Prognostic significance of P53 protein, cyclin D1 and Ki-67 in pineal parenchymal tumours

Abstract

Pineal parenchymal tumours are very rare consisting less than 0.1% of all central nervous system tumours. The aim of this study was to investigate the prognostic significance of Ki-67, cyclin D1 and p53 protein expressions in pineal parenchymal tumours. Ten pineal parenchymal tumours were investigated: 2 pineocytomas, 5 pineal parenchymal tumour of intermediate differentiation and 3 pineoblastomas . Immunohistochemical staining was performed using avidin-biotin-peroxidase method. The number of mitoses ranged from 0-25 in pineal parenchymal tumour of intermediate differentiation and 2-30 in pineoblastomas. In general, Ki-67 was found between 0-53.5 %, cyclin D1 was found between 0-40%, p53 was found between 0-4% in pineal parenchymal tumors. In pineal parenchymal tumour of intermediate differentiation, positive staining rates for Ki-67, cyclin D1 and p53 were found as 4-17.5%, 2-30% and 0-4%, respectively. In pineoblastomas, Ki-67, cyclin D1 and p53 were found as 9.2-53.5%, 5-40% and 1-2%, respectively. The number of mitoses was not significant for the prognosis in pineal parenchymal tumors. The very low level of p53 protein made us think that it does not play an active role in the development of these tumours.