Germline BRCA mutation evaluation in a prospective triple-negative breast cancer registry: implications for hereditary breast and/or ovarian cancer syndrome testing

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.

Cost-Utility Analysis of Adjuvant Olaparib for Germline BRCA1/2-Mutated, High-Risk HER2-Negative Early Breast Cancer in Spain

OBJECTIVE

Here we estimate the cost-effectiveness of olaparib in the Spanish National Health Service (SNHS) as adjuvant treatment of early germline mutations in the BRCA1/2 genes (gBRCAm) HER2-negative (HER2neg) breast cancer (BC) with high risk of recurrence.

METHODS

A semi-Markov model was adapted to the Spanish healthcare setting, using the perspective of the SNHS, and a lifetime horizon. Two scenarios were compared: receiving olaparib versus standard of care (SoC) treatment. The model comprised five health states and included the clinical results of the OlympiA trial, along with the direct healthcare costs associated with the use of early BC and subsequent treatment resources (€2023). A discount rate of 3% was applied for future cost and quality-of-life outcomes. A probabilistic sensitivity analysis (PSA) was carried out.

RESULTS

The introduction of olaparib as adjuvant treatment for patients with early gBRCAm HER2neg BC with high risk of recurrence could involve an incremental cost of €44,273 and €50,164, with an improvement of 1.14 and 1.28 quality-adjusted life years (QALYs) for hormone receptor-positive (HR+) and triple-negative (TN) patients, respectively. Therefore, adjuvant olaparib could be cost-effective for early gBRCAm HER2neg BC, with an incremental cost-effectiveness ratio of €38,839/QALY and €39,084/QALY for HR+ and TN patients, respectively. The results from the PSA showed that 75.7% and 82.2% of the simulations fell below the €60,000/QALY threshold.

CONCLUSIONS

Olaparib as adjuvant treatment could be cost-effective in gBRCAm patients with early HER2neg BC in Spain.

OptimICE-RD: sacituzumab govitecan + pembrolizumab vs pembrolizumab (± capecitabine) for residual triple-negative breast cancer

Patients with early-stage triple-negative breast cancer (TNBC) with residual invasive disease after neoadjuvant therapy have a high risk of recurrence even with neoadjuvant and adjuvant treatment with pembrolizumab. Sacituzumab govitecan, a Trop-2-directed antibody-drug conjugate with a topoisomerase I inhibitor payload, improved progression-free survival (PFS) and overall survival (OS) versus chemotherapy in patients with pre-treated metastatic TNBC. Moreover, preclinical data suggest that topoisomerase I inhibitors may enhance the effects of immune checkpoint inhibitors through activation of the cGAS-STING pathway. Here we describe the international randomized phase III AFT-65/ASCENT-05/OptimICE-RD trial, which evaluates the efficacy and safety of sacituzumab govitecan plus pembrolizumab versus treatment of physician's choice (pembrolizumab ± capecitabine) among patients with early-stage TNBC with residual invasive disease after neoadjuvant therapy.Clinical Trial Registration: NCT05633654 (ClinicalTrials.gov)Other Study ID Number(s): Gilead Study ID: GS-US-595-6184Registration date: 1 December 2022Study start date: 12 December 2022Recruitment status: Recruiting.

Efficacy of metformin and electrical pulses in breast cancer MDA-MB-231 cells

Aim

Triple-negative breast cancer (TNBC) is a very aggressive subset of breast cancer, with limited treatment options, due to the lack of three commonly targeted receptors, which merits the need for novel treatments for TNBC. Towards this need, the use of metformin (Met), the most widely used type-2 diabetes drug worldwide, was explored as a repurposed anticancer agent. Cancer being a metabolic disease, the modulation of two crucial metabolites, glucose, and reactive oxygen species (ROS), is studied in MDA-MB-231 TNBC cells, using Met in the presence of electrical pulses (EP) to enhance the drug efficacy.

Methods

MDA-MB-231, human TNBC cells were treated with Met in the presence of EP, with various concentrations Met of 1 mmol/L, 2.5 mmol/L, 5 mmol/L, and 10 mmol/L. EP of 500 V/cm, 800 V/cm, and 1,000 V/cm (with a pulse width of 100 µs at 1 s intervals) were applied to TNBC and the impact of these two treatments was studied. Various assays, including cell viability, microscopic inspection, glucose, ROS, and wound healing assay, were performed to characterize the response of the cells to the combination treatment.

Results

Combining 1,000 V/cm with 5 mmol/L Met yielded cell viability as low as 42.6% at 24 h. The glucose level was reduced by 5.60-fold and the ROS levels were increased by 9.56-fold compared to the control, leading to apoptotic cell death.

Conclusions

The results indicate the enhanced anticancer effect of Met in the presence of electric pulses. The cell growth is inhibited by suppressing glucose levels and elevated ROS. This shows a synergistic interplay between electroporation, Met, glucose, and ROS metabolic alterations. The results show promises for combinational therapy in TNBC patients.

Germline Testing in Patients With Breast Cancer: ASCO-Society of Surgical Oncology Guideline

PURPOSE

To develop recommendations for germline mutation testing for patients with breast cancer.

METHODS

An ASCO-Society of Surgical Oncology (SSO) panel convened to develop recommendations based on a systematic review and formal consensus process.

RESULTS

Forty-seven articles met eligibility criteria for the germline mutation testing recommendations; 18 for the genetic counseling recommendations.

RECOMMENDATIONS

BRCA1/2 mutation testing should be offered to all newly diagnosed patients with breast cancer ≤65 years and select patients >65 years based on personal history, family history, ancestry, or eligibility for poly(ADP-ribose) polymerase (PARP) inhibitor therapy. All patients with recurrent breast cancer who are candidates for PARP inhibitor therapy should be offered BRCA1/2 testing, regardless of family history. BRCA1/2 testing should be offered to women who develop a second primary cancer in the ipsilateral or contralateral breast. For patients with prior history of breast cancer and without active disease, testing should be offered to patients diagnosed ≤65 years and selectively in patients diagnosed after 65 years, if it will inform personal and family risk. Testing for high-penetrance cancer susceptibility genes beyond BRCA1/2 should be offered to those with supportive family histories; testing for moderate-penetrance genes may be offered if necessary to inform personal and family cancer risk. Patients should be provided enough pretest information for informed consent; those with pathogenic variants should receive individualized post-test counseling. Variants of uncertain significance should not impact management, and patients with such variants should be followed for reclassification. Referral to providers experienced in clinical cancer genetics may help facilitate patient selection and interpretation of expanded testing, and provide counseling of individuals without pathogenic germline variants but with significant family history.Additional information is available at www.asco.org/breast-cancer-guidelines.

Exploring Biomarkers in Breast Cancer: Hallmarks of Diagnosis, Treatment, and Follow-Up in Clinical Practice

Breast cancer is a prevalent malignancy in the present day, particularly affecting women as one of the most common forms of cancer. A significant portion of patients initially present with localized disease, for which curative treatments are pursued. Conversely, another substantial segment is diagnosed with metastatic disease, which has a worse prognosis. Recent years have witnessed a profound transformation in the prognosis for this latter group, primarily due to the discovery of various biomarkers and the emergence of targeted therapies. These biomarkers, encompassing serological, histological, and genetic indicators, have demonstrated their value across multiple aspects of breast cancer management. They play crucial roles in initial diagnosis, aiding in the detection of relapses during follow-up, guiding the application of targeted treatments, and offering valuable insights for prognostic stratification, especially for highly aggressive tumor types. Molecular markers have now become the keystone of metastatic breast cancer diagnosis, given the diverse array of chemotherapy options and treatment modalities available. These markers signify a transformative shift in the arsenal of therapeutic options against breast cancer. Their diagnostic precision enables the categorization of tumors with elevated risks of recurrence, increased aggressiveness, and heightened mortality. Furthermore, the existence of therapies tailored to target specific molecular anomalies triggers a cascade of changes in tumor behavior. Therefore, the primary objective of this article is to offer a comprehensive review of the clinical, diagnostic, prognostic, and therapeutic utility of the principal biomarkers currently in use, as well as of their clinical impact on metastatic breast cancer. In doing so, our goal is to contribute to a more profound comprehension of this complex disease and, ultimately, to enhance patient outcomes through more precise and effective treatment strategies.

Long-term outcomes of young, node-negative, chemotherapy-naïve, triple-negative breast cancer patients according to BRCA1 status

BACKGROUND

Due to the abundant usage of chemotherapy in young triple-negative breast cancer (TNBC) patients, the unbiased prognostic value of BRCA1-related biomarkers in this population remains unclear. In addition, whether BRCA1-related biomarkers modify the well-established prognostic value of stromal tumor-infiltrating lymphocytes (sTILs) is unknown. This study aimed to compare the outcomes of young, node-negative, chemotherapy-naïve TNBC patients according to BRCA1 status, taking sTILs into account.

METHODS

We included 485 Dutch women diagnosed with node-negative TNBC under age 40 between 1989 and 2000. During this period, these women were considered low-risk and did not receive chemotherapy. BRCA1 status, including pathogenic germline BRCA1 mutation (gBRCA1m), somatic BRCA1 mutation (sBRCA1m), and tumor BRCA1 promoter methylation (BRCA1-PM), was assessed using DNA from formalin-fixed paraffin-embedded tissue. sTILs were assessed according to the international guideline. Patients' outcomes were compared using Cox regression and competing risk models.

