title: Expression of TN4 gene and its role in human hepatocarcinogenesis from Qidong, a liver cancer risk area.
abstract: BACKGROUND
  We investigated the expression and role of TN4 in the oncogenesis of human hepatocellular carcinoma (HCC) from Qidong which is a HCC risk area.
  
  
  METHODS
  The expression of TN4 in HCC was observed using immunohistochemical staining (IHC). TN4 levels were manipulated in human liver cancer cell SMMC7721, using pcDNA3.1 eukaryotic expression constructs designed to express the complete TN4 cDNA. The biological changes of the cells were observed before and after transfection of TN4 and the change of gene expression was analysed by atlas cDNA expression array.
  
  
  RESULTS
  Among 100 pairs of samples of HCC, TN4 down-regulation expression and up-regulation expression positive rate were 81% (81/100), 19% (19/100), respectively (P < 0.01). TN4 protein was mainly localized in cytoplasm and membrane. The positive rate of TN4 were 10% (3/30), 100% (70/70) in lymph node metastasis and no lymph node metastasis, respectively (P < 0.01). The growth rates of the derivative SMMC7721-TN4 cell lines were decreased in comparison with that of normal SMMC7721 cells and pcDNA-SMMC7721. Some gene expression was changed before and after transfection of TN4. At 30 days of post-implantation of SMMC7721-TN4, SMMC7721-pcDNA3, SMMC7721 group produced tumors of (301.9 +/- 143.4) mm(3), (2418.7 +/- 362.8) mm(3), (2317.4 +/- 587.8) mm(3), respectively, (P < 0.01). Tumor inhibiting rate was 82.4% in TN4 transfection group. Sections of tumors were observed for their degree of tissue necrosis and there was higher degree of necrosis in tumors of the TN4-SMMC7721 cell group than those of the SMMC7721, SMMC7721-pcDNA groups.
  
  
  CONCLUSIONS
  TN4 may play an important role in the oncogenesis of human HCC, especially in Qidong, the HCC risk area and TN4 could be a candidate tumor suppressor gene for HCC.
authors.affiliation: The College of Life Science, Nanjing Normal University, Nanjing 210097, China. Ludondon88@163.com
authors.forename: Dong-dong
authors.initials: DD
authors.lastname: Lu
authors.forename: Xi-ran
authors.initials: XR
authors.lastname: Zhang
authors.forename: Xiang-rong
authors.initials: XR
authors.lastname: Cao
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000453:epidemiology / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D002681:China / Q000453:epidemiology; D018076:DNA, Complementary / Q000032:analysis; D015870:Gene Expression; D016153:Genes, Suppressor; D006801:Humans; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins; D008113:Liver Neoplasms / Q000453:epidemiology / Q000235:genetics*; D008207:Lymphatic Metastasis / Q000235:genetics; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D009185:Myelin Proteins; D000070798:Nogo Proteins; D012307:Risk Factors; D014162:Transfection
chemical_list: D002352:Carrier Proteins; D018076:DNA, Complementary; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009185:Myelin Proteins; D000070798:Nogo Proteins; C000603199:RTN4 protein, human