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The prognosis of melanoma patients is highly variable due to multiple factors conditioning immune response and driving metastatic progression. In this study, we have correlated the expression of immune-related lncRNAs with patient survival, developed a prognostic model, and investigated the characteristics of immune response in the diverse groups. The gene expression profiles and prognostic information of 470 melanoma patients were downloaded from TCGA database. Significantly predictive lncRNAs were identified by multivariate Cox regression analyses, and a prognostic model based on these variables was constructed to predict survival. Kaplan-Meier curves were plotted to estimate overall survival. The predictive accuracy of the model was evaluated by the area under the ROC curve (AUC). Principal component analysis was used to observe the distribution of immune-related genes. CIBERSORT and ESTIMATE were used to evaluate the composition of immune cells and the immune microenvironment. Eight immune-related lncRNAs were determined to be prognostic by multivariate COX regression analysis. The patient scores were calculated and divided into high- and low-risk groups. The model could effectively predict the prognosis in patients of different stages. The AUC of the model is 0.784, which was significantly higher than that of the other variables. There were significant differences in the distribution of immune-related genes between two groups; the immune score and immune function enrichment score were higher in the low risk group.

Acral melanoma is a rare disease, but is common in Asia. Knowledge of its prognostic indicators is limited. Growing evidence indicates that inflammation plays a critical role in the development and progression of acral melanoma. We developed a novel prognostic model on the basis of preoperative inflammatory markers and examined its prognostic value in a cohort of patients. This retrospective study included 232 acral melanoma patients who underwent radical surgical resection between 2000 and 2010 at the Sun Yat-sen University Cancer Center. Significant predictive factors were identified by multivariate Cox regression analyses, and a prognostic model on the basis of these variables was constructed to predict survival. Kaplan-Meier curves were plotted to estimate overall survival. Multivariate analyses showed that C-reactive protein, albumin/globulin ratio, age, lactic dehydrogenase, and lymph node positivity were related independently to survival. After analyzing these variables, we classified patients into three risk groups. The new prognostic model identified three categories of patients with different prognoses (P<0.001) and significantly stratified patient prognosis into different tumor stages. The area under the curve of the new prognostic model was 0.684 (95% confidence interval: 0.620-0.743), which was significantly higher than that of the other variables (P<0.001). C-reactive protein and albumin/globulin ratio were independently related to survival in our study population and the prognostic model developed using inflammatory-based scores was useful in stratifying patients into different risk groups. Thus, this model will be a valuable complement to the 2009 American Joint Committee on Cancer staging for Asian patients with acral melanoma.

Immune checkpoint blockade of programmed cell death protein 1 (PD-1) had an impressive long-lasting effect in a portion of advanced-stage melanoma patients, however, this therapy failed to induce responses in several patients; how to increase the objective response rate is very important. Cellular FLICE-inhibitory protein (c-FLIP) could inhibit apoptosis directly at the death-inducing signaling complex of death receptors and is also considered to be the main cause of immune escape. The overexpression of c-FLIPL occurs frequently in melanoma and its expression is associated with the prognosis. We found that the level of c-FLIPL expression was associated with the PD-1 blockade response rate in melanoma patients. Thus, we performed this research to investigate how c-FLIPL regulates immunotherapy in melanoma. We demonstrate that down regulation of c-FLIPL enhances the PD-1 blockade efficacy in B16 melanoma tumor model. Down regulation of c-FLIPL could increase the tumor apoptosis and enhance the antitumor response of T cells in the lymphocyte tumor cells co-culture system. Moreover, knockdown of c-FLIPL could decrease the expression of PD-L1 and recruit more effector T cells in the tumor microenvironment. Our results may provide a new combined therapeutic target for further improving the efficacy of PD-1 blockade in melanoma. [ABSTRACT FROM AUTHOR]