HDAC9 and neoplasm: Several drugs have been developed based on these pathways, such as TAS‐116, which inhibits heat shock protein (HSP) 90,45 HDAC inhibitors, which promote RT‐induced cell death and disrupt DNA strand repair,33 AMG 232, which inhibits MDM2 and suppresses tumor growth,34 and BKM120 and BEZ235, which target PI3K pathways and increase the sensitivity of tumor tissue to irradiation.46, 47