In this paper, the genome-wide analysis of melanoma tumor samples in TCGA database found that signaling pathways in melanoma mainly involved the EGF/EGFR–RAS–BRAF–MEK–ERK–CyclinD1/CDK4, Ras–PI3K–PTEN–PKB/AKT, cell-cycle pathway p14/p16 (CDKN2A)–MDM2–p53–p21–cyclinD1/CDK4/6–Rb/E2F, melanogenesis-related MITF, KIT, cell adhesion CDH1, and other genes. The gene discussed is PTEN; the disease is melanoma.