[Amplification, rearrangement and expression of the c-myc and c-Ha-ras1 proto-oncogenes in patients with breast cancer].

The restriction analysis of breast cancer DNA revealed amplification of c-myc and c-Ha-ras oncogenes in 3 of 19 and 4 of 22 carcinomas, respectively. In two tumours containing amplified c-Ha-ras1-fragment an additional ras-band absent in unchanged lymphatic nodule and blood leukocytes of the same patients was revealed. Amplification of myc gene was registered in poorly differentiated carcinomas with high metastatic potential. c-Ha-ras1 activation (amplification and elevated expression) was identified in nonaggressive tumours with prolonged progression.