痰标本FHIT、P16、MGMT、RASSF1A、APC基因甲基化在肺癌诊断中的作用

Effect of promoter hypermethylation of FHIT,P16,MGMT,RASSF1A and APC genes in sputum specimens on diagnosis of lung cancer

目的探讨肺癌患者痰标本中FH IT、P16、MGMT、RASSF1A和APC等抑癌基因启动子异常甲基化及其联合检测在肺癌筛查及早期诊断中的价值。方法采用甲基化特异性PCR(methylation specific PCR,MSP)法,检测47例肺癌组织及对应的痰标本FHIT、P16,MGMT、RASSF1A和APC基因启动子区甲基化状态。24例肺良性疾病患者痰标本作为对照。结果 47例肺癌组织标本中FHIT、P16、MGMT、RASSF1A、APC基因启动子区甲基化检出率分别为40.4%(19/47)、53.2%(25/47)、36.2%(17/47)、21.3%(10/47)和38.3%(18/47);对照的痰标本中五者甲基化检出率分别为38.3%(18/47)、48.9%(23/47)、36.2%(17/47)、17.0%(8/47)和29.8%(14/47),两组甲基化检出率存在着一致性[P>0.05;κ(0.8～1.0)]。24例肺良性病变痰标本中未检测到任何异常甲基化,与肺癌组比较差异有统计学意义(P<0.05)。五项指标联合检测可明显提高肺癌检测的灵敏度(80.9%)和特异度(100.0%)。FHIT和P16基因痰标本甲基化检出率与患者吸烟指数有相关性(P<0.05)。结论痰标本中多个肺癌相关基因甲基化联合检测有望成为肺癌筛查、早期诊断简便有效的指标。

Purpose To determine the aberrant methylation status of FHIT,P16,MGMT,RASSF1A and APC gene promoter region in sputum specimens from lung cancer patients and the value of their combined detection in diagnosing lung cancers.Methods Methylation-specific PCR（MSP） was used to detect the promoter methylation status of FHIT,P16,MGMT,RASSF1A and APC gene in sputum and pathological tissues from 47 patients with lung cancers.Sputum from 24 patients with lung benign lesions were adopted as the control.Results The positive rates of promoter methylation of FHIT,P16,MGMT,RASSF1A and APC genes in pathological tissues from patients with lung cancers were 40.4%（19/47）,53.2%（25/47）,36.2%（17/47）,21.3%（10/47）,and 38.3%（18/47）,respectively,and those in sputum were 38.3%（18/47）,48.9%（23/47）,36.2%（17/47）,17.0%（8/47） and 29.8%（14/47）,respectively.The both results had preferably coherence（P0.05;κ=0.8～1.0）.DNA promoter methylation was not found in sputum samples with lung benign lesion.There was a significant difference between the lung cancer group and lung benign lesion group（P0.05）.Combined detection of FHIT,P16,MGMT,RASSF1A and APC genes methylation in sputum could increase the sensitivity（80.9%）and specificity（100.0%）in diagnosing lung cancer.The methylation rate of FHIT and P16 gene in promoter was significantly correlated to smoking index（P0.05）.Conclusion Combined detection of the promoter hypermethylation of lung cancer related genes in sputum specimens may be used as a simple and effective marker in the screening and early diagnosis of lung cancer.