CCL21 and glioblastoma: The RT‐qPCR assay indicated that seven IRGs (SAA1, CXCL10, CCL13, CCL27, SSTR5, CCL21, and HTR1A) were differentially expressed between NBT, LGG, and GBM, which were in the main consistent with the results of the bioinformatics analysis (Figure 7A–G).