Besides, FPN could also be regulated by hypoxia inducible factor 2 (HIF2α), nuclear factor erythroid (Nrf2), metal regulatory transcriptioan factor 1 (MTF1), and myeloid zinc finger 1 (MZF1) at the transcriptional level in macrophages and tumor cells [26, 35–37]. Here, SLC40A1 is linked to neoplasm.