title: Aberrant methylation of SPARC in human hepatocellular carcinoma and its clinical implication.
abstract: OBJECTIVE
  To investigate the methylation status of secreted protein acidic and rich in cysteine (SPARC) in human hepatocellular carcinoma (HCC) and evaluate its clinical implication.
  
  
  METHODS
  The methylation status of SPARC was analyzed in one HCC cell line (SMMC-7721) and 60 pairs of HCC and corresponding nontumorous tissues by methylation-specific polymerase chain reaction and bisulfite sequencing. The expression of SPARC mRNA and protein were examined by reverse transcription polymerase chain reaction and immunohistochemistry, respectively. The correlations between the methylation status and the gene expression, the clinicopathological parameters, as well as the prognosis after surgery were analyzed.
  
  
  RESULTS
  In the SMMC-7721 cell line, the loss of SPARC expression was correlated with the aberrant methylation and could be reactivated by the demethylating agent 5-aza-2'-deoxycytidine. Methylation frequency of SPARC in HCC was significantly higher than that in the corresponding nontumorous tissues (45/60 vs 7/60, P < 0.001), and it was correlated with the pathological classification (P = 0.019). The downregulation of the SPARC mRNA expression in HCC was correlated with the SPARC methylation (P = 0.040). The patients with methylated SPARC had a poorer overall survival than those without methylated SPARC (28.0 mo vs 41.0 mo, P = 0.043).
  
  
  CONCLUSIONS
  Aberrant methylation is an important mechanism for SPARC inactivation in HCC and SPARC methylation may be a promising biomarker for the diagnosis and prognosis of HCC.
authors.affiliation: Third Central Clinical College of Tianjin Medical University, Tianjin 300170, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhang
authors.forename: Bin
authors.initials: B
authors.lastname: Yang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Du
authors.forename: Tong
authors.initials: T
authors.lastname: Bai
authors.forename: Ying-Tang
authors.initials: YT
authors.lastname: Gao
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Wang
authors.forename: Cheng
authors.initials: C
authors.lastname: Lou
authors.forename: Feng-Mei
authors.initials: FM
authors.lastname: Wang
authors.forename: Yu
authors.initials: Y
authors.lastname: Bai
mesh_terms: D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D045744:Cell Line, Tumor; D019175:DNA Methylation; D000077209:Decitabine; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D015676:Osteonectin / Q000032:analysis / Q000235:genetics*; D011379:Prognosis; D012333:RNA, Messenger / Q000032:analysis
chemical_list: D015676:Osteonectin; D012333:RNA, Messenger; D000077209:Decitabine; D001374:Azacitidine