Immunohistological study to determine the presence of pericryptal myofibroblasts and basement membrane in colorectal epithelial tumors

Pericryptal myofibroblasts (PMFs) are thought to be involved in the product ion of the basement membrane (BM) of the colonic epithelium. To clarify the involvement of PMFs in the formation of the BM during the growth of colon cancer, we conducted an immunohistological study of tumor specimens from 85 patients with colorectal epithelial tumor to detect the presence of PMFs. The tumor specimens were classified as adenoma with low-grade dysplasia, ad enoma with high-grade dysplasia, or colon cancer. PMFs were detected in 66. 6% of the specimens from patients with adenoma with low-grade dysplasia; 20 % of specimens of adenoma with high-grade dysplasia; and 3.2% of specimens of colon cancer. As the degree of dysplasia of the tumor increased, the pro bability that PMFs existed decreased. We also tested 49 of the tumor specim ens for the presence of laminin, a component of the BM, and found that in m ost of these 49 cases, the BM and PMFs co-existed. This provides further ev idence that PMFs are involved in the production of the BM. These findings a re important in gaining an understanding of the cause and growth of colorec tal epithelial tumors.