CDK4 and malignant colon neoplasm: Taken together, these results suggest that GSPT1 regulates CyclinD1, CDK4, and Cdk6 through GSK-3 β, and indirectly affects the expression of cyclinE and CDK2 through p21 and p27, thus regulating the transformation of colon cancer cells from the G1 phase to S phase and promoting tumor progression (Figure 6D).