Whole-Genome And Transcriptome Interrogation Of Metastatic Chemo-Resistant Triple Negative Breast Cancer From African American Patients

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Introduction: Triple negative breast cancer (TNBC) is characterized by the absence of expression of estrogen receptor, progesterone receptor, and Her2-neu, and accounts for ∼15% of all breast cancer diagnoses. Adjuvant chremotherapy and surgery can be effective in many women, although relapse with chemoresistant tumors that are difficult to treat is common. Importantly, these tumors may disproportionately affect African American women. Here, we present initial integrated analysis of matched normal and tumor whole genome and tumor transcriptome sequencing data from three African American patients with metastatic chemo-resistant TNBC, to better understand the compendium of somatic events occurring in these tumors within this high-risk population. Methods: Next Generation Sequencing was performed using the SOLiD version 4.0 system. Patient matched tumor and germline genomes are sequenced to 300 million mappable mate-pair reads (30X) and analyzed using custom paired analysis tools to uncover somatic alterations. Tumor transcriptomes are sequenced (RNA-seq) to 30 million uniquely aligned reads using Life Technologies Bioscope. For expression analysis, patient RNA-seq data are compared to data generated from ethnicity-matched population-based control hyperplastic breast tissue using EdgeR and DEGseq. Results: On average, we detected >3 million germline variants in these three African American patients. Review of germline results also provides information on BRCA1/2 status. Somatic paired analysis has revealed point mutations, small indels, copy number alterations, and translocations, in known cancer genes, and has revealed potential novel genes as well. Among three patients sequenced thus far, we have uncovered both unique and common genomic and transcriptomic perturbations. In both patients, unique somatic genomic alterations are associated with upregulation of specific signaling pathways. RNA-seq-based expression analysis has revealed a profile dominated by perturbations in cell cycle mitotic checkpoint defects. Furthermore, integrated analysis has provided key insights into the transcriptional consequences of a number of genomic alterations including exon skipping events and the discovery of potential fusion transcripts. Importantly, DNA and RNA changes have been validated by independent methods and technologies. Conclusions: Deep genome and transcriptome profiling of chemo-resistant TNBC has provided insights into events occurring in this difficult to treat cancer. These data are being leveraged to provide an opportunity for informed therapeutic options for intervention of this difficult to treat form of cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-267. doi:10.1158/1538-7445.AM2011-LB-267