FTH1 and cancer: Strikingly, upregulated FTH1 expression displayed a significantly positive correlation with macrophage infiltration in most cancers, especially M2 macrophages in most cancers, including ACC, BLCA, BRCA, COAD, GBM, HNSC, KICH, KIRP, LGG, LIHC, LUAD, PAAD, PCPG, PRAD, READ, TGCT, UCS, and LAML (Fig. 4A–D).