CDK4 and renal cell carcinoma: Duan et al. demonstrated that esculetin blocked cell cycle progression at the G0/G1 and G2/M phases in 786-O and SN12-PM6 renal cell carcinoma cell lines, respectively, which was caused by decreasing the expression levels of cyclin D1, CDK4, cell division protein kinase 6, and cellular myelocytomatosis oncogene [28].