Original ArticlesGene Expression Profiling of Head and Neck Tumors Identifies FOXP1 and SOX10 Expression as Useful for Distinguishing Ameloblastoma From Basaloid Salivary Gland TumorsKo, Yen Chen Kevin MD, DMD*; Varma, Sushama MS*; Zhu, Chun Fang MD, PhD*; Zhu, Shirley Xiaolei MD*; Vennam, Sujay BS*; Poh, Catherine F. DDS, PhD†; Jordan, Richard C. DDS, PhD, FRCPath‡,§; Kong, Christina MD*; Pollack, Jonathan R. MD, PhD*; West, Robert B. MD, PhD*Author Information *Department of Pathology, Stanford University School of Medicine, Stanford Departments of ‡Orofacial Sciences §Pathology, and Radiation Oncology, University California San Francisco, San Francisco, CA †Faculty of Dentistry, University of British Columbia, Vancouver, BC, Canada Conflicts of Interest and Source of Funding: Supported in part by NIH grant DE02650. The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article. Correspondence: Robert B. West, MD, PhD, 300 Pasteur Dr, Pathology L215, Stanford, California 94305-5324 (email: [email protected]). The American Journal of Surgical Pathology: May 2020 - Volume 44 - Issue 5 - p 665-672 doi: 10.1097/PAS.0000000000001421 Buy SDC Metrics Abstract Odontogenic tumors show considerable morphologic heterogeneity and at times the diagnosis can be challenging. Ameloblastoma, the most common odontogenic tumor, can have morphologic similarity to some salivary gland tumors and therefore we sought to identify biomarkers that might aid in the diagnosis by performing transcriptome wide gene expression profiling of 80 odontogenic and salivary gland neoplasms. These data identified the FOXP1+/SOX10− expression profile as characteristic of many odontogenic tumors including ameloblastoma but largely absent in salivary gland tumors. We then assessed 173 salivary gland tumors and 108 odontogenic tumors by immunohistochemistry for FOXP1 and SOX10 expression and found that 34/35 (97%) cases of ameloblastomas were diffusely positive for FOXP1 but completely negative for SOX10. None of the basaloid salivary neoplasms (basal cell adenoma, adenoid cystic carcinoma, polymorphous adenocarcinoma, and myoepitheloma) demonstrated FOXP1+/SOX10− expression pattern. Taken together, the results of this study suggest that the FOXP1+/SOX10− immunophenotype is common in odontogenic tumors including ameloblastoma and might be useful distinguishing these from similar appearing basaloid salivary gland tumors. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.