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

BRCA1 and BRCA2 mutations and their clinical relevance in selected women diagnosed with triple-negative breast cancer in Kenya: a descriptive cross-sectional study

Introduction

triple-negative breast cancer (TNBC) is a heterogeneous breast cancer type with a poor prognosis. About 25% of TNBC patients carry breast cancer susceptibility genes 1 and 2 (BRCA1 and BRCA2) mutations. Screening for BRCA mutations would facilitate early detection and initiation of personalized therapy, thus improving prognosis. However, this has not been explored in our population. We aimed at identifying BRCA1 and BRCA2 gene mutations and their clinical relevance among selected women with TNBC in Kenya.

Methods

six participants enrolled in a larger descriptive cross-sectional study who met the inclusion criteria were selected. Structured questionnaires were used to obtain qualitative data. Deoxyribonucleic acid (DNA) was extracted from saliva. Whole exome sequencing of BRCA1 and BRCA2 genes using a next-generation sequencer was done.

Results

overall, 83.3% of BRCA1 and BRCA2 gene mutations with clinical relevance were detected. Most of the variants (63%) were found in BRCA1 whereas 37% were found in BRCA2. Pathogenic mutations in BRCA1 gene included c.5513T>A, c.5291T>C, c.5297T>G, c.110C>A, c.5212G>C, c.122A>C, c.5117G>A, c.5095C>T, c.5054C>T, c.5053A>G, c.115T>A, c.5143A>G, and c.130T>G. Those in BRCA2 gene were c.7878G>A, c.9154C>T, c.8243G>A, c.7976G>A, c.8165C>G, c.8167G>C, and c.8168A>T. One variant (c.5352delG: p. Leu1785Terfs) not matching any in the BRCA Exchange and ClinVar databases was detected.

Conclusion

our study revealed BRCA mutations that could be common among our population. Further, it has shown that BRCA1 and BRCA2 genetic mutations identified are of clinical relevance and there is a need to screen for these mutations in breast cancer patients to understand their implication in patient management outcomes.

Assessment of Predictive Biomarkers in Breast Cancer: Challenges and Updates

The management of patients with breast cancer (BC) relies on the assessment of a defined set of well-established prognostic and predictive markers. Despite overlap, prognostic markers are used to assess the risk of recurrence and the likely benefit of systemic therapy, whereas predictive markers are used to determine the type of systemic therapy to be offered to an individual patient. In this review, we provide an update and present some challenges in the assessment of the main BC-specific molecular predictive markers, namely hormone receptors (oestrogen receptor [ER] and progesterone receptor [PR]), human epidermal growth factor receptor 2 (HER2), and KI67. As the main platform for assessing these markers in BC is immunohistochemistry (IHC), we address the cut-off values used to define positivity, the ER-low subgroup, the existence and significance of the ER-/PR+ phenotype, the use of PR in routine practice, and the role of hormone receptors in ductal carcinoma in situ. We discuss the newly introduced HER2-low class of BC and the clinical/biological difference between different HER2 groups (e.g., HER2 IHC score 3+ BCs vs. those with a HER2 IHC score 2+ with HER2 gene amplification). The review concludes with an update on the applications of KI67 assessment in BC and observations on the role of immune checkpoint identification in BC.

Prevalence, treatment patterns, and prognosis of low estrogen receptor-positive (1% to 10%) breast cancer: a single institution's experience in Korea

PURPOSE

To determine prevalence, clinicopathological characteristics, initial treatments, and outcomes associated with low estrogen receptor (ER)-expressing invasive breast cancer.

METHODS

This retrospective, non-interventional database study included patients undergoing surgery with curative intent for invasive ductal or lobular breast cancer. Patients were treated between January 2003-December 2012. Demographics, clinicopathological characteristics, initial treatments, and outcomes were abstracted from patient records. Patients were categorized using immunohistochemistry to determine ER, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) levels. ER-positive patients were subclassified as ER-low (1% to 10%) and ER-high (> 10%) according to the Allred Proportion Score. Disease-free survival (DFS) and overall survival (OS) were estimated by the Kaplan-Meier method and compared among groups by log-rank test.

RESULTS

5930 patients were included (median follow-up, 80.9 months). Of all patients included, 117 (2.0%) had ER-low tumors: 63 (53.8%) of whom had HER2- tumors and 54 (46.2%) HER2+ tumors. Five-year DFS and OS were highest in the ER-high/HER2- cohort (94.0% and 98.6%, respectively) and lowest in the triple-negative breast cancer (TNBC; 81.3% and 90.1%) and ER-low/HER2- (85.7% and 92.1%) cohorts. Menopausal status, elevated Ki-67, higher nuclear grade, higher tumor stage, presence of lymphovascular invasion, greater regional lymph node involvement, and larger tumor size were all potential prognostic factors for shorter DFS and OS.

CONCLUSION

Patients with ER-low/HER2- breast cancer had similar clinicopathological characteristics, treatments, and outcomes as patients with TNBC irrespective of disease setting. Further research is needed to understand predictive and prognostic factors associated with ER-low/HER2- disease.

Breast-Gynaecological & Immuno-Oncology International Cancer Conference (BGICC) Consensus and Recommendations for the Management of Triple-Negative Breast Cancer

Background: The management of patients with triple-negative breast cancer (TNBC) is challenging with several controversies and unmet needs. During the 12th Breast-Gynaecological & Immuno-oncology International Cancer Conference (BGICC) Egypt, 2020, a panel of 35 breast cancer experts from 13 countries voted on consensus guidelines for the clinical management of TNBC. The consensus was subsequently updated based on the most recent data evolved lately. Methods: A consensus conference approach adapted from the American Society of Clinical Oncology (ASCO) was utilized. The panellists voted anonymously on each question, and a consensus was achieved when ≥75% of voters selected an answer. The final consensus was later circulated to the panellists for critical revision of important intellectual content. Results and conclusion: These recommendations represent the available clinical evidence and expert opinion when evidence is scarce. The percentage of the consensus votes, levels of evidence and grades of recommendation are presented for each statement. The consensus covered all the aspects of TNBC management starting from defining TNBC to the management of metastatic disease and highlighted the rapidly evolving landscape in this field. Consensus was reached in 70% of the statements (35/50). In addition, areas of warranted research were identified to guide future prospective clinical trials.