CDK4 and neoplasm: The levels of eight positive regulators (CDK2, CDK4, CCNE1, CCNE2, E2F1, E2F2, E2F3 and TFDP1) were significantly increased in STS than in LTS tumor samples (Figure 4A, 4B), whereas the levels of the other five positive regulators (CDK6, CCND1, CCND2, CCND3 and TFDP2) did not differ between the two groups (Supplementary Figure 2).