To identify IRF4 transcription factor binding on chromatin at 5' regulatory regions of genes in myeloma cell line models. Keywords: binding site identification design Formaldehyde cross-linked, sonicated chromatin is prepared from cell lines Kms12 (test) and Ly19 (control). Chromatin immunoprecipated with anti-IRF4 antibody is labeled with Cy5 and co-hybridized on Agilent Human Promoter Set arrays with chromatin immunoprecipated with normal sera labeled with Cy3 . Two biological replicates were performed for the Kms12 and Ly19 experiments.