Immunohistological study on collagenous proteins of benign and malignant human cartilaginous tumours of bone.

The immunohistological distribution of collagen types I, II, III, V and VI in human benign and malignant cartilaginous tumours of bone was examined with regard to their aggressiveness. The matrix of enchondromas consisted of type II collagen distributed diffusely, and type VI predominantly localized in the immediate surroundings of the cells. Types I, III and V collagen were not found. These findings were similar to the distribution of collagenous proteins in normal hyaline cartilage where each lobule was consistently rimmed by types I and V collagen. In grade 1 chondrosarcomas, the main collagenous components of matrix were also types II and VI collagen. Type II was sometimes found in the cytoplasm of tumour cells and type VI tended to lose territorial localization. In addition, type I collagen was demonstrated consistently and type V in some cases. In grade 2 chondrosarcomas, type II collagen was demonstrated not only in the matrix but occasionally in the cytoplasm of tumour cells. Type VI was dispersed in the intercellular areas. The other collagenous proteins such as types I, III and V were also present in the matrix. In grade 3 chondrosarcomas, type II collagen was localized predominantly in the cytoplasm of tumour cells and in the adjacent matrix. Type VI was markedly decreased with complete loss of pericellular distribution, whereas types I, III and V were constantly present in the matrix. Those alterations in the distribution of collagen types correlated well with the aggressive behaviour of the tumours. The findings suggest that distribution of different collagen types in cartilaginous tumours reflects the immaturity of the tumour cells and is a useful indicator of their aggressiveness.