Gene and protein expression of cartilage oligomeric matrix protein associated with oncogenesis in canine tumors.

To investigate the expression of cartilage oligomeric matrix protein (COMP) associated with oncogenesis, samples of serum and tumor tissue were obtained from 25 dogs with tumors. The serum levels of COMP in dogs with tumors were significantly higher than in 38 normal controls and correlated with the concentrations of tumor tissue extracts. Positive bands to COMP antibody were detected on immunoblots of tumor extracts. Immunohistochemistry and in situ hybridization demonstrated positive signals of COMP and its mRNA in the cytoplasm of tumor cells from mammary gland tumors, but not in the normal mammary gland. Positive immunohistochemistry results were also obtained for COMP in mast cell tumor and melanoma cells. Oncogenesis might augment production of COMP and the serum level of COMP in dogs.