AR-42 treatment induces acetylation of histones and α-tubulin in malignant mast cells. P815, C2, and BR cell lines were treated with the indicated concentrations of AR-42 or 1μM 17-AAG and canine BMCMCs were treated with 1μM AR-42 or 17-AAG for 24 hours. Effects on the acetylation status of histones H3 and H4 and α-tubulin were determined by Western blotting.