Immunohistochemical analysis of mesocolic lymph node cells in human colorectal cancer

Localization of lymphocyte subsets and macrophages in the mesocolic lymph node of the colorectal cancer and their distribution among the paracolic, intermediate, and main nodes were studied quantitatively by means of immunohistochemical staining with monoclonal antibodies. In all of the three lymph node groups, in the paracortex, helper/inducer T cells were more numerous than suppressor/cytotoxic T cells. The number of whole T cells in the paracortex diminished with increasing proximity to the primary tumor. In the three lymph node groups, no significant difference was found regarding the ratio of the cell number among suppressor/cytotoxic T cells, natural killer cells, and macrophages. Lymphocytes in the paracortex of lymph node had a positive correlation to lymphocytes in the peritumoral stroma and intratumoral fields. These data neither suggest the presence of a powerful immunological reaction in the mesocolic lymph node nor support the concept of conservation of uninvolved regional lymph nodes in the surgery of the colorectal cancer.