Loss of heterozygosity and DNA aneuploidy in colorectal adenocarcinoma

Background: This study evaluated the relationship between DNA aneuploidy and loss of heterozygosity (LOH) at different genetic loci in colorectal adenocarcinoma. Methods: A total of 112 patients with surgically removed colorectal adenocarcinoma in Taipei Veterans General Hospital from January 1999 to July 2001 were included in this study. The pattern of DNA ploidy was determined with DNA flow cytometry, and the LOH of various genetic loci was determined with fluorescence polymerase chain reaction and denaturing gradient gel electrophoresis. The relationship between DNA ploidy, LOH of various genetic loci, and clinicopathologic variables was analyzed with the χ² test with Yates' correction as well as by multivariate binary logistic regression analysis. Results: Seventy-one (63.4%) of the 112 carcinomas had DNA aneuploidy. The DNA aneuploidy was not associated with any clinicopathologic variable. Ninety-one tumors (81.3%) exhibited LOH in at least one genetic locus. In the univariate analysis, the DNA aneuploidy was associated with LOH of Tp53-penta, D8S254, D5S346, and high-frequency LOH (P = .001, P = .016, P = .041, and P < .001, respectively). In the multivariate analysis, the most significant factor influencing DNA aneuploidy was D8S254, followed by Tp53-penta, high-frequency LOH, and D5S346. Conclusions: DNA aneuploidy is strongly associated with LOH at specific genetic loci.