Analysis and generation of HM1.24 cDNA in myeloma cell lines. RT-PCR was performed on polyA-selected RNA to generate HM1.24 cDNA, as described in “Materials and methods.” Note that ARK-B and ARP-1 cell lines expressed HM1.24, as indicated by the appropriately sized band. All the MM cell lines and MM primary cells used in this study were found to express HM1.24 by RT-PCR (data not shown).