Evaluation of Tyrosine Kinase receptor (TrK) Expression in Follicular and Plexiform types of Ameloblastoma: An Immunohistochemical study

INTRODUCTION: Ameloblastoma has two types of cells with different proliferative activity. The peripheral ameloblast like cells are known for their anti -apoptotic character, while the central stellate reticulum like cells are known for their proapoptotic activity. Neurotrophins are proteins with specific roleonnon-neuronal and neuronal cells. High affinity receptors - TrK are present in family of neurotrophins. Trk receptors activation leads to cell differentiation, survival,proliferation, and apoptosis through PI3KIAkt pathway, RasIMAPK pathway, and PLC-yl pathway. This study will evaluate the immunoreactivity of TrKreceptor in follicular and plexiform types of ameloblastoma. AIM OF THE STUDY: The study is aimed at evaluating the expression of Tyrosine Kinase receptor (TrK) in ameloblastoma in order to understand the possible role and mechanism of TrK. OBJECTIVES: 1. To analyze the Immunohistochemical expression pattern of TrK receptor in follicular type of ameloblastoma. 2. To analyze the Immunohistochemical expression pattern of TrK receptor in plexiform type of ameloblastoma. 3. To compare the Immunohistochemical expression pattern of TrK receptor among the follicular and plexiform types of ameloblastoma. MATERIAL AND METHODS: The study sample comprises of 20 follicular and 20 plexiform types of ameloblastoma. Two serial sections of 3-4.5 microns thickness of the study samples were sectioned. The sections were stained immunohistochemically using TrKA+B+C primary antibody. Immunohistochemical reactivity were evaluated depending upon the staining intensity as : Negative (-), Positive (+) and Strongly Positive (++). RESULTS: 4 samples of follicular ameloblastoma and 16samples of plexiform ameloblastoma had positive immuno-expressionfor TrK predominantly in the peripheral preameloblast like cells. The chi square value for the immuno expression between follicular and plexiform ameloblastoma was statistically significant with a p value <.005 . CONCLUSION: The positive expression of Trk in ameloblastoma helps in elucidation of the possible intracellular signal regulation mechanism in this tumor survivaland proliferation. The varied expression of Trkcould be the possible reason behind the differed biological behaviour between follicular and plexiform ameloblastoma.