HER-2/neu overexpression does not predict response to neoadjuvant chemotherapy or prognosticate survival in patients with locally advanced breast cancer

Data about the prognostic and predictive value of HER-2/neu overexpression in patients with locally advanced breast cancer (LABC) treated with primary chemotherapy is limited. Therefore, this retrospective study was performed to examine this issue. Fifty-four consecutive patients with LABC were prospectively managed using a uniform multimodality approach. Response to neoadjuvant, chemotherapy and survival were examined against HER-2/neu overexpression as determined by an immunohistochemistry method on formalin-fixed, paraffin-embedded samples of breast cancer using the commercially available, United States Food and Drug Administration-approved kit HercepTest (Dako Corp, Carpinteria, CA). The number of patients in each HercepTest immunostaining group were as follows; 0 in 12 patients (22%), 1+ in 8 (15%), 2+ in 12 (22%), and 3+ in 22 (41%). None of the clinical variables was significantly associated with HER-2/neu expression. After primary therapy, 22% of patients attained clinical complete response and an additional 70% achieved clinical partial response with an overall response rate of 92% (95% confidence interval: 100% to 79%). There was no significant correlation between clinical response and HercepTest positivity (p = 0.85). Of 52 patients with complete pathological data, there was no significant difference in HercepTest status between those who attained complete pathological response (46%) and those who did not (38%) (p = 0.74). Moreover, there was no significant difference in disease-free survival (75% vs 84%, [p = 0.26]) or overall survival (81% vs 84% [p= 0.31]) between those who overexpressed HER-2/neu and those with negative HercepTest, respectively. In patients with LABC, HER-2/neu overexpression determined using HercepTest assay and according to the manufacturer's approved guidelines failed to demonstrate a predictive or a prognostic role.