MLH1 and pancreatic neoplasm: To establish a model of pancreatic cancer induced by 7,12-dimethylbenzantracene (DMBA) in Sprague–Dawley (SD) rats, and detect the expression of DNA-repair proteins (MGMT, ERCC1, hMSH2, and hMLH1) and their significance in pancreatic cancer and non-cancerous pancreatic tissues of SD rats.