The aberrant methylation of fragile histidine triad(FHIT) gene and its significance of the expression of FHIT protein in lung cancer

Objective:To detect the expression of fragile histidine triad(FHIT)protein and aberrant methylation of its gene in lung carcinoma tissue and discuss their significance in tumorigenesis of lung cancer.Methods:The expression of FHIT protein was determined by immunohistochemical SP staining and its aberrant methylation was detected by methylation-specific PCR(MSP) in lung cancer and adjacent lung tissues(n=60).The sequencing of the amplified products of MSP was performed.The 60 patients were followed up.Results:The expression of FHIT protein in adjacent lung tissues was obviously higher than that in lung cancer tissues.There was significant difference between them(76.7% vs 50%,P0.05).The aberrant methylation of FHIT gene was significantly higher in lung cancer tissues than that in adjacent lung tissues(68.3% vs 35.0%,P0.001).And the aberrant methylation of FHIT gene occurred frequently in FHIT-negative patients compared with FHIT-positive patients(83.3% vs 53.5%,P0.05).The expression of FHIT protein and the aberrant methylation of FHIT gene had no correlation with clinicopathological parameters(age,sex,smoking status,histological type,general classification,TNM staging,and lymph node metastasis) in the patients with lung cancer(P0.05).The survival time was longer in FHIT-positive patients than FHIT-negative patients(P0.05).The FHIT protein was the risk factor associated with the disease-free survival time of patients(P0.01).Conclusion:The aberrant methylation of FHIT gene occurrs frequently and the expression of FHIT protein is significantly down-regulated in lung cancer.FHIT may play an important role in the tumorigenesis and development of lung cancer.FHIT protein could be used as an important factor for predicting the prognosis of patients.