ObjectiveTo study the expression of HOX A9 mRNA and its clinicopathological significance in the benign and malignant lesions of pancreas. MethodsIn situ hybridization for HOX A9 mRNA was used on routine paraffinembedded sections. ResultsThe positive rate and scoring mean of HOX A9 mRNA expression was significanfly lower in pancreatic carcinoma (49%, 3.3±2.1) than that in chronic pancreatitis (95%, 5.4±0.8) and pericancerous tissues (80%, 4.6±1.2), the negative case of HOX A9 mRNA in chronic pancreatitis and pericancerous tissues showed middle or severelyatypical hyperplasis of the ductal epitheli. The positive rate and scoring mean of HOX A9 mRNA expression was significantly higher in the cases of welldifferentiation (63%, 4.0±2.2) or without metastasis (64%, 4.1±2.2) than that in the ones of poorlydifferentiation (32%, 2.6±2.3) or with metastasis (32%, 2.7±2.2). ConclusionThe expression of HOX A9 mRNA might be related the carcinogenesis, progress, biological behaviors, and prognosis of pancreatic carcinoma. The assay of HOX A9 mRNA expression in the benign lesions of pancreas might have important clinical values in the prevention and earlystage finding of the pancreatic carcinoma.