Midkine expression in malignant salivary gland tumors and its role in tumor angiogenesis

Received 3 May 2010; received in revised form 5 June 2010; accepted 7 June 2010. published online 16 July 2010.

Summary

The aims of this study were to investigate midkine (MK) expression patterns in salivary gland tumors (SGTs) and to evaluate the correlation between MK expression and the degree of malignancy. We performed immunohistochemistry to examine MK expression in specimens of adenoid cystic carcinoma (ACC), mucoepidermoid carcinoma (MEC), and pleomorphic adenoma (PA). In addition, we performed immunohistochemistry for CD31 and measured microvessel density (MVD), which is an indicator of angiogenesis. Immunohistochemistry showed that MK protein expression was significantly higher in specimens of malignant SGTs (ACC [P<0.01] and MEC [P<0.001]) than in benign SGT (PA) samples. Furthermore, MVD values tended to be higher in cases that exhibited high expression of MK, which indicated a significant correlation between the degree of MK expression and MVD (P<0.001). These results suggest that MK may play important roles in malignant transformation and tumor angiogenesis in SGTs.

Keywords: Midkine, Head and neck cancer, Salivary gland tumor, Adenoid cystic carcinoma, Mucoepidermoid carcinoma, Pleomorphic adenoma, Pathologic angiogenesis, CD31antigen, Immunohistochemistry

a Department of Oral and Maxillofacial Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan

b Department of Diagnostic Medicine, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan

c Department of Orthopaedic and Neuro-Musculoskeletal Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan

Corresponding author. Tel.: +81 96 373 5288; fax: +81 96 373 5286.

PII: S1368-8375(10)00187-9

doi:10.1016/j.oraloncology.2010.06.004

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