Evaluation of heterogeneity of DNA ploidy in early gastric cancers

DNA ploidy has been shown to be a predictive parameter for prognosis in var ious solid tumours. The prognostic value of DNA-ploidy in gastric cancers i s still a matter of controversy. A possible explanation for the discrepant results reported in the literature could be sampling error in tumours with multiple stemlines differing in DNA-ploidy. In order to determine whether or not such heterogeneity exists in early gas tric carcinoma, we have performed DNA cytophotometry on multiple samples of a group of 17 early gastric carcinomas, of which 8 were pure intramucosal and 9 were infiltrating into the submucosa. We found an aneuploid DNA-stemline in 8 (47%) early gastric cancers, more o ften in tumours invading into the submucosa (5/9) than in purely mucosal ru mours (3/8). Multiple DNA-stemlines were found more frequently in submucosa lly infiltrating rumours (4/5). These results confirm the presence of DNA-aneuploid early gastric carcinoma which are frequently heterogeneous and suggest that heterogeneity occurs m ore frequently in tumours invading the submucosa. This heterogeneity is bes t detected by analysing multiple samples of tumours for DNA-ploidy.