Immunohistological identification of T and B cells in normal and malignant tissues of the uterine endometrium.

We examined the state of T and B cells in tissues from 61 cases of endometrial cancer by immunohistochemistry with monoclonal antibodies. In cancer tissues, T cells frequently appear in clusters at the tip of the infiltrating cancer. As to age, both T and B cells were rare in 9 out of 11 cases involving endometrial cancer in patients in their 40s. In the normal endometrium, infiltration of numerous T cells was seen in only 2 out of 27 cases (7.4%). However, it was seen in cancer tissues in 28 out of 61 cases (45.9%). Thus the infiltration of numerous T cells into cancer tissues was confirmed. Within the same uterus, T cells seldom infiltrated into the area of the benign endometrium while T cells were seen in large numbers in the cancer foci. This indicates that T cells infiltrate after having recognized cancer cells. Compared to stages I and II, T cell infiltration tended to decrease in stages III and IV. While no fixed relation was found between the degree of histologic differentiation and T cell infiltration, fewer T cells were observed in the cases where cancer penetrated to the depth of cancer invasion and where it occupied a large area. Thus, it was assumed that in the host-immune defence mechanism in particular, T cell infiltration played a key role in tumor immunology of patients with endometrial cancer.