic disease. CONCLUSIONS This case is the first report of pleomorphic ILC with a triple-negative receptor status and a complete pathological response in a BRCA1 mutation carrier. Our study expands the heterogeneous spectrum of TNBC and contributes to a better understanding of the molecular genetic landscape that characterizes invasive pleomorphic lobular neoplasia.

General analysis of breast cancer patients tested for BRCA mutations and evaluation of acute radiotherapy toxicity

OBJECTIVE

The objective of our study is to evaluate breast cancer patients with BRCA1 or BRCA2 gene mutations and compare them with patients without these mutations. Specifically, we aim to assess the acute side effects of radiotherapy in both groups.

METHODS

Data were collected from four participating centers, comprising information from 73 patients who underwent known mutation analysis and had complete data. Patients were monitored on a weekly basis throughout their treatment for acute toxicity, which was evaluated using the Radiation Therapy Oncology Group (RTOG) acute toxicity criteria.

RESULTS

The median age of the 73 patients included in our study was 43. Among them, 17 had BRCA1-positive mutations and 19 had BRCA2-positive mutations. Invasive ductal carcinoma was present in 67 patients, all of whom underwent surgery. Of the patients, 57 received conventional radiotherapy doses, while 16 received hypofractionated radiotherapy doses. During follow-up, metastasis occurred in three patients. In BRCA-positive patients, those under 40 years of age (p<0.001), with high nodal positivity (p=0.008), grade 2-3 (p=0.022), and lymphovascular invasion (p=0.002) were significantly more frequent compared to BRCA-negative patients (p<0.001). The median survival was 35.8 months. Grade 1 dysphagia developed in seven BRCA-negative patients and four BRCA-positive patients, with no significant difference observed between the two groups (p=0.351). There was also no statistical difference observed in the occurrence of grade 2-3 skin reactions, with 11 BRCA-negative patients and eight BRCA-positive patients experiencing these side effects.

CONCLUSION

Our study supports existing literature by identifying an association between the presence of BRCA mutations and young age, nodal status, grade, and lymphovascular invasion. Additionally, we found no significant difference in the occurrence of radiotherapy toxicity between BRCA-positive and BRCA-negative patients. These findings suggest that radiotherapy can be safely administered to BRCA-positive patients after breast-conserving surgery or mastectomy. Keywords for our study include breast cancer, BRCA mutation, radiotherapy, and side effects.

Pathologic complete response after neoadjuvant systemic therapy for breast cancer in BRCA mutation carriers and noncarriers

BRCA1 and BRCA2 pathogenic variant carriers develop breast cancers with distinct pathological characteristics and mutational signatures that may result in differential response to chemotherapy. We compared rates of pathologic complete response (pCR) after NAC between BRCA1/2 variant carriers and noncarriers in a cohort of 1426 women (92 [6.5%] BRCA1 and 73 [5.1%] BRCA2) with clinical stage I-III breast cancer treated with NAC followed by surgery from 11/2013 to 01/2022 at Memorial Sloan Kettering Cancer Center. The majority received doxorubicin/cyclophosphamide/paclitaxel therapy (93%); BRCA1/2 carriers were more likely to receive carboplatin (p < 0.001). Overall, pCR was achieved in 42% of BRCA1 carriers, 21% of BRCA2 carriers, and 26% of noncarriers (p = 0.001). Among clinically node-positive (cN+) patients, nodal pCR was more frequent in BRCA1/2 carriers compared to noncarriers (53/96 [55%] vs. 371/856 [43%], p = 0.015). This difference was seen in HR+/HER2- (36% vs. 20% of noncarriers; p = 0.027) and TN subtypes (79% vs. 45% of noncarriers; p < 0.001). In a multivariable analysis of the overall cohort, BRCA1 status, and TN and HER2+ subtypes were independently associated with pCR. These data indicate that BRCA1 carriers may be more likely to achieve overall and nodal pCR in response to NAC compared with BRCA2 carriers and patients with sporadic disease. Further studies with a larger cohort of BRCA1/2 mutation carriers are needed, as a small sample size may have a restricted ability to detect a significant association between mutational status and pCR in sensitivity analyses stratified by subtype and adjusted for clinically relevant factors.

