THE CELL-TYPE-SPECIFIC IGF2 EXPRESSION DURING EARLY HUMAN-DEVELOPMENTCORRELATES TO THE PATTERN OF OVERGROWTH AND NEOPLASIA IN THE BECKWITH-WIEDEMANN SYNDROME

Overstimulation by insulin-like groath factor II is implied in several overgrowth conditions and childhood cancers. We have therefore studie d spatial and temporal expression patterns of the insulin-like growth factor II gene (IGF2) and the insulin-like growth factor type I recept or gene during normal human development (5.5 to 23.0 weeks postfertili zation). The set of cell types with the most abundant IGF2 expression correlated strikingly to the organomegaly and tumor predisposition of the Beckwith-Wiedemann syndrome. Intrauterine growth and postnatal org an weights of a prematurely born child with a full-blown syndrome are presented. The cell type-specific IGf2 expression of these organs and of multifocal Wilms' tumors from two other children affected by the Be ckwith-Wiedemann syndrome were also studied. The results clarify and e xtend previous findings concering human prenatal IGF2 expression and a re consistent with a short range over-stimulatory role of locally prod uced IGF II ensuing after the first trimester in the Beckwith-Wiedeman n syndrome.