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The Scientific World Journal
Volume 2015, Article ID 325721, 10 pages
http://dx.doi.org/10.1155/2015/325721
Research Article

Downregulation of S100 Calcium Binding Protein A9 in Esophageal Squamous Cell Carcinoma

1Institute of Bioinformatics, International Technology Park, Bangalore 560066, India
2Rajiv Gandhi University of Health Sciences, Bangalore 560041, India
3Department of Pathology, Kidwai Memorial Institute of Oncology, Bangalore 560029, India
4Department of Zoology, Savitribai Phule Pune University, Ganeshkhind, Pune, Maharashtra 411007, India
5Centre of Excellence in Bioinformatics, School of Life Sciences, Pondicherry University, Pondicherry 605014, India
6McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
7Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
8Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0960, USA
9Government Medical College and Hospital, Sector 32, Chandigarh 160030, India
10Department of Surgical Oncology, Kidwai Memorial Institute of Oncology, Bangalore 560029, India
11Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
12Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA

Received 18 June 2015; Accepted 16 November 2015

Academic Editor: Emidio Scarpellini

Copyright © 2015 Harsh Pawar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The development of esophageal squamous cell carcinoma (ESCC) is poorly understood and the major regulatory molecules involved in the process of tumorigenesis have not yet been identified. We had previously employed a quantitative proteomic approach to identify differentially expressed proteins in ESCC tumors. A total of 238 differentially expressed proteins were identified in that study including S100 calcium binding protein A9 (S100A9) as one of the major downregulated proteins. In the present study, we carried out immunohistochemical validation of S100A9 in a large cohort of ESCC patients to determine the expression and subcellular localization of S100A9 in tumors and adjacent normal esophageal epithelia. Downregulation of S100A9 was observed in 67% () of 288 different ESCC tumors, with the most dramatic downregulation observed in the poorly differentiated tumors (99/111). Expression of S100A9 was restricted to the prickle and functional layers of normal esophageal mucosa and localized predominantly in the cytoplasm and nucleus whereas virtually no expression was observed in the tumor and stromal cells. This suggests the important role that S100A9 plays in maintaining the differentiated state of epithelium and suggests that its downregulation may be associated with increased susceptibility to tumor formation.