Immunohistochemical studies on c-erbB-2 oncoprotein expression in paraffin embedded tissues in invasive and non-invasive human breast lesions.

The c-erb-B2 protein expression was evaluated by immunohistochemistry in two series of breast lesions. In a retrospective study on a series of 140 breast lesions, among 34 benign lesions, 16 showed an intense or moderate membrane reaction of tumoral cells; of 15 atypical lesions, 6 exhibited a membrane reaction and 34/60 in situ lesions expressed intensely or moderately c-erb-B2 oncoprotein. A prospective investigation was made on a series of 41 lesions from 25 patients, which were selected for their clinico-pathological features. All the samples were positive but the staining intensity was heterogenous. However, it was similar in the various lesions from the same patient. A strong signal was observed in 12 lesions from 7/25 patients, moderate in those of 13 patients and weak in 6 lesions from 5 patients. Taken together, our findings show that a large number of human breast lesions expressed c-erb-B2 oncoprotein, whether benign, atypical or in situ carcinomas. The intensity of the reaction may depend on the patients rather than on the aggressivity of the lesion, except for the infiltrating carcinomas. This suggests that c-erb-B2 oncoprotein in overexpressed at early stages of breast cancer lesions. Although c-erb-B2 oncoprotein is probably not a good marker for prognosis, it may be an indication for a future progression towards or recurrence.