A 33-year-old woman discovers a lump in her left breast on self-examination. Her mother and sister both had breast cancer. A mammogram demonstrates an ill-defined density in the outer quadrant of the left breast, with microcalcifications. Needle aspiration reveals the presence of malignant, ductal epithelial cells. Genetic screening identifies a mutation in BRCA1. In addition to cell cycle control, BRCA1 protein promotes which of the following cellular functions?
High-Yield Explanation
Breast (BR) cancer (CA) susceptibility genes (BRCA1 and BRCA2) encode tumor suppressor proteins involved in checkpoint functions related to the progression of the cell cycle into the S phase. BRCA1 and BRCA2 proteins also promote DNA repair by binding to RAD51, a molecule that mediates DNA double-strand repair breaks. The other choices may be abnormal in neoplasia, but they are not primarily affected by BRCA1.