Original ArticlesCalretinin Expression in the Differential Diagnosis of Human Ameloblastoma and Keratocystic Odontogenic TumorDeVilliers, Patricia DDS, MS*; Liu, Hao DDS†; Suggs, Cynthia BS‡; Simmons, Darrin BS‡; Daly, Bill BS‡; Zhang, Shaoping DDS‡; Raubenheimer, Erich DDS, PhD§; Larsson, Åke DDS, PhD∥; Wright, Tim DDS, MS†Author Information *Department of Pathology, University of Alabama, Birmingham, AL †Department of Oral Surgery, Tianjin Union Medicine Centre, PR China ‡Dental Research Center, University of North Carolina at Chapel Hill §Department of Oral Pathology, University of Limpopo, South Africa ∥Department of Oral Pathology, Malmö University, Sweden Sponsored by NIH Grant DE016079. Patricia DeVilliers and Hao Liu authors contributed equally to this work. Presented in part at the annual meeting of the United States and Canadian Academy of Pathology, San Diego, CA, March 2007. Reprints: Patricia DeVilliers, DDS, MS, Department of Pathology PD6A 149E, 619 19th street South, Birmingham, AL 35249-6815 (e-mail: firstname.lastname@example.org). The American Journal of Surgical Pathology: February 2008 - Volume 32 - Issue 2 - p 256-260 doi: 10.1097/PAS.0b013e3181452176 Buy SDC Metrics Abstract Ameloblastoma is a benign, locally aggressive epithelial odontogenic tumor that has the potential to become malignant and produce metastasis to distant sites such as lungs and kidneys. The histologic presentation can be, in some instances, mistaken for keratocystic odontogenic tumor (KCOT) (formerly known as odontogenic keratocyst). The expression of calretinin [calbindin2 (CALB2)] was investigated on both ameloblastoma and KCOT. Nineteen cases of ameloblastoma and 17 cases of KCOT were stained with calretinin antiserum 18-0211 (Zymed, San Francisco, CA). All cases (100%) of ameloblastoma showed positive calretinin staining, restricted to the neoplastic epithelial component and none (0%) of the 17 KCOTs showed positive calretinin staining. Gene expression profiling of ameloblastomas showed CALB2 expressed in the basal cell layer of columnar cells resembling preameloblasts, in all 5 of the ameloblastomas evaluated. Taken together, the results of this study strongly support calretinin as a useful immunohistochemical marker for ameloblastoma and malignant ameloblastoma and it can also be used in the differential diagnosis of KCOT. © 2008 Lippincott Williams & Wilkins, Inc.