[Cell kinetics and nuclear ploidy pattern in relation to the growth of gastric cancers as analyzed by DNA-RNA cytofluorometry].

We investigated the cell kinetics and nuclear ploidy pattern of human gastric cancers (12 early and 30 advanced cancers) using DNA-RNA cytofluorometry (NIKON SPM-RF1-D) with AO stain. The results showed that the gastric cancers studied could be divided into two main groups on the basis of ploidy pattern determined both by DNA and RNA contents: group I without, and group II with polyploidization. Cells having nuclear DNA contents between 2 n and 4 n were regarded as representing those in the S phase, and it was found that both groups had similar proliferative activity. In group I, cell proliferation without polyploidization seemed to be maintained during tumor growth regardless of the extent of invasion, and the fraction of 2 n cells was 72-94%, compared to 93-99% in control cells from the non-neoplastic gastric epithelium. In group II, however, the extent of polyploidization appeared to be increased in association with both the tumor growth and its invasion into deeper tissues; thus the fraction of 2 n cells was low, ranging from 12 to 79%. Especially, the fraction of 2 n cells in cancers with aneuploid-polyploidization was further decreased to 6-25%. Based on these results, it is hypothesized that, in the early stages of gastric cancers, the cell population may be composed mostly of diploid cells, but with both further tumor development and its invasion, the neoplastic cells may gradually differentiate into two distinct cell populations.