Based on our analysis results, CCND1, PLK1, and CD44 genes’ signaling were significantly expressed in multiple cancer types, including melanoma (SKMC), lung cancer (LAUD), ovarian cancer (OV), renal cancer (READ), bladder cancer (BLCA), colorectal cancer (COAD), prostate cancer (PRAD) and breast cancer (BRCA). This evidence concerns the gene PLK1 and bladder transitional cell carcinoma.