Upregulated necroptosis-pathway-associated genes are unfavorable prognostic markers in low-grade glioma and glioblastoma multiforme

BACKGROUND: Glioma accounts for 70% of primary brain malignancies in adults with unfavorable prognoses. In the past decades, much efforts have been invested to identify better biomarkers for predicting prognoses. Recently, necroptosis has been reported as a specialized pathway of programmed necrosis. Moreover, regulators of necroptosis-pathway-associated genes (RIPK1, RIPK3 and MLKL) were reported to be related to prognoses of many types of tumors. However, the prognostic value of these genes in diffuse glioma including low-grade glioma (LGG) and glioblastoma multiforme (GBM) remains unknown. METHODS: An online tool-Gene Expression Profiling Interactive Analysis (GEPIA) (http://gepia.cancer-pku.cn/) was used to analyze different expression of necroptosis-pathway-associated genes between tumor and normal tissue, correlation between RIPK1, RIPK3 and MLKL, the relationship between necroptosis-pathway-associated genes and prognosis [overall survival (OS) and disease-free survival (DFS)] in LGG and GBM. The median expression of RIPK1, RIPK3 and MLKL was used to divide patients into high- versus low-expression group. All graphic presentations were drawn by Gepia database. RESULTS: Expression of RIPK1 and RIPK3 were significantly higher in tumor tissue of GBM as compared with normal tissue. A moderate correlation between MLKL and RIPK3 was demonstrated in both LGG (R =0.79) and GBM (R =0.79). In LGG, higher expression of RIPK1, RIPK3, and MLKL were associated with poor OS and DFS with HR values of 2.2, 2, 1.9 for OS and 1.7, 1.8, 1.6 for DFS, respectively. In GBM, only a higher expression of MLKL was associated with worse OS and DFS with HR values of 1.5 and 1.6, respectively. CONCLUSIONS: Regulators of necroptosis-pathway-associated genes appear to have a potential to serve as biomarkers of prognosis in both LGG and GBM.