Proto-oncogene abnormalities in human breast cancer: c-ERBB-2 amplification does not correlate with recurrence of disease.

The incidence of c-ERBB-2 amplification in breast cancers and its usefulness as a predictor of tumor recurrence after treatment have been subjects of controversy (Ali et al., 1988, Slamon et al., 1987). We re-examined this subject by analysing 157 primary and 14 metastatic breast cancers with c-ERBB-2 and 18 other molecular probes as controls. Five proto-oncogenes were found to be occasionally amplified in primary breast cancers: c-ERBB-2 (11%), c-MYB (3%), c-RAS-Ki (3%), INT-2 (4%) and c-MYC (6%). No statistically significant correlation between amplification of c-ERBB-2 and recurrence of tumors was observed. The only significant correlation observed was between early recurrence of advanced (stage III) tumors and amplification of one or another of the above five proto-oncogenes. We conclude that breast cancer utilize multiple genetic mechanisms in their progression and metastasis, and that analysis of c-ERBB-2 alone is not a useful guide.