INSULIN-LIKE GROWTH FACTOR-II AND WT1 TRANSCRIPT LOCALIZATION IN HUMAN FETAL KIDNEY AND WILMS-TUMOR

In situ hybridization was used to examine, in parallel, the localizati on of insulin-like growth factor II (Igf2) and WT1 transcripts in norm al fetal kidney and Wilms' tumor. The expression of Igf2 and WT1 trans cripts in the fetal kidney is almost complementary in both the epithel ial and stromal cell lineages derived from the undifferentiated metane phrogenic blastema. The patterns of transcription of Igf2 in three Wil ms' tumors appeared to be perturbed as compared to the normal fetal ki dney. In these tumors Igf2 transcripts were detected in structures tha t are developmentally equivalent to the renal vesicle, which in the no rmal kidney do not contain Igf2 transcripts. These results suggest tha t Wilms' tumors arise from an alteration in the regulation of Igf2 mRN A synthesis.