Trefoil factor 1

Trefoil factor 1 is a is_associated_with::protein that in humans is encoded by the TFF1 is_associated_with::gene (also called pS2 gene ).

Function
Members of the trefoil family are characterized by having at least one copy of the trefoil motif, a 40-amino acid domain that contains three conserved is_associated_with::disulfides. They are stable secretory proteins expressed in is_associated_with::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. This gene, which is expressed in the gastric mucosa, has also been studied because of its expression in human tumors. This gene and two other related trefoil family member genes are found in a cluster on chromosome 21.

In gastric carcinoma
TFF1 expression is frequently lost in is_associated_with::gastric carcinoma, probably through mechanism of DNA methylation, and it is therefore considered as a tumor suppressor gene.