The Research Of Application Of In Del Polymorphisms Loci And STR Loci On The Source Identification Of Body Of Paraffin Embedding Tumor Tissue

Objective: To study the application of insertion/deletion(Indel) polymorphisms loci and short tandem repeats(STR) loci on the source identification of body of paraffin embedding tumor tissue.Methods: 28 cases of tumor tissues were fixed by formaldehyde, and then embedded by paraffin for 1 year. DNA extracted from these samples was detected by Power Plex? 21 system with 20 STR loci, Identifiler system with 15 STR loci, and Investigator? DIPplex system with 30 Indel polymorphisms loci respectively. Likelihood ratios of different detection system in tumor tissues were calculated according to genotype frequency acquired by comparing detection rates of STR loci and Indel polymorphisms loci of tumor tissues.Results:(1) By the application of Power Plex ? 21 system, the detected rate of STR loci of all samples was 68.57%(384/560). However, by the application of Identifiler system, the detected rate of STR loci of all samples was only 23.33%(98/420). By the application of Investigator ? DIPplex system, the detected rate of Indel polymorphisms loci of all samples was 94.88%(797/840).(2) The ranges of likelihood ratios of all samples of Power Plex ? 21 system, Identifiler system and Investigator ? DIPplex system were 8.8772×106-4.4962×1032,and 3.0278×109-1.5283×1018respectively.(3) By the comparison of the likelihood ratios of 10 samples detected in all above three systems, the likelihood ratio of Investigator ? DIPplex system was significantly lower than that of the Power Plex ?21 system(P ? 0.0001), and had no significant difference from that of Identifiler system(P?0.05).Conclusions:(1) Among the detection sensitivity of loci of highly degradable meterials such as formaldehyde-fixed paraffin embedding tumor tissue, Investigator ?DIPplex system occupies first place, and Power Plex ? 21 system comes second.(2)Among the reliability of source identification of body of different tumor tissue,Investigator ? DIPplex system occupies first place, and Power Plex ? 21 system comes second.(3) Among the efficiency of source identification of body in highly degradable meterials such as formaldehyde fixed paraffin embedding tumor tissue,Power Plex ? 21 system is the highest. There is no significant difference between Investigator ? DIPplex system and Identifiler system.(4) Indel polymorphism loci detection might serve as a good complementary scheme for the application of genetic markers in the individual identification and source identification of body in the trace and highly degradable materials, which STR loci alleles are lost or loci for judgement are inadequate.