CDK4 in lung, and head and neck cancers in old age: evaluation as a biomarker.

BACKGROUND: Cyclin dependent kinases (CDK) are key factors in promoting the initiation and development of tumors. These kinases are important for maintenance of mitochondrial biogenesis and imbalance in their expression in old age may lead to the oxidative stress. Lung cancer (LC), and head and neck squamous cell carcinoma (HNSCC) are two very prominent cancers in older Indians. Both the cancers are showing increasing trend in older population. The present study assessed serum concentration of one of the kinases; CDK4 in older LC and HNSCC patients.

METHODS: The study included 100 subjects each of LC and HNSCC; and older subjects without cancer or any major health problems as controls. Serum CDK4 concentration was estimated using real-time label-free Surface plasmon resonance (SPR) and was verified by western blot.

RESULTS: Significant elevation in serum CDK4 was observed in cases with LC and HNSCC compared to controls. HNSCC patients with higher CDK4 expression had distinctly shorter survival than patients with comparatively lower CDK4 expression. No such difference was observed in LC patients. The germ line mutation study of this gene in Exon-2 was performed and none was observed among cases and controls.

CONCLUSION: It can be concluded that older patients with HNSCC and lung cancer have raised serums CDK4 levels, which has the potential to emerge as a biomarker in clinical practice.