Response Rates to Neoadjuvant Cyclophosphamide and Doxorubicin (AC) in Breast Cancer Patients Exhibiting Her-2/Neu (Her-2) Negative, Topoisomerase II (TOPO 2A) Normal, Chromosome 17 (C17) Normal Phenotype.
Authors: Kaplan H. , Malmgren J. , Atwood M. , Wiseman C. , Goldstein L. 
Published: December 2010

Background: Recent reports have suggested that Her-2, TOPO2A and polysomy 17 (C17) status may predict responsiveness of tumors to doxorubicin (DOX) therapy. These studies predominantly evaluated long term survival in the adjuvant setting. In this study we evaluate the actual response rate to neoadjuvant AC as a function of these parameters.Material and method: We identified all breast cancer patients in our registry cohort treated with neoadjuvant DOX and cyclophosphamide only prior to surgery. All had hormone receptor (HR) and Her-2 testing as part of their prior clinical evaluation. Forty patients were found, 33 of whom had sufficient tissue for testing and adequate signal for measurement of TOPO2A and C17. Fluorescence in situ hybridization (FISH) testing was done on deparaffinized tissue sections pretreated using a modification of the vendor's standard protocol, and then incubated with the FDA-approved Vysis PathVysion™ probe set, which includes Spectrum-Green-conjugated probe to the α-satellite DNA located at the centromere of chromosome 17 (17p11.1–q11.1) and a Spectrum Orange-conjugated probe to the TOP2A gene (Abbott Diagnostics, Chicago, IL, USA). Morphometric analysis was performed using a MetaSystems image analysis system, incorporating the Metafer software with extended focus/tile sampling methodology (Meta-Systems, Altlussheim, Germany). Manual counting was performed on all samples in which autofluorescence and/or artifact prevented the counting of sufficient numbers of cells. A ratio &gt; 2.0 is considered positive for TOPO2A amplification. C17 presence was defined as signal of ≥ 2.5.Results: Out of 33 patients tested, one was Topo2A amplified (HR-/Her-2-/C17-, partial responder) and one had polysomy 17 present (HR+/Her-2+/TOPO2A-, partial responder). 17 out of 33 were HR+ and eight were Her-2+. Among the TOPO2A non-amplified and C17 normal patients (n=31), treatment response was pathologically proven complete response (pCR) = 5 (16%), PR = 19 (61%), and NR = 7 (23%). Distribution by marker status and response to therapy for the 31 cases was the following: 1) HR-/Her-2- (n=9), 22% pCR, 56% PR, 22% NR; 2) HR+/Her-2- (n=15), 7% pCR, 67% PR, 27% NR; 3) HR-/Her-2+ (n=6), 33% pCR, 67% PR; 4) EstrogenR+/ProgesteroneR-/Her-2+ (n=1), NR. Among TOPO2A non-amplified and C17 normal patients the majority (77%) had significant responsiveness (CR or PR) to AC. The patients that lacked all three postulated indicators of DOX sensitivity (her-2 negative, TOPO2A normal, C17 normal) still exhibited 13% pCR (3/24) and 63% PR (15/24), with HR/Her-2 neg (triple negative) patients being more responsive than HR+ patients.Discussion: Prior predictive studies have not looked directly at response rates to doxorubicin (DOX). This data suggests that even in patients lacking all three postulated predictors there is significant response to therapy that would be difficult to attribute to cyclophosphamide alone. Patients lacking Her-2, TOPO2A and C17 should not be excluded from receiving DOX-containing regimens, either as primary therapy or as therapy for metastatic disease.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2033.