RESULTS

Among the 399 patients with BRCA1 status, 26.3% had a gBRCA1m, 5.3% had a sBRCA1m, 36.6% had tumor BRCA1-PM, and 31.8% had BRCA1-non-altered tumors. Compared to BRCA1-non-alteration, gBRCA1m was associated with worse overall survival (OS) from the fourth year after diagnosis (adjusted HR, 2.11; 95% CI, 1.18-3.75), and this association attenuated after adjustment for second primary tumors. Every 10% sTIL increment was associated with 16% higher OS (adjusted HR, 0.84; 95% CI, 0.78-0.90) in gBRCA1m, sBRCA1m, or BRCA1-non-altered patients and 31% higher OS in tumor BRCA1-PM patients. Among the 66 patients with tumor BRCA1-PM and ≥ 50% sTILs, we observed excellent 15-year OS (97.0%; 95% CI, 92.9-100%). Conversely, among the 61 patients with gBRCA1m and < 50% sTILs, we observed poor 15-year OS (50.8%; 95% CI, 39.7-65.0%). Furthermore, gBRCA1m was associated with higher (adjusted subdistribution HR, 4.04; 95% CI, 2.29-7.13) and tumor BRCA1-PM with lower (adjusted subdistribution HR, 0.42; 95% CI, 0.19-0.95) incidence of second primary tumors, compared to BRCA1-non-alteration.

CONCLUSIONS

Although both gBRCA1m and tumor BRCA1-PM alter BRCA1 gene transcription, they are associated with different outcomes in young, node-negative, chemotherapy-naïve TNBC patients. By combining sTILs and BRCA1 status for risk classification, we were able to identify potential subgroups in this population to intensify and optimize adjuvant treatment.

PLK1 and PARP positively correlate in Middle Eastern breast cancer and their combined inhibition overcomes PARP inhibitor resistance in triple negative breast cancer

Background

Despite advancements in treatment approaches, patients diagnosed with aggressive breast cancer (BC) subtypes typically face an unfavorable prognosis. Globally, these cancers continue to pose a significant threat to women's health, leading to substantial morbidity and mortality. Consequently, there has been a significant struggle to identify viable molecular targets for therapeutic intervention in these patients. Polo-like Kinase-1 (PLK1) represents one of these molecular targets currently undergoing rigorous scrutiny for the treatment of such tumors. Yet, its role in the pathogenesis of BC in Middle Eastern ethnicity remains unexplored.

Methods

We investigated the expression of PLK1 protein in a cohort of more than 1500 Middle Eastern ethnicity BC cases by immunohistochemistry. Association with clinicopathological parameters and prognosis were performed. In vitro studies were conducted using the PLK1 inhibitor volasertib and the PARP inhibitor olaparib, either alone or in combination, in PTC cell lines.

Results

Overexpression of PLK1 was detected in 27.4% of all BC cases, and this was notably correlated with aggressive clinicopathological markers. PLK1 was enriched in the triple-negative breast cancer (TNBC) subtype and exhibited poor overall survival (p = 0.0347). Notably, there was a positive correlation between PLK1 and PARP overexpression, with co-expression of PLK1 and PARP observed in 15.7% of cases and was associated with significantly poorer overall survival (OS) compared to the overexpression of either protein alone (p = 0.0050). In vitro, we studied the effect of PLK1 and PARP inhibitors either single or combined treatments in two BRCA mutated, and one BRCA proficient TNBC cell lines. We showed that combined inhibition significantly reduced cell survival and persuaded apoptosis in TNBC cell lines. Moreover, our findings indicate that inhibition of PLK1 can reinstate sensitivity in PARP inhibitor (PARPi) resistant TNBC cell lines.

Conclusion

Our results shed light on the role of PLK1 in the pathogenesis and prognosis of Middle Eastern BC and support the potential clinical development of combined inhibition of PLK1 and PARP, a strategy that could potentially broaden the use of PLK1 and PARP inhibitors beyond BC cases lacking BRCA.

Low rate of complications in nipple-sparing mastectomy for patients with BRCA1 and BRCA2 mutation

Background: To describe the indications and outcomes of BRCA mutation carriers undergoing nipple-sparing mastectomy (NSM). Methods: In this retrospective study, 76 BRCA mutation carriers with no cancer who opted to undergo risk reduction NSM or diagnosed with breast cancer (BC) who opted to undergo therapeutic NSM were included. Results: Indications for NSM: cancer treatment (n = 33), bilateral risk reduction (n = 39) and contralateral prophylactic NSM (n = 4). In a mean follow-up of 45 months (median: 30 months), one patient (2.5%) undergoing risk-reducing NSM developed a new BC. One (3%) local, one (3%) ipsilateral axillary and one (3%) distant recurrence were observed in BC patients. No partial or total nipple necrosis occurred. Conclusion: NSM is safe for reducing the risk of BC development in BRCA mutation carriers and for treating cancer.

A Progressively Disassembled DNA Repair Inhibitors Nanosystem for the Treatment of BRCA Wild-Type Triple-Negative Breast Cancer

Background

Olaparib, a poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitor has demonstrated promising efficacy in patients with triple-negative breast cancer (TNBC) carrying breast cancer gene (BRCA) mutations. However, its impact on BRCA wild-type (BRCAwt) TNBC is limited. Hence, it is crucial to sensitize BRCAwt TNBC cells to olaparib for effective clinical practice. Novobiocin, a DNA polymerase theta (POLθ) inhibitor, exhibits sensitivity towards BRCA-mutated cancer cells that have acquired resistance to PARP inhibitors. Although both of these DNA repair inhibitors demonstrate therapeutic efficacy in BRCA-mutated cancers, their nanomedicine formulations' antitumor effects on wild-type cancer remain unclear. Furthermore, ensuring effective drug accumulation and release at the cancer site is essential for the clinical application of olaparib.

Materials and Methods

Herein, we designed a progressively disassembled nanosystem of DNA repair inhibitors as a novel strategy to enhance the effectiveness of olaparib in BRCAwt TNBC. The nanosystem enabled synergistic delivery of two DNA repair inhibitors olaparib and novobiocin, within an ultrathin silica framework interconnected by disulfide bonds.

Results

The designed nanosystem demonstrated remarkable capabilities, including long-term molecular storage and specific drug release triggered by the tumor microenvironment. Furthermore, the nanosystem exhibited potent inhibitory effects on cell viability, enhanced accumulation of DNA damage, and promotion of apoptosis in BRCAwt TNBC cells. Additionally, the nanosystem effectively accumulated within BRCAwt TNBC, leading to significant growth inhibition and displaying vascular regulatory abilities as assessed by magnetic resonance imaging (MRI).

Conclusion

Our results provided the inaugural evidence showcasing the potential of a progressively disassembled nanosystem of DNA repair inhibitors, as a promising strategy for the treatment of BRCA wild-type triple-negative breast cancer.

A BRCA2 germline mutation and high expression of immune checkpoints in a TNBC patient

Triple-negative breast cancer (TNBC) is the most aggressive subtype of mammary carcinoma. Here, we describe a case of an 81-year-old female diagnosed with ductal triple negative breast cancer with a germline pathogenic variant in BReast CAncer gene2 (BRCA2). Genetic testing also revealed the presence of four somatic mutations in the ephrin type-A receptor 3 (EphA3), TP53, BRCA1-associated protein (BAP1), and MYB genes. The BRCA2, TP53, and BAP1 gene mutations are highly predictive of a defective homologous recombination repair system and subsequent chromosomal instability in this patient. Coherently, the patient displayed a strong homologous recombination deficiency signature and high tumor mutational burden status, which are generally associated with increased probability of immune neoantigens formation and presentation, and with tumor immunogenicity. Analysis of immune checkpoint revealed high expression of programmed cell death ligand 1 (PD-L1), programmed cell death ligand 2 (PD-L2), programmed death 1 (PD1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA 4), suggesting that the patient might likely benefit from immunotherapies. Altogether, these findings support an unveiled link between BRCA2 inactivation, HR deficiency and increased expression of immune checkpoints in TNBC. This clinical case highlights the importance of screening TNBC patients for genetic mutations and TMB biomarkers in order to predict the potential efficacy of immunotherapy.

Impact of platinum-based chemotherapy on the prognosis of early triple-negative breast cancer: a systematic review and meta-analysis

Although platinum-based chemotherapy can improve pathologic complete response (pCR) in patients with triple-negative breast cancer (TNBC), the impact on survival of platinum-based neoadjuvant and adjuvant chemotherapy is still controversial. Our meta-analysis aimed at analyzing survival with platinum-based neoadjuvant and adjuvant chemotherapy in patients with TNBC. We searched PubMed, EMBASE, MEDLINE, Cochrane databases, and several major conferences up to January 2021. Fixed and random models were used for our meta-analysis. Disease-free survival (DFS), overall survival (OS), and side effects data were extracted from the included literature in addition to the corresponding pooled hazard ratio (HR) and odds ratio (OR) with 95% confidence intervals (CIs). A total of nine studies involving 3247 patients were included. The pooled analysis suggested that compared with anthracycline- and/or paclitaxel-based chemotherapy, platinum-based chemotherapy could further improve DFS (HR = 0.56, 95% CI 0.45-0.67, p < 0.01) and OS (HR = 0.54, 95% CI 0.38-0.70, p < 0.01) in patients with TNBC. The subgroup analysis showed that platinum-based chemotherapy could further improve DFS (HR = 0.59, 95% CI 0.43-0.74, p < 0.01) and OS (HR = 0.61, 95% CI 0.40-0.83, p < 0.01) in neoadjuvant chemotherapy and DFS (HR = 0.53, 95% CI 0.37-0.69, p < 0.01) and OS (HR = 0.46, 95% CI 0.23-0.69, p < 0.01) in adjuvant chemotherapy compared with anthracycline- and/or paclitaxel-based chemotherapy in patients with TNBC. In addition, compared with anthracycline-based chemotherapy, platinum-based chemotherapy without anthracycline chemotherapy could further improve DFS (HR = 0.53, 95% CI 0.37-0.70, p < 0.01) and OS (HR = 0.46, 95%CI 0.19-0.72, p < 0.01) in patients with TNBC. Compared with anthracycline- and/or paclitaxel-based chemotherapy, all-grade diarrhea, fatigue, and grade ≥ 3 anemia were higher in platinum-based chemotherapy. In contrast, all-grade anemia, leukopenia, neutropenia, peripheral neuropathy, myalgia/arthralgia, cardiac toxicity were lower in platinum-based chemotherapy; grade ≥ 3 leukopenia, neutropenia and myalgia/arthralgia were also lower. Compared with anthracycline- and/or paclitaxel-based chemotherapy, platinum-based chemotherapy was more associated with improved DFS and OS in TNBC patients. The benefit of survival is consistent with platinum-based neoadjuvant and adjuvant chemotherapy. The side effects of platinum-based chemotherapy are tolerable.

