Subtypes in BRCA-mutated breast cancer

BRCA Mutations and MicroRNA Expression Patterns in the Peripheral Blood of Breast Cancer Patients

Breast cancer (BC) persists as the predominant malignancy globally, standing as the foremost cause of cancer-related mortality among women. Despite notable advancements in prevention and treatment, encompassing the incorporation of targeted immunotherapies, a continued imperative exists for the development of innovative methodologies. These methodologies would facilitate the identification of women at heightened risk, enhance the optimization of therapeutic approaches, and enable the vigilant monitoring of emergent treatment resistance. Circulating microRNAs (miRNAs), found either freely circulating in the bloodstream or encapsulated within extracellular vesicles, have exhibited substantial promise for diverse clinical applications. These applications range from diagnostic and prognostic assessments to predictive purposes. This study aimed to explore the potential associations between BRCA mutations and specific miRNAs (miR-21, miR-155, miR-126, and miR-200c) expression that are known to be dysregulated in BC patient samples. Our findings indicate a robust correlation between miRNA expression status and disease subtypes. We found a correlation between the expression status of miRNAs and distinct disease subtypes. Intriguingly, however, no significant associations were discerned between disease status, subtypes, or miRNA expression levels and the presence of BRCA mutations. To advance the validation of miRNAs as clinically relevant biomarkers, additional investigations within larger and meticulously selected patient cohorts are deemed imperative. These microRNA entities hold the potential to emerge as groundbreaking and readily accessible tools, poised for seamless integration into the landscape of clinical practice.

Spatial Transcriptomics Suggests That Alterations Occur in the Preneoplastic Breast Microenvironment of BRCA1/2 Mutation Carriers

Breast cancer is the most common cancer in females, affecting one in every eight women and accounting for the majority of cancer-related deaths in women worldwide. Germline mutations in the BRCA1 and BRCA2 genes are significant risk factors for specific subtypes of breast cancer. BRCA1 mutations are associated with basal-like breast cancers, whereas BRCA2 mutations are associated with luminal-like disease. Defects in mammary epithelial cell differentiation have been previously recognized in germline BRCA1/2 mutation carriers even before cancer incidence. However, the underlying mechanism is largely unknown. Here, we employ spatial transcriptomics to investigate defects in mammary epithelial cell differentiation accompanied by distinct microenvironmental alterations in preneoplastic breast tissues from BRCA1/2 mutation carriers and normal breast tissues from noncarrier controls. We uncovered spatially defined receptor-ligand interactions in these tissues for the investigation of autocrine and paracrine signaling. We discovered that β1-integrin-mediated autocrine signaling in BRCA2-deficient mammary epithelial cells may differ from BRCA1-deficient mammary epithelial cells. In addition, we found that the epithelial-to-stromal paracrine signaling in the breast tissues of BRCA1/2 mutation carriers is greater than in control tissues. More integrin-ligand pairs were differentially correlated in BRCA1/2-mutant breast tissues than noncarrier breast tissues with more integrin receptor-expressing stromal cells.

IMPLICATIONS

These results suggest alterations in the communication between mammary epithelial cells and the microenvironment in BRCA1 and BRCA2 mutation carriers, laying the foundation for designing innovative breast cancer chemo-prevention strategies for high-risk patients.

Functional delineation of the luminal epithelial microenvironment in breast using cell-based screening in combinatorial microenvironments

Microenvironment signals are potent determinants of cell fate and arbiters of tissue homeostasis, however understanding how different microenvironment factors coordinately regulate cellular phenotype has been experimentally challenging. Here we used a high-throughput microenvironment microarray comprised of 2640 unique pairwise signals to identify factors that support proliferation and maintenance of primary human mammary luminal epithelial cells. Multiple microenvironment factors that modulated luminal cell number were identified, including: HGF, NRG1, BMP2, CXCL1, TGFB1, FGF2, PDGFB, RANKL, WNT3A, SPP1, HA, VTN, and OMD. All of these factors were previously shown to modulate luminal cell numbers in painstaking mouse genetics experiments, or were shown to have a role in breast cancer, demonstrating the relevance and power of our high-dimensional approach to dissect key microenvironmental signals. RNA-sequencing of primary epithelial and stromal cell lineages identified the cell types that express these signals and the cognate receptors in vivo. Cell-based functional studies confirmed which effects from microenvironment factors were reproducible and robust to individual variation. Hepatocyte growth factor (HGF) was the factor most robust to individual variation and drove expansion of luminal cells via cKit+ progenitor cells, which expressed abundant MET receptor. Luminal cells from women who are genetically high risk for breast cancer had significantly more MET receptor and may explain the characteristic expansion of the luminal lineage in those women. In ensemble, our approach provides proof of principle that microenvironment signals that control specific cellular states can be dissected with high-dimensional cell-based approaches.

