Onkológia 6/2014

Clinical, histopathological, immunohistochemical and genetic aspects of stratification medulloblastomas

Medulloblastoma belongs to embryonal brain tumors occurring in posterior fossa and is a most frequent malignant brain neoplasm in children. Once considered a single diagnostic entity, they are in fact a biologically heterogeneous group of neoplasms with at least four biologically and prognostically distinct groups: WNT, SHH, group 3, group 4. Indisputable progress in medulloblastoma treatment is hampered by serious side effects of therapy in long-term survivors. This led to the need of accurate prognostic stratification with the possibility of reduction in a dose of chemo- and radiotherapy in lower risk group. Classically medulloblastomas were stratified by age, metastatic status at the time of diagnosis, radicallity of resection, histologic type, MYCC and MYCN amplification. This stratification is being improved by separating meduloblastomas into the described genetic groups. Last but not least, identification of genetic signaling pathways is important for new targeted therapies. Differentiation into specific genetic medulloblastoma groups should be reflected in the new WHO classification of tumors of the central nervous system.

Keywords: medulloblastoma, genetics, WNT, SHH, group 3, group 4.