These proteins are encoded by members of the trefoil family genes. They are characterized by having at least one copy of the trefoil motif, a 40-amino acid domain containing three conserved intrachain disulfide bonds. They are stable secretory proteins expressed in gastrointestinal mucosa. Their functions are not defined, but they may protect the mucosa from insults, stabilize the mucus layer and affect healing of the epithelium. (NCI) [ ]