Objective: To investigate Va1384Asp of hMLH1 gene in Chinese, Japanese and German after the missense mutation were identified in Chinese colorectal cancer patients and to inquire into the etiological role of this mutation in colorectal cancer.
Methods: Genomic DNA extracted from normal colon tissue or peripheral blood were subjected to analysis in exon 12 of the hMLH1 gene by single strand conformation polymorphism (SSCP) followed by DNA sequencing of aberrant bands in 26 Chinese and 109 German colorectal cancer patients and in 80 healthy Chinese, 80 Japanese and 100 German individuals .
Results: Va1384Asp in hMLH1 gene was found in 4 out of 26 Chinese colorectal patients; 3 of them were out of the 9 patients with colorectal cancer at young age (<50 years). Although 3 and 4 carriers of Va1384Asp in hMLH1 gene were identified in 80 healthy Chinese and 80 healthy Japanese individuals respectively, none were identified in German neither in 109 colorectal cancer patients, nor in 100 healthy German individuals. The frequency of Va1384Asp in hMLH1 gene in the Chinese with colorectal cancer at young age was higher than that in Chinese healthy individuals (P=0.013).
Conclusion: Va1384Asp can be taken as a polymorphism in hMLH1 gene in Chinese and Japanese populations and may have a potential effect on age at onset of colorectal cancer.