IGFBP6 and glioblastoma: In GBM, the four TILs that had the strongest correlation with IGFBP6 were type 1 T helper cells (Th1, Spearman: r = 0.632, P < 2.2e − 16), central memory CD4 T cells (Tcm_CD4; Spearman: r = 0.624, P < 2.2e − 16), regulatory T cells (Treg, Spearman: r = 0.614, P < 2.2e − 16), and activated dendritic cells (Act_DC, Spearman: r = 0.587, P < 2.2e − 16) (Figure 8(b)).