Background: Adding adjuvant trastuzumab to chemotherapy for patients (pts) with resected HER2+ breast cancer (BC) improves disease free and overall survival (Perez EA, et al. J Clin Oncol 2011). Understanding which pts are most likely to benefit from these therapies is a goal of our team.
Methods: Baseline 1639 annotated tumor specimens from pts enrolled in the phase III N9831 adjuvant trastuzumab trial (NCT00005970) were processed via the >29,000 gene probe DASL technology (Illumina) to identify genomic predictors of pt outcome to Arm A chemotherapy or Arm C chemotherapy plus concurrent trastuzumab. Samples were spotted in 96 well plates, with appropriate replicates. Extensive quality control and internal validation were performed. The association of each gene with recurrence-free survival (RFS) was determined for each treatment arm separately using CoxPH models adjusted for clinical and tumor risk factors. A p < 0.0001 was used to define significance. A geneset analysis (using 408 Kegg/BioCarta genesets) was performed to determine pathways associated with RFS.
Results: PRPF4B, EWSR1, BMI1, CNNM1, FOXO4, CLIP2, MCCC1, CHRM2 were found to be significantly associated with RFS for Arm A and AAK1, DAZAP2, TP53INP1, MACF1 and ADHFE1 were associated with RFS for Arm C. The most significant pathway associated with RFS in Arm A was the KEGG hypertrophic cardiomyopathy pathway and for Arm C, the BioCarta pertussis toxin-insensitive CCR5 signaling in macrophage pathway.
Conclusions: We have identified 8 genes associated with RFS for pts treated with adjuvant chemotherapy, and 5 genes associated with RFS for pts treated with concurrent trastuzumab and chemotherapy in pts with HER2 early stage BC. In addition, geneset analysis identified BioCarta and Kegg pathways associated with RFS for each arm. Validation in an independent cohort is expected to be completed by the end of 2012.
Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD10-04.
#56
Background: Recent findings from NSABP B-31 suggested that breast cancer (BC) patients (pts) with c-MYC (MYC)/HER2 co-amplification in their primary tumors may benefit more in terms of disease-free survival (DFS) from adjuvant trastuzumab (n=471; p<0.0001, HR 0.24; 13 vs. 51 events) than those pts with only HER2 amplification in their primary tumors (n=1078, p=0.007, HR 0.63; 55 vs. 82 events).
 Purpose: The overall objective of this analysis is to determine the association between MYC/HER2 co-amplification and outcome of pts randomized to receive chemotherapy alone (Arm A) or chemotherapy with concurrent trastuzumab (Arm C) on N9831.
 Patients/Methods: This analysis included 868 pts from the HER2+ NCCTG N9831 Intergroup adjuvant trastuzumab phase III clinical trial on Arms A or C. Fluorescent in situ hybridization (FISH) was performed at a central laboratory, Mayo Clinic Clinical Cytogenetics Laboratory, using dual probe mixtures for HER2 (17q11.2-12/centromere 17) and for MYC (8q24/centromere 8). The HER2 amplification status in whole tissue sections was evaluated to determine eligibility of pts for N9831. Tissue microarrays containing three cores from each patient's tumor were analyzed for MYC amplification status. The gene and centromere copy number as well as the distribution of the signals for each marker were determined in sixty non-overlapping interphase nuclei.
 Results: Of 273 pts with completed FISH analyses, 34 (12%) pts had MYC amplification. The rate of MYC amplification was similar across arms (18/135 [13%] vs. 16/138 [12%]; ChiS p=0.66). Co-amplification of MYC/HER2 was observed in 32 (12%) pts with similar co-amplification rates across arms (17/135 [13%] vs. 15/138 [11%]; ChiS p=0.66). Based on preliminary analyses, MYC amplification and MYC/HER2 co-amplification do not appear to be associated with race, menopausal status, hormone receptor status, nodal status, tumor histology, tumor grade, or tumor size (all ChiS p>0.05); however, MYC amplified pts were significantly younger than MYC non-amplified pts (mean 46.4 vs. 51.0, t-test p=0.02) and MYC/HER2 co-amplified pts were significantly younger than MYC/HER2 non-co-amplified pts (mean 45.9 vs. 51.0, t-test p=0.01).
 Conclusions: In our initial analyses of 239 pts, we observed a lower frequency of MYC/HER2 co-amplification than the previously reported 30% for NSABP B-31. Complete FISH analyses of 868 pts in N9831 and association with DFS will be presented.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 56.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.