PTEN gene mutation in gastric carcinoma / 中国现代普通外科进展

Objective:To study the mutation frequencies of the exon 5 and the exon 8 of PTEN (phosphatase and tensin homology deleted on chromosome ten) gene in gastric carcinoma and investigate the relationship of the gene mutation and pathological differentiation and clinical stage.Methods:The mutation of exon 5 and exon 8 of PTEN gene was detected in 42 gastric carcinoma samples and the matched adjacent normal gastric mucosa with polymerase chain reaction-single strand conformation polymorphism(PCR-SSCP) method.The PCR products of mutant samples were analysed by DNA sequencing technique.Results:The mutation of PTEN was shown in 3 of the 42 gastric carcinoma tissues and in none of the adjacent normal tissues.The mutation rates of PTEN gene in poorly differentiated and well differentiated samples were 12.00% and 0,respectively (P0.05).The mutation rates of PTEN gene in clinical stage Ⅰand Ⅱ (5.88%) had no significant difference with that in clinical stage Ⅲand Ⅳ (8.00%) (P0.05).Conclusion:PTEN gene mutation occurs mainly in poorly differentiated gastric carcinoma tissues,and the mutation rate is not related to pathological differentiation and clinical stage.

Ras Gene Mutations and Expression of ERK1 and ERK2 Proteins in Stomach Cancer

BACKGROUND: We investigated stomach cancers for ras abnormalities and expression of ERK1 and ERK2 to determine their significance in the tumor development and/or progression and to evaluate their potential correlation with clinicopathologic parameters. METHODS: Seventy gastric adenocarcinomas were studied immunohistochemically in paraffin-embedded tissue sections for the expression of ERK1 and ERK2 proteins. All tumors were further analyzed with the use of a polymerase chain reaction technique and a direct sequence analysis procedure for the presence of the mutated ras gene. RESULTS: ERK1 and/or ERK2 was expressed in 65.7% (46/70) of the tumors; overexpression of ERK1 was observed in 38 (54.3%) tumors, whereas ERK2 was detected in 29 (41.4%). Nine (12.8%) samples demonstrated multations in the ras gene: 4 in H-ras and 5 in K-ras. Seven of the 9 (77.8%) mutated tumors were of the intestinal type. No association was established between the ras abnormalities and the overexpression of ERK1 and/or ERK2. However, the correlation between ERK2 and progression (early vs. advanced) was statistically significant (p<0.05). CONCLUSIONS: These data indicate that ras abnormalities are uncommon events in gastric adenocarcinomas. The majority of ras mutations, however, occurred in intestinal-type tumors, supporting the notion of different molecular mechanisms involved between the intestinal-and diffuse-type lesions. Enhanced ERK2 activity may provide assistance in the determination of tumor penetration in these tumors.

EXPRESSION OF Rb AND p53 GENE IN GASTRIC CARCINOMAS IN RELATION TO PROGNOSIS / 中国癌症杂志

PURPOSE Expression of Rb and p53 gene in gastric carcinomas and its relationship to prognosis as well as clinico pathology were investigated.METHODS Expression of Rb and p53 products and p53 gene mutation in gastric carcinomas were analysed by means of immunohistochemistry and in situ hybridazation.RESULTS p53 gene mutation was found in 6/20(30%).Over expression of Rb and p53 products was found in 62/85(72.94%) and 42/85(49.41%).Both the positive grades showed significant inverse correlation with patient survival( P