[An immunohistological study of local immunity of colorectal cancer]

The surgical specimens from forty-two patients with colorectal cancer were studied by the immunoperoxidase method for immunoglobulin (Ig); the number of Ig containing cells and round cells within the lamina propria adjacent to the tumor was calculated. The results were as follows; 1) Population per 0.025 mm2 of IgA, IgM, IgG containing cells in the adjacent part to the tumor were 15.5 +/- 0.9, 13.6 +/- 1.4, 8.9 +/- 0.4, respectively. 2) IgA containing cells in the adjacent part to the tumor decreased in number compared with the histologically normal part, while IgG containing cells were more frequently observed in the adjacent part. The differences were statistically significant (p less than 0.05). 3) The number of IgG containing cells was closely related to the size of the tumor, and IgM containing cells was in proportion to the presence of the lymph node metastasis. 4) The number of IgG containing cells in the adjacent part differed significantly between rectal cancer and colon cancer; the number being fewer in rectal cancer. 5) The round cells within the adjacent part increased in number, compared to the histologically normal part, and were observed to be more numerous in the localized ulcerative type of cancer than in the invasive ulcerative type. From these results it could be concluded that Ig containing cells play an important role in the local immunity of colorectal cancer.