The c-myc oncogene was not rearranged in any of five different human breast carcinoma cell lines examined. A 10-fold amplification and an elevated expression of the oncogene were detected in one of these cell lines, and the four other lines expressed low or undetectable levels of c-myc transcripts. Thus, c-myc amplification and elevated expression may be found only in a minority of human breast carcinomas.
