TATI as a biomarker

• TATI inhibits trypsin but also several other peptidases.
• TATI is an acute phase reactant and a growth factor.
• TATI has a role in reproduction, apoptosis, normal tissue differentiation and repair.
• In cancer, TATI expression is often increased.
• TATI can be used as a diagnostic and prognostic marker for certain cancers.
• Identification of N34S-TATI mutation carriers may improve the identification of patients in high risk for chronic pancreatitis.

Tumor-associated trypsin inhibitor (TATI) [also called serine peptidase inhibitor Kazal type1, SPINK1 and, in the pancreas, pancreatic secretory trypsin inhibitor (PSTI)] inhibits trypsin and other serine proteinases and is expressed in several tissues. In addition to being a protease inhibitor, it also acts as an acute phase reactant and a growth factor. Furthermore, it may modulate apoptosis, play a role in reproduction, and be essential for normal tissue differentiation and repair. Serum TATI is elevated in many cancers and can thus be used as a diagnostic marker. Over-expression of TATI predicts an unfavorable outcome in several cancers and serum TATI can be used to identify patients at increased risk of aggressive disease. Serum TATI also increases in acute pancreatitis. Some TATI mutations predict susceptibility to recurrent or chronic pancreatitis. Recent developments in assay technologies may help in identifying mutation carriers conveniently without DNA testing. As TATI acts as a growth factor in some cancers, it has also been suggested as a therapeutic target. Taken together, assessment of TATI has several potentially important clinical applications.