Anti-Trefoil Factor 1 antibodies are used in the immunodetection of the protein encoded by the TFF1 gene. In humans, the canonical protein has a reported length of 84 amino acid residues and a mass of 9.2 kDa. It is known to be a secreted protein. The trefoil factor 1 protein is involved with carbohydrate metabolism and homeostasis and cell differentiation, among other functions. Other names for this target antigen include D21S21, HP1.A, HPS2, pNR-2, pS2, and BCEI.