Mechanisms predisposing to childhood overgrowth and cancer.

Several overgrowth conditions are believed to be associated with elevated risks of cancer, particularly in childhood. Beckwith-Wiedemann syndrome and Sotos syndrome are the most common overgrowth conditions, and both carry increased risks of certain tumors. In recent years, the identification of both the gene causing Sotos syndrome and the epigenetic subgroups underlying Beckwith-Wiedemann syndrome have enabled clarification of the cancer types and risks associated with these conditions. This has revealed striking differences in the cancer phenotypes associated with different molecular abnormalities. Elucidation of the mechanisms underlying cancer in overgrowth syndromes might yield important insights into the molecular basis of childhood tumors.