[Clinicopathological features of typical and non-typical hereditary non-polyposis colorectal cancer and their germline mutation of hMLH1 and hMSH2].

Objective: To study the clinicopathological features of the Chinese hereditary non-polyposis colorectal cancer and its germline mutation of hMLH(1) and hMSH(2).

Methods: Thirteen typical Chinese hereditary non-polyposis colorectal carcinoma (HNPC)C kindreds and 19 non-typical HNPCC families were registered and followed up. The germline mutation of the hMLH(1) and hMSH(2) of 12 index cases of 6 typical and 6 non-typical HNPCC were screened by PCR-SSCP. Samples with abnormal mobility were sequenced directly.

Results: The average age of typical HNPCC was 47, no difference existed between sexes. Location of the tumors of typical HNPCC represented 44.7% on the right half colon and non-typical HNPCC 65.8% on the rectum. The rate of the metachronos cancer was 11.5%. The 3-, 5-and 10-year survival rate was 64.0%, 45.3% and 31.2% respectively. Among 12 cases, 8 showed abnormal mobility. Except for an intron polymorphism, six exons abnormalities were found in 5 of 12 proband. Sequencing showed 4 missense, 7 insertion and a nonsense mutations.

Conclusions: Chinese HNPCC is early onset, more common on proximal colon and better prognosis. Mutation of hMSH(2) is dominant in the Chinese typical HNPCC, but mutation of hMLH(1) is more common in the non-typical group.