The CCN family of proteins is a group of matricellular proteins that are involved in various cellular processes such as mitosis, adhesion, apoptosis, extracellular matrix production, growth arrest and migration of multiple cell types. The acronym CCN is derived from the first three members of the family discovered, namely CYR61 (cysteine-rich angiogenic protein 61 or CCN1), CTGF (connective tissue growth factor or CCN2), and NOV (nephroblastoma overexpressed or CCN3). The CCN family shares similar structures and they mutually reinforce and neutralize each other to serve various roles that are tightly regulated in a spatiotemporal manner by the tumor microenvironment.
