Evaluation Of Commen Used STR Loci In Tumor Tissues From Human Digestive System

Objective:To screen STR markers with low mutation rate and more strong stability by systematic analysis of variation information of commonly used STR loci in human digestive system tumor tissue and summary of variable type and rule.Methods: The analysis was performed on 99 tumor tissues as well as their normal tissues from human digestive system. The genomic DNA was extracted by Chelex-100 and was amplified by AmpF1STR Identifiler PCR Amplification Kit. Electrophoresis of PCR amplified products were carried out on ABI PrismTM 3100-Avant Genetic analyzer. The alleles were analyzed using Genemapper3.2 software. According to the genetic and genomic characteristic of commonly used STR loci, special primers were designed in order to construct a PCR amplification system to validate the STR mutation.Results: All of the tumor tissues and their normal tissues were successfully genotyped and compared respectively. A total of 49 (～50%) samples were found to possess allelic alterations including additional alleles, new alleles, loss of heterozygosity and partial loss of heterozygosity. Partial loss of heterozygosity was the most frequent type. Additional alleles were detected from 37 samples, new alleles were detected from 3 samples. 14 samples were found loss of heterozygosity, and 83 samples were found part loss of heterozygosity.Conclusion: Four kinds of changes between normal and tumor tissue were detected. They were distributed over all 15 STR loci. The STRs mostly affected were FGA, D18S51, D5S818, D13S317 and D8S1179. TH01, D2S1338 and TPOX had the lowest mutation rate and more strong stability. The PCR amplification system constructed could validate the STR mutation effectively.