CDK6 and esophageal squamous cell carcinoma: Meanwhile, we noticed that RBM4 ablation led to the increased level of the cell cycle inhibitor P27, and decreased levels of cyclin D1, cyclin D3, CDK4, CDK6, and p-RB, however, the levels of P21 and P53, the well-known genes associated with pre-mature aging, were not elevated in ESCC cells (Fig. 2g and Supplementary Fig. 2f).