CDKN2A and breast cancer: Studies have reported that mutations in genes such as PTEN (Phosphatase and TENsin homologue deleted on chromosome 10), CDKN2A (cyclin‐dependent kinase inhibitor 2A), TP53, KRAS (K‐Ras), SMAD4 (Mothers against decapentaplegic homologue 4) and BRCA1/2 (Breast cancer 1 and 2) have been associated with metastatic cancer.39