Neutrophil to lymphocyte ratio, a simple and effective marker of inflammation, is easily calculated from routinely available data. Trichostatin A moa During the past five years, some studies have demonstrated that an elevated NLR is an important prognostic factor in patients with a variety of digestive system malignancies including esophageal cancer, gastric cancer, colorectal cancer, colorectal liver metastases, pancreatic adenocarcinoma, intrahepatic cholangiocarcinoma, and HCC. However, in all these studies, the cut-off value for NLR of 5 has been set empirically except for one study of gastric cancer with the cut-off level of 4 based on Kaplan-Meier analysis. To our knowledge, this is the first report discussing the appropriate cut-off point of NLR in predicting prognosis in patients with HCC. First, we determined the optimal cut-off point for preoperative NLR to predict HCC patients with high risk of tumor recurrence after LT. By using ROC curve analysis, we found that the cut-off value of 3.0 had a relatively high specificity. Although patients with NLR values between 3.0 and 5.0 were classified as having an elevated NLR based on our new cut-off value, our results showed that patients with NLR,3 showed significantly better DFS and better OS than those of patients with NLR$3. The results of multivariate regression analysis revealed that NLR$3 was the independent prognostic predictor of poor DFS. This is consistent with the above studies. Although the relationship between elevated NLR and increased risk for early recurrence and poor prognosis is largely unclear, there are several possible mechanisms explaining the predictive role of preoperative elevated NLR. The systemic and local inflammatory response to tumor may provide a favorable environment for tumor invasion and metastases. Furthermore, high expressions of granulocyte colony-stimulating factor in tumor tissue and macrophage colony-stimulating factor in peritumoral tissue are also associated with the elevated circulating neutrophils and poor prognosis. Circulating elevated levels of vascular endothelial growth factor secreted mainly by circulating neutrophils have been associated with increased risk of recurrence in patients with HCC. On the other hand, reduced lymphocyte infiltration, reflecting an impaired host immune response, has been shown to predict recurrence in HCC patients following LT. NLR reflects an immune microenvironment that both favors tumor vascular invasion and suppresses the host immune surveillance. In addition, NLR can not only predict tumor recurrence but also be used for diagnosis of tumor. A recent study has showed that NLR can be a useful tool for preoperative diagnosis in patients with uterine sarcomas. Although univariate analysis in this study showed that tumor size, AFP level, and HBV-DNA level were preoperative prognostic predictors of poorer DFS, none of these factors were identified as independent predictors on multivariate analysis. However, this result did not mean that these factors were not associated with recurrence.