James Rutka, MD, PhD.
Editor in Chief
The clinical features of pediatric brain tumors have been well characterized, and a specific histopathological classification exists (W.H.O. classification, 2007) that allows stratification into treatment regimens and an estimated prediction of natural history and survival. The molecular pathobiology of pediatric brain tumors and its clinical correlates remain an area of active research that holds the promise of a similar stratification with improved diagnosis, therapy, and prognostic implications. Given the complex nature of biological signaling systems and the growing understanding of the genetic diversity in pediatric brain tumors, it is likely that no magic bullet or single therapy will be effective for all types of tumors or even for all tumors that look the same when the W.H.O. classification criteria are applied.
We seek in this chapter to define the current concepts of molecular cancer biology and how they apply in the setting of the most common pediatric CNS malignancies: medulloblastoma, ependymoma, and malignant gliomas. While the discussion will be centered on these three histologically distinct tumors, reference will be made to the tumorigenic process in inherited conditions such as neurofibromatosis and tuberous sclerosis and how these special cases can reveal insights into the neoplastic process in the developing CNS. As such, focus will be on defining key themes in the molecular mechanisms underlying brain neoplasias in children.
- Molecular regulation: Advances in the understanding of the molecular regulation of multiple cellular processes have greatly enhanced our knowledge of brain tumor biology and will likely lead to new ways to treat these tumors.
- Classification: Major discoveries have been made to date that are stimulating new theories about tumor classification and pathogenesis as well as opening new avenues for therapeutic intervention.
- Pediatric tumors distinct: It is clear that pediatric brain tumors are molecularly distinct from adult variants and therefore deserve independent study as well as careful consideration in the therapeutic modalities used.