Adjuvant treatment in hormone receptor-positive early breast cancer: New approaches of endocrine therapy

Breast cancer is the most common cancer in women, and luminal breast cancer is the predominant subtype, characterized by the presence of estrogen receptors and/or progesterone receptors in tumor cells. Adjuvant endocrine therapy is the pivotal approach in the management of luminal early breast cancer. Hence, new therapeutic approaches have been studied during the last few years, especially in patients with high risk of recurrence.Here we provide a summary of the most recent clinical trials evaluating adjuvant treatment in hormone-receptors-positive early breast cancer. First, the main cornerstone is related to the role of extended endocrine treatment, which has been widely investigated to access a benefit in disease-free survival and overall survival (only the GIM4 trial has positive feedback about survival) and to tailor the treatment according to patient compliance. The results highlighted an advantage in extending the use of endocrine treatment for at least seven full years, considering aromatase inhibitors as principal drugs. Second, the shift of CDK4/6 inhibitors (CDK4/6i) from advanced to early setting reported positive outcomes, with favorable results from MonarchE and NATALEE trials, using Abemaciclib and Ribociclib respectively, even if non-negligible toxicities have been reported. Last, the use of PARP inhibitors for BRCA1/2 mutated patients has been evaluated in the OlympiA trial (Olaparib), observing a comparable benefit between hormone-receptors-positive and triple-negative early breast cancer.However, more data are still required to better select patients that could benefit more from CDK4/6i considering side effects too, and sequential treatments are still not codified.

Non-BRCA1/BRCA2 high-risk familial breast cancers are not associated with a high prevalence of BRCAness

BACKGROUND

Familial breast cancer is in most cases unexplained due to the lack of identifiable pathogenic variants in the BRCA1 and BRCA2 genes. The somatic mutational landscape and in particular the extent of BRCA-like tumour features (BRCAness) in these familial breast cancers where germline BRCA1 or BRCA2 mutations have not been identified is to a large extent unknown.

METHODS

We performed whole-genome sequencing on matched tumour and normal samples from high-risk non-BRCA1/BRCA2 breast cancer families to understand the germline and somatic mutational landscape and mutational signatures. We measured BRCAness using HRDetect. As a comparator, we also analysed samples from BRCA1 and BRCA2 germline mutation carriers.

RESULTS

We noted for non-BRCA1/BRCA2 tumours, only a small proportion displayed high HRDetect scores and were characterized by concomitant promoter hypermethylation or in one case a RAD51D splice variant previously reported as having unknown significance to potentially explain their BRCAness. Another small proportion showed no features of BRCAness but had mutationally active tumours. The remaining tumours lacked features of BRCAness and were mutationally quiescent.

CONCLUSIONS

A limited fraction of high-risk familial non-BRCA1/BRCA2 breast cancer patients is expected to benefit from treatment strategies against homologue repair deficient cancer cells.

A New Landscape of Testing and Therapeutics in Metastatic Breast Cancer

Predictive biomarker testing on metastatic breast cancer is essential for determining patient eligibility for targeted therapeutics. The National Comprehensive Cancer Network currently recommends assessment of specific biomarkers on metastatic tumor subtypes, including hormone receptors, HER2, and BRCA1/2 mutations, on all newly metastatic breast cancers subtypes; programmed death-ligand 1 on metastatic triple-negative carcinomas; and PIK3CA mutation status on estrogen receptor-positive carcinomas. In select circumstances mismatch repair protein deficiency and/or microsatellite insufficiency, tumor mutation burden, and NTRK translocation status are also testing options. Novel biomarker testing, such as detecting PIK3CA mutations in circulating tumor DNA, is expanding in this rapidly evolving arena.

