A panel of 73 samples, including 52 primary breast carcinomas, 10 normal breast tissues and 11 axillary lymph nodes, has been analysed for the presence of amplifications and gross structural alterations, in the oncogenes c-erbB-2, c-erbA, c-myc, N-myc, c-mos and c-Ha-ras. This evidence concerns the gene THRA and breast carcinoma.