Challenges and Opportunities in Developing Targeted Therapies for Triple Negative Breast Cancer

Triple negative breast cancer (TNBC) is a heterogeneous group of breast cancers characterized by their lack of estrogen receptors, progesterone receptors, and the HER2 receptor. They are more aggressive than other breast cancer subtypes, with a higher mean tumor size, higher tumor grade, the worst five-year overall survival, and the highest rates of recurrence and metastasis. Developing targeted therapies for TNBC has been a major challenge due to its heterogeneity, and its treatment still largely relies on surgery, radiation therapy, and chemotherapy. In this review article, we review the efforts in developing targeted therapies for TNBC, discuss insights gained from these efforts, and highlight potential opportunities going forward. Accumulating evidence supports TNBCs as multi-driver cancers, in which multiple oncogenic drivers promote cell proliferation and survival. In such multi-driver cancers, targeted therapies would require drug combinations that simultaneously block multiple oncogenic drivers. A strategy designed to generate mechanism-based combination targeted therapies for TNBC is discussed.

Which Patients Do We Need to Test for BRCA1/2 Mutation? Feasibility of Adjuvant Olaparib Treatment in Early Breast Cancer-Real-World Data from Two Large German Breast Centers

BACKGROUND

Approximately 6% of women with breast cancer carry pathogenic germline variants in predisposition genes such as BRCA1 and BRCA2. Depending on personal and family cancer history, it is therefore recommended to test for hereditary breast cancer. Moreover, as shown by the phase III OlympiA trial, olaparib significantly improves overall survival in patients with HER2 negative (HER2-) early breast cancer who (1) carry a BRCA1 or BRCA2 germline mutation (gBRCA1/2-positive), (2) have received (neo)adjuvant chemotherapy and (3) are at high clinical risk. The objective of the current analysis was to determine the number of patients with early HER2- breast cancer who are at high clinical risk, according to the inclusion criteria of OlympiA, and to estimate how many of these patients would meet the criteria for hereditary cancer testing in a real-world analysis.

METHODS

All patients included in this retrospective analysis were treated for early breast cancer (eBC) at the Department of Gynecology and Obstetrics, Ulm University Hospital, Germany, and the Department of Women's Health at Tuebingen University Hospital, Germany, between January 2018 and December 2020. Patients were identified as high risk, in line with the clinicopathological determiners used in the OlympiA trial. The criteria of the German Consortium for Hereditary Breast and Ovarian Cancer were used to identify patients who qualify for hereditary cancer testing.

RESULTS

Of 2384 eligible patients, 1738 patients (72.9%) showed a hormone receptor positive (HR+)/HER2- tumor biology, 345 patients (14.5%) displayed HER2+ breast cancer and 301 patients (12.6%) suffered from HR-/HER2- breast cancer (TNBC). Of 2039 HER2- breast cancer patients, 271 patients (13.3%) were at high clinical risk. This cohort encompassed 130 of the 1738 patients with HR+/HER2- breast cancer (7.5%) and 141 of 301 patients with TNBC (46.8%). A total of 121 of 271 patients (44.6%) with high clinical risk met the criteria for hereditary cancer testing (34 of 130 (26.2%) HR+/HER2- patients and 87 of 141 (61.7%) patients with TNBC).

CONCLUSION

Approximately one in ten patients with HR+/HER2-, and half of the patients with TNBC, meet the high-risk criteria according to OlympiA. Half of these patients do not meet the criteria for hereditary cancer testing and should therefore be tested for the presence of gBRCA1/2 mutations, irrespective of their own or family cancer history. The overall number of patients with early breast cancer benefiting from olaparib needs to be investigated in future studies.

An overview of the research progress of BRCA gene mutations in breast cancer

The breast cancer susceptibility gene (BRCA) is an important tumor suppressor gene, including BRCA1 and BRCA2, a biomarker that assesses the risk of breast cancer and influences a patient's individualized treatment options. BRCA1/2 mutation (BRCAm) increases the risk of breast cancer. However, breast-conserving surgery is still an option for BRCAm, and prophylactic mastectomy and nipple-sparing mastectomy may also reduce the risk of breast cancer. BRCAm is sensitive to Poly (ADP-ribose) polymerase inhibitor (PARPi) therapy due to specific types of DNA repair defects, and its combination with other DNA damage pathway inhibitors and endocrine therapy and immunotherapy are also used for the treatment of BRCAm breast cancer. The current treatment and research progress of BRCA1/2 mutant breast cancer in this review provides a basis for the individualized treatment of patients with this type of breast cancer.

Prevalence of Pathogenic Germline Variants in Women with Non-Familial Unilateral Triple-Negative Breast Cancer

INTRODUCTION

International guidelines recommend genetic testing for women with familial breast cancer at an expected prevalence of pathogenic germline variants (PVs) of at least 10%. In a study sample of the German Consortium for Hereditary Breast and Ovarian Cancer (GC-HBOC), we have previously shown that women with TNBC diagnosed before the age of 50 years but without a family history of breast or ovarian cancer (sTNBC) meet this criterion. The present study investigates the PV prevalence in BRCA1, BRCA2, and nine additional cancer predisposition genes in an extended sTNBC study sample including a cohort of women with a later age at sTNBC diagnosis.

PATIENTS AND METHODS

In 1,600 women with sTNBC (median age at diagnosis: 41 years, range 19-78 years), we investigated the association between age at diagnosis and PV occurrence in cancer predisposition genes using logistic regression.

RESULTS

260 sTNBC patients (16.2%) were found to have a PV in cancer predisposition genes (BRCA1: n = 170 [10.6%]; BRCA2: n = 46 [2.9%], other: n = 44 [2.8%]). The PV prevalence in women diagnosed between 50 and 59 years (n = 194) was 11.3% (22/194). Logistic regression showed a significant increase in PV prevalence with decreasing age at diagnosis (OR 1.41 per 10 years younger age at diagnosis; 95% confidence interval: 1.21-1.65; p < 0.001). The PV prevalence predicted by the model was above 10% for diagnoses before the age of 56.8 years.

CONCLUSION

Based on the data presented, we recommend genetic testing by gene panel analysis for sTNBC patients diagnosed before the age of 60 years. Due to the still uncertain estimate for women with sTNBC diagnosed above the age of 60 years, further studies are needed.

Outcomes of the "BRCA Quality Improvement Dissemination Program": An initiative to improve patient receipt of cancer genetics services at five health systems

OBJECTIVE

A quality improvement initiative (QII) was conducted with five community-based health systems' oncology care centers (sites A-E). The QII aimed to increase referrals, genetic counseling (GC), and germline genetic testing (GT) for patients with ovarian cancer (OC) and triple-negative breast cancer (TNBC).

METHODS

QII activities occurred at sites over several years, all concluding by December 2020. Medical records of patients with OC and TNBC were reviewed, and rates of referral, GC, and GT of patients diagnosed during the 2 years before the QII were compared to those diagnosed during the QII. Outcomes were analyzed using descriptive statistics, two-sample t-test, chi-squared/Fisher's exact test, and logistic regression.

RESULTS

For patients with OC, improvement was observed in the rate of referral (from 70% to 79%), GC (from 44% to 61%), GT (from 54% to 62%) and decreased time from diagnosis to GC and GT. For patients with TNBC, increased rates of referral (from 90% to 92%), GC (from 68% to 72%) and GT (81% to 86%) were observed. Effective interventions streamlined GC scheduling and standardized referral processes.

CONCLUSION

A multi-year QII increased patient referral and uptake of recommended genetics services across five unique community-based oncology care settings.

Targeting Breast Cancer: An Overlook on Current Strategies

Breast cancer (BC) is one of the most widely diagnosed cancers and a leading cause of cancer death among women worldwide. Globally, BC is the second most frequent cancer and first most frequent gynecological one, affecting women with a relatively low case-mortality rate. Surgery, radiotherapy, and chemotherapy are the main treatments for BC, even though the latter are often not aways successful because of the common side effects and the damage caused to healthy tissues and organs. Aggressive and metastatic BCs are difficult to treat, thus new studies are needed in order to find new therapies and strategies for managing these diseases. In this review, we intend to give an overview of studies in this field, presenting the data from the literature concerning the classification of BCs and the drugs used in therapy for the treatment of BCs, along with drugs in clinical studies.

Cisplatin with veliparib or placebo in metastatic triple-negative breast cancer and BRCA mutation-associated breast cancer (S1416): a randomised, double-blind, placebo-controlled, phase 2 trial

BACKGROUND

Poly(ADP-ribose) polymerase (PARP) inhibitors are effective in germline BRCA1 or BRCA2 (BRCA1/2) mutation-associated metastatic breast cancer. However, studies evaluating PARP inhibitors plus platinum-based chemotherapy in germline BRCA1/2-wildtype triple-negative breast cancer are scarce. A large proportion of germline BRCA1/2-wildtype triple-negative breast cancer shows homologous recombination deficiency (HRD), resulting in a BRCA-like phenotype that might render sensitivity to PARP inhibitors. The S1416 trial assessed the efficacy of cisplatin combined with the PARP inhibitor veliparib in three predefined groups of metastatic breast cancer: germline BRCA1/2-mutated, BRCA-like, and non-BRCA-like.

