Dendritic cells prevent lymph node metastasis in patients with gastric cancer

Infiltration of S-100 protein positive dendritic cells into tumor tissues was investigated immunohistochemically. Although the survival time of patients with Stage I, II or IV gastric cancer did not relate to the density of dendritic cells, survival time in Stage III patients correlated with the density of dendritic cells. In patients with a marked infiltration, survival time was longer than in cases of only a slight infiltration (P < 0.001). The frequency in the marked infiltration group at the mucosal stage did not change in proportion to invasion into the deeper layers. There was a similar incidence of lymph node metastasis between the marked and slight infiltration groups in each grade of tumor invasion. However, marked infiltration of dendritic cells prevented widespread nodal involvement beyond the primary node in cases of advanced cancer (P < 0.05). This may be one of the reasons why the infiltration of dendritic cells is clinically effective in patients with Stage III gastric cancer.