CDK4/6 act to control cell cycle progression through the early G1 phase and are positively regulated by the interaction with cyclins (e.g., D1/D2/D3) and negatively regulated by tumour suppressors (e.g., p16 INK4 A) that stop CDK4/6 interaction with D-type cyclins [4]. The gene discussed is CDK4; the disease is neoplasm.