Germline rare variants in HER2-positive breast cancer predisposition: a systematic review and meta-analysis.

Introduction: Approximately 10% of breast cancer (BC) cases result from hereditary causes. Genetic testing has been widely implemented in BC care to determine hereditary cancer syndromes and personalized medicine. Thus, identification of individuals carrying germline pathogenic variants could be useful to provide appropriate prophylactic or screening measures for each BC subtype, however, there are few formal recommendations for genetic testing in this sense so far. In this study, we assessed rare germline variants in a specific group of genes in order to determine the association with human epidermal growth factor 2 enriched (HER2+) BC phenotype through a systematic review and meta-analysis comparing subtypes overexpressing HER2 with other clinically recognized subtypes of BC. This review was registered with PROSPERO (ID: CRD42023447571). Methods: We conducted an online literature search in PubMed (MEDLINE), Scopus, and EMBASE databases. We included original studies that investigated germline variants in HER2+ BC patients and selected the studies that reported only rare and/or pathogenic germline variants. We assessed the risk of bias and quality of the studies using the Joanna Briggs Institute Critical Appraisal checklists and the Modified Newcastle-Ottawa Scale for Genetic Studies, respectively. Considering hormone receptor and HER2 expression status, we compared gene-based risks initially in HR-HER2-, HR+HER2-, HR+HER2+, and HR-HER2+ groups, conducting separate meta-analyses using the random effects model for each comparison, and within them for each gene. Results: Of the total 36 studies describing germline variants, 11 studies provided information on the prevalence of variants in the different clinically relevant BC subtypes and allowed comparisons. Germline variants within eight genes showed significant differences when meta-analyzed between the BC groups: BRCA1, BRCA2, TP53, ATM, CHEK2, PALB2, RAD51C, and BARD1. Notably, TP53, ATM, and CHEK2 germline variants were identified as predisposing factors for HER2+ subtypes, whereas BRCA1, BRCA2, PALB2, RAD51C, and BARD1 germline variants were associated with a predisposition to low HER2 expression. Main concerns about bias and quality assessment were the lack of confounding factors control; and comparability or outcome assessment, respectively. Discussion: Our findings underscore the connection between germline variants and differential expression of the HER2 protein and BC subtypes. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023447571.

Implications of tumor-infiltrating lymphocytes in early-stage triple-negative breast cancer: clinical oncologist perspectives.

Breast cancer (BC) is the most common neoplasm in women worldwide and one of the leading causes of female death. The triple-negative subtype, characterized by the absence of hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2), tends to occur in younger patients, be more aggressive and less differentiated. Furthermore, this subtype is considered the most immunogenic and associated with higher levels of tumor cell infiltration, mainly lymphocytes. Tumor-infiltrating lymphocytes (TILs) play a crucial role in the interaction of the host's immune system and cancer cells. The microenvironment is critical in tumor development and progression. Assessment of infiltrating lymphocytes can provide valuable information about the immune response and, given the lack of biomarkers to guide treatment decisions and predict outcomes in triple-negative tumors and can be considered as a potential biomarker. Some evidence suggests that higher levels of these lymphocytes are associated with better responses to systemic treatment, longer progression-free survival and overall survival (OS). However, treatment escalation or de-escalation strategies for triple-negative BC (TNBC) currently do not consider the presence or density of TILs for therapeutic decisions. TILs appear to be useful predictive and prognostic indicators. Further clinical studies are needed to confirm these relationships and integrate TILs as a biomarker consistently into clinical practice. This article summarizes key concepts relating to the role of the immune infiltrate in BC, along with the current status and future prospects regarding TILs as a predictive and prognostic biomarker.

Mapping breast and prostate cancer in the Brazilian public health system: study protocol of the Onco-Genomas Brasil.