METHODS

S1416 was a randomised, double-blind, placebo-controlled, phase 2 trial conducted at 154 community and academic clinical sites across the USA. Eligible patients aged 18 years or older had metastatic or recurrent triple-negative breast cancer or germline BRCA1/2-associated metastatic or recurrent breast cancer, an Eastern Cooperative Oncology Group performance status of 0-2, and had received up to one line of chemotherapy for metastatic disease. Patients were randomly assigned (1:1) via the National Clinical Trials Network open interactive system with dynamic balancing on number of previous cytotoxic regimens for metastatic disease to receive intravenous cisplatin (75 mg/m2, day 1) combined with either veliparib or matching placebo (300 mg orally twice a day, days 1-14) on a 21-day cycle. Investigators, patients, and the sponsors were masked to treatment assignment; the study statisticians were unmasked. Central testing after ran domisation classified patients as having mutated or wildtype germline BRCA1/2. A biomarker panel established a priori was used to classify patients with wildtype germline BRCA1/2 into BRCA-like and non-BRCA-like phenotype groups, with BRCA-like status based on at least one of the biomarkers: genomic instability score (≥42), somatic BRCA1/2 mutations, BRCA1 promoter methylation, or non-BRCA1/2 homologous recombination repair germline mutations. The primary endpoint was investigator-assessed progression-free survival, analysed separately for the three predefined biomarker groups with a prespecified α value for each analysis. Efficacy analyses were done by intention to treat and included all eligible patients. Safety analyses of toxicities attributed to treatment included all patients who received at least one dose of veliparib or placebo. The study is ongoing and registered with ClinicalTrials.gov, NCT02595905.

FINDINGS

Between July 7, 2016, and June 15, 2019, 335 patients were enrolled and randomly assigned. 320 patients (n=162 to cisplatin plus veliparib, all women; and n=158 to cisplatin plus placebo, 157 women and one man) were eligible for efficacy evaluation. 247 patients were classified into the three biomarker groups: germline BRCA1/2-mutated (n=37), BRCA-like (n=101), and non-BRCA-like (n=109). 73 patients could not be classified due to missing biomarker information. Median follow-up was 11·1 months (IQR 5·6-20·8). In the germline BRCA1/2-mutated group, median progression-free survival was 6·2 months (95% CI 2·3-9·2) in the cisplatin plus veliparib group and 6·4 months (4·3-8·2) in the cisplatin plus placebo group (HR 0·79 [95% CI 0·38-1·67]; log-rank p=0·54). In the BRCA-like group, median progression-free survival was 5·9 months (95% CI 4·3-7·8) in the cisplatin plus veliparib group versus 4·2 months (2·3-5·0) in the cisplatin plus placebo group (HR 0·57 [95% CI 0·37-0·88]; p=0·010). In the non-BRCA-like group, median progression-free survival was 4·0 months (95% CI 2·5-4·7) in the cisplatin plus veliparib group versus 3·0 months (2·2-4·4) in the cisplatin plus placebo group (HR 0·89 [95% CI 0·60-1·33]; p=0·57). The most common grade 3 or worse adverse events attributed to treatment were neutropenia (71 [46%] of 155 patients in the cisplatin plus veliparib group vs 29 [20%] of 147 in the cisplatin plus placebo group), leukopenia (42 [27%] vs 11 [7%]), anaemia (35 [23%] vs 12 [8%]), and thrombocytopenia (29 [19%] vs four [3%]). Serious adverse events attributed to treatment occurred in 48 (31%) patients in the cisplatin plus veliparib group and 53 (36%) patients in the cisplatin plus placebo group. Treatment-related adverse events led to death in one patient in the cisplatin plus veliparib group (sepsis) and one patient in the cisplatin plus placebo group (acute kidney injury due to cisplatin plus heart failure from previous doxorubicin exposure).

INTERPRETATION

The addition of veliparib to cisplatin significantly improved progression-free survival in patients with BRCA-like metastatic triple-negative breast cancer, but not in patients with non-BRCA-like metastatic breast cancer. PARP inhibitors combined with platinum-based chemotherapy should be explored further in BRCA-like triple-negative breast cancer.

FUNDING

National Cancer Institute and National Institute of General Medical Sciences (US National Institutes of Health); AbbVie; Myriad Genetics; the Biomarker, Imaging, and Quality of Life Studies Funding Program (awarded by the National Cancer Institute); and The University of Kansas Cancer Center.

'Why is survival with triple negative breast cancer so low? insights and talking points from preclinical and clinical research'

INTRODUCTION

Triple negative breast cancer is typically related to poor prognosis, early metastasis, and high recurrence rate. Intrinsic and extrinsic biological features of TNBC and resistance mechanisms to conventional therapies can support its aggressive behavior, characterizing TNBC how extremely heterogeneous. Novel combination strategies are under investigation, including immunotherapeutic agents, anti-drug conjugates, PARP inhibitors, and various targeting agents, exploring, in the meanwhile, possible predictive biomarkers to correctly select patients for the optimal treatment for their specific subtype.

AREAS COVERED

This article examines the main malignity characteristics across different subtype, both histological and molecular, and the resistance mechanisms, both primary and acquired, to different drugs explored in the landscape of TNBC treatment, that lead TNBC to still has high mortality rate.

EXPERT OPINION

The complexity of TNBC is not only the main reason of its aggressivity, but its heterogeneity should be exploited in terms of therapeutics opportunities, combining agents with different mechanism of action, after a correct selection by biologic or molecular biomarkers. The main goal is to understand what TNBC really is and to act selectively on its characteristics, with a personalized anticancer treatment.

BRCA Mutation Status in Triple-Negative Breast Cancer Patients Treated with Neoadjuvant Chemotherapy: A Pivotal Role for Treatment Decision-Making

Triple-negative breast cancer (TNBC) is characterized by earlier recurrence and shorter survival compared with other types of breast cancer. Moreover, approximately 15 to 25% of all TNBC patients harbor germline BRCA (gBRCA) 1/2 mutations, which confer a more aggressive phenotype. However, TNBC seems to be particularly sensitive to chemotherapy, the so-called ‘triple negative paradox’. Therefore, Neoadjuvant chemotherapy (NACT) is currently considered the preferred approach for early-stage TNBC. BRCA status has also been studied as a predictive biomarker of response to platinum compounds. Although several randomized trials investigated the addition of carboplatin to standard NACT in early-stage TNBC, the role of BRCA status remains unclear. In this retrospective analysis, we evaluated data from 136 consecutive patients with Stage I-III TNBC who received standard NACT with or without the addition of carboplatin, in order to define clinical features and outcomes in BRCA 1/2 mutation carriers and non-carrier controls. Between January 2013 and February 2021, 67 (51.3%) out of 136 patients received a standard anthracyclines/taxane regimen and 69 (50.7%) patients received a platinum-containing chemotherapy regimen. Deleterious germline BRCA1 or BRCA2 mutations were identified in 39 (28.7%) patients. Overall, patients with deleterious gBRCA1/2 mutation have significantly higher pCR rate than non-carrier patients (23 [59%] of 39 vs. 33 [34%] of 97; p = 0.008). The benefit of harboring a gBRCA mutation was confirmed only in the subset of patients who received a platinum-based NACT (17 [65.4%] of 26 vs. 13 [30.2%] of 43; p = 0.005) while no differences were found in the platinum-free subgroup. Patients who achieved pCR after NACT had significantly better EFS (OR 4.5; 95% CI 1.9–10.7; p = 0.001) and OS (OR 3.3; 95% CI 1.3–8.9; p = 0.01) than patients who did not, regardless of BRCA1/2 mutation status and type of NACT received. Our results based on real-world evidence show that TNBC patients with the gBRCA1/2 mutation who received platinum-based NACT have a higher pCR rate than non-carrier patients, supporting the use of this chemotherapy regimen in this patient population. Long-term follow-up analyses are needed to further define the role of gBRCA mutation status on clinical outcomes in patients with early-TNBC.

Efficacy of different neoadjuvant treatment regimens in BRCA-mutated triple negative breast cancer: a systematic review and meta-analysis

PURPOSE

Triple negative breast cancer (TNBC) is an aggressive breast cancer strongly associated with BRCA mutation. Standard neoadjuvant chemotherapy remains the standard of care for early stage TNBC, the optimal chemotherapy regimen is still a matter of discussion. Other agents, such as poly-ADP-ribosyl polymerase inhibitors (PARPi) and anti-vascular endothelial growth factor (VEGF) antibodies were evaluated in the neoadjuvant setting. This systematic review and meta-analysis intend to evaluate the impact of neoadjuvant treatments in pCR rates in TNBC gBRCA mutation, beyond traditional standard chemotherapy.

METHODS

PubMed, Clinicaltrials.gov, Cochrane CENTRAL, Embase and key oncological meetings for trials were searched for studies reporting neoadjuvant chemo-immunotherapy in BRCA positive TNBC.

