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

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.