Histological and biochemical characterization of murine sarcomas

A mouse fibrosarcoma and rat osteosarcoma were examined histologically and biochemically with regard to collagen content. The fibrosarcoma was composed of undifferentiated mesenchymal cells without distinct fibroblastic characteristics. Collagen production and deposition were consistent with those observed in cultured fibroblasts. Type I and type III collagens were evident as determined by immunofluorescence staining and biochemical analysis. The osteosarcoma appeared similar to bone with regard to a high content of type I collagen, limited calcification and poor vascularization. While these sarcomas do not histologically resemble their non-transformed counterparts, analysis of their macromolecular composition confirmed the identity of their presumed cell of origin. Similar methodology could be readily applied for identification and classification of human malignant sarcomas.