CYLD: a deubiquitination enzyme with multiple roles in cancer.

The post-translational modification of different proteins via direct ubiquitin attachment is important for various cellular processes. Dysregulation of components of the ubiqutin system have been linked to many diseases including cancer. CYLD is a deubiquitination enzyme that can cleave the lysine 63-linked polyubiquitin chains from target proteins and regulate cell survival or cell proliferation. Since loss of CYLD expression can be observed in different types of human cancer, it is now well established that CYLD acts as a tumor suppressor gene. Besides its loss of function in human tumors by gene deletion or mutation, CYLD expression can be downregulated at the RNA level if necessary through transcriptional regulation or at the protein level through post-translational modifications. This article summarizes recent advances that link CYLD to different types of human cancer. Identification of CYLD-mediated signaling pathways during the progression of cancer will provide a solid foundation for diagnosis and lead to the development of novel tools for cancer therapy.