SS18 and neoplasm: HDAC2 was supposed to take part in the MDM2 ubiquitination pathway, acting to maintain, in SyS cells, low levels of MULE (Mcl-1 ubiquitin ligase E3), a ubiquitin E3 ligase exhibiting tumor-suppressor function in synovial sarcoma, by targeting the SS18-SSX oncoprotein for ubiquitination and degradation.