ObjectiveTo investigate the abnormal methylation of multiple tumor suppressor 1(p16), death-associated protein kinase（DAPK) and adenomatosis polyposis coli (APC) genes promoters in peripheral blood of the patients with lung cancer and its significance in the early diagnosis of lung cancer. MethodsThe peripheral blood of 79 patients with primary lung cancer (lung cancer group) and 40 patients with lung benign lesions (control group) were collected. Then the methylation of p16, DAPK and APC genes promoters were detected by methylation specific PCR. The correlation of the three genes with the clinical characteristics was analyzed in the lung cancer patients. ResultsThe methylation rates of serum p16, DAPK and APC in the lung cancer group ［51.9% (41/79), 50.6% (40/79) and 35.4% (28/79) respectively］ were higher than those in the control group ［2.5% (1/40), 5.0% (2/40) and 2.5% (1/40) respectively］ (P＜0.05). The sensitivity of p16, DAPK and APC gene methylation for identifying lung cancer were 51.9% (41/79), 50.6% (40/79) and 35.4% (28/79) respectively. The sensitivity of the combination of the three genes methylation for identifying lung cancer was 73.4% (58/79) and was higher than that of the single gene methylation. There was no correlation between methylation of each gene and sex, age, smoking history, histological type, tumor stage or lymph node metastasis (P＞0.05). ConclusionThe methylation of p16, DAPK and APC genes promoters in the peripheral blood is related to lung cancer. The combined detection of p16, DAPK and APC genes methylation can improve the diagnostic accuracy of lung cancer.

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