Alterations in the preneoplastic breast microenvironment of BRCA1/2 mutation carriers revealed by spatial transcriptomics

Breast cancer is the most common cancer in females, affecting one in every eight women and accounting for the majority of cancer-related deaths in women worldwide. Germline mutations in the BRCA1 and BRCA2 genes are significant risk factors for specific subtypes of breast cancer. BRCA1 mutations are associated with basal-like breast cancers, whereas BRCA2 mutations are associated with luminal-like disease. There are currently few chemoprevention strategies available for BRCA1/2 mutation carriers, and irreversible prophylactic mastectomy is the primary option. Designing chemo-preventive strategies requires an in-depth understanding of the physiological processes underlying tumor initiation. Here, we employ spatial transcriptomics to investigate defects in mammary epithelial cell differentiation accompanied by distinct microenvironmental alterations in preneoplastic breast tissues from BRCA1/2 mutation carriers and normal breast tissues from non-carrier controls. We uncovered spatially defined receptor-ligand interactions in these tissues for the investigation of autocrine and paracrine signaling. We discovered that β1-integrin-mediated autocrine signaling in BRCA2-deficient mammary epithelial cells differs from BRCA1-deficient mammary epithelial cells. In addition, we found that the epithelial-to-stromal paracrine signaling in the breast tissues of BRCA1/2 mutation carriers is greater than in control tissues. More integrin-ligand pairs were differentially correlated in BRCA1/2-mutant breast tissues than non-carrier breast tissues with more integrin receptor-expressing stromal cells. These results reveal alterations in the communication between mammary epithelial cells and the microenvironment in BRCA1 and BRCA2 mutation carriers, laying the foundation for designing innovative breast cancer chemo-prevention strategies for high-risk patients.

Hereditary breast cancer: syndromes, tumour pathology and molecular testing

Hereditary factors account for a significant proportion of breast cancer risk. Approximately 20% of hereditary breast cancers are attributable to pathogenic variants in the highly penetrant BRCA1 and BRCA2 genes. A proportion of the genetic risk is also explained by pathogenic variants in other breast cancer susceptibility genes, including ATM, CHEK2, PALB2, RAD51C, RAD51D and BARD1, as well as genes associated with breast cancer predisposition syndromes - TP53 (Li-Fraumeni syndrome), PTEN (Cowden syndrome), CDH1 (hereditary diffuse gastric cancer), STK11 (Peutz-Jeghers syndrome) and NF1 (neurofibromatosis type 1). Polygenic risk, the cumulative risk from carrying multiple low-penetrance breast cancer susceptibility alleles, is also a well-recognised contributor to risk. This review provides an overview of the established breast cancer susceptibility genes as well as breast cancer predisposition syndromes, highlights distinct genotype-phenotype correlations associated with germline mutation status and discusses molecular testing and therapeutic implications in the context of hereditary breast cancer.

Characteristics of breast cancer patients tested for germline BRCA1/2 mutations by next-generation sequencing in Ramathibodi Hospital, Mahidol University

INTRODUCTION

Germline mutations in BRCA1/2 are the most common cause of hereditary breast and ovarian cancer (HBOC) syndrome. Few studies published during the past decade reported the prevalence of germline BRCA mutations in Asian patients with breast cancer. We aimed to assess the prevalence and characteristics of Thai patients with breast cancer with germline BRCA1/2 mutations.

METHODS

We retrospectively reviewed all breast cancer patients who were tested for germline BRCA1/2 mutations during 2014-2018. BRCA mutations were detected using next-generation sequencing and confirmed using Sanger sequencing. We analyzed the characteristics of patients with or without BRCA mutations. Disease-free survival (DFS) and the associated factors were determined.

