Increased content of Type V Collagen in desmoplasia of human breast carcinoma.

Type V (AB) collagen is present in increased amounts in desmoplasia of human breast carcinoma. Type V collagen occurs as linear deposits in the interstitium (desmoplastic stroma surrounding the tumor), as demonstrated by immunofluorescence and immunoperoxidase techniques utilizing antibodies to Type V collagen. In contrast, no demonstratable Type V occurs in the interstitium of fibroadenoma, fibrocystic disease, or normal breast tissue. As identified and quantitated by pepsin extraction, salt fractionation, and polyacrylamide gel electrophoresis, Type V constitutes 10% +/- 5% of all interstitial collagens (Types I, III, and V) in desmoplasia, compared with 1.5% +/- 0.5% in fibroadenoma and less than 0.1% in all types of fibrocystic disease, including sclerosing adenosis, and less than 0.1% in normal breast tissue. For infiltrating ductal carcinoma, Type V collagen is not secreted by the invasive carcinoma cells, nor is it present in an extracellular basement membrane location. By immunohistologic methods, Type V collagen can be seen exclusively in the desmoplastic stroma. The authors propose that desmoplasia of human breast carcinoma manifests a characteristic collagen profile and that the increased Type V may be produced by specialized cells such as myofibroblasts in the interstitium, which are recruited in response to invasive carcinoma.