1034 Braz J Oral Sci. April-June 2006 - Vol. 5 - Number 17 P53 gene mutation and protein expression in ameloblastomas K. A. Al-Salihi 1 Ling Yoke Li 1 Azlina A. 2 1 School of Dental Sciences, 2 Human Genome Center Received for publication: January 30, 2006 Accepted: May 08, 2006 Correspondence to: K. A. Al-Salihi Universiti Sains Malaysia, 16150, Kubang kerian, Kelantan, Malaysia E-mail: elsalihi@yahoo.com Abstract P53 gene is commonly found to be mutated in human cancer. Currently, limited data exist on the occurrence of p53 gene mutation in ameloblastomas. This study designed to evaluate the expression of p53 proteins and their gene mutations in human ameloblastomas. Four cases of epithelial odontogenic tumors were used. Normal cells of a 7 months aborted fetus’s mandible were used as negative control. P53 Protein expression was detected immunohistochemically. DNA was extracted and amplified using PCR. Gene sequences analyzed to determine p53 mutation. p53 was overexpressed in one case of unicystic ameloblastoma and 2 cases of variant types of ameloblastoma. The Coding sequencing analyses demonstrated p53 gene alteration in cases of ameloblastoms in Exon 7 while, fetus epithelial mucosal cells showed the wild type DNA sequence in Exon 4. In conclusion p53 protein overexpression was detected by immunohistochemical staining as well as by DNA sequence analysis in cases of ameloblastomas. Key Words: ameloblastoma, p53, immunohistochemistry, mandible