CDKN1A and cancer: Within the important genes, gene frequency was further calculated, and genes co-occurred in more than ten cancer types were identified as hot cancer genes, which included MYC, AKT1, BCL2, MCL1, CASP8, BAX, MAPK8, CDKN1A, PCNA, MTOR, PTEN, BCL2L11, VEGFA, FASN, PARP1, PIK3R1, EGFR, CDK2, JUN, CASP3, BCL2L1, FLT4, XIAP, BAD, PRKAA1, PRKAB1, CDK1, STAT3, BECN1, and MAP1LC3B.