The pro-oncogenic functions are believed to be mediated by cytoplasmic p21 through inhibitory binding with cytosolic pro-apoptotic proteins including caspases, Ask1, JNK etc. [12, 35] as well as by promoting assembly of cyclindD-CDK4/6 complex [36–38] and ability to repair DNA in tumor cells [39]. The gene discussed is CDK4; the disease is neoplasm.