C3 and central nervous system cancer: Bulk RNA-Seq from TCGA data sets on GBM and low-grade glioma (TCGA_GBM and TCGA_GBMLGG) showed that C3 expression increased with glioma grade (Figure 1A) and IDH-WT status (Figure 1B) and was expressed at higher levels in GBM compared with nontumor brain (Figure 1C).