PDCD1 and cancer: The results demonstrated that these immune checkpoints are closely related to FTH1 expression in different cancers, namely PDCD1, CTLA4, CD274, and TIGIT exhibited a positive association with FTH1 in ACC, BCLA, BRCA, DLBC, KIRP, LAML, LGG, LUSC, OV, PCPG, PRAD, SARC, SKCM, TGCT, THCA, THYM, UCEC, and UCS (Fig. 5B).