ACACA and breast carcinoma: There is strong scientific rationale for testing metformin in chemoprevention of breast cancer in BRCA mutation carriers: (1) metformin activates AMPK and (2) signaling networks regulated by both AMPK and BRCA1, include PTEN, p53, and acetyl coenzyme A carboxylase alpha (ACCA) (83, 91, 92).