This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Breast, Subject name: Surgery
Most common Familial Breast cancer gene: 
Select and explain. 
A. BRCA1, B. BRCA 2, C. Li-Fraumeni syndrome, D. STK 11
A: BRCA1
Answer: A: BRCA1 
Explanation: Ans. (a) BRCA 1(Ref Sabiston 20th Edition 832)* Hereditary breast cancer - 5-10%# BRCA1 - 45% (MC hereditary Breast cancer)# BRCA2 - 35%# P53(Lifraumeni) - < 1%# Peutz jeughers, Cowden disease, Muir torre syndrome, Ataxia telangiectasia all less than 1% each.