Abstract 1166: Identification of predictive markers for clinical efficacy of triple-negative breast cancer chemotherapy

Triple Negative Breast Cancer (TNBC) is uncommon type of invasive breast cancer accounting for about 10~20% of all breast cancers. TNBC is characterized by a lack of expression of estrogen receptors (ER), human epidermal growth factor receptor 2 (HER2) and progesterone receptors (PR). Due to this characteristic, common treatments including hormone therapy and drugs targeting these receptors are not effective against TNBC despite more aggressive clinical behavior when compared to other subtypes. Paclitaxel is one of the well-known chemotherapeutic agents used in treatment for patients with breast cancer. However, previous studies have reported that advanced breast cancer treated with paclitaxel often develop resistance to the paclitaxel. To understand molecular characteristics and mechanism associated with molecular adaption in cancer cell when treated with paclitaxel, we performed next generation sequencing (NGS) and in vivo experiment using patient derived xenograft (PDX) models. We established ten PDX models from two cases with TNBC each. Mice were divided into two group consisting of control (n=5) and paclitaxel treatment (n=5). We performed exome and transcriptome sequencing on three of five samples for each group. We didn9t find significant differences between control and paclitaxel treatment groups in exome data. In transcriptome data, We identified 14 differentially expressed genes (DEGs) including members of CXCL gene family between control and paclitaxel treatment groups. Among these DEGs, 13 DEGs were up-regulated in paclitaxel treatment groups when compared to control group. We are conducting in vitro experiment for several genes among these 13 DEGs. Furthermore, we will perform transcriptome sequencing on PDX tumor samples of additional cases with TNBC for validation of the results so far achieved. Citation Format: Jihui Yun, Saem Hur, Wonyoung Kang, Deukchae Na, Jeesoo Chae, Jinjoo Kang, Ju-Hee Kim, Jiwoo Lee, Woohang Heo, Wonshik Han, Charles Lee, Dong-Young Noh, Hyeong-Gon Moon, Jong-Il Kim. Identification of predictive markers for clinical efficacy of triple-negative breast cancer chemotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1166.