title: Low expression of the putative tumour suppressor spinophilin is associated with higher proliferative activity and poor prognosis in patients with hepatocellular carcinoma.
abstract: BACKGROUND
  Spinophilin, a multifunctional intracellular scaffold protein, is reduced in certain types of cancer and is regarded as a novel putative tumour suppressor protein. However, the role of spinophilin in hepatocellular carcinoma (HCC) has never been explored before.
  
  
  METHODS
  In this study, we determined for the first time the expression pattern of spinophilin in human HCC by immunohistochemistry and quantitative reverse transcriptase-PCR analysis. In addition, we performed immunohistochemical analysis of p53, p14(ARF) and the proliferation marker Ki-67. Kaplan-Meier curves and multivariate Cox proportional models were used to study the impact on clinical outcome. Small interfering RNA (siRNA) was used to silence spinophilin and to explore the effects of reduced spinophilin expression on cellular growth.
  
  
  RESULTS
  In our study, complete loss of spinophilin immunoreactivity was found in 44 of 104 HCCs (42.3%) and reduced levels were found in an additional 37 (35.6%) cases. After adjusting for other prognostic factors, multivariate Cox regression analysis identified low expression of spinophilin as an independent prognostic factor with respect to disease-free (hazard ratio (HR)=1.8; 95% confidence interval (CI)=1.04-3.40; P=0.043) and cancer-specific survival (HR=2.0; CI=1.1-3.8; P=0.025). Reduced spinophilin expression significantly correlated with higher Ki-67 index in HCC (P=0.014). Reducing spinophilin levels by siRNA induced a higher cellular growth rate and increased cyclin D2 expression in tumour cells (P<0.05).
  
  
  CONCLUSIONS
  This is the first study of the expression pattern and distribution of spinophilin in HCC. According to our data, the loss of spinophilin is associated with higher proliferation and might be useful as a prognostic marker in patients with HCC.
authors.affiliation: Institute of Pathology, Medical University of Graz, Graz, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Aigelsreiter
authors.forename: A L
authors.initials: AL
authors.lastname: Ress
authors.forename: K
authors.initials: K
authors.lastname: Bettermann
authors.forename: S
authors.initials: S
authors.lastname: Schauer
authors.forename: K
authors.initials: K
authors.lastname: Koller
authors.forename: F
authors.initials: F
authors.lastname: Eisner
authors.forename: T
authors.initials: T
authors.lastname: Kiesslich
authors.forename: T
authors.initials: T
authors.lastname: Stojakovic
authors.forename: H
authors.initials: H
authors.lastname: Samonigg
authors.forename: P
authors.initials: P
authors.lastname: Kornprat
authors.forename: C
authors.initials: C
authors.lastname: Lackner
authors.forename: J
authors.initials: J
authors.lastname: Haybaeck
authors.forename: M
authors.initials: M
authors.lastname: Pichler
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000401:mortality*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D056742:Cyclin D2 / Q000096:biosynthesis; D018572:Disease-Free Survival; D005260:Female; D056945:Hep G2 Cells; D006801:Humans; D053208:Kaplan-Meier Estimate; D019394:Ki-67 Antigen / Q000378:metabolism; D008113:Liver Neoplasms / Q000378:metabolism* / Q000401:mortality*; D008297:Male; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D011379:Prognosis; D016016:Proportional Hazards Models; D034622:RNA Interference; D034741:RNA, Small Interfering; D015996:Survival Rate; D025803:Tumor Suppressor Protein p14ARF / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D000099273:Neurabins
chemical_list: D014408:Biomarkers, Tumor; D056742:Cyclin D2; D019394:Ki-67 Antigen; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D034741:RNA, Small Interfering; D025803:Tumor Suppressor Protein p14ARF; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D000099273:Neurabins