RESULTS

Among 67 patients, 12 (18%) were BRCA1/2 carriers (6 each), 4 (6%) harbored variants of uncertain significance, and 51 (76%) were non-carriers. We discovered two novel BRCA2 frameshift mutations (c.2380delA and c.8855dupT). Mean ages at breast cancer diagnosis of BRCA1, BRCA2, and non-carriers were 39.8, 46.2, and 42.0 years, respectively. The 12 tumors of BRCA carriers were mainly the luminal-B subtype. Two of these tumors were HER2-positive luminal-B, and the triple-negative subtype was not detected. After adjusting for stages and luminal subtypes, BRCA carriers experienced worse 3-year DFS than non-carriers (81.5% vs. 90.3%, HR 2.04 [0.64-6.49], p = .229). The stage at diagnosis was the sole factor significantly associated with 3-year DFS (100%, 84.8%, and 72.7%; stages I, II, and III, respectively).

CONCLUSION

Thai patients with breast cancer with BRCA1/2 mutations were mainly the luminal-B subtypes with worse prognosis than those without mutations.

Identification of biomarkers of response to preoperative talazoparib monotherapy in treatment naïve gBRCA+ breast cancers

Germline mutations in BRCA1 or BRCA2 exist in ~2–7% of breast cancer patients, which has led to the approval of PARP inhibitors in the advanced setting. We have previously reported a phase II neoadjuvant trial of single agent talazoparib for patients with germline BRCA pathogenic variants with a pathologic complete response (pCR) rate of 53%. As nearly half of the patients treated did not have pCR, better strategies are needed to overcome treatment resistance. To this end, we conducted multi-omic analysis of 13 treatment naïve breast cancer tumors from patients that went on to receive single-agent neoadjuvant talazoparib. We looked for biomarkers that were predictive of response (assessed by residual cancer burden) after 6 months of therapy. We found that all resistant tumors exhibited either the loss of SHLD2, expression of a hypoxia signature, or expression of a stem cell signature. These results indicate that the deep analysis of pre-treatment tumors can identify biomarkers that are predictive of response to talazoparib and potentially other PARP inhibitors, and provides a framework that will allow for better selection of patients for treatment, as well as a roadmap for the development of novel combination therapies to prevent emergence of resistance.

Immunohistochemical Evaluation of BAP1 Expression in Breast Cancer with Known BRCA1 and BRCA2 Mutations and Comparison with Histopathological Features

Introduction. BRCA-mutated breast cancers have specific pathological characteristics. BAP1 is a tumor suppressor gene that is important in many cancers with different pathways. The relationship between BRCA1 mutation and BAP1 immunohistochemical staining is still unclear. Our aim is to determine whether BAP1 immunohistochemical expression indicates BRCA mutation status in breast carcinomas with specific pathological characteristics. In addition, we aim to determine the histopathological characteristics of tumors according to BRCA mutations. Methods. Histomorphology, molecular subtypes and BAP1 immunohistochemical expression patterns of the BRCA1/BRCA2 mutated and non-mutated tumors were evaluated. The BAP1 immunohistochemical stain was applied to nine tumor tissues with the BRCA1 mutation, six tumor tissues with the BRCA2 mutation, and 16 tumor tissues without any BRCA mutation. Pearson's chi square test and the Fisher Freeman Halton test were used to analyze the associations between the datas. The statistical significance was considered as P value of <.05. Results. Immunohistochemical BAP1 loss was not detected in any mutated or non-mutated tumor group. BRCA1 mutated tumors had the statistically highest histopathological grade (P = .04) and BRCA1/2 mutated tumors had significant immunohistochemical triple negative expression pattern (P = .01). Conclusions. Intrinsic and histopathological characteristics may vary between BRCA1 mutated and non-BRCA1 mutated tumors. Also, BAP1 loss was not detected in BRCA mutated breast tumors because of several effects of BAP1 that are non-related with BRCA in the cell cycle.

