ORIGINAL ARTICLE EXPRESSION OF A NOVEL MARKER, Ubc9, IN SQUAMOUS CELL CARCINOMA OF THE HEAD AND NECK Ohad Ronen, MD, 1,2 James P. Malone, MD, 1,2 Paul Kay, PhD, MD, 3 Christopher Bivens, BS, 2,4 Kelly Hall, BS, 4 Lakshmi P. Paruchuri, MD, 5 Yin-Yuan Mo, PhD, 2,4 K. Thomas Robbins, MD, 1,2 Sophia Ran, PhD 2,4 1 Department of Surgery, Southern Illinois University School of Medicine, Springfield, Illinois 2 SimmonsCooper Cancer Institute, Southern Illinois University School of Medicine, Springfield, Illinois 3 Department of Pathology, Southern Illinois University School of Medicine, Springfield, Illinois 4 Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, Illinois. E-mail: sran@siumed.edu 5 Department of Internal Medicine, Southern Illinois University School of Medicine, Springfield, Illinois Accepted 1 October 2008 Published online 23 March 2009 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/hed.21048 Abstract: Background. Ubiquitin-conjugating enzyme (Ubc9) is a novel enzyme involved in posttranslational modification of cellular proteins. The objective of this study was to determine the expression of Ubc9 in squamous cell carci- noma of the head and neck (SCCHN). Methods. SCCHN specimens were stained with anti-Ubc9 antibodies, scored using a semiquantitative method, and stat- istically analyzed. Results. Forty-six tumors were stained, 26 of which included adjacent mucosa. Ubc9 was significantly upregulated in the malignant and peritumoral tissues compared with mu- cosa from normal individuals. In peritumoral tissues, Ubc9 expression was detected in the basal and suprabasal epithelial layers. No Ubc9 was detected in epithelial cells in normal mu- cosa. These differences in Ubc9 expression were statistically significant (p < .0001). Tumor Ubc9 expression significantly correlated with clinical and pathologic stage. Conclusions. Ubc9 is significantly overexpressed in the pri- mary SCCHN tumors and peritumoral mucosa compared with normal epithelial cells. These findings suggest that Ubc9 may play an important role in tumorigenesis and tumor progression of SCCHN. V V C 2009 Wiley Periodicals, Inc. Head Neck 31: 845–855, 2009 Keywords: Ubc9; sumoylation; head and neck cancer; novel SCCHN; endothelial marker A variety of genetic and epigenetic alterations has been demonstrated in the genesis and pro- gression of squamous cell carcinoma of the head and neck (SCCHN). 1 These complex molecular events ultimately affect critical cellular path- ways such as cell cycle regulation, apoptosis, and cell growth and differentiation. Despite in- tensive research, 2,3 no molecular markers are currently available that can accurately predict the development, progression and response to treatment of SCCHN. 4,5 At the present time, Correspondence to: S. Ran Contract grant sponsors: Central Research Committee (Southern Illinois University School of Medicine), American Physicians Fellowship for Medicine (Israel). A part of this work was presented at the Annual Meetings of the Ameri- can Academy of Otolaryngology – Head and Neck Surgery Foundation, Washington, DC, September 2007. V V C 2009 Wiley Periodicals, Inc. Ubc9 Expression in SCCHN HEAD & NECK—DOI 10.1002/hed July 2009 845