RESULTS

Out of 1238 records reviewed, thirty-one trials were included, resulting in a total 619 BRCA-mutated TNBC patients. In BRCA mutated TNBC patients who received cisplatin in monotherapy the proportion of patients who achieved pCR was 0.53 (95%CI [0.30, 0.76]), and when treatment combined standard chemotherapy and platin derivatives the proportion of pCR increased to 0.62 (95% CI [0.48, 0.76]). The group of patients treated with platin derivatives, anthracyclines ± taxanes achieved the highest proportion of pCR, 0.66. Patients treated with PARPi alone show a pCR proportion of 0.55 (95% CI [0.30, 0.81]); and when standard chemotherapy and platin derivatives were combined with PARPi the proportion of pCR did not vary.

CONCLUSIONS

Patients with BRCA mutated TNBC treated with cisplatin in monotherapy demonstrate inferior proportion in the pCR achievement when compared with standard chemotherapy plus platin derivates. The best pCR was achieved with platin derivates in association with anthracyclines ± taxanes. No difference in pCR was found between PARPi alone vs PARPi with standard chemotherapy.

Management of patients with early-stage triple-negative breast cancer following pembrolizumab-based neoadjuvant therapy: What are the evidences?

New therapy options have changed the treatment landscape of early-stage triple-negative breast cancer (TNBC) in recent years. Most patients are candidates for neoadjuvant chemotherapy, which helps to downstage the tumor and tailor adjuvant systemic therapy based on pathologic response. Capecitabine, pembrolizumab, and olaparib have been incorporated into the armamentarium of adjuvant treatment for selected patients. The KEYNOTE-522 trial, that demonstrated the benefit of pembrolizumab, given in addition to neoadjuvant chemotherapy and adjuvantly after surgery, represented a paradigm shift for early-stage TNBC treatment. Pembrolizumab was continued in the adjuvant setting irrespective of response to neoadjuvant therapy, and other adjuvant therapies were not administered in the trial. Many questions were then raised on the selection of adjuvant therapy regimens for patients with residual disease (RD). Prior to the routine use of immune-checkpoint inhibitors (ICI), the value of adjuvant capecitabine for patients with RD after neoadjuvant polychemotherapy was demonstrated. Given the poor prognosis of some patients with RD after neoadjuvant chemo-immunotherapy, while the survival advantage of adding capecitabine during the adjuvant phase of pembrolizumab is unknown, it does appear safe and can be considered. Regarding patients harboring germline BRCA mutations with RD after neoadjuvant ICI-containing regimens, the combination of olaparib with pembrolizumab can be an option based on existing safety data.

Impact of low versus negative estrogen/progesterone receptor status on clinico-pathologic characteristics and survival outcomes in HER2-negative breast cancer

Triple-negative breast cancer (TNBC) is classically defined by estrogen receptor (ER) and progesterone receptor (PR) immunohistochemistry expression <1% and absence of HER2 amplification/overexpression. HER2-negative breast cancer with low ER/PR expression (1–10%) has a gene expression profile similar to TNBC; however, real-world treatment patterns, chemotherapy response, endocrine therapy benefit, and survival outcomes for the Low-ER group are not well known. 516 patients with stage I-III HER2-negative breast cancer and ER/PR expression ≤10% who were enrolled in a multisite prospective registry between 2011 and 2019 were categorized on the basis of ER/PR expression. TNBC (ER and PR < 1%) and Low-ER (ER and/or PR 1–10%) groups comprised 87.4% (n = 451) and 12.6% (n = 65) of patients, respectively. Demographic, clinical, and treatment characteristics, including prevalence of germline BRCA1/2 mutation, racial and ethnic distribution, and chemotherapy use were not different between TNBC and Low-ER groups. No difference was observed in recurrence-free survival (RFS) and overall survival (OS) between TNBC and Low-ER groups (3-year RFS 82.5% versus 82.4%, respectively, p = 0.728; 3-year OS 88.0% versus 83.4%, respectively, p = 0.632). Among 358 patients receiving neoadjuvant chemotherapy, rates of pathologic complete response were similar for TNBC and Low-ER groups (49.2% vs 51.3%, respectively, p = 0.808). The HER2-negative Low-ER group is often excluded from TNBC clinical trials assessing novel treatments (immunotherapy and antibody-drug conjugates), thus limiting efficacy data for newer effective therapies in this group. Given that HER2-negative Low-ER disease displays clinical characteristics and outcomes similar to TNBC, inclusion of this group in TNBC clinical trials is encouraged.

Durable Disease-free Survival in a Patient with Metastatic Triple-negative Breast Cancer Treated with Olaparib Monotherapy

BACKGROUND

Metastatic triple-negative breast cancer (mTNBC) has a poor prognosis and few effective targeted therapy options. Olaparib, a poly (ADP-ribose) polymerase (PARP) inhibitor, has been granted accelerated approval by FDA for patients with deleterious BRCA-mutated human epidermal growth factor receptor 2 (HER2)-negative advanced/metastatic breast cancer. However, there is little data demonstrating that patients with particular forms of germline and/or somatic BRCA1/2, such as large fragment variation, can benefit from PARP inhibitors.

CASE PRESENTATION

In 2011, a 40-year-old woman was diagnosed with TNBC having pT2N0M0 in the right breast, and a new irregular lesser tubercle in the left breast appeared after approximately 3 years, which was also diagnosed as TNBC. In 2017, computed tomography (CT) showed TNBC metastases to the lung and brain. A next-generation sequencing (NGS) was performed with a lung metastasis sample, and results showed a homologous recombination deficiency (HRD) score of 67, a germline large deletion of exon 2 in BRCA1, a novel somatic BRCA2-STARD13 rearrangement and copy number loss of RAD51. Since September 2017, the patient was treated with olaparib. Till the report date of this case, the patient underwent regular follow-up without disease recurrence.

CONCLUSION

To our knowledge, this is the first case describing a patient with lung- and brainmetastatic TNBC with combined germline and somatic large rearrangement and a high HRD score who achieved a long-term benefit from olaparib monotherapy. The use of NGS is promising in the treatment of TNBC in clinical practice.

Homologous recombination deficiency predicts the response to platinum-based neoadjuvant chemotherapy in early-stage triple-negative breast cancer patients: a systematic review and meta-analysis

Background:

Recent studies have shown that homologous recombination deficiency (HRD) may be correlated with the pathological complete response (pCR) rate. This meta-analysis aimed to determine the predictive value of HRD for the pCR rate in patients with triple-negative breast cancer (TNBC) receiving platinum-based neoadjuvant chemotherapy (NCT).

Methods:

Published articles were searched in the PubMed, Embase, Medline, Web of Science, and Cochrane databases up to 1 June 2021, and studies reporting the pCR rate for HRD carriers on platinum-based NCT were selected. Odds ratios (ORs) with 95% confidence intervals (CIs) were determined for the pCR rate, clinical response rate, and Grade 3 or higher adverse events (AEs) using the random-effects model. Bias risk was evaluated using the Cochrane Collaboration tool (PROSPERO, registration number CRD42021249874).

Results:

Seven studies were eligible. The results showed that HRD carriers had higher pCR rates than non-HRD carriers across all treatment arms (OR = 3.84, 95% CI = [1.93, 7.64], p = 0.0001). Among HRD carriers, the pCR rate was higher in patients on platinum-based NCT than in those without platinum exposure (OR = 1.95, 95% CI = [1.17, 3.23], p = 0.01). We did not observe marked pCR improvements in non-HRD carriers. Among HRD carriers, the pCR rates in the mutant and wild-type breast cancer susceptibility gene (BRCA) groups did not differ significantly (OR = 2.00, 95% CI = [0.77, 5.23], p = 0.16), but HRD carriers with wild-type BRCA had a significant advantage over non-HRD carriers on platinum-based NCT (OR = 3.64, 95% CI = [1.83, 7.21], p = 0.0002).

Conclusion:

HRD is an effective predictor of increased pCR rates in platinum-based NCT, especially in wild-type BRCA patients. Adding platinum to NCT for non-HRD carriers can increase the incidence of AEs but may not improve the therapeutic effect.

Comprehensive Analysis of Regulatory Factors and Immune-Associated Patterns to Decipher Common and BRCA1/2 Mutation-Type-Specific Critical Regulation in Breast Cancer

Background: BRCA1/2 mutations are closely related to high lifetime risk of breast cancer (BC). The objective of this study was to identify the genes, regulators, and immune-associated patterns underlying disease pathology in BC with BRCA1/2 somatic mutations and their associations with clinical traits. Methods: RNA sequencing data and clinical information from The Cancer Genome Atlas (TCGA; N = 36 BRCA1-mutant BC; N = 49 BRCA2-mutant BC; and N = 117 BRCA1/2-wild-type BC samples) were used for discovery, which included consensus network analysis, function enrichment, and analysis of hub genes; other TCGA data (N = 117 triple-negative BC) and two Gene Expression Omnibus database expression profiles were used as validation cohorts. Results: Consensus network analysis helped to identify specific co-expressed modules that showed positive correlations with tumor stage, number of positive lymph nodes, and margin status in BRCA1/2-mutant BC but lacking correlations in BRCA1/2-wild-type BC. Functional enrichment suggested potential mechanisms in BRCA1/2 carriers that could regulate the cell cycle, immune response, cellular metabolic processes, and cell migration, via enriched pathways including p53 and JAK-STAT signaling. Consensus network analysis identified the specific and common carcinogenic mechanisms involving BRCA mutations. Regulators cross-linking these modules include E2F or IRF transcription factor family, associated with cell cycle or immune response regulation module, respectively. Eight hub genes, including ISG15, BUB1, and TTK, were upregulated in several BRCA1/2-mutant BC datasets and showed prognostic value in BC. Furthermore, their genetic expression was related to higher levels of immune infiltration in BRCA1/2-mutant BC, which manifested as recruitment of T helper cells (Th1 cells), follicular helper T cells, and regulatory T cells, and T cell exhaustion. Moreover, important indicators for evaluation of BC immunotherapy, tumor mutational burden and neoantigen load also positively correlated with expression of some hub genes. Conclusion: We constructed a BRCA1/2 mutation-type-specific co-expressed gene network with related transcription factors and immune-associated patterns that could regulate and influence tumor metastasis and immune microenvironment, providing novel insights into the pathological process of this disease and the corresponding BRCA mutations.

