At six and twelve months, homozygous Cux1 deletion in Cux1fl/fl;Vav-iCre+ mice led to progressive macrocytic anemia and leukocytosis due to monocytosis and neutrophilia, which was similarly observed in Cux1-knockdown mice24 (Supplementary Fig. 3a–e). Here, CUX1 is linked to anemia.