Evolving Management of Breast Cancer in the Era of Predictive Biomarkers and Precision Medicine

Breast cancer is the most common cancer among women in the world as well as in the United States. Molecular and histological differentiation have helped clinicians optimize treatments with various therapeutics, including hormonal therapy, chemotherapy, immunotherapy, and radiation therapy. Recently, immunotherapy has become the standard of care in locally advanced triple-negative breast cancer and an option across molecular subtypes for tumors with a high tumor mutation burden. Despite the advancements in personalized medicine directing the management of localized and advanced breast cancers, the emergence of resistance to these therapies is the leading cause of death among breast cancer patients. Therefore, there is a critical need to identify and validate predictive biomarkers to direct treatment selection, identify potential responders, and detect emerging resistance to standard therapies. Areas of active scientific and clinical research include novel personalized and predictive biomarkers incorporating tumor microenvironment, tumor immune profiling, molecular characterization, and histopathological differentiation to predict response and the potential emergence of resistance.

What Proportion of BRCA-Associated Breast Cancer Is Human Epidermal Growth Factor 2-Low and Eligible for Additional Targeted Therapy?

INTRODUCTION

DESTINY B04 provided clinical meaning to a new classification of human epidermal growth factor 2 (HER2) expression in breast cancer: HER2-low. Patients with germline breast cancer type 1 gene pathogenic variants (gBRCA1) often develop triple negative breast cancer (TNBC), but the proportion who could be classified as HER2-low and qualify for an additional targeted therapy option is unknown. This study aims to characterize the proportion of gBRCA1 or germline breast cancer type 2 gene pathogenic variants patients for whom these novel targeted therapies may be an option.

METHODS

We performed a retrospective chart review of patients with gBRCA1/2 treated at our institution for invasive breast cancer from 2000 to 2021. Synchronous or metachronous contralateral breast cancers were recorded separately. HER2 status was determined by immunohistochemistry and fluorescence in situ hybridization. We excluded patients without complete HER2 data.

RESULTS

Among the 95 breast cancers identified in our cohort of 85 gBRCA1/2 patients, 41 (43%) were TNBC, 38 (40%) were hormone receptor positive (HR+)/HER2-negative, and 16 (17%) were HER2-positive based on standard conventions. We found that 82% of the HR+/HER2-cancers and 66% of TNBCs would be reclassified as HER2-low. After stratifying by BRCA gene status, 64% of cancers in patients with gBRCA1 and 58% of cancers in patients with germline breast cancer type 2 gene pathogenic variants were HER2-low.

CONCLUSIONS

A significant portion of gBRCA1/2 patients who were previously diagnosed with TNBC or HR+/HER2- breast cancer would now be classified as HER2-low and could be considered for the use of trastuzumab deruxtecan in the metastatic setting. Outcome differences from therapy changes in this cohort should now be assessed.

Genetic Testing of Breast Cancer Patients with Very Early-Onset Breast Cancer (≤30 Years) Yields a High Rate of Germline Pathogenic Variants, Mainly in the BRCA1, TP53, and BRCA2 Genes

Early-onset breast cancer constitutes a major criterion for genetic testing referral. Nevertheless, studies focusing on breast cancer patients (≤30 years) are limited. We investigated the contribution and spectrum of known breast-cancer-associated genes in 267 Greek women with breast cancer ≤30 years while monitoring their clinicopathological characteristics and outcomes. In this cohort, a significant proportion (39.7%) carried germline pathogenic variants (PVs) distributed in 8 genes. The majority, namely 36.7%, involved BRCA1, TP53, and BRCA2. PVs in BRCA1 were the most prevalent (28.1%), followed by TP53 (4.5%) and BRCA2 (4.1%) PVs. The contribution of PVs in CHEK2, ATM, PALB2, PTEN, and RAD51C was limited to 3%. In the patient group ≤26 years, TP53 PVs were significantly higher compared to the group 26-30 years (p = 0.0023). A total of 74.8% of TP53 carriers did not report a family history of cancer. Carriers of PVs receiving neoadjuvant chemotherapy showed an improved event-free survival (p < 0.0001) compared to non-carriers. Overall, many women with early-onset breast cancer carry clinically actionable variants, mainly in the BRCA1/2 and TP53 genes. The inclusion of timely testing of TP53 in these patients provides essential information for appropriate clinical management. This is important for countries where reimbursement involves the cost of genetic analysis of BRCA1/2 only.

