Ten cases of basal cell carcinoma (BCC), including nine of the nodulo-ulcerative type and one of the morphea-form type, were investigated for stromelysin-3 (ST3) gene expression by in situ hybridization. The ST3 gene, which codes for a putative matrix metalloproteinase expressed in stromal cells of invasive breast carcinomas, was also expressed in stromal cells of BCCs when they displayed active local invasiveness. ST3 RNA was specifically detected in fibroblastic cells of tumor areas exhibiting loss of peripheral palisading in cancer cell islands. This pattern of expression was characteristic of the ST3 gene and was not observed with any of the other matrix metalloproteinase genes tested. We suggest that ST3 gene expression, which was also observed in fibroblasts during cutaneous scar formation, corresponds to a normal wound-healing response that has been subverted in carcinomas.
