As shown in Figure 5, the methylation levels of CDK1 were significantly lower in CHOL, LIHC, READ, testis germ cell tumor, and THCA tumor tissues compared to that in the normal tissues (all P values <0.05), whereas the methylation levels of CDK1 in COAD, ESCA, HNSC, KIRC, KIRP, LUSC, PAAD, and SARC tumor tissues were significantly higher (all P values <0.05). Here, CDK1 is linked to testicular germ cell tumor.