Relationship of nuclear DNA content to clinicopathologic features in colorectal cancer.

Nuclear DNA content was determined in 123 colorectal adenocarcinomas by flow cytometry using multiple frozen tumor samples. Thirty-three (26.8%) carcinomas were classified as diploid and 90 as aneuploid (73.2%). Presence of DNA aneuploidy was found to be unrelated to tumor stage and grade of differentiation and to other histopathological variables such as pattern of growth, degree of peritumoral lymphocytic infiltration, and venous invasion. However, multiploid tumors (20/123, 16.3%) were more frequently noted in advanced stages of disease (Stages III and IV, P < 0.025) and more often showed unfavorable histopathological features, especially an infiltrating pattern of growth (P < 0.05), compared with diploid and single aneuploid carcinomas. Nuclear DNA content was found to be closely related to tumor site. Carcinomas of the proximal (right and transverse) colon were more frequently diploid (19/43, 44.2% versus 14/80, 17.5%--P < 0.005) and more often displayed a DNA index (DI, defined as the ratio of the DNA content of neoplastic cells to that of normal cells) < or = 1.20 (27/43, 62.8% versus 19/80, 23.7%--P < 0.001) than did tumors localized distally to the splenic flexure. Nuclear DNA content was also found to be related to tumor type. A high proportion of mucinous adenocarcinomas showed DI values < or = 1.20 (14/21, 66.7%); conversely only 32 of 102 (31.4%) non-mucinous adenocarcinomas had a DI < or = 1.20 (P < 0.01). The nuclear DNA content of mucinous adenocarcinomas seemed to be independent of tumor location.(ABSTRACT TRUNCATED AT 250 WORDS)