[DNA content in colorectal carcinomas: application of image analysis to archival material].

The most studied biological parameter of human tumours is the DNA nuclear content. In the present study we assessed the DNA content of 197 colorectal cancers from 180 patients using archival material (tissues routinely processed and paraffin-embedded) for image analysis. The metastatic lymph nodes were also included in the study in 54 Dukes "C" stage cases and 19/25 Dukes "D" stage cases. A total of 452 sections, 5 mu thick, were submitted to image analysis in static cytometry. DNA diploid pattern was found in 72/452 samples (15.9%) and the DNA-aneuploid pattern in 380/452 (84.1%). Two different areas for each tumour were examined but we found a concordance of diploid pattern in only 23 cases. DNA-aneuploidy, regarded as presence of at least one sample with an aneuploid peak in the same tumour, reached 88% in our study. In conclusion the image analysis of several samples obtained from different areas of the same tumour clearly revealed: a pronounced heterogeneity of ploidy patterns in colon cancer; an overall prevalence of DNA-aneuploidy in colon cancer; a prevalence of diploid pattern in tumours localized in right portion of the colon and in younger patients.