PROGRESSES IN THE UNDERSTANDING OF THE PATHOGENESIS OF CRANIOPHARYNGIOMAS

Craniopharyngiomas (CP) are rare, dysembryoplastic tumors of the hypothalamo-pituitary area. There are two very distinct pathological types: adamantinomatous (ACP) and papillary (PCP). ACP and PCP also have significant clinical differences, pointing to a different pathogenesis. This only began to be elucidated lately and indeed discovered specific, mutually exclusive mutations with pathogenetic role in ACP and PCP, respectively. The vast majority of ACP harbor an activating mutation of the CTNNB1 gene coding for β-catenin (member of the Wnt pathway). The mutation was proved to be pathogenetic in animal models and a tumorigenesis model has already been created. In contrast, in PCP, BRAF (gene coding for a main actor in the MAPkinase pathway) mutations have been found in the majority of cases. These findings can improve the differential diagnosis of intracranian tumors (by specifically designed immunohistochemistry-antibodies) and the design of molecules to inhibit the disordered intracellular pathways. Such molecules are already available and promising for the BRAF/MAPkinase pathway. In conclusion, extremely significant progresses have been made in revealing the complex process of tumorigenesis in CP and they are likely to solve in the foreseeable future many challenges we typically face in the clear positive diagnosis and optimal management of these rare tumors.