Oligodendroglioma: impact of molecular biology on its definition, diagnosis and management.

Molecular genetics and biology have been having significant influence on the practice of neuro-oncology in recent years, with oligodendrogliomas being the most prominent example. The majority of oligodendrogliomas show remarkable sensitivity to chemotherapy, and the finding that the loss of chromosome 1p was tightly associated with the response opened a new era in which the treatment can be tailored for each tumor patient based on molecular genetic diagnosis. It has been noticed that histological features, when closely examined, are also correlated with the molecular genetic data, such as losses of 1p/19q/10q and TP53 mutation. Furthermore, expression profiling using microarray technology showed that oligodendrogliomas with 1p loss express high levels of neuronal genes, suggesting that the progenitor of those tumors may be shared with neurons. Considering the rapid progress of the knowledge in neural developmental biology, it is possible that the classification, definition and diagnosis of gliomas will be rewritten based on such knowledge at the molecular level in the near future, if they reflect the biological features of each tumor better than the histological diagnosis based mostly on morphology.