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Veterinary Medicine International
Volume 2012 (2012), Article ID 761034, 8 pages
http://dx.doi.org/10.1155/2012/761034
Research Article

Vitamin D Receptor, Retinoid X Receptor, Ki-67, Survivin, and Ezrin Expression in Canine Osteosarcoma

1BluePearl Veterinary Partners, Overland Park, KS 66210, USA
2Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA
3Oncology Division, Department of Medicine, Kansas University Medical Center, Kansas City, KS 66160, USA
4Department of Dietetics and Nutrition, Kansas University Medical Center, Kansas City, KS 66160, USA
5Department of Orthopedic Surgery, Kansas University Medical Center, Kansas City, KS 66160, USA
6Department of Pathology and Laboratory Medicine, Kansas University Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
7LACF at University of Illinois College of Medicine at Peoria, One Illini Drive, Peoria, IL 61656, USA

Received 10 September 2012; Revised 27 November 2012; Accepted 29 November 2012

Academic Editor: Ingo Nolte

Copyright © 2012 John Davies 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

Canine osteosarcoma (OS) is an aggressive malignant bone tumor. Prognosis is primarily determined by clinical parameters. Vitamin D has been postulated as a novel therapeutic option for many malignancies. Upon activation, vitamin D receptors (VDRs) combine with retinoid receptor (RXR) forming a heterodimer initiating a cascade of events. Vitamin D's antineoplastic activity and its mechanism of action in OS remain to be clearly established. Expression of VDR, RXR, Ki-67, survivin, and ezrin was studied in 33 archived, canine OS specimens. VDR, RXR, survivin, and ezrin were expressed in the majority of cases. There was no statistically significant difference in VDR expression in relationship with tumor grade, type, or locations or animal breed, age, and/or sex. No significant association ( ) between tumor grade and Ki-67 expression was found; in particular, no difference in Ki-67 expression between grades 2 and 3 OSs was found, while a negative correlation was noted between Ki-67 and VDR expression ( ), a positive correlation between survivin and RXR expression was found ( ). A significant relationship exists between VDR and RXR expression in OSs and proliferative/apoptosis markers. These results establish a foundation for elucidating mechanisms by which vitamin D induces antineoplastic activity in OS.