CDK4 and neoplasm: Besides, the interference of the CDK4 gene in tumor progression was disclosed by the observations that repression of CDK4 can contribute to terminal differentiation of erythroleukemia cells, whereas overexpression of CDK4 leads to tumorigenesis of different assortment of cancers inluding glioblastomas and sarcomas, lung cancer, and breast cancers [4–7].