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Int J Clin Exp Pathol 2012;5(4):315-325

Original Article
The PIWI protein acts as a predictive marker for human gastric cancer

Yang Wang*, Yanxia Liu*, Xiaoying Shen, Xiaoyan Zhang, Ximei Chen, Changqin Yang, Hengjun Gao

Department of Gastroenterology, Institute of Digestive Diseases, Tongji Hospital Affliated to Tongji University, Shanghai 200065, China;
National Engineering Center for Biochip at Shanghai, 201203, China. *These authors contributed equally to this work

Received April 6, 2012; accepted April 17, 2012; Epub April 19, 2012; Published May 30, 2012

Abstract: Purpose: To investigate the expression of the human PIWI subfamily proteins in gastric cancer and their potential roles in the
occurrence,development and prognosis of gastric cancer. Methods and patients: Expression of the PIWI proteins were assessed by
immunohistochemistry(IHC) in tissue microarrays(TMA), containing paired tumor tissue and adjacent non-cancer tissue from 182 patients who
had undergone surgery in hospital for histologically proven gastric cancer(GC). Prognostic value and correlation with other clinicopathologic
factors were evaluated in two classifications. Results: The expression of PIWIL1-4 was significantly higher in tumor tissue than that in adjacent
tissue; A significant correlation was observed between the higher expression of PIWI protein with the T stage, lymph node metastasis and
clinical TNM (cTNM); Survival analysis by Kaplan-Meier survival curve and log-rank test demonstrated that elevated PIWL1 and PIWIL2
expression in cancer tissue predicted poorer overall survival (OS) compared with group in lower expression (36.5% VS 67.6%; 37.4% VS
54.2%; respectively). Notably, multivariate analyses by Cox’s proportional hazard model revealed that expression of PIWIL1 was an
independent prognostic factor in gastric cancer. Conclusions: The PIWI subfamily protein is an absolutely key molecular factor along with the
tumor occurrence and development. And the PIWI protein could act as a potential biomarker for prognosis evaluation of gastric cancer.

Keywords: Argonaute protein, tissue microarray, Immunohistochemistry, gastric cancer

Address all correspondence to:
Dr. Heng Jun Gao
Institute of Digestive Diseases
Tongji Hospital Affiliated to Tongji University
Shanghai 200065, China.
Tel: (+86) 021-51320288-5431; Fax: 86-21-51320287
Email: hengjun_gao@shbiochip.com; Or: iggsnrt@126.com