title: [The imprinting status of genetic imprinted gene PEG10 in human hepatocellular carcinomas].
abstract: OBJECTIVE
  To study the imprinting status of genetic imprinted gene PEG10 (perternally expressed gene 10) in human hepatocellular carcinoma (HCC) tissues and liver cancer cell lines.
  
  
  METHODS
  Genomic DNA was extracted from 20 HCC tissues and its adjacent tissues, 15 normal liver tissues, 5 liver cancer cell lines (PLC/PRF/5, smmc-7721, HepG2, Hep3B, SK-HEP-1) and 2 normal human liver cell lines (changliver, HL7702). The DNA fragments containing single nucleotide polymorphism (SNP) site of PEG10 were amplified by polymerase chain reaction (PCR) and the genotype of samples was detected by DNA sequencing. Total RNA was extracted from heterozygous samples, the imprinting status and expression level of PEG10 were evaluated by quantitative real time reverse transcription-polymerase chain reaction (qRT-PCR) and DNA sequencing.
  
  
  RESULTS
  It was found that 16/40 of HCC and its adjacent tissues were heterozygous, 3/15 of normal liver tissue were heterozygous. A site of heterozygous mutation was found in HepG2 cells by DNA sequencing. The other liver tissues and cell lines were all homozygous. PEG10 was biallelically expressed and showed loss of imprinting (LOI) in 82.4% (14/17) liver cancer samples (16 HCC tissues and HepG2), however it was a monoallelic expression and showed genomic imprinting in17.6% (3/17) liver cancer samples. In HCC, the expression levels of PEG10 were increased apparently, but it was negative expressed in cancer adjacent tissues and normal liver tissues. Expression levels of PEG10 were not significantly different between imprinted HCC tissues and HCC tissues with LOI (t = 1.311, P value is more than 0.05).
  
  
  CONCLUSIONS
  PEG10 imprinting is lost in a majority of HCC and no correlation exists between the imprinting status of PEG10 and its expressions in HCC tissues.
authors.affiliation: Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030,China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Gao
authors.forename: Hou-de
authors.initials: HD
authors.lastname: Zhang
authors.forename: Ju-sheng
authors.initials: JS
authors.lastname: Lin
authors.forename: Mei-ping
authors.initials: MP
authors.lastname: Zhang
authors.forename: Rong-gang
authors.initials: RG
authors.lastname: Zhang
mesh_terms: D051017:Apoptosis Regulatory Proteins; D006528:Carcinoma, Hepatocellular / Q000235:genetics*; D004268:DNA-Binding Proteins; D015870:Gene Expression; D018392:Genomic Imprinting; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics*; D011506:Proteins / Q000235:genetics*; D016601:RNA-Binding Proteins
chemical_list: D051017:Apoptosis Regulatory Proteins; D004268:DNA-Binding Proteins; C432965:PEG10 protein, human; D011506:Proteins; D016601:RNA-Binding Proteins