In the context of cancer, CDKs are often dysregulated, leading to uncontrolled cell proliferation. Overexpression or mutation of CDKs and cyclins can disrupt the normal cell cycle checkpoints, allowing cells to divide uncontrollably. Specifically, the overactivation of CDK4 and CDK6, in association with cyclin D, is frequently observed in many types of cancer. This overactivation bypasses the G1 checkpoint, a critical control point where the cell assesses whether to enter the DNA synthesis (S) phase.
