CDK4

Type

Gene (protein-coding, cell cycle regulator)

Description

CDK4 (Cyclin-Dependent Kinase 4) encodes a serine/threonine kinase that regulates the G1-to-S phase transition of the cell cycle. CDK4 forms a complex with cyclin D to phosphorylate retinoblastoma (RB1) protein, promoting cell cycle progression. CDK4/6 inhibitors (palbociclib, ribociclib, abemaciclib) are standard-of-care for HR+/HER2- breast cancer. Resistance mutations in CDK4 and downstream pathway alterations are detected via ctDNA.

External identifiers

• HGNC: 1773
• NCBI Gene: 1019
• UniProt: P11802

Wiki sources

• wander2026-ctdna-cdk46-breast-cancer — ctDNA detection of CDK4/6 inhibitor resistance
• pcawg2020-pan-cancer-analysis — Pan-cancer driver catalog