[Clinicopathological studies of nuclear DNA distribution in colorectal cancer]

The nuclear DNA content of paraffin-embedded materials was measured by microfluorometry in 108 colorectal (59 colon and 49 rectal) cancers and 29 metastatic liver tumors from the colorectum. The classification of the nuclear DNA distribution is as follows: Low ploidy, 10% greater than over 4C; intermediate ploidy, 10% less than or equal to over 4C and 10% greater than over 6C; high ploidy, 10% less than or equal to over 6C. In primary lesions, thirty-one (29%) were found to contain cells with high ploidy. The ploidy pattern was not related to pathological stage. However, in curatively resected cases, only 24% of patients with high ploidy survived 10 years. This 10 year-survival rate was significantly lower as compared with 80% and 88% of patients with intermediate and low ploidy, respectively (p less than 0.05). In non-curatively resected cases, no patients with high ploidy survived 2 years, although 21% and 67% of patients with intermediate and low ploidy survived, respectively. In metastatic liver lesions, eleven materials (42%) were found to contain cells with high ploidy. Prognosis of patients with high ploidy was worse than that with intermediate and low ploidy (p less than 0.05). These observations suggest that the nuclear DNA distribution in colorectal cancers may be an important prognostic factor, independent of pathological stage.