Cis- and trans-eQTL TWASs of breast and ovarian cancer identify more than 100 susceptibility genes in the BCAC and OCAC consortia

Transcriptome-wide association studies (TWASs) have investigated the role of genetically regulated transcriptional activity in the etiologies of breast and ovarian cancer. However, methods performed to date have focused on the regulatory effects of risk-associated SNPs thought to act in cis on a nearby target gene. With growing evidence for distal (trans) regulatory effects of variants on gene expression, we performed TWASs of breast and ovarian cancer using a Bayesian genome-wide TWAS method (BGW-TWAS) that considers effects of both cis- and trans-expression quantitative trait loci (eQTLs). We applied BGW-TWAS to whole-genome and RNA sequencing data in breast and ovarian tissues from the Genotype-Tissue Expression project to train expression imputation models. We applied these models to large-scale GWAS summary statistic data from the Breast Cancer and Ovarian Cancer Association Consortia to identify genes associated with risk of overall breast cancer, non-mucinous epithelial ovarian cancer, and 10 cancer subtypes. We identified 101 genes significantly associated with risk with breast cancer phenotypes and 8 with ovarian phenotypes. These loci include established risk genes and several novel candidate risk loci, such as ACAP3, whose associations are predominantly driven by trans-eQTLs. We replicated several associations using summary statistics from an independent GWAS of these cancer phenotypes. We further used genotype and expression data in normal and tumor breast tissue from the Cancer Genome Atlas to examine the performance of our trained expression imputation models. This work represents an in-depth look into the role of trans eQTLs in the complex molecular mechanisms underlying these diseases.

Germline pathogenic variants associated with triple-negative breast cancer in US Hispanic and Guatemalan women using hospital and community-based recruitment strategies

PURPOSE

Recruit and sequence breast cancer subjects in Guatemalan and US Hispanic populations. Identify optimum strategies to recruit Latin American and Hispanic women into genetic studies of breast cancer.

METHODS

We used targeted gene sequencing to identify pathogenic variants in 19 familial breast cancer susceptibility genes in DNA from unselected Hispanic breast cancer cases in the US and Guatemala. Recruitment across the US was achieved through community-based strategies. In addition, we obtained patients receiving cancer treatment at major hospitals in Texas and Guatemala.

RESULTS

We recruited 287 Hispanic US women, 38 (13%) from community-based and 249 (87%) from hospital-based strategies. In addition, we ascertained 801 Guatemalan women using hospital-based recruitment. In our experience, a hospital-based approach was more efficient than community-based recruitment. In this study, we sequenced 103 US and 137 Guatemalan women and found 11 and 10 pathogenic variants, respectively. The most frequently mutated genes were BRCA1, BRCA2, CHEK2, and ATM. In addition, an analysis of 287 US Hispanic patients with pathology reports showed a significantly higher percentage of triple-negative disease in patients with pathogenic variants (41% vs. 15%). Finally, an analysis of mammography usage in 801 Guatemalan patients found reduced screening in women with a lower socioeconomic status (p < 0.001).

CONCLUSION

Guatemalan and US Hispanic women have rates of hereditary breast cancer pathogenic variants similar to other populations and are more likely to have early age at diagnosis, a family history, and a more aggressive disease. Patient recruitment was higher using hospital-based versus community enrollment. This data supports genetic testing in breast cancer patients to reduce breast cancer mortality in Hispanic women.

Timing of genetic testing in BRCA1/2 and PALB2-Associated breast cancer: Preoperative result disclosure increases uptake of risk-reducing mastectomy and reduces unnecessary exposure to radiotherapy

INTRODUCTION

The impact of timing of genetic testing on uptake of risk reducing mastectomy (RRM) in affected female BRCA1/2 or PALB2 carriers remains an area of evolving interest, particularly with the introduction of mainstream genetic testing initiatives.

METHODS

Women with stage I-III breast cancer and a confirmed germline pathogenic variant in BRCA1/2 or PALB2 between 2000 and 2023 were identified from an institutional genetics database. Uptake of RRM was evaluated according to disclosure of genetic testing results before or after index surgery for a first diagnosis of breast cancer.

RESULTS

The cohort included 287 female BRCA1/2 or PALB2 carriers with a median age of 44 years (IQR, 36-52). Overall, 155 (54 %) carriers received genetic testing results before and 132 (46 %) after index breast surgery. Receipt of genetic testing results before surgery was associated with a higher rate of index bilateral mastectomy (58.7 % vs. 7.6 %, p < 0.001) and a commensurate decrease in adjuvant radiation (41.9 % vs. 74.2 %, p < 0.001). At a median follow up of 4.4 years after genetic testing, 219 (76.3 %) affected carriers had undergone bilateral RRM, including 83.9 % with preoperative knowledge and 67.4 % of patients with postoperative knowledge of their germline pathogenic variant (log rank, p < 0.001). On multivariate regression, disclosure of genetic testing results before index breast surgery was independently associated with long-term uptake of bilateral mastectomy (HR 1.69, 95 % CI 1.21-2.38).

