Molecular characterization of central neurocytomas: potential markers for tumor typing and progression

Central neurocytomas (CNs) are rare intraventricular tumors presenting a favorable prognosis after surgery. Their transcriptomic profile is poorly characterized. We performed a microarray transcriptomic study to search for molecular markers that might improve diagnostic accuracy. Microarray analysis was performed on five CNs (3 primary and 2 recurrent CNs) using CodeLink human whole genome bioarrays, and the gene expression in CNs was compared with that in four pineal parenchymal tumors, consisting of two pineocytomas (PCs) and two pineoblastomas (PBs), other periventricular tumors which may present neuronal differentiation. We identified genes that were highly expressed in CNs compared to normal brain and might be candidates for the molecular typing of CNs. Several genes are part of the Wnt/β-catenin and sonic hedgehog signaling pathways or mainly linked to calcium function or maintenance of neural progenitors. Moreover, several genes are overexpressed in both CNs and PCs and/or PBs such as INSM1 and NEUROD4, involved in neural or neuroendocrine differentiation. The overexpression of eight candidate genes in CNs (CHRDL2, IGF2, KiSS-1, CAL2, NTS, NHLH1, RGS16 and SCGN) was confirmed by real-time RT-PCR. Of the genes overexpressed in the recurrent CNs compared to the primary CNs, AQP5, KiSS-1, FZD7, AURKB, UBE2C and PTTG1 are genes which may be involved in tumor progression. Our study shows the potential involvement of various genes in the pathogenesis of CNs. These genes could be potential candidate markers for improving the characterization of CNs and some could be involved in CN tumorigenesis.