AIM:To assess the prognostic significance of cathepsin L,a cysteine protease that degrades the peri-tumoral tissue,in patients with pancreatic cancer.METHODS:Plasma samples from 127 pancreatic cancer patients were analyzed for cathepsin L levels by ELISA.Out of these patients,25 underwent surgeryand their paraffin-embedded tissue was analyzed for cathepsin L expression by immunohistochemistry.Survival of patients and clinicopathological parameters was correlated with cathepsin L expression in plasma and tissue using appropriate statistical analysis.RESULTS:The mean(±SD)cathepsin L in plasma samples of pancreatic cancer patients was 5.98±2.5ng/m L that was significantly higher compared to the levels in healthy controls(3.83±0.45)or chronic pancreatitis patients(3.97±1.06).Using ROC curve,a cut-off level of 5.0 ng/m L was decided for survival analysis.Elevated plasma levels of cathepsin L were found to be associated with poor prognosis(P=0.01)in multivariate analysis.The plasma levels of the protease decreased after surgery.Though no significant correlation was seen between plasma and tissue expression of this protease,a trend did emerge that high cathepsin L expression in tissue correlated with its high levels in plasma.CONCLUSION:Cathepsin L levels in plasma of pancreatic cancer patients may be used as a potential prognostic marker for the disease. AIM: To assess the prognostic significance of cathepsin L, a cysteine ​​protease that degrades the peri-tumoral tissue, in patients with pancreatic cancer. METHODS: Plasma samples from 127 pancreatic cancer patients were analyzed for cathepsin L levels by ELISA. Out of these patients , 25 underwent surgery and their paraffin-embedded tissue were analyzed for cathepsin L expression by immunohistochemistry. Survival of patients and clinicopathological parameters was correlated with cathepsin L expression in plasma and tissue using appropriate statistical analysis .RESULTS: The mean (± SD) cathepsin L in plasma samples of pancreatic cancer patients were 5.98 ± 2.5 ng / m L that was significantly higher than the levels in healthy controls (3.83 ± 0.45) or chronic pancreatitis patients (3.97 ± 1.06). Using ROC curve, a cut-off level of 5.0 ng / m L was decided for survival analysis. Elevated plasma levels of cathepsin L were found associated with poor prognosis (P = 0.01) in multivariate analysis. Plasma level s of the protease decreased after surgery. Howough no significant correlation was seen between plasma and tissue expression of this protease, a trend did emerge that high cathepsin L expression in tissue correlated with its high levels in plasma. CONCLUSION: Cathepsin L levels in plasma of pancreatic cancer patients may be used as a potential prognostic marker for the disease.