Hypermethylation of p16 gene in clinical specimens of patients with lung cancer

Objective To evaluate aberrant methylation of the p16 promoter as a useful biomarker of lung cancer. Methods A modified methylation-specific semi-nested PCR was performed to detect p16 hypermethylation in the matched samples of tumor tissue, blood plasma and sputum derived from 51 cases of lung cancer patients. Results Hypermethylation of p16 promoter was demonstrated in 84.3% of the tumor tissues, 70.6% of the blood plasma and 76.5% of the sputum specimens, respectively. Only the patients whose tumor tissues had p16 hypermethylation exhibited aberrant methylation in their plasma and/or sputum specimens. Combining with cytological examination, 92.2% of the patients with lung cancer could be detected by p16 hypermethylation assay in both sputum and plasma samples. Conclusion The results indicate that p16 hypermethylation in plasma and sputum identified by semi-nested PCR is a biomarker of lung cancer which can be useful as an auxillary diagnostic parameter.