Effects of BRCA2 cis-regulation in normal breast and cancer risk amongst BRCA2 mutation carriers, Breast Cancer Research

Introduction Cis-acting regulatory single nucleotide polymorphisms (SNPs) at specific loci may modulate penetrance of germline mutations at the same loci by introducing different levels of expression of the wild-type allele. We have previously reported that BRCA2 shows differential allelic expression and we hypothesize that the known variable penetrance of BRCA2 mutations might be associated with this mechanism. Methods We combined haplotype analysis and differential allelic expression of BRCA2 in breast tissue to identify expression haplotypes and candidate cis-regulatory variants. These candidate variants underwent selection based on in silico predictions for regulatory potential and disruption of transcription factor binding, and were functionally analyzed in vitro and in vivo in normal and breast cancer cell lines. SNPs tagging the expression haplotypes were correlated with the total expression of several genes in breast tissue measured by Taqman and microarray technologies. The effect of the expression haplotypes on breast cancer risk in BRCA2 mutation carriers was investigated in 2,754 carriers. Results We identified common haplotypes associated with differences in the levels of BRCA2 expression in human breast cells. We characterized three cis-regulatory SNPs located at the promoter and two intronic regulatory elements which affect the binding of the transcription factors C/EBPα, HMGA1, D-binding protein (DBP) and ZF5. We showed that the expression haplotypes also correlated with changes in the expression of other genes in normal breast. Furthermore, there was suggestive evidence that the minor allele of SNP rs4942440, which is associated with higher BRCA2 expression, is also associated with a reduced risk of breast cancer (per-allele hazard ratio (HR) = 0.85, 95% confidence interval (CI) = 0.72 to 1.00, P-trend = 0.048). Conclusions Our work provides further insights into the role of cis-regulatory variation in the penetrance of disease-causing mutations. We identified small-effect genetic variants associated with allelic expression differences in BRCA2 which could possibly affect the risk in mutation carriers through altering expression levels of the wild-type allele.

Real-world clinical outcomes of patients with BRCA-mutated, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer: a CancerLinQ® study

Allele-specific miRNA-binding analysis identifies candidate target genes for breast cancer risk

When breaks get hot: inflammatory signaling in BRCA1/2-mutant cancers - ScienceDirect

Effects of BRCA2 cis-regulation in normal breast and cancer risk amongst BRCA2 mutation carriers, Breast Cancer Research

Mapping of cis-regulatory variants by differential allelic expression analysis identifies candidate risk variants and target genes of 27 breast cancer risk loci

Frontiers Role of BRCA Mutations in the Modulation of Response to Platinum Therapy

Patterns of recurrence and metastasis in BRCA1/BRCA2‐associated breast cancers - Song - 2020 - Cancer - Wiley Online Library

Herpesvirus infections eliminate safeguards against breast cancer and its metastasis: comparable to hereditary breast cancers

Frontiers Familial Breast Cancer: Disease Related Gene Mutations and Screening Strategies for Chinese Population

Cancers, Free Full-Text

BRCA1/2 testing: therapeutic implications for breast cancer management

The role of BRCA mutation testing in determining breast cancer therapy

Mapping of cis-regulatory variants by differential allelic expression analysis identifies candidate risk variants and target genes of 27 breast cancer risk loci

Cancers, Free Full-Text