Immunohistologic analysis of the extracellular matrix components of the fibrous stroma of human colon cancer.

In order to elucidate the gross composition of fibrous stroma and to better understand the obstructive nature of advanced human colonic cancers the extracellular matrix components of its stroma were analyzed immunohistologically, emphasizing the process of fibrosis and possible tissue constriction. Collagenous material, identified by Masson's trichrome stain, was distributed mainly in the invasive area, where type I and III collagens and chondroitin 4-sulfate stained intensely in the periacinar area, and further, fibronectin stained. Conversely, in the invasive area away from tumor acini type III collagen stained weakly and fibronectin not at all. Type V collagen and myofibroblasts stained in the periacinar area and did not stain in the invasive area away from tumor acini, the findings of myofibroblasts being prominent in cases with obstructive type carcinomas. In conclusion, the invasive area, especially the periacinar area, displayed signs of active ongoing fibrosis and tissue contraction, which may be responsible for the genesis of obstructing type colonic carcinomas.