N-MYC PROTEIN EXPRESSION IN HUMAN BREAST-CARCINOMA - PROGNOSTIC IMPLICATIONS

The overexpression of N-myc gene ann its protein products has been tho ught to be limited to cases of neuroblastoma, retinoblastoma and small cell lung carcinoma, but there is increasing evidence of its wider di stribution in human tumors. This study showed that the protein of N-my c gene is associated in normal, benign and malignant human breast tiss ues. We found that N-myc oncoprotein is overexpressed in most breast c arcinomas and that N-myc overexpression is significantly con-elated wi th clinical stage, and histological grading of the tumors, and more im portantly with the clinical outcome of the patients. Analysis of DNA, mRNA and protein levels suggested that the high N-myc expression in br east cancer occurs without concomitant gene amplification. The finding of a direct inverse correlation between N-myc overexpression and the prognosis of patients with breast carcinoma suggests that N-myc expres sion may be useful as a prognostic factor in human breast cancer.