Localization of types I, II, and X collagen in the transplanted tumor derived from human osteogenic sarcoma

We have succeeded in transplanting human osteogenic sarcoma of the mandible into nude mice. As the transplanted tumor shows features of calcified chondrosarcoma, this tumor is thought to be an excellent model for study of the process of dystrophic endochondral calcification. Using this model, we studied relations between the expression of types I, II, and X collagen and chondrogenic differentiation of the transplanted tumor. Collagen distribution during the development and growth of the transplanted tumor was investigated by immunofluorescence with specific antibodies against type I, II or X collagen. Type X collagen was intensely stained in the mineralized region. Almost all tumor cells in this region were hypertrophic. Type II collagen was chiefly distributed in the unmineralized region where tumor cells showed chondrocytic or hypertrophic feature. These results indicate that the type of collagen changes from type II to type X in the hypertrophic region and the type X collagen may be synthesized by hypertrophic tumor cells. Type I collagen was localized in the marginal region of the tumor, though it disappeared in the mineralized region.