[One of the etiological factors of digestive tract cancers in Chinese: the missense mutation Val384Asp in the hMLH1 gene].

OBJECTIVE

To investigate the etiological role of Val384Asp in the hMLH1 gene, which may be a polymorphism in Chinese, in colorectal, gastric and esophageal cancers.

METHODS

Genomic DNA extracted from normal tissues 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 101 colorectal, 79 gastric and 76 esophageal cancer patients; in 79 and 76 first degree relatives of gastric cancer and esophageal cancer patients respectively; and in 100 healthy control individuals.

RESULTS

Six percent of Chinese healthy individuals were the carriers of Val3 84Asp in the hMLH1 gene. There were significant differences in the frequencies of Val384Asp in the hMLH1 gene between the patients with colorectal cancer at young age(<45 years) and the control individuals (P<0.05), and between the gastric cancer patients with family history, the first degree relatives and the control group (P<0.05 and P<0.01 respectively). No difference was found between the esophageal cancer patients, their relatives and healthy controls.

CONCLUSION

The alleles frequency of Val384Asp in the hMLH1 gene in Chinese is three percent. This missense mutation may play a part in the etiology of colorectal and gastric cancers in Chinese.