Approximately 5–10% of breast cancers are hereditary and up to 25% are due to mutations in the following high-penetrance genes: BRCA1, BRCA2, PTEN, TP53, CDH1, and STK11 (Oosterwijk et al. 2014; Shiovitz and Korde 2015). The gene discussed is STK11; the disease is breast carcinoma.