A New Landscape of Testing and Therapeutics in Metastatic Breast Cancer

Predictive biomarker testing on metastatic breast cancer is essential for determining patient eligibility for targeted therapeutics. The National Comprehensive Cancer Network currently recommends assessment of specific biomarkers on metastatic tumor subtypes, including hormone receptors, HER2, and BRCA1/2 mutations, on all newly metastatic breast cancers subtypes; programmed death-ligand 1 on metastatic triple-negative carcinomas; and PIK3CA mutation status on estrogen receptor-positive carcinomas. In select circumstances mismatch repair protein deficiency and/or microsatellite insufficiency, tumor mutation burden, and NTRK translocation status are also testing options. Novel biomarker testing, such as detecting PIK3CA mutations in circulating tumor DNA, is expanding in this rapidly evolving arena.

Evaluation of the indication of BRCA1/2 genetic tests in Iranian women and acceptance rate of risk-reducing surgeries in BRCA mutation carriers

BACKGROUND

A higher risk for breast and ovarian cancer has been reported in BRCA carriers and prophylactic surgeries are proposed to reduce this risk. This retrospective cohort study has evaluated the indication of BRCA1/2 genetic tests in Iranian women and the rate of women's acceptance of prophylactic surgeries recommended by the surgeon.

METHODS

Medical records of 147 high-risk women according to NCCN clinical practice guidelines who referred for BRCA mutations testing were assessed. Individual information, indications for BRCA1/2 genetic testing and their results, physician recommendations, and type of accepted surgery were registered. To evaluate the current status of women an active visit follow-up every six months was conducted.

RESULTS

The mean age of women was 43.40 ± 10.94 and the median follow-up time was 1.92 years. Genetic test results showed 49(33.3%) women were positive for either BRCA1/2 mutations. Although the occurrence of breast cancer younger than 40 was the most common indication for genetic tests (26.5%), positive breast cancer history in first-degree relatives and two relatives younger than 50 was the most common indications with positive results. The rate of acceptance of prophylactic mastectomy and bilateral salpingo-oophorectomy was (14.3% and 34.7%) in BRCA mutation carriers.

CONCLUSION

If the onset of breast cancer at a young age (less than 40) will be the only indication for a BRCA analysis, the rate of a positive result (12.8%) is very low. Further studies are warranted to evaluate the age limit for genetic testing in our country. Prophylactic mastectomy acceptance is very low in BRCA1/2 carriers in our centers.

Homologous Recombination Deficiencies and Hereditary Tumors

Homologous recombination (HR) is a vital process for repairing DNA double-strand breaks. Germline variants in the HR pathway, comprising at least 10 genes, such as BRCA1, BRCA2, ATM, BARD1, BRIP1, CHEK2, NBS1(NBN), PALB2, RAD51C, and RAD51D, lead to inherited susceptibility to specific types of cancers, including those of the breast, ovaries, prostate, and pancreas. The penetrance of germline pathogenic variants of each gene varies, whereas all their associated protein products are indispensable for maintaining a high-fidelity DNA repair system by HR. The present review summarizes the basic molecular mechanisms and components that collectively play a role in maintaining genomic integrity against DNA double-strand damage and their clinical implications on each type of hereditary tumor.

Tumour-infiltrating CD4-, CD8- and FOXP3-positive immune cells as predictive markers of mortality in BRCA1- and BRCA2-associated breast cancer

BACKGROUND

The prognostic value of tumour-infiltrating lymphocytes (TILs) in breast cancer is well-established. However, the investigation of specific T-cell subsets exclusively in BRCA-associated breast cancer is sparse.

METHODS

Tumour tissues from 414 BRCA-mutated breast cancer patients were analysed by immunohistochemistry and digital image analysis for expression of CD4, CD8 and FOXP3 immune markers. Distribution of CD4-, CD8- and FOXP3-positive cells and clinicopathological characteristics were assessed according to groups of low or high expression. The prognostic value was evaluated as continuous variables in univariate and multivariate analyses of overall survival and disease-free survival.

RESULTS

Both CD4 and CD8 expression are associated with histological diagnosis, tumour grade and oestrogen and progesterone receptor expression status. CD4 expression is associated with BRCA gene status. A high percentage of tumour-infiltrating CD4-, CD8- or FOXP3-positive cells is significantly associated with lower mortality in BRCA1- and BRCA2-associated breast cancer and CD8-positive cells are associated with disease-free survival. No heterogeneity according to BRCA gene status was found for the prognostic value of the immune markers.

