CYP3A4 and plasma cell myeloma: CYP3A4 levels in BM stroma were about 30–50% of the levels in HepG2 cells, whereas its expression was barely detectable in acute myeloid leukemia (AML) (Kasumi 1, OCI-AML3 and KG1) and multiple myeloma (MM) (H929 and RPMI 8226) cells (Figure 1B).