Construction of immune-related risk model for prognosis of hepatocellular carcinoma.

Abstract

e16683 Background: Hepatocellular carcinoma is the most common malignant tumor. Although the treatment of HCC has significantly improved, the 5-year survival rate is still only 18%. There is increasing evidence that tumor immune microenvironment (TIM) plays critical roles during cancer initiation and progression. Based on the comprehensive exploration of the immunogenomic, an immune-related risk model was constructed to predict hepatocellular carcinoma prognosis. Methods: Transcriptomic data of HCC patients were downloaded from the TCGA database, and the differentially expressed immune-related genes (IRGs) (FDR < 0.01, |log2fold change| > 2) were identified. Functional enrichment analysis was performed to explore potential molecular mechanisms of the differentially expressed IRGs. By univariate and multivariate Cox regression analysis, we identified eight prognosis-related IRGs. Based on the expression levels of IRGs, we constructed the immune-related risk model. The Kaplan‐Meier (K‐M) survival curves, ROC curves, univariate and multivariate analysis were used to evaluate the immune-related risk model. According to the risk score, HCC patients were stratified into low and high-risk groups. CIBERSORT was applied to analyze the profiling difference of infiltrating immune cells between the two groups. Results: A total of 113 differentially expressed IRGs were identified, of which nine IRGs were correlated with the prognosis of HCC patients. Functional enrichment analysis showed that these genes were involved in immune response and immune signal pathway. The immune-related risk model consisted of eight IRGs (FABP6, RBP2, MAPT, BIRC5, PLXNA3, CSPG5, IL17D and STC2). The immune risk score was an independent prognostic factor (HR, 2.63 [1.93−3.58]; P = 8.16E−10) and the patients with a high-risk score tended to have a shorter OS than those with a low-risk score. In the TCGA cohort, high-risk patients tended to have an advanced stage. Moreover, we found that the patients in the high-risk group had higher fractions of T follicular cells helper and macrophages M0. The patients with low-risk scores had higher fractions of CD8+ T cells and CD4+ T cells. Conclusions: We have identified the immune-related risk model of hepatocellular carcinoma based on the expression profiles of eight immune-related genes. This model could predict prognosis and reflect the tumor immune microenvironment of HCC patients, which can provide new insights in the individualized treatment of HCC and potential novel targets for immunotherapy.