Scirrhous carcinoma is characterized by remarkable amount of
collagen fibrils, mainly Type I and Type III
collagens. The origin of the
collagens is still under debate.
cDNA fragments of Type I and Type III procollagens were subcloned into Gemini pGEM vectors to synthesize the 35S-labeled
cRNA probes. By in situ hybridization, we have found the fibroblasts surrounding the
tumor cells and cords contained abundant Type I and
Type III procollagen mRNAs which decreased with the distance of fibroblasts from the
tumor cells. In all freshly prepared tissues, the
tumor cells also contained significant pro alpha 1(I) and pro alpha 1(III) mRNAs, but no or little pro alpha 2(I)
mRNA. The results indicated that Type I and Type III
collagens in human
scirrhous carcinoma of breast are mainly produced by fibroblasts.
Tumor cells also participate in the disposition of
collagen fibrils, probably Type I trimer and Type III
collagens in accordance with what was observed in biochemical analysis and cell culture studies.