S100A9 and glioblastoma: The well-known gene sets closely related to S100A9, which are involved in tumor malignant progression (Figure 4G) and immune inflammation (Figure 4H), have been screened and shown in the line graphs, such as HALLMARK_HYPOXIA, HALLMARK_ANGIOGENES, HALLMARK_COMPLEMETN, HALLMARK_INFLAMMATORY RESPONSE, etc. The above results indicated that S100A9 was involved in multiple biological processes during the occurrence and development of GBM.