AIM: To study the status of hMLH1 gene point mutations of gastric cancer kindreds and gastric cancer patients from northern China, and to find out gene mutation status in the population susceptible to gastric cancer.

METHODS: Blood samples of 120 members from five gastric cancer families, 56 sporadic gastric cancer patients and control individuals were collected. After DNA extraction, the mutations of exon 8 and exon 12 of hMLH1 gene were investigated by PCR-SSCP-CE, followed by DNA sequencing.

RESULTS: In the five kindreds, the mutation frequency was 25% (5/16) for the probands and 18% (19/104) for the non-cancerous members, which were significantly higher than the controls (P＜0.01 χ² = 7.71, P＜0.01 χ² = 8.65, respectively). In the sporadic gastric cancer, the mutation frequency was 7% (4/56), which was similar to that (5/100) in the healthy controls. The mutation point of exon 8 was at 219 codon of hMLH1 gene (A-G), resulting in a substitution of Ile-Val (ATC-GTC), whereas the mutation of exon 12 was at 384 codon of hMLH1 gene (T-A) resulting in a substitution of Asp-Val (GTT-GAT), which were the same as previously found in hereditary nonpolyposis colorectal carcinoma.

CONCLUSION: The members of gastric cancer families from northern China may have similar genetic background of hMLH1 gene mutation as those of hereditary nonpolyposis colorectal carcinoma.

• Gastric cancer kindred
• Mismatch repair
• Mutation
• HNPCC

• Adaptor Proteins, Signal Transducing
• Adult
• Carrier Proteins
• China
• Exons
• Female
• Humans
• Male
• Middle Aged
• MutL Protein Homolog 1
• Neoplasm Proteins/genetics
• Nuclear Proteins/genetics
• Point Mutation
• Stomach Neoplasms/genetics

AIM: To study the clinical characteristics of hereditary nonpolyposis colorectal cancer (HNPCC) in the Chinese population and discuss the identification and management of the patients with HNPCC.

METHODS: A series of 140 patients with colorectal cancers (CRC) and HNPCC associated tumors from 30 families fulfilling the Amsterdam criteria were analyzed.

RESULTS: A total of 118 patients had CRC. Average age at diagnosis of the first CRC was 45.7 years, 56.8% and 23.4% of the first CRC were located proximal to the splenic flexure and in the rectum respectively. Twenty-three (19.5%) had synchronous and metachronous CRC. Twenty-seven patients were found to have extracolonic tumors. Gastric carcinoma was the most common tumor type in our series (44.4%).

CONCLUSION: The frequency of HNPCC was 2.6% in our series of patients. The main features are an excess of early onset with a propensity to involve the proximal colon, and high frequency of multiple foci. Management and surveillance for these patients should be different from sporadic CRC. Contrary to American and European reports, gastric cancer seems more frequent than endometrial cancer in Chinese. It is necessary to formulate a new HNPCC criterion for Chinese patients.

• Adult
• Aged
• Colorectal Neoplasms, Hereditary Nonpolyposis/epidemiology
• Colorectal Neoplasms, Hereditary Nonpolyposis/pathology
• Humans
• Incidence
• Middle Aged
• Neoplasms, Second Primary
• Stomach Neoplasms