The expression of MK-1 and RegIV was detected by immunohistochemical method in paraffin-embedded sections of surgical resected specimens from gallbladder adenocarcinoma (n = 108), peritumoral tissues (n = 46), adenomatous polyp (n = 15), and chronic cholecystitis (n = 35). This evidence concerns the gene REG4 and gallbladder adenocarcinoma.