HDAC9 and cancer: The consequences of HDAC inhibition were tested by the use of SAHA, a HDACi that completely inhibits both class I and class II HDACs, and by the use of specific siRNAs targeting HDAC2 or HDAC7. SAHA has been largely used for HDACs inhibition in cancer cells and is approved by the FDA for the treatment of cutaneous T-cell lymphoma.