DNA ploidy of tumor cells and the degree of infiltration of dendritic cells were determined in 93 gastric cancer tissue specimens, and the mechanisms of tumor‐host interaction on the prognosis were investigated. DNA ploidy patterns were grouped into low and high ploidy, and the degree of infiltration of dendritic cells (DC) was graded into marked and slight infiltration. In the low ploidy group, the 5‐year survival rates in patients with marked and slight DC infiltration were 80.7% and 61.5%, respectively (P < 0.05). In the high ploidy group, however, there were no significant differences. In cases of low ploidy, the incidence of lymph node metastasis was significantly lower in the marked DC infiltration group compared with findings in the slight DC group. Thus, markedly infiltrating dendritic cells in gastric cancer tissue may lead to prolongation of survival time for patients with a carcinoma of the low ploidy profile, by preventing widespread nodal involvement. © 1993 Wiley‐Liss, Inc.
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