Analyses of TCGA BC datasets identified several mutations in both previously implicated genes (PIK3CA, phosphatase and tensin homolog (PTEN), AKT1, tumor protein p53 (TP53), GATA3, CDH1, retinoblastoma 1 (RB1), MLL3, MAP3K1, and CDKN1b) and new genes (TBX3, RUNX1, CBFB, AFF2, PIK3R1, PTPN22, PTPRD, NF1, SF3B1, and CCND3) [14,15,16]. The gene discussed is PTEN; the disease is breast cancer.