Gene amplification and expression of the neu (c-erbB-2) sequence in human mammary carcinoma.

Alterations in the structure and expression of the neu oncogene were investigated in 15 human mammary tumors. In 7 of the samples (46%), amplification by the factor up to 14 was detected, some samples displaying an additional EcoRI restriction fragment at 3.4 kb. In tumor tissue with amplified neu sequences from which intact RNA was available, enhanced expression was noted. Correlation of the molecular data to clinical parameters indicated a correlation of the neu oncogene amplification to tumor grading and thus poor prognosis.