Flow cytometric DNA analysis of poorly differentiated adenocarcinoma of the colorectum.

DNA ploidy patterns in 11 poorly differentiated adenocarcinomas of the colorectum were examined by flow cytometry using paraffin-embedded specimens. Measurements of DNA content were made of the superficial (Sup) half and deeper (Deep) half of the primary tumors in all cases, and of lymph node metastases in five cases. All the primary tumors showed invasion beyond the muscularis propria of the colorectum. Aneuploidy or polyploidy in either Sup or Deep of the primary tumor was found in six of the 11 (54.5%) tumors. Out of the six aneuploid tumors, five were in Dukes' stage C with distant metastases at the time of operation, and four died within one year of surgery. Conversely, out of five diploid tumors, none had distant metastases at the time of operation and two survived for longer than three years after surgery. The DNA ploidy pattern of Deep differed from that of Sup in four out of six aneuploid tumors, and two showed aneuploidy in Sup and diploidy in Deep. All the lymph node metastases in the five tumors had a diploid pattern, although three had aneuploid patterns in the primary tumors. The findings suggest the DNA ploidy pattern of a primary tumor to be correlated with the degree of metastasis at the time of operation or prognosis, but the population of tumor cells having different DNA contents may be apt to change between Sup and Deep in aneuploid tumor.