PURPOSE: Human epidermal growth factor receptor 2 (HER2)/neu, topoisomerase II 
alpha (TOP2A), and polysomy 17 may predict tumor responsiveness to doxorubicin 
(DOX) therapy.
METHODS: We identified neoadjuvant DOX/cyclophosphamide treated breast cancer 
patients in our registry from 1997 to 2008 with sufficient tissue for testing (n 
= 34). Fluorescence in situ hybridization (FISH) testing was done on 
deparaffinized tissue sections pretreated using vendor's standard protocol 
modification, and incubated with US Food and Drug Administration approved Abbott 
Diagnostics Vysis PathVysion™ probe set, including Spectrum-Green-conjugated 
probe to α-satellite DNA located at the centromere of chromosome 17 
(17p11.1-q11.1) and a Spectrum-Orange-conjugated probe to the TOP2A gene. 
Morphometric analysis was performed using a MetaSystems image analysis system. 
Manual counting was performed on all samples in which autofluorescence and/or 
artifact prevented the counting of sufficient numbers of cells. A ratio >2.0 was 
considered positive for TOP2A amplification. Polysomy 17 (PS17) presence was 
defined as signals of ≥2.5. Outcomes were pathological complete response (pCR), 
partial response (PR), and nonresponse (NR).
RESULTS: Of 34 patients tested, one was TOP2A amplified (hormone receptor 
negative/HER2 negative, partial responder). The subset of TOP2A nonamplified, 
HER2 negative, and PS17 absent (n = 23) patients had treatment response: pCR = 2 
(9%), PR = 14 (61%), and NR = 7 (30%). Including the two PS17 present and 
HER2-positive patients (n = 33), 76% of TOP2A nonamplified patients had pCR or 
PR.
CONCLUSIONS: We observed substantial treatment response in patients lacking 
three postulated predictors that would be difficult to attribute to 
cyclophosphamide alone. Patients who are HER2 negative and lack TOP2A 
amplification and PS17 should not be excluded from receiving DOX-containing 
regimens.