CYLD and neoplasm: CYLD encodes a ubiquitin hydrolase enzyme involved in the posttranslational modification deubiquitination.16, 17, 18, 19 By removing ubiquitin chains from relevant protein substrates, CYLD normally negatively regulates cell signaling pathways that are implicated in tumor formation, such as nuclear factor κB, Wnt, and transforming growth factor–β.2