Correlation of DNA content between endoscopic biopsy and surgically resected specimens in gastric and colorectal cancer

To investigate DNA heterogeneity and the consistency of DNA content between endoscopic biopsy and the corresponding resected specimens, the DNA content of 749 different samples from 30 gastric and 30 colorectal cancers was analyzed and the results were compared with those obtained from endoscopic biopsy specimens. The incidence of DNA heterogeneity was 33% in patients with gastric cancer and 40% in those with colorectal cancer. Most of the cases of heterogeneity were caused by differences in DNA indices in aneuploidy. The consistency of DNA ploidy pattern between endoscopic biopsies and the corresponding resected specimens was 100% in both gastric and colorectal cancer, while the consistency in the DNA index of aneuploid tumors was approximately 90%. From these results, it seems possible that analysis of the DNA content of a biopsy specimen could provide an adequate measure of the DNA content of the corresponding resected specimen.