Immunohistochemistry was performed on sections from 50 patients with pancreatic cancer (n = 27), ampullary cancer (n = 12), low bile duct cancer (n = 3), neuroendocrine tumours (n = 3) and chronic pancreatitis (n = 5), using antibodies raised against collagenase (MMP2), stromelysin (MMP3) and tissue inhibitor of metalloproteinase (TIMP1) and developed using the avidin-biotin complex method. The gene discussed is TIMP1; the disease is carcinoma of the ampulla of vater.