title: Nuclear expression of the deubiquitinase CYLD is associated with improved survival in human hepatocellular carcinoma.
abstract: OBJECTIVE
  The deubiquitinase CYLD removes (K-63)-linked polyubiquitin chains from proteins involved in NF-κB, Wnt/ß-catenin and Bcl-3 signaling. Reduced CYLD expression has been reported in different tumor entities, including hepatocellular carcinoma (HCC). Furthermore, loss of CYLD has been shown to contribute to HCC development in knockout animal models. This study aimed to assess subcellular CYLD expression in tumor tissues and its prognostic significance in HCC patients undergoing liver resection or liver transplantation.
  
  
  METHODS
  Subcellular localization of CYLD was assessed by immunohistochemistry in tumor tissues of 95 HCC patients undergoing liver resection or transplantation. Positive nuclear CYLD staining was defined as an immunohistochemical (IHC) score ≥ 3. Positive cytoplasmic CYLD staining was defined as an IHC score ≥ 6. The relationship with clinicopathological parameters was investigated. Cell culture experiments were performed to analyze subcellular CYLD expression in vitro.
  
  
  RESULTS
  Cytoplasmic CYLD expression was observed in 57 out of 95 (60%) HCC specimens (cyt°CYLD+). Nuclear CYLD staining was positive in 52 out of 95 specimens (55%, nucCYLD+). 13 out of 52 nucCYLD+ patients (25%) showed a lack of cytoplasmic CYLD expression. nucCYLD+ was associated with prolonged overall survival in patients after resection or liver transplantation (P = 0.007). 5-year overall survival rates were 63% in nucCYLD+ vs. 26% in nucCYLD- patients. Nuclear CYLD staining strongly correlated with tumor grading (P<0.001) and Ki67 positivity (P = 0.005). nucCYLD+ did not prove to be an independent prognostic parameter. In vitro, Huh7, Hep3B and HepG2 showed reduced CYLD levels compared to the non-malignant liver cell line THLE-2. Induction of CYLD expression by doxorubicin treatment led to increased cytoplasmic and nuclear expression of CYLD.
  
  
  CONCLUSIONS
  Expression of nuclear CYLD is a novel prognostic factor for improved survival in patients with HCC undergoing liver resection or transplantation.
authors.affiliation: National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Welte
authors.affiliation: National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Toni
authors.initials: T
authors.lastname: Urbanik
authors.affiliation: National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Christin
authors.initials: C
authors.lastname: Elßner
authors.affiliation: National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Kautz
authors.affiliation: National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Bruno Christian
authors.initials: BC
authors.lastname: Koehler
authors.affiliation: Institute of Pathology, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Nina
authors.initials: N
authors.lastname: Waldburger
authors.affiliation: Institute of Medical Biometry and Informatics, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Justo Lorenzo
authors.initials: JL
authors.lastname: Bermejo
authors.affiliation: Institute of Pathology, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Federico
authors.initials: F
authors.lastname: Pinna
authors.affiliation: Department of Gastroenterology, Toxicology, and Infectious Diseases, Heidelberg University Hospital, Internal Medicine IV, Heidelberg, Germany.
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Weiss
authors.affiliation: Department of General and Transplant Surgery, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Schemmer
authors.affiliation: National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Jaeger
authors.affiliation: Institute of Pathology, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Longerich
authors.affiliation: Institute of Pathology, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Breuhahn
authors.affiliation: National Center for Tumor Diseases, Department of Medical Oncology, Internal Medicine VI, Heidelberg University Hospital, Heidelberg, Germany; Department of Gastroenterology, Diabetology and Rheumatology, Internal Medicine II, Marien-Hospital, Wesel, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Schulze-Bergkamen
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D000074749:Deubiquitinating Enzyme CYLD; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D056945:Hep G2 Cells; D006801:Humans; D053208:Kaplan-Meier Estimate; D008113:Liver Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D016031:Liver Transplantation; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D025521:Tumor Suppressor Proteins; C409984:CYLD protein, human; D000074749:Deubiquitinating Enzyme CYLD