title: Elevated expression of the stem cell marker CD133 associated with Line-1 demethylation in hepatocellular carcinoma.
abstract: BACKGROUND
  The relationship of Line-1 demethylation and the CD133 expression of cancer stem cells were discussed in hepatocellular carcinoma (HCC).
  
  
  METHODS
  In 95 HCC and matched nontumor tissues, we analyzed the methylation level of Line-1 by quantitative real-time methylation-specific polymerase chain reaction, and the expression of CD133 by real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry.
  
  
  RESULTS
  Unmethylation of Line-1 increased from nontumor tissues (1.23 × 10(7) copies/μg DNA) toward HCC tissues (2.99 × 10(7) copies/μg DNA), but methylation of Line-1 kept 2 × 10(8) copies/μg DNA around in HCC and nontumor tissues. The methylation index (MI) of Line-1 decreased from 0.919 in nontumor samples to 0.755 in HCC. Results showed that cumulative survival was significantly shorter in HCC patients with MI < 0.76 than that in patients with MI ≥ 0.76. CD133 mRNA expression were higher in HCC tissues (mean -∆(Ct) = -5.751) than that in nontumor tissues (mean -∆(Ct) = -6.742). A total of 73 (76.8%) patients had demethylation of Line-1 (∆MI < 0), and 22 (23.2%) patients had hypermethylation of Line-1 (∆MI ≥ 0). HCC with demethylation of Line-1 had elevated CD133 expression in tumor rather than matched nontumor tissues (mean -∆(∆Ct) = 1.101), but HCC with hypermethylation of Line-1 was considered to be lower with CD133 expression in tumor (mean -∆(∆Ct) = -0.409).
  
  
  CONCLUSIONS
  Line-1 hypomethylation is the most common molecular abnormality during the carcinogenic process. Elevated expression of CD133 was associated with demethylation of Line-1 in HCC.
authors.affiliation: Tumor Immunology and Gene Therapy Center, Eastern Hepatobiliary Surgery Hospital, The Second Military Medical University, Shanghai, China.
authors.forename: Changsong
authors.initials: C
authors.lastname: Zhang
authors.forename: Yun
authors.initials: Y
authors.lastname: Xu
authors.forename: Jun
authors.initials: J
authors.lastname: Zhao
authors.forename: Lieying
authors.initials: L
authors.lastname: Fan
authors.forename: Guocheng
authors.initials: G
authors.lastname: Jiang
authors.forename: Rong
authors.initials: R
authors.lastname: Li
authors.forename: Yang
authors.initials: Y
authors.lastname: Ling
authors.forename: Mengchao
authors.initials: M
authors.lastname: Wu
authors.forename: Lixin
authors.initials: L
authors.lastname: Wei
mesh_terms: D000071916:AC133 Antigen; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000235:genetics* / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D004247:DNA / Q000235:genetics; D019175:DNA Methylation; D005260:Female; D005500:Follow-Up Studies; D006023:Glycoproteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D008099:Liver / Q000378:metabolism / Q000473:pathology; D008113:Liver Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D014411:Neoplastic Stem Cells / Q000378:metabolism; D010455:Peptides / Q000235:genetics* / Q000378:metabolism; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; D012333:RNA, Messenger; D004247:DNA