Table 1 summarizes the most commonly mutated genes (27, 44). Copy number alterations have been observed in PIK3CA, ERBB2, TP53, MAP2K4, MLL3, CDKN2A, PTEN, and RB1 (44). Approximately 35-40% of primary breast cancers harbor mutations in TP53 and PIK3CA, as well as amplification of ERBB2, FGFR1, and CCND (~15%), and mutations in MUC16, AHNAK2, SYNE1, KMT2C, AKT1, and GATA3 genes (10%) (25, 45). In 2012, the Cancer Genome Atlas Network (CGAN) identified novel significantly mutated genes (SMGs), including TBX3, RUNX1, CBFB, AFF2, PIK3R1, PTPN22, PTPRD, NF1, SF3B1, and CCND3 (26). Here, CDKN2A is linked to breast cancer.