Several breast cancer susceptibility genes have been identified, including breast cancer susceptibility genes 1 and 2 (BRCA1 and BRCA2, respectively), partner and localizer of BRCA2 (PALB2), TP-dependent DNA helicase Q1 (RECQL), neurofibromin 1 (i.e., NF1), phosphatase and tensin homolog deleted from chromosome 10 (i.e., PTEN), and tumor protein 53 (i.e., TP53) (4). The gene discussed is PTEN; the disease is breast cancer.