In the bile duct and ampullary carcinomas calpain-1 expression had a statistically significant correlation with cytoplasmic calpastatin expression (r = 0.425, P < 0.001) and nuclear calpastatin expression (r = 0.295, P = 0.002), but not with calpain-2 expression. The gene discussed is CAST; the disease is carcinoma of the ampulla of vater.