Table 1.

Breast cancer predisposition genes confer varying risk for carcinogenesis due to their role in critical molecular processes.

Breast Cancer Predisposition Genes (CPGs)
Risk Level	Gene	Estimated Incidence of Mutations in Hereditary Breast Cancer	Associated Process
High Risk	BRCA1	~50% between BRCA1 and BRCA2 [4]	HR (several functions) [6,8]
	BRCA2	~50% between BRCA1 and BRCA2 [4]	HR (loading and leading RAD51) [6,8]
	PALB2	<3% [9,10]	HR (recruitment of BRCA2 and DNA replication via ICL) [6]
	BARD1	<1% [8,11]	HR (ubiquitin ligase) [6]
Moderate Risk	TP53	25–30% [12,13]	Cell cycle checkpoint protein (triggered by DNA damage) [7]
	BRIP1	<3% [9,10]	HR (complexes with BRCA1) [7]
	RAD51C	<3% [9,10]	HR (promotes invading strand exchange) [8]
	MSH6	<1% [8]	Mismatch repair (MMR)-associated protein [14]
Low Risk	ATM	<3% [9,10]	Cell cycle checkpoint protein [7]
	CHEK2	<3% [9,10]	Cell cycle checkpoint protein (checkpoint kinase-2) [7]
	Nbn	<1% [8]	DDR (complexes with MRE11 and RAD50 in DSB) [15]
	RAD50	<1% [8]	DDR (complexes with MRE11 and Nbn in DSB) [15]