COMP and osteoarthritis: In rheumatoid arthritis and osteoarthritis injury to chondrocytes leads to increased secretion of COMP [25] and interaction of COMP with rheumatoid arthritis synovial fibroblasts through integrins has been reported [28], [29] COMP secretion from skin fibroblasts has been reported in affected skin of keloids [30] and systemic sclerosis patients [31]–[33].