Role of Wnt pathway in medulloblastoma oncogenesis

Abstract

To clarify the roles of Wnt pathway in medulloblastoma oncogenesis, immunohistochemical staining of β-catenin and Wnt-1 and genomic analyses of CTNNB1 (β-catenin) and AXIN1 (axin 1) were examined in 23 sporadic cases. Accumulation of β-catenin in tumor cells was immunohistochemically proven in 5 cases; 2 cases showed positive immunoreactivity for Wnt-1 and another 2 showed mutation of either CTNNB1 or AXIN1. AXIN1 mutation was in exon 3, corresponding to GSK-3β binding site and CTNNB1 mutation was in exon 3, corresponding to its phosphorylation site. Disruption of these proteins could result in upregulation of the Wnt signaling and accumulation of β-catenin, followed by cell proliferation and medulloblastoma oncogenesis.