Abstract： Objectives To study the expression of lipoxygenase-12 (12-LOX) in human pancreatic adenocarcinoma and its relationship with the clinicopathological parameters.Methods Expression of 12-LOX in pancreatic carcinoma tissue,pancreatic cancer cell lines SW1990 and PANC1,and adjacent normal pancreatic tissue was detected by using immunohistochemistry,RT-PCR,and Western blot,respectively.The relationship between 12-LOX expression and clinicopathological parameters was analyzed.Results Expression of 12-LOX was negative in 8 cases,weak positive in 7 cases and strong positive in 15 cases of pancreatic carcinoma.The overall positive rate in pancreatic carcinoma was 73.3％.The expressions of 12-LOX mRNA and protein were positive in pancreatic cancer cell lines SW1990 and PANC1,and negative in adjacent normal pancreatic tissue.The strong positive expression of 12-LOX in pancreatic cancer was associated with TNM stage,pathological grade,lymph node metastasis (P ＜ 0.05 ).Conclusions The expression of 12-LOX was up-regulated in pancreatic cancer and is correlated well to malignant behaviors of tumor.