[Expression of type I and type III procollagen genes in human scirrhous carcinoma of breast by in situ hybridization].

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.