Apoptotic Proteins and Markers of Differentiation in Childhood Pineal Parenchymal Tumors: Relationships and Prognostic Value

Abstract

Pineal parenchymal tumors (PPTs) in children and adolescents are uncommon and more data on their biological activity and behavior are still needed. The aim of our study was to estimate the expression and prognostic value of some proteins regulating apoptosis and cell cycle as well as being markers of cellular differentiation in PPTs. Tumor specimens obtained from 27 patients who underwent surgical treatment for PPTs were evaluated in immuno-histochemical analysis. The expression of Bcl-2, Bax, p53, NSE (neuron specific enolase), GFAP (glial fibrillary acidic protein), beta-III tubulin and nestin were studied. Co-localization of two chosen antibodies (e.g. Bcl-2/Bax, BCl-2/NSE, p53/NSE, etc.) was also made with a scanning confocal microscope. Histopathological examination revealed: 15 pineocytomas, 1 intermediately differentiated PPT and 11 pineoblastomas. For further analysis two groups were created: Group I: patients with pineocytoma or intermediately differentiated PPTs (16 cases) Group II: patients with pineoblastoma (11 cases). A statistically significant positive correlation between patients' survival time and tubulin and NSE expression was found. Bcl-2, p53 and nestin correlated negatively with survival time.

Histopathology of Tumors of the Pineal Region

“…However, the few studies that have explored the MIB-1 index in the grading of PPTs have shown that the proliferation index is significantly higher in PBs than in PCs [45,77,88]. Other prognostic factors involved in apoptosis, such as Bcl2 and p53, have recently been shown to be negatively correlated with survival time [89].…”