AIM:To verify the effectiveness of denaturing high-performance liquid chromatography (DHPLC) in detectingsomatic mutation of p53 gene in gastric carcinoma tissues.The superiority of this method has been proved in thedetection of germline mutations,but it was not veryaffirmative with respect to somatic mutations in tumorspecimens.ST7 gene,a candidate tumor suppressor geneidentified recently at human chromosome 7q31.1,was alsodetected because LOH at this site has also been widelyreported in stomach cancer.METHODS:DNA was extracted from 39 cases of surgicalgastric carcinoma specimen and their correspondent normalmucosa.Seven fragments spanning the 11 exons were usedto detect the mutation of p53 gene and the four exonsreported to have mutations in ST7 gene were amplified byPCR and directly analyzed by DHPLC without mixing withwild-type allele.RESULTS:In the analysis of p53 gene mutation,9 aberrantDHPLC chromatographies were found in tumor tissues,whiletheir normal-adjacent counterparts running in parallelshowed a normal shape.Subsequent sequencing revealednine sequence variations,1 polymorphism and 8 mutationsincluding 3 mutations not reported before.The mutationrate of p53 gene (21%) was consistent with that previouslyreported.Furthermore,no additional aberrant chromatographywas found when wild-type DNA was added into the DNA ofother 30 tumor samples that showed normal shapespreviously.The positivity of p53 mutations was significantlyhigher in intestinal-type carcinomas (40 %) than that indiffuse-type (8.33 %) carcinomas of the stomach.Nomutation of ST7 gene was found. CONCLUSION:DHPLC is a verydetection of SomatiCamount of wild tyPemUt tionsConvenient method for thein gastric eareinoma.Thea Ileles suPPiied by the non一tumorouseells in gastrie tumor sPeeimens is enough to formheteroduPlex with munt alleles for DHPLC detection.ST7gene may not be the target gene of inaCtivation at 7q31 site in gastric carcinoma AIM: To verify the effectiveness of denaturing high-performance liquid chromatography (DHPLC) in detecting somatic mutation of p53 gene in gastric carcinoma tissues. The superiority of this method has been proved in thedetection of germline mutations, but it was not veryaffirmative with respect to somatic mutations in tumorspecimens. ST7 gene, a candidate tumor suppressor geneidentified recently at human chromosome 7q31.1, was alsodetected because LOH at this site has also been widelyreported in stomach cancer. METHODS: DNA was extracted from 39 cases of surgicalgastric carcinoma specimen and their correspondent Normalmucosa. Seven fragments spanning the 11 exons were usedto detect the mutation of p53 gene and the four exonsreported to have mutations in ST7 gene were amplified by PCR and directly analyzed by DHPLC without mixing with wild-type allele .RESULTS: In the analysis of p53 gene mutation , 9 aberrant DHP chromatographies were found in tumor tissues, while their normal-adjacent counterparts run ning in parallelshowed a normal shape. Subsequent sequencing revealed nine sequence variations, 1 polymorphism and 8 mutationsincluding 3 mutations not reported before. mutation rate of p53 gene (21%) was consistent with that previouslyreported.Furthermore, no additional aberrant chromatographywas found when wild-type DNA was added into the DNA of other 30 tumor samples that showed normal shapes previously. The positivity of p53 mutations was significantlyhigher in intestinal-type carcinomas (40%) than that indiffuse-type (8.33%) carcinomas of the stomach. Notation of ST7 gene was found. CONCLUSION: DHPLC is a very important part of SomatiCamount of wild tyPemUt tionsConvenient method for the in gastric eareinoma.Thea Ileles suPPiied by the non-tumor in gastrie tumor sPeeimens is enough to formheteroduPlex with munt alleles for DHPLC detection. ST7gene may not be the target gene of inaCtivation at 7q31 site in gastric carcinoma