N‐myc oncogene expression and amplification in metastatic lesions of stage IV‐S neuroblastoma

Abstract

The authors determined the levels of N‐myc oncogene amplification and RNA expression in three infants with metastatic neuroblastoma. By clinical staging Patients 1 and 2 were Stage IV‐S, a disease with limited metastatic potential and generally favorable outcome; Patient 3 was Stage IV. Southern blots of chromosomal DNA showed normal N‐myc copy number in the primary tumor of Patient 1, extensive (200‐fold) gene amplification in the primary tumor from Patient 2, and intermediate (100‐fold) gene amplification in the primary tumor and metastatic lesions from Patient 3. N‐myc RNA was expressed in all of the primary and metastatic tumor tissues tested. The level of N‐myc RNA expression roughly corresponded to the extent of N‐myc gene amplification in Patients 2 and 3 and was overexpressed from a single N‐myc gene copy in Patient 1. N‐myc gene amplification and RNA expression levels were approximately the same in the primary and metastatic lesions for each of the patients tested. The two patients with N‐myc gene amplification had a poor outcome, but the patient with normal N‐myc gene copy number had no evidence of disease. Despite the clinical picture in Patient 2 of Stage IV‐S neuroblastoma, the pattern of N‐myc amplification and expression more closely resembled that of Patient 3 (Stage IV neuroblastoma) than that of Patient 1 (bona fide Stage IV‐S neuroblastoma). Copyright © 1990 American Cancer Society