Childhood cancer: etiologic clues from epidemiology.

Epidemiologic reseach has revealed a wide spectrum of etiologic information concerning childhood cancer. Often, important clues have come from observations made by alert practitioners. The school health professional can help further progress in cancer research by observing peculiarities of environmental exposures as well as the family's medical history when cancer affects a child. Any unusual findings should be referred to an appropriate research center for evaluation.