ERBB2 overexpression in breast carcinomas: no positive correlation with complete pathological response to preoperative high-dose anthracycline-based chemotherapy

The predictive value of ERBB2 amplification/expression to doxorubicin use i s controversial. Preoperative chemotherapy, followed by the pathological as sessment of tumour response to treatment provide optimal conditions for the evaluation of the predictive value of biological parameters. We report her e data on the predictive value of ERBB? in a series of 54 cases of breast c ancer treated by preoperative high-dose anthracycline-based chemotherapy. O ur series consisted of 16 women presenting an inflammatory breast cancer (I BC) and of 28 women with poor prognosis primary cancer (PPPC). Patients rec eived a total of four cycles with doxorubicin (75 mg/m(2) for IBC or 70 mg/ m(2) for PPPC) and cyclophosphamide (6 g/m(2) for IBC or 1400 mg/m(2) for P PPC), every 21 days. ERBB2 expression was determined by immunohistochemistr y (clone CB11) performed on a tumour biopsy taken before chemotherapy. All patients underwent surgery as a second step of treatment, and the tumour re sponse was assessed on pathological specimens. A complete pathological resp onse was observed in 24 of the 54 cases (44%) (95% confidence interval (CI) , 31-57). Pathological complete response was positively correlated with hig h histological grade (P = 0.02) and with the absence of oestrogen (P = 0.00 3) or progesterone (P = 0.02) receptor expression. ERBB? overexpression was found in 18 of the 54 cases (33%), A complete pathological response was ob served in 33% of these cases (6/18). This figure was not significantly diff erent from the 50% rate of complete response observed for tumours with no d etectable ERBB2 expression (18/36). In this small series, ERBB2 overexpress ion was not a significant predictive marker of the pathological response to high-dose doxorubicin-based chemotherapy. (C) 2000 Elsevier Science Ltd. A ll rights reserved.