Brief Article
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World J Gastroenterol. Jan 28, 2013; 19(4): 536-541
Published online Jan 28, 2013. doi: 10.3748/wjg.v19.i4.536
Cdx2 expression and its promoter methylation during metaplasia-dysplasia-carcinoma sequence in Barrett's esophagus
Kenji Makita, Riko Kitazawa, Shuho Semba, Koto Fujiishi, Miku Nakagawa, Ryuma Haraguchi, Sohei Kitazawa
Kenji Makita, Riko Kitazawa, Koto Fujiishi, Miku Nakagawa, Ryuma Haraguchi, Sohei Kitazawa, Division of Molecular Pathology, Ehime University Graduate School of Medicine, Toon 791-0295, Japan
Shuho Semba, Division of Pathology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
Author contributions: Makita K, Nakagawa M and Fujiishi K performed the majority of experiments and wrote the manuscript; Semba S and Haraguchi R provided vital reagents and analytical tools; Kitazawa S and Kitazawa R designed the study and were also involved in editing the manuscript.
Supported by Grant-in Aid from Ministry of Education, Sports and Culture (GP Program for Basic Science), Japan
Correspondence to: Dr. Sohei Kitazawa, Division of Molecular Pathology, Ehime University Graduate School of Medicine, Shitsukawa, Toon City, Ehime 791-0295, Japan. kitazawa@m.ehime-u.ac.jp
Telephone: +81-89-9605265   Fax: +81-89-9605267
Received: September 1, 2012
Revised: December 4, 2012
Accepted: December 22, 2012
Published online: January 28, 2013
Processing time: 150 Days and 5 Hours
Abstract

AIM: To examine how the expression of caudal type homebox transcription factor 2 (Cdx2) is regulated in the development of malignancy in Barrett’s esophagus.

METHODS: Cdx2, mucin (MUC) series (MUC2, MUC5AC and MUC6), p53 and E-cadherin expression in Barrett’s esophagus and adenocarcinoma specimens were examined by immunostaining. Isolated clusters of cells from (1) MUC2 and Cdx2-positive intestinal metaplastic mucosa; (2) MUC5AC and MUC6-positive, and MUC2 and Cdx2-negative high-grade dysplasia (HD), or intramucosal adenocarcinoma (IMC); and (3) MUC5AC, MUC6 and Cdx2-positive poorly-differentiated invasive adenocarcinoma (PDA) were analyzed by methylation-specific polymerase chain reaction using sets of primers for detecting methylation status of the Cdx2 gene.

RESULTS: Most of the non-neoplastic Barrett’s esophageal mucosa showing intestinal-type metaplasia with or without low-grade dysplasia was positive for E-cadherin, MUC series and Cdx2, but negative for p53. A portion of the low-grade to HD was positive for E-cadherin, MUC5AC, MUC6 and p53, but negative for MUC2 and Cdx2. The definite IMC area was strongly positive for MUC5AC, MUC6 and p53, but negative for MUC2 and Cdx2. Methylation of the Cdx2 promoter was not observed in intestinal metaplasia, while hypermethylation of part of its promoter was observed in hot dipped and IMC. Hypermethylation of a large fraction of the Cdx2 promoter was observed in PDA.

CONCLUSION: Cdx2 expression is restored irrespective of the methylation status of its promoter. Apparent positive immunohistochemical results can be a molecular mark for gene silencing memory.

Keywords: Barrett¡’s esophagus; Caudal type homebox transcription factor 2; Intestinal metaplasia; Promoter hypermethylation