Molecular Targets and Promising Therapeutics of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is one of the most heterogeneous diseases in solid tumors and has limited therapeutic options. Due to the lack of appropriate targetable markers, the mainstay therapeutic strategy for patients with TNBC has been chemotherapy for the last several decades. Indeed, TNBC tumors have no expression of estrogen receptor, progesterone receptor, or human epidermal growth factor receptor 2 (HER2); therefore, they do not respond to hormone therapy and HER2-targeted therapy. In this review paper, the molecular heterogeneities, possible therapeutic targets, and recently approved and upcoming drugs for TNBC will be summarized.

Identification of a novel pathogenic variant in PALB2 and BARD1 genes by a multigene sequencing panel in triple negative breast cancer in Morocco

Pathogenic variants (PVs) in BRCA genes have been mainly associated with an increasing risk of triple negative breast cancer (TNBC). The contribution of PVs in non-BRCA genes to TNBC seems likely since the processing of homologous recombination repair of double-strand DNA breaks involves several genes. Here, we investigate the susceptibility of genetic variation of the BRCA and non-BRCA genes in 30 early-onset Moroccan women with TNBC. Methods: Targeted capture-based next generation sequencing (NGS) method was performed with a multigene panel testing (MGPT) for variant screening. Panel sequencing was performed with genes involved in hereditary predisposition to cancer and candidate genes whose involvement remains unclear using Illumina MiSeq platform. Interpretation was conducted by following the American College of Medical Genetics and Genomics-Association for Molecular Pathology (ACMG-AMP) criteria. Results: PVs were identified in 20% (6/30) of patients with TNBC. Of these, 16.7% (5/30) carried a BRCA PV [10% (3/30) in BRCA1, 6.7% (2/30) in BRCA2] and 6.6% (2/30) carried a non-BRCA PV. The identified PVs in BRCA genes (BRCA1 c.798_799delTT, BRCA1 c.3279delC, BRCA2 c.1310_1313del, and BRCA2 c.1658T>G) have been reported before and were classified as pathogenic. The identified founder PVs BRCA1 c.798_799del and BRCA2 c.1310_1313delAAGA represented 10% (3/30). Our MGPT allowed identification of several sequence variations in most investigated genes, among which we found novel truncating variations in PALB2 and BARD1 genes. The PALB2 c.3290dup and BARD1 c.1333G>T variants are classified as pathogenic. We also identified 42 variants of unknown/uncertain significance (VUS) in 70% (21/30) of patients with TNBC, including 50% (21/42) missense variants. The highest VUS rate was observed in ATM (13%, 4/30). Additionally, 35.7% (15/42) variants initially well-known as benign, likely benign or conflicting interpretations of pathogenicity have been reclassified as VUS according to ACMG-AMP. Conclusions: PALB2 and BARD1 along with BRCA genetic screening could be helpful for a larger proportion of early-onset TNBC in Morocco.

Untangling Triple-Negative Breast Cancer Molecular Peculiarity and Chemo-Resistance: Trailing Towards Marker-Based Targeted Therapies

Triple-negative breast cancer (TNBC), characterized by the absence of estrogen receptor, progesterone receptor, or human epidermal growth factor receptor-2, affects nearly 15% of women with breast cancer. To date, the mainstay of treatment remains chemotherapy, with all the associated consequences, such as the significant toxicity and the suboptimal effect on the five-year survival rates. RNA-expression profiling showed that TNBC is biologically a heterogeneous malignancy. Therefore, predictive biomarkers matched with the diverse subtypes of TNBC could classify patients that would most benefit from a certain targeted treatment. Three biomarker-driven therapies are currently available: poly-adenosine diphosphate (ADP) ribose polymerase inhibitors for patients with germline BReast CAncer gene (BRCA) mutations, atezolizumab combined with nab-paclitaxel for patients expressing programmed death-ligand 1 (PD-L1) on tumor-infiltrating immune cells, and sacituzumab govitecan, an antibody-drug conjugate targeting human trophoblast cell-surface antigen 2 (TROP-2). Identifying predictive biomarkers is crucial for the optimum generation and implementation of targeted agents for TNBC, while further relevant treatments are in the pipeline given the promising results in clinical trials. Finally, newly developed immunotherapies and other targeted agents should also be investigated in earlier stages of the disease, especially in the neoadjuvant setting, broadening the therapeutic application of such regimens.

Selinexor, a selective inhibitor of nuclear export, enhances the anti-tumor activity of olaparib in triple negative breast cancer regardless of BRCA1 mutation status

Triple negative breast cancer (TNBC) is a deadly disease with limited treatment options. Selinexor is a selective inhibitor of nuclear export that binds covalently to exportin 1 thereby reactivating tumor suppressor proteins and downregulating expression of oncogenes and DNA damage repair (DDR) proteins. Olaparib is a poly (ADP-ribose) polymerase (PARP) inhibitor approved for the treatment of patients with breast cancer harboring BRCA mutations. We examined the effects of co-treatment with selinexor and olaparib in TNBC cell lines. BRCA1 wildtype (BRCA1-wt) and BRCA1 mutant (BRCA1-mut) TNBC cell lines were treated with selinexor and/or olaparib and effects on cell viability and cell cycle were evaluated. The effects of treatment were also evaluated in mouse xenograft models generated with BRCA1-wt and BRCA1-mut TNBC cell lines. Treatment with selinexor inhibited cell proliferation and survival of all TNBC cell lines tested in vitro. This effect was enhanced following treatment of the cells with the combination of selinexor and olaparib, which showed synergistic effects on tumor growth inhibition in MDA-MB-468-derived (BRCA1-wt) and MDA-MB-436-derived (BRCA1-mut) xenografts. As co-treatment with selinexor and olaparib exhibits anti-tumor activity regardless of BRCA1 mutation status, the clinical implications of the combination warrant further investigation.

BRCA Mutational Status is a Promising Predictive Biomarker for Platinum- based Chemotherapy in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) can be distinguished from other breast malignancies by the lack of expression of estrogen receptors (ER), progesterone receptors (PR) as well as human epidermal growth factor receptor 2 (HER2). TNBC is associated with adverse clinical outcomes and high risk of metastasis. Currently, several clinical and translational reports are focusing on developing targeted therapies for this aggressive cancer. In addition to approved targeted drugs such as poly(ADP-ribose) polymerase inhibitors (PARPi) and immune-checkpoint inhibitors, platinum-based chemotherapy is still a cornerstone therapeutic option in TNBC. However, despite the observed improved outcomes with platinum- based chemotherapy in TNBC, there is still a large proportion of patients who do not respond to this treatment, hence, the need for predictive biomarkers to stratify TNBC patients and therefore, avoiding unwanted toxicities of these agents. With the emergence of genetic testing, several recent studies suggested mutations in breast cancer susceptibility gene (BRCA) in TNBC patients as important predictors of outcomes. These mutations alter the homologous recombination repair (HRR) mechanisms leading to genomic instability. Consequently, sensitivity to platinum-based treatments in this subpopulation of TNBC patients may be explained by cell death enhanced by deoxyribonucleic acid (DNA) damage induced by these potent anticancer drugs. Through this paper, we review several recent studies on this topic to better understand the mechanisms and discuss the potential of BRCA mutational status as a predictive biomarker of platinum-based chemotherapy in TNBC.

Emerging drugs for the treatment of triple-negative breast cancer: a focus on phase II immunotherapy trials

Introduction: Triple-negative breast cancer accounts for 10-20% of invasive breast cancers and is characterized by an aggressive phenotype and poor outcomes in the early and advanced settings compared to other breast cancer subtypes. Chemotherapy continues to be the mainstay of treatment, but recent advances have demonstrated the benefit of adding immune checkpoint inhibitors (ICIs) to chemotherapy regimens for patients with both early and advanced TNBC, particularly if PD-L1-positive. Despite these results, further improvements are needed.Areas covered: This review covers immunotherapy drugs which have recently completed, involved in ongoing or due to start phase II trials. This includes approaches to augment the response to existing ICIs, next-generation ICIs, combination treatments with targeted agents and drugs that target the tumor microenvironment. Potential development issues are also discussed.Expert opinion: The field of immunotherapy is developing rapidly and holds great promise for patients with TNBC. Promising avenues of research currently in phase II trials include targeting multiple immune checkpoints simultaneously and the addition of phosphatidylinositol 3-kinase (PI3K)/AKT inhibitors to ICI/chemotherapy regimens. A better understanding of the immunosuppressive role played by the tumor microenvironment has also been important. However, challenges remain, particularly regarding the need for more effective predictive biomarkers.

Management of patients with BRCA mutation from the point of view of a breast surgeon

Germ-line mutation in BRCA (BReast CAncer gene) 1 or BRCA2 are found in 3–4% of all women with breast cancer. These patients have a significant increased risk of breast and ovarian cancer. They are often younger when diagnosed with the mutation, and the possible breast cancer they get is often aggressive with inferior outcome. There are risk reducing strategies, and the most powerful strategy is risk reducing surgery, both risk reducing bilateral mastectomy (RRM) and risk reducing bilateral salpino-oophorectomy (PBSO). This review is meant to address breast surgery in patients with germline BRCA mutation. The guidelines and techniques applied is under continuous change and it is important for the clinicians to be well informed to provide the patient with the information needed for them to make an informed decision on what risk strategy to choose.

•

Patients with germ-line mutation in BRCA1 or BRCA2 have a significant increased risk of breast and ovarian cancer.

