P210 Cyclin-dependent kinase 4 overexpression confers an independent prognosticator of nasopharyngeal carcinoma

Background Data mining on a public domain demonstrated that cyclin dependent kinase 4 (CDK4) was highly expressed in nasopharyngeal carcinoma (NPC). Associated with cyclin-D, CDK4 phosphorylates and inactivates retinoblastoma (Rb) protein family members and mediates progression through G1 to S-phase in the cell cycle. Overexpression of CDK4 has been identified in oral squamous cell carcinoma, lung and breast cancers, sarcomas, and melanomas. However, the expression of CDK4 has never been reported in NPC. This study investigated the expression status, correlation with clinicopathological features, and prognostic implications of CDK4 in a well-defined cohort of NPC. Methods We retrospectively assessed CDK4 immunoexpression in biopsies of 124 consecutive NPC patients who did not have initial distant metastasis and who received treatment according to consistent guidelines. The results were correlated with clinicopathological features, local recurrence-free survival (LRFS), distant metastasis-free survival (DMeFS), and disease-specific survival (DSS). Findings High levels of CDK4 protein were positively correlated with T3,4 status (p = 0.024), N2,3 status (p  Interpretation CDK4 overexpression represents a potential prognostic biomarker in NPC and may confer tumour aggressiveness through cell cycle dysregulation.