To test the effects of HDAC inhibitors on tumor growth and differentiation in vitro, two pan-HDAC inhibitors, TSA and suberoylanilide hydroxamic acid (SAHA), were tested in a panel of ERMS cell lines (RD, 381T and SMS-CTR) and ARMS cell lines (Rh3, Rh5 and Rh30). The gene discussed is RHD; the disease is neoplasm.