Abstract
Growth and advance of gastric cancer and colo-rectal cancer were investigated by the following two methods. 1. Biochemical Studies: Collagen and collagenase activity in the cancerous tissue were examined to clarify the etiology of scirrhus cancer of the stomach, which is characterized by diffuse cancerous invasion and remarked proliferation of fibrous connective tissue in the cancerous tissue. Collagenase activity of cancer cells and fibroblasts was markedly high at the growing edge of the cancer, where collagen fibers were decomposed and replaced by the invading cancer cells and the markedly proliferating collagens promoted by fibroblasts. This leads to the characteristic appearance of scirrhus cancer of the stomach. 2. Immunohistochemical Studies: The biological characteristics of cancer were investigated immunohistochemically to clarify the growth and advance of cancer. Abnormal expression of the “growth factor-receptor system” or oncogenes was closely related to advance of the cancer. The HLA antigen, as one of the factors of the “cancer vs host interaction”, was proved to be correlated to advance of cancer through the immune response of the host. This correlation was supported by the finding that the cancer was apt to advance especially when the HLA antigen was only slightly expressed (“escape theory”).
