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World J Gastroenterol. Aug 14, 2012; 18(30): 3923-3930
Published online Aug 14, 2012. doi: 10.3748/wjg.v18.i30.3923
Osteopontin as potential biomarker and therapeutic target in gastric and liver cancers
Dong-Xing Cao, Zhi-Jie Li, Xiao-Ou Jiang, Yick Liang Lum, Ester Khin, Nikki P Lee, Guo-Hao Wu, John M Luk
Dong-Xing Cao, Zhi-Jie Li, Xiao-Ou Jiang, Yick Liang Lum, Ester Khin, John M Luk, Department of Pharmacology and Department of Surgery, National University Health System, National University of Singapore, Singapore 117597, Singapore
Dong-Xing Cao, Guo-Hao Wu, Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, China
Zhi-Jie Li, John M Luk, Department of Oncology, Roche R and D Center (China) Ltd., Shanghai 201203, China
Nikki P Lee, John M Luk, Department of Surgery, The University of Hong Kong, Hong Kong, China
Author contributions: Cao DX and Li ZJ wrote the manuscript; Jiang XO, Lum YL and Khin E collected the relevant references and provided materials; and Lee NP, Wu GH and Luk JM drew the figures and revised the manuscript.
Correspondence to: John M Luk, Professor, Department of Oncology, Roche R and D Center (China) Ltd., 720 Cai Lun Road, Shanghai 201203, China. john.luk@roche.com
Telephone: +86-21-38954910 Fax: +86-21-50790293
Received: February 11, 2012
Revised: May 11, 2012
Accepted: May 26, 2012
Published online: August 14, 2012

Gastric cancer and liver cancer are among the most common malignancies and the leading causes of death worldwide, due to late detection and high recurrence rates. Today, these cancers have a heavy socioeconomic burden, for which a full understanding of their pathophysiological features is warranted to search for promising biomarkers and therapeutic targets. Osteopontin (OPN) is overexpressed in most patients with gastric and liver cancers. Over the past decade, emerging evidence has revealed a correlation of OPN level and clinicopathological features and prognosis in gastric and liver cancers, indicating its potential as an independent prognostic indicator in such patients. Functional studies have verified the potential of OPN knockdown as a therapeutic approach in vitro and in vivo. Furthermore, OPN mediates multifaceted roles in the interaction between cancer cells and the tumor microenvironment, in which many details need further exploration. OPN signaling results in various functions, including prevention of apoptosis, modulation of angiogenesis, malfunction of tumor-associated macrophages, degradation of extracellular matrix, activation of phosphoinositide 3-kinase-Akt and nuclear factor-κB pathways, which lead to tumor formation and progression, particularly in gastric and liver cancers. This editorial aims to review recent findings on alteration in OPN expression and its clinicopathological associations with tumor progression, its potential as a therapeutic target, and putative mechanisms in gastric and liver cancers. Better understanding of the implications of OPN in tumorigenesis might facilitate development of therapeutic regimens to benefit patients with these deadly malignancies.

Keywords: Osteopontin, Gastrointestinal cancer, Metastasis, Prognosis, Biomarker