title: cDNA representational difference analysis of differentially expressed cDNA sequences in human nasopharyngeal carcinoma.
abstract: OBJECTIVE
  To search differentially expressed sequences correlated with pathogenesis of human nasopharyngeal carcinoma (NPC), including the candidates of tumor suppressor genes.
  
  
  METHODS
  Representational difference analysis (RDA) was performed to isolate differentially expressed sequences between cDNA from normal human primary cultures of nasopharyngeal epithelial cells and cDNA from NPC cell line HNE1. The source of differentially expressed products were proved by Southern blot, Northern blot and in situ hybridization. The fragments were cloned with pGEM-T easy kit and sequenced by the chain termination reaction.
  
  
  RESULTS
  Four differentially expressed cDNA fragments were isolated in the fourth subtractive hybridization using cDNA from normal human nasopharyngeal epithelial cells as tester amplicon and cDNA from NPC cell line HNE1 as driver amplicon by cDNA RDA. These differential cDNA fragments revealed that they really came from the tester amplicon and were not expressed or down-regulated in the NPC HNE1 cells. Some of the genes were expressed only in human nasopharyngeal epithelial cells but deleted or down-regulated in the biopsies of NPC. Of these obtained clones, some were the sequences of the human known genes including house-keeping genes, the others represented novel gene sequences.
  
  
  CONCLUSIONS
  The differentially expressed products including the candidates of tumor-suppressor genes may be associated with the initiation of the NPC.
authors.affiliation: Cancer Research Institute, Hunan Medical University, Changsha 410078, China.
authors.forename: F
authors.initials: F
authors.lastname: Zhan
authors.forename: L
authors.initials: L
authors.lastname: Cao
authors.forename: L
authors.initials: L
authors.lastname: Bin
authors.forename: N
authors.initials: N
authors.lastname: Jiang
authors.forename: L
authors.initials: L
authors.lastname: Deng
authors.forename: Y
authors.initials: Y
authors.lastname: Xie
authors.forename: G
authors.initials: G
authors.lastname: Tan
authors.forename: G
authors.initials: G
authors.lastname: Li
mesh_terms: D018076:DNA, Complementary / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics; D020869:Gene Expression Profiling; D016147:Genes, Tumor Suppressor; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000473:pathology; D017422:Sequence Analysis, DNA; D014407:Tumor Cells, Cultured
chemical_list: D018076:DNA, Complementary; D004273:DNA, Neoplasm