[Application of number of matched STR loci and identical alleles in individual discrimination of colorectal cancer].
OBJECTIVE
To establish a feasible algorithm for individual identification of colorectal cancer tissue by investigating its STR mutation.


METHODS
Fifty pairs of fresh colorectal cancer and homologous normal tissues (CR-N group) were genotyped with Identifiler Kit and the mutations generated in cancer tissues were determined. The mutation rates, the numbers of locus matched without identical allele (A0), 1 identical allele (A1), or 2 identical alleles (A2) and the number of total identical alleles (IA(n)) were calculated. Frequency distributions of A0, A1, A2 and IA(n) were compared among CR-N group, unrelated individual pairs (UI group) and full sibling pairs (FS group). Discrimination functions were established for individual identification from tumor tissues with discriminatory analysis.


RESULTS
The frequency of STR genotypic alteration (STR(GA)) was 3.33% in the 50 colorectal cancer samples. A1, A1 and IA(n) were fitted to skew distribution in CR-N group, which were significantly different from those in UI or FS group. Based on IA, and A,/A2, discrimination functions were established and validated with an error rate as low as 0.00% for individual identification from colorectal cancer tissue.


CONCLUSIONS
Discrimination functions established in this study could be a feasible method for individual identification of colorectal cancer samples, which usually have a high frequency of STR(GA).
Zhao
Shu-Min
SM
Shanghai Key Laboratory of Forensic Medicine, Institute of Forensic Science, Ministry of Justice, PR China, Shanghai 200063, China. zhaoshuminxl@hotmail.com
Li
Cheng-Tao
CT
Zhang
Su-Hua
SH
Li
Li
L
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000483:Alleles; D015179:Colorectal Neoplasms / Q000235:genetics*; D004252:DNA Mutational Analysis; D016002:Discriminant Analysis; D005260:Female; D005787:Gene Frequency; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D012372:ROC Curve; D020080:Tandem Repeat Sequences / Q000235:genetics*