The ficolin (FCN) family of proteins in humans is comprised of three members, FCN1, FCN2, and FCN3, and they participate in activating the lectin complement pathway by binding their mannose-binding lectin (MBL)-like structure to proteins of the MBL-associated serine proteases (MASP) family, and therefore act as tumor suppressors. This evidence concerns the gene FCN3 and neoplasm.