CONCLUSIONS

The results support a prognostic role of specific T-cell subsets in BRCA-associated breast cancer and the promising potential of targeting the immune system in the treatment of these patients.

Prediction of BRCA Gene Mutation in Breast Cancer Based on Deep Learning and Histopathology Images

BACKGROUND

Breast cancer is one of the most common cancers and the leading cause of death from cancer among women worldwide. The genetic predisposition to breast cancer may be associated with a mutation in particular genes such as gene BRCA1/2. Patients who carry a germline pathogenic mutation in BRCA1/2 genes have a significantly increased risk of developing breast cancer and might benefit from targeted therapy. However, genetic testing is time consuming and costly. This study aims to predict the risk of gBRCA mutation by using the whole-slide pathology features of breast cancer H&E stains and the patients' gBRCA mutation status.

METHODS

In this study, we trained a deep convolutional neural network (CNN) of ResNet on whole-slide images (WSIs) to predict the gBRCA mutation in breast cancer. Since the dimensions are too large for slide-based training, we divided WSI into smaller tiles with the original resolution. The tile-based classification was then combined by adding the positive classification result to generate the combined slide-based accuracy. Models were trained based on the annotated tumor location and gBRCA mutation status labeled by a designated breast cancer pathologist. Four models were trained on tiles cropped at 5×, 10×, 20×, and 40× magnification, assuming that low magnification and high magnification may provide different levels of information for classification.

RESULTS

A trained model was validated through an external dataset that contains 17 mutants and 47 wilds. In the external validation dataset, AUCs (95% CI) of DL models that used 40×, 20×, 10×, and 5× magnification tiles among all cases were 0.766 (0.763-0.769), 0.763 (0.758-0.769), 0.750 (0.738-0.761), and 0.551 (0.526-0.575), respectively, while the corresponding magnification slides among all cases were 0.774 (0.642-0.905), 0.804 (0.676-0.931), 0.828 (0.691-0.966), and 0.635 (0.471-0.798), respectively. The study also identified the influence of histological grade to the accuracy of the prediction.

CONCLUSION

In this paper, the combination of pathology and molecular omics was used to establish the gBRCA mutation risk prediction model, revealing the correlation between the whole-slide histopathological images and gRCA mutation risk. The results indicated that the prediction accuracy is likely to improve as the training data expand. The findings demonstrated that deep CNNs could be used to assist pathologists in the detection of gene mutation in breast cancer.

Correlation between family history and characteristics of breast cancer

Family history is a major risk factor for breast cancer; approximately 5–10% cases of breast cancer are associated with a family history. Herein, we investigated the link between family history and breast cancer features to elucidate the importance of family history in the diagnosis and treatment of breast cancer. Data from 10,549 patients with breast cancer were collected from 2014 to 2017. Detailed information about the family history of the patients including the degree and number of relatives affected and the types of cancer was recorded. The tumors were pathologically and clinically classified based on the stage, grade, ER, PR, HER2, Ki-67 status, and subtypes, according to standard guidelines. Data were analyzed using χ² test and multiple logistic regression. Patients with a family history of other cancer types were significantly older at diagnosis than patients with a family history of breast/ovarian cancer (p = 0.002) and those without a family history of cancer (p < 0.001). Patients without a family history of cancer were typically diagnosed at a later stage, including high frequency in N2 (p = 0.035) and TNM stage III (p = 0.015). Compared with patients with second-/third-degree relatives, those with first-degree relatives having breast/ovarian cancer had a higher median age (54.1, p < 0.001) at diagnosis and showed more advanced disease. No significant difference was found between ER, PR, and HER2 status in patients with and without a family history of cancer. Family history of breast cancer can influence the cancer characteristics of the patients at diagnosis, especially patient age, tumor stage, and grade.

