Chitinase-3-like protein 1 (CHI3L1) is also known as Cartilage glycoprotein 39 (CGP-39), YKL-40, which belongs to the glycosyl hydrolase 18 family. CHI3L1 is present in activated macrophages, articular chondrocytes, synovial cells as well as in liver. CHI3L1 may play a role in defense against pathogens, or in tissue remodeling and also may play an important role in the capacity of cells to respond to and cope with changes in their environment.