目的　检测 p16基因在肺癌患者癌组织及相应痰液脱落细胞中甲基化状态 ,以探讨其在肺癌早期诊断中的价值。方法　采用甲基化敏感的核酸内切酶 Sma 、Sac 酶切基因组 DNA,对 5 6份肺癌组织及相应痰液、6 0份非恶性病变肺组织及 2 8份痰液进行 PCR分析。结果　 p16基因在肺癌组织中甲基化率为 30 .4% (17/5 6 ) ,相应的痰液中为 2 8.6 % (16 /5 6 ) ,两组差异无显著性 (χ2 =0 .0 430 ,P=0 .836 )。 6 0份非恶性病变肺组织甲基化率为 3.3% (2 /6 0 ) ,2 8份痰液无 1份发现 p16基因甲基化。结论　肺癌组织及相应的痰液脱落细胞 p16基因 5′- Cp G岛甲基化率相似 ,即痰液脱落细胞 p16基因甲基化状态可以反映肺癌组织 p16基因甲基化状态。因此 ,检测痰液脱落细胞 p16基因甲基化状态有助于肺癌的早期诊断 Objective To detect the methylation status of p16 gene in cancerous tissues of patients with lung cancer and corresponding sputum exfoliated cells and to explore its value in the early diagnosis of lung cancer. Methods Genomic DNA was digested by methylation-sensitive endonuclease Sma and Sac, and PCR was performed on 56 lung cancer tissues and corresponding sputum, 60 lung tissues of non-malignant lesions and 28 sputum samples. Results The methylation rate of p16 gene was 30.4% (17/5 6) in lung cancer tissues and 26.6% (16/56) in the corresponding sputum samples. There was no significant difference between the two groups (χ2 = 0. 0 430, P = 0 .836). Sixty non-malignant lesions of lung tissue methylation rate was 3.3% (2/60), 28 samples of sputum found no methylation of p16 gene. Conclusion The methylation rates of 5’-CpG island of p16 gene in lung cancer tissues and corresponding sputum exfoliated cells are similar, that is, the methylation status of p16 gene in sputa exfoliated cells can reflect the methylation status of p16 gene in lung cancer. Therefore, the detection of sputum exfoliated cells p16 gene methylation status contribute to the early diagnosis of lung cancer