[Lymphoid cell infiltration of malignant epithelial tumors in humans]

210 malignant tumors of different sites were studied by morphohistochemical, ultrastructural and stereometric means. Lymphoid cell infiltration was shown to be a morphologic manifestation of immune antitumor reactions. Neoplasms may show very high levels of lymphoid cell infiltration. However, the level of the said cells in the parenchyma and degree of cytotoxic effect on cancer cells are insufficient for antitumor effect to come about. Such factors as parenchyma/stroma ratio, degree of cell differentiation and stage of tumor may influence the level and pattern of infiltration.