title: Differential MicroRNA Expression Between Gastric Cancer Tissue and Non-cancerous Gastric Mucosa According toHelicobacter pyloriStatus.
abstract: BACKGROUND
  MicroRNAs (miRNAs) are key post-translational mechanisms which can regulate gene expression in gastric carcinogenesis. To identify miRNAs responsible for gastric carcinogenesis, we compared expression levels of miRNAs between gastric cancer tissue and non-cancerous gastric mucosa according toHelicobacter pyloristatus.
  
  
  METHODS
  Total RNA was extracted from the cancerous regions of formalin-fixed, paraffin-embedded tissues ofH. pylori-positive (n = 8) orH. pylori-negative (n = 8) patients with an intestinal type of gastric cancer. RNA expression was analyzed using a 3,523 miRNA profiling microarray based on the Sanger miRBase. Validation analysis was performed using TaqMan miRNA assays for biopsy samples from 107 patients consisted of control and gastric cancer with or withoutH. pylori. And then, expression levels of miRNAs were compared according to subgroups.
  
  
  RESULTS
  A total of 156 miRNAs in the aberrant miRNA profiles across the miRNA microarray showed differential expression (at least a 2-fold change,P< 0.05) in cancer tissue, compared to noncancerous mucosa in both ofH. pylori-negative and -positive samples. After 10 promising miRNAs were selected, validations by TaqMan miRNA assays confirmed that two miRNAs (hsa-miR-135b-5p and hsa-miR-196a-5p) were significantly increased and one miRNA (hsa-miR-145-5p) decreased in cancer tissue compared to non-cancerous gastric mucosa atH. pylori-negative group. ForH. pylori-positive group, three miRNAs (hsa-miR-18a-5p, hsa-miR-135b-5p, and hsa-miR-196a-5p) were increased in cancer tissue. hsa-miR-135b-5p and hsa-miR-196a-5p were increased in gastric cancer in both ofH. pylori-negative and -positive.
  
  
  CONCLUSIONS
  miRNA expression of the gastric cancer implies that different but partially common gastric cancer carcinogenic mechanisms might exist according toH. pyloristatus.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea; Department of Internal Medicine, Samsung Changwon Hospital, Changwon, Korea.
authors.forename: Jung Won
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea; Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Nayoung
authors.initials: N
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea; Department of Internal Medicine, Myongji Hospital, Goyang, Korea.
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Hyun
authors.initials: H
authors.lastname: Chang
authors.affiliation: NAR Center, Inc., Daejeon Oriental Hospital of Daejeon University, Daejeon, Korea.
authors.forename: Jung Min
authors.initials: JM
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea; Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Jin-Wook
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea; Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Lee
keywords: Gastric cancer; Helicobacter pylori; Microarray; microRNAs