CD38 and plasma cell myeloma: For the effective use of T cells transduced with anti-CD38-CAR for AML, the enhancement of CD38 on AML cells is a prerequisite because the expression of CD38 accounts for 83% in AML cells from patients with AML.10, 11 Furthermore, the intensity of CD38 expression is much lower than that of B-lymphoma and myeloma cells.23, 24, 25, 26 ATRA is clinically available for APL patients through the induction of differentiation and apoptosis in APL cells.