Breast cancer genes: beyond BRCA1 and BRCA2

Area of Science:

• Oncology
• Genetics
• Cancer Research

Background:

• Breast cancer (BC) is a heterogeneous disease, with approximately 30% of cases having a familial component.
• Familial BC is linked to various susceptibility genes, categorized by their penetrance levels (high, moderate, and low).
• High-penetrance genes like BRCA1/2, PTEN, and TP53 are well-established in inherited cancer syndromes.

Purpose of the Study:

• To review the genetic components contributing to familial breast cancer risk.
• To discuss the role of different gene penetrance categories in BC susceptibility.
• To highlight the implications of genetic discoveries for clinical practice and future genetic testing.

Main Methods:

• Review of family linkage studies identifying high-penetrance genes.
• Integration of family-based and population-based approaches for moderate-risk genes.
• Analysis of genome-wide association studies (GWAS) for low-penetrance alleles.

Main Results:

• High-penetrance genes (BRCA1, BRCA2, PTEN, TP53) are clinically significant for inherited BC.
• Moderate-risk genes (CHEK2, ATM, BRIP1, PALB2, RAD51C) are associated with increased BC risk.
• Common low-penetrance alleles identified through GWAS influence BC risk slightly.

Conclusions:

• Current clinical practice primarily utilizes high-penetrance genes for genetic testing.
• Advancements in next-generation sequencing may enable broader testing of familial BC genes.
• Further research is needed for clinical management of moderate and low-risk variants before widespread multi-gene panel implementation.