DNAs of chromatin, immunoprecipitated by ChIP and re-ChIP assay using antibodies for Sp1 and c-Myc in each myeloma cell line, either treated or untreated with each HDACi for the indicated times (3.0, 6.0, 12, 24 hours), were subject to qPCR and amplified at the CD26 promoter, including the proximal G-C box (Supplementary Table S1). Here, SP1 is linked to plasma cell myeloma.