Serine protease inhibitor Kazal-type 1 (SPINK1), also known as tumor-associated trypsin inhibitor (TATI) and pancreatic secretory trypsin inhibitor (PSTI) is a cytosolic trypsin inhibitor secreted by pancreatic acinar cells and foveolar cells of the stomach that protects the gastrointestinal system from premature trypsinogen auto-digestion.  Mutations in SPINK1 are associated with hereditary pancreatitis.  Recently, SPINK1 demonstrated utility in differentiating hepatocellular carcinoma (HCC) from precancerous lesions.  SPINK1 is detected in all hereditary haemochromatosis HCC and most (79%) of HCC cases, but limited to the luminal surface of large bile ducts in normal liver.  SPINK1 expression is also detected in neoplasms of the ovary, bladder, kidney, pancreas, colon, lung, and breast. High expression of SPINK1 is often associated with advanced tumor staging, making it a useful prognostic marker.