Open Access Research article

Deregulation of manganese superoxide dismutase (SOD2) expression and lymph node metastasis in tongue squamous cell carcinoma

Xiqiang Liu12, Anxun Wang3, Lorenzo Lo Muzio4, Antonia Kolokythas5, Shihu Sheng3, Corrado Rubini6, Hui Ye1, Fei Shi17, Tianwei Yu8, David L Crowe19 and Xiaofeng Zhou129*

  • * Corresponding author: Xiaofeng Zhou xfzhou@uic.edu

  • † Equal contributors

Author Affiliations

1 Center for Molecular Biology of Oral Diseases, College of Dentistry, University of Illinois at Chicago, Chicago, IL, USA

2 Research Institute & the Affiliated Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, China

3 Department of Oral and Maxillofacial Surgery, the First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China

4 Department of Surgical Sciences, Faculty of Medicine, School of Dentistry, University of Foggia, Foggia, Italy

5 Department of Oral and Maxillofacial Surgery, College of Dentistry, University of Illinois at Chicago, Chicago, IL, USA

6 Department of Pathology, Faculty of Medicine, Marche Polytechnic University, Ancona, Italy

7 Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, IL, USA

8 Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA, USA

9 Graduate College, UIC Cancer Center, University of Illinois at Chicago, Chicago, IL, USA

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BMC Cancer 2010, 10:365  doi:10.1186/1471-2407-10-365

Published: 9 July 2010

Abstract

Background

Lymph node metastasis is a critical event in the progression of tongue squamous cell carcinoma (TSCC). The identification of biomarkers associated with the metastatic process would provide critical prognostic information to facilitate clinical decision making. Previous studies showed that deregulation of manganese superoxide dismutase (SOD2) expression is a frequent event in TSCC and may be associated with enhanced cell invasion. The purpose of this study is to further evaluate whether the expression level of SOD2 is correlated with the metastatic status in TSCC patients.

Methods

We first examined the SOD2 expression at mRNA level on 53 TSCC and 22 normal control samples based on pooled-analysis of existing microarray datasets. To confirm our observations, we examined the expression of SOD2 at protein level on an additional TSCC patient cohort (n = 100), as well as 31 premalignant dysplasias, 15 normal tongue mucosa, and 32 lymph node metastatic diseases by immunohistochemistry (IHC).

Results

The SOD2 mRNA level in primary TSCC tissue is reversely correlated with lymph node metastasis in the first TSCC patient cohort. The SOD2 protein level in primary TSCC tissue is also reversely correlated with lymph node metastasis in the second TSCC patient cohort. Deregulation of SOD2 expression is a common event in TSCC and appears to be associated with disease progression. Statistical analysis revealed that the reduced SOD2 expression in primary tumor tissue is associated with lymph node metastasis in both TSCC patient cohorts examined.

Conclusions

Our study suggested that the deregulation of SOD2 in TSCC has potential predictive values for lymph node metastasis, and may serve as a therapeutic target for patients at risk of metastasis.