Objective: To study the relationship between status of methylation of hMLH1 promoter and expression of its protein in lung cancer.
Methods: Methylation of the hMLH1 gene promoter and hMLH1 protein was examined in 50 primary lung cancer tissues by Hpa II digestion-PCR and immunohistochemistry.
Results: The incidence of the hMLH1 promoter methylation was 32.0% (16/50). Methylation frequeney did not correlate with sex, smoking and clinicopathological characteristics. Negative expression of hMLH1 protein occurred in 14/46 tumors, of which 11 tumors had hMLH1 promoter methylation (78.6%, 11/14), while only 5 had methylation in 32 specimens positive for hMLH1 protein expression.
Conclusion: In about one-third of lung cancer tissues examined there exists methylation of hMLH1 promoter, which correlates well with the absence of expression of hMLH1 protein.