BRCA1 and BRCA2 associated breast cancer and the roles of current modelling systems in drug discovery

For a drug candidate to be fully developed takes years and investment of hundreds of millions of dollars. There is no doubt that drug development is difficult and risky, but vital to protecting against devastating disease. This difficulty is clearly evident in BRCA1 and BRCA2 related breast cancer, with current treatment options largely confined to invasive surgical procedures, as well as chemotherapy and radiotherapy regimes which damage healthy tissue and can leave remnant disease. Consequently, patient survival and relapse rates are far from ideal, and new candidate treatments are needed. The preclinical stages of drug discovery are crucial to get right for translation to hospital beds. Disease models must take advantage of current technologies and be accurate for rapid and translatable treatments. Careful selection of cell lines must be coupled with high throughput techniques, with promising results trialled further in highly accurate humanised patient derived xenograft models. Traditional adherent drug screening should transition to 3D culture systems amenable to high throughput techniques if the gap between in vitro and in vivo studies is to be partially bridged. The possibility of organoid, induced pluripotent stem cell, and conditionally reprogrammed in vitro models is tantalising, however protocols are yet to be fully established. This review of BRCA1 and BRCA2 cancer biology and current modelling systems will hopefully guide the design of future drug discovery endeavours and highlight areas requiring improvement.

Genomic Signatures in Luminal Breast Cancer

Background

Breast cancer is a very heterogeneous disease and luminal breast carcinomas represent the hormone receptor-positive tumors among all breast cancer subtypes. In this context, multigene signatures were developed to gain further prognostic and predictive information beyond clinical parameters and traditional immunohistochemical markers.

Summary

For early breast cancer patients these molecular tools can guide clinicians to decide on the extension of endocrine therapy to avoid over- and undertreatment by adjuvant chemotherapy. Beside the predictive and prognostic value, a few genomic tests are also able to provide intrinsic subtype classification. In this review, we compare the most frequently used and commercially available molecular tests (OncotypeDX®, MammaPrint®, Prosigna®, EndoPredict®, and Breast Cancer Index^SM). Moreover, we discuss the clinical utility of molecular profiling for advanced breast cancer of the luminal subtype.

Key Messages

Multigene assays can help to de-escalate systemic therapy in early-stage breast cancer. Only the Oncotype DX® and MammaPrint®test are validated by entirely prospective and randomized phase 3 trials. More clinical evidence is needed to support the use of genomic tests in node-positive disease. Recent developments in high-throughput sequencing technology will provide further insights to understand the heterogeneity of luminal breast cancers in early-stage and metastatic disease.

Outcomes and risk of subsequent breast events in breast-conserving surgery patients with BRCA1 and BRCA2 mutation

Purpose

Previous studies provide inconsistent interpretations of the effect of inherited genetic factors on the survival and prognosis of patients with breast cancer. The aim of this study was to examine the effect of germline BRCA1 and BRCA2 mutation on survival and subsequent breast events in Chinese women who underwent breast‐conserving surgery.

Methods

A retrospective review of the clinical and pathological records was performed in patients diagnosed with primary invasive breast cancer between 2005 and 2018 in the cancer registry database. Clinicopathological data and data regarding treatment and outcomes, including date and site of disease progression, were collected. The survival outcomes and independent risk factors were conducted using SPSS.

Results

Overall, a total of 501 patients who underwent breast‐conserving surgery were identified and subjected to analyses, of which 63 cases with BRCA1 or BRCA2 mutation. The median age at diagnosis was 41 (range, 24‐74) for carriers and 37 (range, 17‐84) for noncarriers. After a median follow‐up time of 61 months (range, 8‐161) and 70 months (range, 0‐153), respectively, in carriers and noncarriers, the overall survival (P = .173) and disease‐free survival (P = .424) were not significantly different. Analogously, there was no significant difference between the two groups about the outcomes of ipsilateral breast tumor recurrence (P = .348), yet the contralateral breast cancer (CBC) was overt worse than noncarriers (P < .001). When adjusted to confounding factors, BRCA mutation was the only independent risk factors to CBC (HR = 7.89, P = .01).

Conclusion

In this study, BRCA mutation carriers have higher risk of CBC. And, BRCA mutation is the only independent risk factor to CBC. Therefore, intensive surveillance and follow‐up as well as more effective individual prevention are urgent. Decisions on alternatively effective prevention, especially the prevention of CBC, are urgent and should take into account patient prognosis and preferences.