Prognostic factors of adult medulloblastomas: A review of the literature and perspectives

Adult medulloblastoma is a rare disease. Characteristics which are different from those of the pediatric population have been reported in recent years: a more frequent localization in the cerebellar hemispheres, higher proportion of the desmoplastic subtype, lower incidence of metastatic spread and delayed recurrences. It is probable that these differences are a consequence of specific cytogenetic and molecular characteristics distinguishing the two populations. A number of prognostic factors have been described in the adult population such as age, gender, histopathology, residual disease after surgery, M stage. However, the increased presence of activating mutations in the Sonic Hedgehog cell pathway, and to a lesser degree in the Wingless pathway, may explain the clinical discrepancies. Also, differences in the cytogenetic profile such as the loss of 10q and gain of 17q seem to play a critical role in the prognosis of these patients. It is obvious that knowledge of oncogene amplifications and cytogenetic markers is the key to the future management of medulloblastomas. Molecular inhibitors targeting cell signaling pathways that are activated in medulloblastoma will play an increasing role in future trials.