“An Immunohistochemical Study” of Parathyroid Hormone - Related Protein: A Comparative Analysis In Ameloblastoma and Dentigerous Cyst

It has been pointed out that Parathyroid Hormone related Protein (PTHrP) secreted by the developing enamel epithelium targets receptors in overlying bone, thereby activating bone resorption and allowing tooth eruption. Accordingly, it is conceivable that ameloblastoma, which to a degree recapitulates certain characteristics of enamel epithelium, would also express PTHrP. This study is done to assess the PTH rP expression in ameloblastoma, to investigate its role in local bone resorption and provide explanation for the infiltrative growth and destructive behavior of this tumor which may hold significant therapeutic implications. A group of 50 histo-pathologically diagnosed, formalin-fixed, paraffin embedded tissue samples, consisting of 30 samples of am eloblastoma and 20 samples of dentigerous cyst were collected from the Department of Oral and M axillofacial Pathology, Govt. Dental College, Bangalore, and were subjected to immunohistochemical methods using anti PTHrP Antibody with indirect immuno-enzyme Labeled StreptAvidin Biotin method (LSAB). Out of 30 cases of ameloblastoma 26(86.7%) cases showed positivity for PTHrP. Among the 20 cases of dentigerous cysts 9(45%) cases showed positivity for PTHrP expression. When we compared the percentage of cases showing positivity for PTHrP expression in ameloblastoma (86.7%) and dentigerous cyst (45.0%) we obtained a statistically significant p-value of 0.0012. The current study may suggest increased PTHrP expression by ameloblastoma may play a significant role in local bone resorption and may provide explanation for the infiltrative growth and the destructive behavior of this tumor.