CONCLUSION

Genetic testing results delivered prior to index breast surgery increase uptake of bilateral RRM in affected BRCA1/2 and PALB2 carriers. Efforts to mainstream genetic testing would help optimize surgical decision-making.

Improving the Lives of Women With Ovarian Cancer

Being a gynecologic oncologist is a privilege. Women with cancer address their challenges with grit and resilience. Their most basic questions motivated my career-long search for scientific answers hidden in genetics, novel therapeutics, and cancer prevention. But medicine is a team sport. Working alongside gifted colleagues and mentoring trainees to assume starring roles on the team has sustained and enriched my career. Advocating for patients and the specialty of gynecologic oncology provided another means to advance research and cancer awareness to improve patient outcomes. The author believe the most exciting times are yet to come.

Effects of Endocrine Interventions Targeting ERα or PR on Breast Cancer Risk in the General Population and Carriers of BRCA1/2 Pathogenic Variants

There is evidence suggesting that endocrine interventions such as hormone replacement therapy and hormonal contraception can increase breast cancer (BC) risk. Sexual steroid hormones like estrogens have long been known for their adverse effects on BC development and progression via binding to estrogen receptor (ER) α. Thus, in recent years, endocrine interventions that include estrogens have been discussed more and more critically, and their impact on different BC subgroups has increasingly gained interest. Carriers of pathogenic variants in BRCA1/2 genes are known to have a high risk of developing BC and ovarian cancer. However, there remain open questions to what extent endocrine interventions targeting ERα or the progesterone receptor further increase cancer risk in this subgroup. This review article aims to provide an overview and update on the effects of endocrine interventions on breast cancer risk in the general population in comparison to BRCA1/2 mutation carriers. Finally, future directions of research are addressed, to further improve the understanding of the effects of endocrine interventions on high-risk pathogenic variant carriers.

PARP Inhibitors for Breast Cancer Treatment: A Review

Importance

Poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitors have revolutionized the treatment of patients with germline BRCA1/2-associated breast cancer, representing the first targeted therapy capable of improving outcomes in patients with hereditary tumors. However, resistance to PARP inhibitors occurs in almost all patients.

Observations

This narrative review summarizes the biological rationale behind the use of PARP inhibitors in breast cancer, as well as the available evidence, recent progress, and potential future applications of these agents. Recent studies have shown that the benefit of PARP inhibitors extends beyond patients with germline BRCA1/2-associated metastatic breast cancer to patients with somatic BRCA1/2 variants and to those with germline PALB2 alterations. Moreover, these agents proved to be effective both in the metastatic and adjuvant settings. However, patients with metastatic breast cancer usually do not achieve the long-term benefit from PARP inhibitors observed in other tumor types. Mechanisms of resistance have been identified, but how to effectively target them is largely unknown. Ongoing research is investigating both novel therapeutics and new combination strategies to overcome resistance. PARP1-selective inhibitors, by sparing the hematological toxic effects induced by the PARP2 blockade, are promising agents to be combined with chemotherapy, antibody-drug conjugates, and other targeted therapies.

Conclusions and Relevance

Although the efficacy of PARP inhibitors is well established, many questions persist. Future research should focus on identifying predictive biomarkers and therapeutic strategies to overcome resistance. Integrating well-designed translational efforts into all clinical studies is thereby crucial to laying the groundwork for future insights from ongoing research.

BRCA testing and management of BRCA-mutated early-stage breast cancer: a comprehensive statement by expert group from GCC region

BReast CAncer (BRCA)1 and BRCA2 gene pathogenic variants account for most hereditary breast cancers (BC). Identification of BRCA mutations can significantly influence both prognosis and treatment outcomes. Furthermore, it enables the identification of individuals who are at heightened risk of developing BC due to inherited genetic mutations. Many developing countries rely on western guidelines for BRCA testing and BC management; however, there exist wide disparities in the prevalence of risk factors, availability of medical resources, and practice patterns. Guidelines tailored to specific regions can help mitigate healthcare variations, promote consistency in treatment, and aid healthcare providers in identifying effective therapies for improving patient outcomes. Hence, oncologists from the Gulf Cooperation Council (GCC) congregated virtually in March 2023 and reviewed existing data on the epidemiology of BC, BRCA mutations, practices and challenges associated with BRCA testing and management of BRCA mutated early-stage BC in the GCC region. They also provided insights on the real-world diagnostic and treatment practices and challenges in the GCC region in the BRCA-mutated early-stage BC domain and suggested some variations to international guidelines to aid their uptake in this region.