c-erbB2 expression predicts response to preoperative chemotherapy for locally advanced breast cancer

BACKGROUND: Previous work suggests that the presence of c-erbB2 oncoprotein immunostaining and the proliferation rate of tumours, may be relevant to chemo-sensitivity in breast cancer. PATIENTS AND METHODS: To investigate this we assessed pretreatment biopsies from 50 patients with locally advanced breast cancer for expression of c-erbB2 and MIB1 (proliferative marker) in relation to clinical response after 3 months preoperative chemotherapy. RESULTS: Objective response was significantly more likely (22/30, 73%) for tumours negative for c-erbB2 membrane staining, compared to positively staining tumours (6/20, 30%, p = 0.0025). The percentage of cells staining positively for MIB1 was not predictive of response (p = 0.56). CONCLUSIONS: This study has shown an increased likelihood of response to preoperative chemotherapy for breast cancers negative for c-erbB2 staining. Previous studies have shown that c-erbB2 immunostaining can correlate with either chemo-resistance or chemo-response. We postulate that this conflict may be due to differences in the type of chemotherapy administered. This raises the possibility of biological markers being use to assist in the selection of the type of chemotherapy regimen administered to particular tumour biological phenotype