Chitinase 3-Like-1 (CHI3L1) is a recently discovered human glycoprotein which is related in amino acid sequence to the chitinase protein family, but has no chitinase activity. CHI3L1 is upregulated in a number of cancers and in non-neoplatic disease states characterized by chronic inflammation and tissue remodeling. Its pattern of expression is associated with pathogenic processes related to inflammation, extracellular tissue remodeling, fibrosis and solid carcinomas. CHI3L1 may play an important role in the capacity of cells to respond to and cope with changes in their environment.