Development of cancer models with Irp1−/− and Irp2−/− mice is expected to better define the roles of IRPs in cancer and to elucidate the molecular basis underlying the association of IRP2 (IREB2) genomic locus with susceptibility to lung cancer (Hansen et al., 2010; Cho et al., 2012; Fehringer et al., 2012). Here, ACO1 is linked to lung cancer.