Advances in the care of the child with cancer. The importance of histologic subclassification of tumors.

The importance of histologic subclassification of tumors lies principally in the correlation between nosology and tumor biology, including response to therapy. Subclassifications that are practically achieved, reproducible and uniquely predictive are of great value. As new methods are engaged and new clinical data are reported, classifications may be changed. Subclassifications of solid tumors with proven therapeutic application are exemplified by renal tumors and lymphomas that are commonly referred to as "favorable" or "unfavorable histology." Subclassification of soft tissue sarcomas, neuroblastoma and tumors of the central nervous system are being investigated, but are presently of undetermined relevance. Classifications and subclassifications of solid tumors of children are presented in the context of prognostic relevance.