[Expression of the p185neu oncoprotein indicates an unfavorable prognosis in small, node negative breast cancer without systemic adjuvant treatment (T1N0)].

In a retrospective study, paraffin-embedded tissues from 110 primary T1 breast carcinomas (tumour diameter < or = 2 cm) were examined for the presence of the Her-2/neu encoded oncoprotein p185neu, using an immunohistochemical technique. Primary surgical therapy revealed no node involvement in 76 cases. These patients did not receive an adjuvant systemic therapy. 25% of tumours were positive for p185neu. Expression of the oncoprotein was inversely correlated to oestrogen receptor status (p < 0.05). In patients with lymph node metastases and poorly differentiated tumours, the incidence of p185neu was higher than in node negative and/or well differentiated carcinomas. However, this finding was statistically not significant. No correlations were found between the detection of the oncoprotein and age, menopausal and progesterone receptor status. The median follow-up is 85 months. In patients without lymph node metastases (n = 76), presence of the oncoprotein was significantly correlated to a shorter relapse-free and/or overall survival (p < 0.05). No such correlation was found for 34 patients with lymph node involvement. Expression of p185neu seems to mark a group of T1N0 breast cancer patients, which is at high risk and might benefit from an adjuvant therapy.