CDK4 and colorectal cancer: Correlation analysis shows that QOSX2 is negatively correlated with p21 and p27, and positively correlated with cyclin D1, but not p53, and the results of qRT-PCR showed that QSOX2 knockdown significantly caused the accumulation of p21 and p27 mRNA and the decrease in the mRNA expression of cyclin D1, cyclin E2, CDK2, CDK4, which suggests that QSOX2 may promote the proliferation of colorectal cancer by partially regulating G1/S phase transition independent of p53.