Activation of myc-family oncogenes has been implicated in the genesis of a variety of neoplasms. In addition, these genes exhibit specific patterns of expression during murine development. We now report that N- and c-myc are differentially expressed in normal developing human renal tissues and in Wilms' tumor, a neoplasm which derives from primitive kidney cells. Twelve of 13 Wilms' tumors tested exhibited greatly enhanced levels of expression which occurred in the absence of gene amplification. We also detected N-myc expression in other primitive neoplasms including medulloblastoma and hepatoblastoma. Our observations suggest that N-myc expression is not limited to neuroectodermal tumors as was previously thought, but is a marker for several neoplasms that derive from primitive cell precursors. Finally, high level expression of N-myc was associated with markedly diminished levels of c-myc, suggesting that enhanced expression of N-myc gene might lead to down-regulation of c-myc.
This work was supported by the Rosalind and Sol Chaikin Institute for Childhood Cancer Research of the Schneider Children's Hospital and by NIH grants 2-POI CA23767-06 and CA 42335, American Cancer Society Grant CD-269, and a Searle Scholars Award to F. A. F. A. is an Irma T. Hirschl Career Scientist and Malinckrodt Scholar.