A comparison between the two monocytic leukemia cell lines, MOLM-14 (FAB type M5) and U-937 (FAB type M5a), further revealed similarities amongst the monocytic leukemias as they both also incited upregulation of CCL3, CCL4 and IL-8 in HSPCs, which were not observed in HL-60 (promyelocytic leukemia; FAB type M2). This evidence concerns the gene CXCL8 and acute promyelocytic leukemia.