title: Differential gene expression profiling of gastric intraepithelial neoplasia and early-stage adenocarcinoma.
abstract: OBJECTIVE
  To investigate the differentiated whole genome expression profiling of gastric high- and low-grade intraepithelial neoplasia and early-stage adenocarcinoma.
  
  
  METHODS
  Gastric specimens from an upper magnifying chromoendoscopic targeted biopsy were collected from March 2010 to May 2013. Whole genome expression profiling was performed on 19 low-grade intraepithelial neoplasia (LGIN), 20 high-grade intraepithelial neoplasia (HGIN), 19 early-stage adenocarcinoma (EGC), and 19 chronic gastritis tissue samples using Agilent 4 × 44K Whole Human Genome microarrays. Differentially expressed genes between different types of lesions were identified using an unpaired t-test and corrected with the Benjamini and Hochberg false discovery rate algorithm. A gene ontology (GO) enrichment analysis was performed using the GeneSpring software GX 12.6. The differentially expressed gene was verified using a real-time TaqMan® PCR assay with independent tissue samples, including 26 LGIN, 15 HGIN, 14 EGC, and 20 chronic gastritis. The expression of G0S2 were further validated by immunohistochemical staining (IHC) in 24 LGIN, 40 HGIN, 30 EGC and 61 chronic gastritis specimens.
  
  
  RESULTS
  The gene expression patterns of LGIN and HGIN tissues were distinct. There were 2521 significantly differentially expressed transcripts in HGIN, with 951 upregulated and 1570 downregulated. A GO enrichment analysis demonstrated that the most striking overexpressed transcripts in HGIN compared with LGIN were in the category of metabolism, defense response, and nuclear factor κB (NF-κB) cascade. While the vast majority of transcripts had barely altered expression in HGIN and EGC tissues, only 38 transcripts were upregulated in EGC. A GO enrichment analysis revealed that the alterations of the immune response were most prominent in the progression from HGIN to EGC. It is worth noting that, compared with LGIN, 289 transcripts were expressed at higher levels both in HGIN and EGC. A characteristic gene, G0/G1 switch 2 (G0S2) was one of the 289 transcripts and related to metabolism, the immune response, and the NF-κB cascade, and its expression was validated in independent samples through real-time TaqMan® PCR and immunohistochemical staining. In real-time PCR analysis, the expression of G0S2 was elevated both in HGIN and EGC compared with that in LGIN (P < 0.01 and P < 0.001, respectively). In IHC analysis, G0S2 immunoreactivity was detected in the cytoplasmic of neoplastic cells, but was undetectable in chronic gastritis cells. The G0S2 expression in HGIN was higher than that of LGIN (P = 0.012, χ (2) = 6.28) and EGC (P = 0.008, χ (2) = 6.94).
  
  
  CONCLUSIONS
  A clear biological distinction between gastric high- and low-grade intraepithelial neoplasia was identified, and provides molecular evidence for clinical application.
authors.affiliation: Xue Xu, Gui-Jun Fei, Xi Wu, Fang Yao, Xing-Hua Lu, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Xu
authors.affiliation: Xue Xu, Gui-Jun Fei, Xi Wu, Fang Yao, Xing-Hua Lu, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Feng
authors.affiliation: Xue Xu, Gui-Jun Fei, Xi Wu, Fang Yao, Xing-Hua Lu, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Xue Xu, Gui-Jun Fei, Xi Wu, Fang Yao, Xing-Hua Lu, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
authors.forename: Wei-Xun
authors.initials: WX
authors.lastname: Zhou
authors.affiliation: Xue Xu, Gui-Jun Fei, Xi Wu, Fang Yao, Xing-Hua Lu, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
authors.forename: Ying-Cai
authors.initials: YC
authors.lastname: Ma
authors.affiliation: Xue Xu, Gui-Jun Fei, Xi Wu, Fang Yao, Xing-Hua Lu, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
authors.forename: Gui-Jun
authors.initials: GJ
authors.lastname: Fei
authors.affiliation: Xue Xu, Gui-Jun Fei, Xi Wu, Fang Yao, Xing-Hua Lu, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
authors.forename: Ning
authors.initials: N
authors.lastname: An
authors.affiliation: Xue Xu, Gui-Jun Fei, Xi Wu, Fang Yao, Xing-Hua Lu, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Xue Xu, Gui-Jun Fei, Xi Wu, Fang Yao, Xing-Hua Lu, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Wu
authors.affiliation: Xue Xu, Gui-Jun Fei, Xi Wu, Fang Yao, Xing-Hua Lu, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Yao
authors.affiliation: Xue Xu, Gui-Jun Fei, Xi Wu, Fang Yao, Xing-Hua Lu, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
authors.forename: Shu-Jun
authors.initials: SJ
authors.lastname: Cheng
authors.affiliation: Xue Xu, Gui-Jun Fei, Xi Wu, Fang Yao, Xing-Hua Lu, Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
authors.forename: Xing-Hua
authors.initials: XH
authors.lastname: Lu
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics*; D001706:Biopsy; D002278:Carcinoma in Situ / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D018797:Cell Cycle Proteins / Q000032:analysis / Q000235:genetics; D019295:Computational Biology; D030541:Databases, Genetic; D003937:Diagnosis, Differential; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D015972:Gene Expression Regulation, Neoplastic; D020022:Genetic Predisposition to Disease; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D011237:Predictive Value of Tests; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D014158:Transcription, Genetic
chemical_list: D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; C508073:G0S2 protein, human
keywords: G0/G1 switch 2; Gastric early-stage adenocarcinoma; High-and low-grade intraepithelial neoplasia; Immunohistochemical staining; Quantitative real-time PCR; Whole genome expression microarray