Type I and III collagens in human colon cancer and diverticulosis

Background: Collagens are major proteins in the extracellular matrix, provi ding tissues with tensile strength. They are also important for cell adhesi on and the invasion of malignant rumours. Methods: Thirty-nine samples of h uman colon (24 diverticulosis, 6 malignant rumours, 9 controls) were collec ted during elective surgery. Immunoassays for different domains of type I a nd III collagens and procollagens were used in soluble tissue extracts and trypsin digests of tissue samples. Results: The contents of crosslinked typ e I and III collagen telopeptides and total collagen were similar in divert iculosis and healthy tissue, whereas in malignant tissue maturely cross-lin ked type III collagen was scarce. Furthermore, some of the cross-linked typ e I telopeptide antigens were exceptionally small in size, indicating that the crosslinking of type I collagen in collagen fibres is impaired in cance r. The rate of type I collagen synthesis was clearly increased in malignanc y, but not significantly in diverticulosis. However, type III collagen synt hesis was increased in diverticulosis, but not in malignancy. Conclusions: In colon malignancy, the collagen cross-linking process was aberrant and th e synthesis of type I collagen increased. In diverticulosis, the synthesis of type III collagen was increased, suggesting only moderately increased me tabolic activity.