IL4I1 and glioblastoma: Furthermore, the forest plot of PFI confirmed the risky role of IL4I1 in GBM, KIRC, KIRP, LGG, PRAD, and THYM, and its role as a protective factor in CESC, HNSC, OV, and SKCM (Supplementary Figure S2A), and the K-M curves identified that upregulated IL4I1 was also linked to a poor outcome in GBM, LGG, and THCA, but a better outcome in CESC and SKCM (Supplementary Figures S2B–F).