[The relation of the DNA ploidy pattern to lymphatic permeation in pure-type diffuse infiltrative carcinomas of the stomach].

Lymphatic permeation (ly) is considered an important prognostic factor, even in the case of a diffuse infiltrative carcinoma (DICA) of the stomach, which generally has the poorest prognosis among the various types of gastric carcinomas. Our previous study has revealed that the ly in DICA is strongly related to the histological type of carcinoma that infiltrates the tumor tissue: the "mixed type", i.e., a type that includes tubular/trabeculoacinar element in 10% or more of the tumor tissue presents a significantly higher incidence of ly than the "pure type", i.e., a type that consists almost exclusively of anaplastic/mucocellular carcinoma. However, even in the "pure type" cases, some show a high ly incidence. To clarify this discrepancy, the DNA ploidy pattern in the "pure type" DICA was investigated, since the DNA ploidy has been reported to correlate well with the invasiveness or the metastatic tendency of the tumor. Although most of the cases (70%) showed a heteroploidy, such an incidence was significantly higher in the cases with a marked ly (86%) than in the cases without ly. (60%). As a result, we have concluded that in cases of a DICA, the lymphatic permeation (ly) is remarkably influenced not only by the histological type seen but also by the DNA ploidy pattern of the carcinoma.