This receptor subtype is primarily expressed on myeloid-lineage hematopoietic cells, and is upregulated in the setting of malignancy.119 FRβ is expressed in 70% of cases of primary AML, and its expression can be further upregulated following treatment with all-trans retinoic acid.120 In a recent publication the effect of FRβ-specific CART cells therapy in vitro as well as in AML xenograft was reported. The gene discussed is FOLR2; the disease is acute myeloid leukemia.