Tumour-associated trypsin inhibitor, TATI, in patients with pancreatic cancer, pancreatitis and benign biliary diseases.

The serum and urine concentrations of a tumour-associated trypsin inhibitor, TATI, were determined by radioimmunoassay in patients with pancreatic cancer and with benign pancreatic and biliary diseases. Elevated serum levels (greater than 20 micrograms l-1) were found in 85% of the patients with pancreatic cancer, and elevated urine levels (greater than 50 micrograms g-1 creatinine) in 96% of the patients. Thus low TATI level, especially in urine, makes the possibility of pancreatic cancer less likely. Serial assay of TATI in serum from three patients with surgically removed pancreatic cancer showed elevation of the TATI level at the time of detection of recurrence. However, high serum and urine levels were also seen in pancreatitis and in benign extrahepatic cholestasis. Thus TATI is a sensitive, although not specific, indicator of pancreatic and biliary disease, but the use of TATI as a tumour marker in the primary diagnosis of pancreatic cancer is limited. Immunohistochemical staining of pancreatic lesions showed that half of the pancreatic tumours expressed TATI, but the pancreatic tissue adjacent to a carcinoma always stained stronger than the carcinoma. It therefore seems that the main source of TATI in serum and urine of patients with pancreatic cancer are the normal acini and not the tumour tissue. In pancreatitis the staining was intense and clearly stronger than in normal pancreas.