Background: Breast and prostate cancers are the most common malignancies diagnosed in women and men respectively, and present with great clinical heterogeneity, even in tumors with the same histology and same site of origin. Somatic and germline molecular alterations in DNA may have prognostic and predictive impact, influencing response to therapies and overall survival. Our aim is to characterize the somatic and germline genomic landscape of women with locally advanced HER2-positive breast cancer and men with metastatic prostate cancer in Brazil. Secondarily, we aim to identify genetic variants associated with tumor prognosis and treatment response, identify patients carrying pathogenic alterations in cancer-predisposing genes, and characterize the genetic ancestry of the population included in the study. Methods: This observational multicenter cohort study will include 550 adult patients from the five macro-regions of Brazil, divided into two arms: 1) breast cancer and 2) prostate cancer. Clinical and pathological data will be collected, as well as DNA samples from peripheral blood and tumor samples. In arm 1, the inclusion criteria are a histological diagnosis of breast carcinoma with overexpression of HER-2, clinical stage II or III, and current neoadjuvant treatment with chemotherapy plus trastuzumab. In arm 2, the criterion is a histological diagnosis of prostate adenocarcinoma, clinical stage IV. Whole-exome sequencing (WES) will be performed to identify variants that may be drivers and/or actionable in a specific patient or tumor. These variants will be interpreted and classified according to their population frequencies, in silico predictors, functional studies, and literature data, following international guidelines proposed by expert societies. Discussion: This trial will contribute to the construction of a robust database that should provide a better understanding of the genomic profile of patients with breast and prostate cancer in Brazil. Considering the miscegenation of the Brazilian population, knowledge generated from these data will have implications for future studies of this specific population. Clinical trial registration: [clinicaltrial.gov], identifier [NCT05306600].

Perspectives on the Systemic Staging in Newly Diagnosed Breast Cancer.

Breast cancer is a complex disease, and accurate systemic staging is an essential aspect of the evaluation of a patient with newly diagnosed breast cancer. Considering that the chance of having metastatic disease at breast cancer diagnosis is different in each patient and depends on a variety of anatomic and biologic factors, it is crucial to understand that some populations may benefit from more intensive staging because their pretest probability of metastatic disease is higher than that of the average patient. Identifying these patients with de novo stage IV breast cancer is associated with substantial prognostic and therapeutic implications. Unfortunately, recent advances in understanding breast cancer heterogeneity and molecular biology have not been incorporated in the international guidelines and recommendations about imaging examinations for detecting de novo metastatic breast cancer. This review article discusses important issues regarding the rationale for performing systemic staging, addresses current and innovative imaging methods, and proposes an algorithm for systemic staging in patients with newly diagnosed breast cancer.

Real-world Data on First-line Systemic Therapy for Hormone Receptor-positive HER2-negative Metastatic Breast Cancer: A Trend Shift in the Era of CDK 4/6 Inhibitors.

Hormone receptor-positive (HR+) human epidermal growth factor receptor-2 negative (HER2-) tumors represent the most common subtype of metastatic breast cancer (MBC). International guidelines clearly state that endocrine therapy (ET) should be considered the preferred first-line therapy for these patients in the absence of very symptomatic visceral disease or evidence of endocrine resistance. Nonetheless compliance with guidelines significantly vary worldwide for many different reasons. Historically, a substantial proportion of patients with HR+ HER2- MBC have been treated with chemotherapy (CT) in first-line setting, jeopardizing patients' quality of life without a significant benefit in outcome. In 17 observational studies, including more than 63,000 patients, ET was most frequently used in first-line treatment of HR+/HER2- MBC (range, 42%-87%), nonetheless a high proportion of patients received CT (13%-66%) as initial therapy. More recently, results of clinical trials with CDK 4/6 inhibitors improved response, progression-free and overall survival in this population and are currently the standard of care. There was a trend toward increased use of ET in recent years. This review article aims to evaluate real-world data on patterns of first-line treatment of HR+ HER2- MBC with a special focus on the use of CT in this setting and the potential implications and perceived preliminary changes after the introduction of CDK 4/6 inhibitors.