The impact of molecular analysis on the survival of children with embryonal tumors.

Embryonal tumors represent a heterogeneous group of malignancies characterized by poorly differentiated cells and generally aggressive behavior. Although advances in survival rates have been made in several of these tumor types, including Wilms' tumor, retinoblastoma, and medulloblastoma, survival of patients with central nervous system (CNS) embryonal tumors, including primitive neuro-ectodermal tumors (PNETs) and atypical teratoid rhabdoid tumors (AT/RT), are particularly poor. Advancing molecular analysis techniques and the development of gene expression profiles has led to the formulation of different subdivisions within many of the umbrella CNS tumor groups with clinical and prognostic implications. Some subgroups have been identified as having improved survivorships, likely not captured by large scale population data given their small numbers and relatively recent characterization. Importantly, identification of differing molecular pathways has begun to result in targeted therapies which may pave the way for even more surviving patients in the coming years.