•

There are different risk reducing strategies and the most powerful strategy is risk-reducing surgery, both risk reducing bilateral mastectomy and risk reducing bilateral salpingo-oophorectomy.

•

Guidelines and techniques for the risk reducing surgery of the breast are under continuous change and improvement.

•

Breast conserving therapy is not associated with worse survival and is a good option for a BRCA mutation carrier diagnosed with breast cancer. Risk-reducing mastectomy can be performed in a later setting.

•

The management of BRCA mutation carriers, both affected and unaffected, should be performed in a multidisciplinary team. Physicians need to be systematically educated and updated on the most recent literature.

Research advances and new challenges in overcoming triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a pathological term used to identify invasive breast cancers that lack expression of estrogen and progesterone receptors and do not have pathologic overexpression of the HER2 receptor or harbor ERBB2 gene amplification. TNBC includes a collection of multiple distinct disease entities based upon genomic, transcriptomic and phenotypic characterization. Despite improved clinical outcomes with the development of novel therapeutics, TNBC still yields the worst prognosis among all clinical subtypes of breast cancer. We will systematically review evidence of the genomic evolution of TNBC, as well as potential mechanisms of disease progression and treatment resistance, defined in part by advances in next-generation DNA sequencing technology (including single cell sequencing), providing a new perspective on treatment strategies, and promise to reveal new potential therapeutic targets. Moreover, we review novel therapies aimed at homologous recombination deficiency, PI3 kinase/AKT/PTEN pathway activation, androgen receptor blockade, immune checkpoint inhibition, as well as antibody-drug conjugates engaging novel cell surface targets, including recent progress in pre-clinical and clinical studies which further validate the role of targeted therapies in TNBC. Despite major advances in treatment for TNBC, including FDA approval of 2 PARP inhibitors for metastatic TNBC, the crossing of the superiority boundary in a phase 3, placebo-controlled study of adjuvant olaparib in early-stage patients with germline BRCA-mutated high-risk HER2-negative early breast cancer, the FDA approval of 2 PD-(L)1 checkpoint antibodies for metastatic TNBC, and the FDA approval of the first antibody drug conjugate for TNBC, significant challenges remain. For example, despite the dawn of immunotherapy in metastatic TNBC, durable responses are limited to a small subset of patients, definitive biomarkers for patient selection are lacking, and the Oncology Drug Advisory Committee to the FDA has recently voted against approval of an anti-PD-1 checkpoint antibody high risk early-stage TNBC in the neoadjuvant setting. Also, despite early positive randomized phase 2 studies of AKT inhibition in metastatic TNBC, a recent phase 3 registration trial failed to validate earlier phase 2 data. Finally, we note that level one evidence for clinical efficacy of androgen receptor blockade in TNBC is still lacking. To meet these and other challenges, we will catalogue the ongoing exponential increase in interest in basic, translational, and clinical research to develop new treatment paradigms for TNBC.

PARP inhibitor treatment of advanced breast cancer beyond the BRCA-mutated type: a meta-analysis

Background: We conducted this meta-analysis to compare the efficacy and safety of PARP inhibitors with or without chemotherapy versus chemotherapy alone for advanced breast cancer. Methods: A meta-analysis and trial sequential analysis were performed using RevMan 5.2 analysis software. Results: Six eligible randomized clinical trials involving 2080 patients were included. Regimens containing PARP inhibitors were significantly associated with higher objective response rate, longer progression-free survival and overall survival. The PARP inhibitor regimen group had a significantly higher rate of grade ≥3 thrombocytopenia than the chemotherapy-only group. Conclusion: Regimens containing PARP inhibitors are effective and safe for BRCA-mutated advanced breast cancer patients. The efficacy appears to be only marginal in patients with BRCA status unselected.

Prevalence of MMTV-Like env Sequences and Its Association with BRCA1/2 Genes Mutations Among Egyptian Breast Cancer Patients

Background

Mouse mammary tumor virus (MMTV) is thought to have a role in human breast cancer (BC) pathogenesis. BRCA1 and 2 genes mutations are well-established risk factors for BC. The purpose of this study was to evaluate the presence of MMTV in familial and non-familial Egyptian breast cancer patients. We also aimed to establish a correlation between BRCAs genes mutations and MMTV infection in those patients.

Patients and Methods

The study was included 80 BC patients and 10 healthy women were included as a control group. We used PCR to amplify a 250-bp MMTV-like env sequence. We also used PCR followed by direct sequencing to identify the genetic variation of exons 2, 13, 19 of BRCA1 gene and exon 9 and region f of exon 11 of BRCA2 gene. High resolution melting (HRM) analysis was used to screen the selected exons of BRCA1/2 genes in order to detect different variants.

Results

MMTV DNA-like env sequences were detected in 70%, 76% of familial and non-familial BC patients, respectively, and it was not detected in any of the control subjects. The presence of viral sequences was associated with larger tumor size in the sporadic patients. Seventy BC patients showed variations in BRCA1/2 genes according to HRM analysis and sequencing analysis showed two different sequences of polymorphism among 22 familial and non-familial BC patients.

Conclusion

MMTV DNA was present among BC patients and it was associated with increased tumor growth. This indicates a potential role for MMTV in BC patients with and without deleterious mutation in BRCA1/2 genes.

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

Background

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

Methods

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

Results

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

Conclusions

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

Prevalence of BRCA1 and BRCA2 mutations in Japanese patients with triple-negative breast cancer: A single institute retrospective study

Numerous databases for risk assessment of BRCA1/2 gene mutations contain insufficient data about Asians. Furthermore, few studies have reported the prevalence of germline BRCA1/2 mutations in Japanese patients, particularly those with triple-negative breast cancer (TNBC). The present study was a retrospective analysis of data from patients with TNBC who underwent BRCA1/2 mutation testing at Osaka International Cancer Institute (Osaka, Japan) between October 2014 and March 2020. A total of 65 patients with TNBC underwent a test for BRCA1/2 mutations, and 13 (20.0%) had deleterious mutations in the BRCA1 or BRCA2 genes. Furthermore, 12 out of 29 patients with a family history of breast or ovarian cancer had deleterious BRCA1/2 mutations, and only 1 of 34 without a family history had a mutation (41.4 vs. 2.9%; P=0.014). No patients aged >60 years had BRCA1/2 mutations; however, the age of diagnosis was not a significant risk factor for BRCA1/2 mutations (P=0.60). The prevalence of BRCA1/2 mutations in the present cohort of Japanese patients with TNBC was slightly higher than those reported in other larger studies from Europe and North America. Further data from large prospective studies are required to more precisely define the prevalence of BRCA1/2 mutations.

An open-label, pilot study of veliparib and lapatinib in patients with metastatic, triple-negative breast cancer

BACKGROUND

Poly (ADP-ribose)-polymerase inhibitors (PARPi) have been approved for cancer patients with germline BRCA1/2 (gBRCA1/2) mutations, and efforts to expand the utility of PARPi beyond BRCA1/2 are ongoing. In preclinical models of triple-negative breast cancer (TNBC) with intact DNA repair, we have previously shown an induced synthetic lethality with combined EGFR inhibition and PARPi. Here, we report the safety and clinical activity of lapatinib and veliparib in patients with metastatic TNBC.

METHODS

A first-in-human, pilot study of lapatinib and veliparib was conducted in metastatic TNBC (NCT02158507). The primary endpoint was safety and tolerability. Secondary endpoints were objective response rates and pharmacokinetic evaluation. Gene expression analysis of pre-treatment tumor biopsies was performed. Key eligibility included TNBC patients with measurable disease and prior anthracycline-based and taxane chemotherapy. Patients with gBRCA1/2 mutations were excluded.

RESULTS

Twenty patients were enrolled, of which 17 were evaluable for response. The median number of prior therapies in the metastatic setting was 1 (range 0-2). Fifty percent of patients were Caucasian, 45% African-American, and 5% Hispanic. Of evaluable patients, 4 demonstrated a partial response and 2 had stable disease. There were no dose-limiting toxicities. Most AEs were limited to grade 1 or 2 and no drug-drug interactions noted. Exploratory gene expression analysis suggested baseline DNA repair pathway score was lower and baseline immunogenicity was higher in the responders compared to non-responders.

CONCLUSIONS

Lapatinib plus veliparib therapy has a manageable safety profile and promising antitumor activity in advanced TNBC. Further investigation of dual therapy with EGFR inhibition and PARP inhibition is needed.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT02158507 . Registered on 12 September 2014.

Receptor-Defined Breast Cancer in Five East African Countries and Its Implications for Treatment: Systematic Review and Meta-Analysis

PURPOSE

Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2) are determinants of treatment and mortality for patients with breast cancer (BC). In East Africa, the estimated 5-year survival (37.7%) is far lower than the US average (90%). This meta-analysis investigates BC receptor subtypes within five East African countries to ascertain cross-country patterns and prioritize treatment needs.

METHODS

From a PubMed search, January 1, 1998-June 30, 2019, for all English-only BC articles for Ethiopia, Kenya, Rwanda, Tanzania, and Uganda, eligible studies had receptor distributions for female BC samples ≥ 30 patients. Outcomes were proportions of ER+, PR+, and HER2-positive (HER2+), and/or molecular subtypes. Data included study characteristics and mean or median patient age. Using metaprop, Stata 16, we estimated pooled proportions (ES) with 95% CIs and assessed heterogeneity.

RESULTS

Among 36 BC studies with receptor data, 21 met criteria. Weighted mean age was 47.5 years and median, 48. Overall ES were as follows: 55% for ER-positive (ER+) (95% CI, 47 to 62), 23% for HER2+ (95% CI, 20 to 26), and 27% for triple-negative BC (TNBC) (95% CI, 23 to 32).

