Old man river. The flow of pediatric oncology.

Progress in pediatric oncology has been made by gathering individual investigators and their work into even larger research groups. The authors liken this process to the way small waters coalesce to form large rivers. This pattern can be traced back for most of the entities included under the rubric pediatric oncology, but it is more convenient and informative to do so with respect to two specific entities: acute lymphoblastic leukemia and Wilms' tumor. These malignancies are used as surrogates for the liquid and solid tumors and are addressed in this article.