CDK6 (Cyclin-Dependent Kinase 6): CDK6 is a protein that, when combined with D-type cyclins, plays a key role in regulating the cell cycle, particularly the transition from the G1 phase to the S phase. It is essential for cell proliferation and differentiation. Dysregulation of CDK6 has been linked with various cancers, making it a significant target for cancer therapies, especially in tumours exhibiting CDK6 overexpression or abnormal activity.