CONCLUSION

We found differences between countries, for example, lower distribution of TNBC in Ethiopia (21%) compared with Uganda (35%). ER+, the dominant BC subtype overall at 55%, emphasizes the need to prioritize endocrine therapy. Overall proportions of HER2+ BC (with or without ER+ or PR+), 23%, approached proportions of TNBC, 27%, yet HER2 testing and treatment were infrequent. Testing and reporting of receptor subtypes would promote delivery of more effective treatment reducing the mortality disparity.

Deep exploration of PARP inhibitors in breast cancer: monotherapy and combination therapy

OBJECTIVE

Nearly 5% of patients with breast cancer carry germline BRCA mutations, which are more common in triple-negative breast cancer (TNBC). Previous clinical trials demonstrated the therapeutic efficacy of poly (ADP-ribose) polymerase inhibitors (PARPis) against BRCA-mutated metastatic breast cancer. The current study conducted a systemic review and meta-analysis of the clinical efficiency and safety of PARPis, either alone or combined with chemotherapy, in patients with TNBC.

METHODS

We searched PubMed, EMBASE, and ClinicalTrials.gov to identify randomized controlled trials comparing PARPi therapy with chemotherapy, and comparisons of chemotherapy plus PARPis with chemotherapy alone were included. The study endpoints included the clinical response, progression-free survival, and adverse event rates.

RESULTS

PARPi therapy was revealed to improve progression-free survival in patients with advanced breast cancer, either alone or in combination with chemotherapy. Subgroup analysis illustrated that patients with mutant BRCA1 and mutant BRCA2 and those who had not been treated with platinum-based agents could specifically benefit from PARPis.

CONCLUSION

PARPi monotherapy can significantly improve clinical outcomes in patients with advanced breast cancer, especially those with TNBC, those who had not previously received platinum therapy, and those with mutant BRCA1/2. PARPis combined with chemotherapy represent new treatment options for patients with advanced cancer.

A predictor of pathological complete response to neoadjuvant chemotherapy in triple-negative breast cancer patients with the DNA repair genes

Background

We conducted this study to investigate the prevalence of potential chemo-response-related gene mutations in triple-negative breast cancer (TNBC) patients and to evaluate the potential relationship between these gene mutations and neoadjuvant chemotherapy response in TNBC patients.

Methods

One hundred sixty-two TNBC patients in Fudan University Shanghai Cancer Center who received NAC with 4 cycles of paclitaxel and carboplatin were enrolled in this study. Fifty-six pathological complete response (pCR) patients and 56 non-pCR patients were enrolled in this retrospective study for the training set. Clinical assessments of postoperative residual tumors were performed according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria. Forty chemo-response-related genes were screened in each tumor specimen by second-generation sequencing analysis. Fifty TNBC patients who received neoadjuvant chemotherapy with paclitaxel and carboplatin were enrolled in the validation group.

Results

Fifty-seven of 112 (50.9%) TNBCs contained at least one detected somatic mutation. As expected, TP53 mutation was the most common alteration, which was observed in 21.4% of patients. BRCA1, BRCA2, RET, PI3KCA, and PTEN mutations were each observed in 11.6%, 4.5%, 5.4%, 2.7% and 3.6% of all cases, respectively. No significant differences in any gene mutation frequency between pCR and non-pCR groups were identified. We found that the mutation status of 10 DNA repair genes involved in homologous recombination (HR) pathway successfully discriminated between responding and nonresponding tumors in the training group. Up to 18 patients who were mutation-positive experienced pCR compared to only 6 in the non-pCR group (P=0.006), and 75% the HR related gene mutation patients achieved pCR. In the validation group, TNBC patients with DNA repair gene mutations achieved 77.8% pCR.

Conclusions

A subset of TNBC patients carry deleterious somatic mutations in 10 HR-related genes. The mutation status of this expanded gene panel is likely to effectively predict respond rate to neoadjuvant chemotherapy based on paclitaxel and carboplatin. Our findings need to be validated through follow-up studies in this and additional cohorts.

BRCA1/2 pathogenic variants in triple-negative versus luminal-like breast cancers: genotype-phenotype correlation in a cohort of 531 patients

BACKGROUND

Several available data suggest the association between specific molecular subtypes and BRCA1/2 mutational status. Previous investigations showed the association between BRCA1/2 pathogenic variants (PVs) in specific genomic regions and phenotypic variations of cancer relative risk, while the role of PV type and location in determining the breast cancer (BC) phenotypic features remains still unclear. The aim of this research was to describe the germline BRCA1/2 PVs in triple-negative breast cancer (TNBC) versus luminal-like BC and their potential leverage on BC phenotype.

PATIENTS & METHODS

We retrospectively collected and analyzed all clinical information of 531 patients with BC genetically tested for germline BRCA1/2 PVs by Next-Generation Sequencing analysis at University Hospital Policlinico "P. Giaccone" of Palermo (Sicily) from January 2016 to February 2020.

RESULTS

Our results corroborate the evidence that BRCA1-related tumors often have a profile which resembles the TNBC subtype, whereas BRCA2-associated tumors have a profile that resembles luminal-like BC, especially the Luminal B subtype. Interestingly, our findings suggest that the PVs identified in TNBC were not largely overlapping with those in luminal-like tumors. Differences in the frequency of two PVs potentially associated with different molecular tumor subtypes were observed. BRCA1-633delC was detected with relatively higher prevalence in patients with TNBC, whereas BRCA2-1466delT was found mainly in Luminal B tumors, but in no TNBC patient.

CONCLUSION

Future studies examining the type and location of BRCA1/2 PVs within different molecular subtypes are required to verify our hypothesis and could provide an interesting insight into the complex topic of genotype-phenotype correlations. Additionally, a more in-depth understanding of the potential correlations between BRCA PVs and clinical and phenotypic features of hereditary BC syndrome patients could be the key to develop better strategies of prevention and surveillance in BRCA-positive carriers without disease.

Heritability of Low ER Staining/HER2-Breast Tumors: Are We Missing an Opportunity for Germline Testing?

In 2010, the genetic testing criteria was changed to allow women diagnosed ≤ 60 years old with triple negative breast cancer (TNBC) to undergo germline testing. In the same year, estrogen receptor (ER) positivity was defined as having ≥1% ER staining cells. While tumors with 1–10% ER staining cells and HER2 negative (HER2-) status share characteristics with TNBC, the utility of germline testing in women with ER low positive/HER2- (ERLP/HER2-) tumors is not well-understood. To this end, all patients with hormone receptor positive staining cells ≤ 10% and negative HER2 status were identified. Clinical genetic test results were extracted for patients who underwent testing. Panel testing was performed for those women who had genomic DNA available for research purposes. ERLP/HER2-tumors constituted 2.7% of all tumors in the database. Patients did not differ significantly from those with TNBC by age at diagnosis, ethnicity, family history or tumor size, stage or grade (p > 0.05). Mutation frequency did not differ significantly (p = 0.757) between groups (ERLP/HER2- 16.1%; TNBC 16.7%). Hereditary forms of breast cancer were similar in both ERLP/HER2- and TNBC, thus current guidelines may result in the under testing of women with low ER tumors, resulting in missed opportunities to improve patient management.

Prevalence of germline BRCA mutations in HER2-negative metastatic breast cancer: global results from the real-world, observational BREAKOUT study

BACKGROUND

The global observational BREAKOUT study investigated germline BRCA mutation (gBRCAm) prevalence in a population of patients with human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC).

METHODS

Eligible patients had initiated first-line cytotoxic chemotherapy for HER2-negative MBC within 90 days prior to enrollment. Hormone receptor (HR)-positive patients had experienced disease progression on or after prior endocrine therapy, or endocrine therapy was considered unsuitable. gBRCAm status was determined using baseline blood samples or prior germline test results. For patients with a negative gBRCAm test, archival tissue was tested for somatic BRCAm and homologous recombination repair mutations (HRRm). Details of first-line cytotoxic chemotherapy were also collected.

RESULTS

Between March 2017 and April 2018, 384 patients from 14 countries were screened and consented to study enrollment; 341 patients were included in the full analysis set (median [range] age at enrollment: 56 [25-89] years; 256 (75.3%) postmenopausal). Overall, 33 patients (9.7%) had a gBRCAm (16 [4.7%] in gBRCA1 only, 12 [3.5%] in gBRCA2 only, and 5 [1.5%] in both gBRCA1 and gBRCA2). gBRCAm prevalence was similar in HR-positive and HR-negative patients. gBRCAm prevalence was 9.0% in European patients and 10.6% in Asian patients and was higher in patients aged ≤ 50 years at initial breast cancer (BC) diagnosis (12.9%) than patients aged > 50 years (5.4%). In patients with any risk factor for having a gBRCAm (family history of BC and/or ovarian cancer, aged ≤ 50 years at initial BC diagnosis, or triple-negative BC), prevalence was 10.4%, versus 5.8% in patients without these risk factors. HRRm prevalence was 14.1% (n = 9/64) in patients with germline BRCA wildtype.

CONCLUSIONS

Patient demographic and disease characteristics supported the association of a gBRCAm with younger age at initial BC diagnosis and family history of BC and/or ovarian cancer. gBRCAm prevalence in this cohort, not selected on the basis of risk factors for gBRCAm, was slightly higher than previous results suggested. gBRCAm prevalence among patients without a traditional risk factor for harboring a gBRCAm (5.8%) supports current guideline recommendations of routine gBRCAm testing in HER2-negative MBC, as these patients may benefit from poly(ADP-ribose) polymerase (PARP) inhibitor therapy.

TRIAL REGISTRATION

NCT03078036 .