Abstract 4880: Characterization of genetic concordance between primary tumor cells, circulating tumor cells, and metastatic tumor cells from patients with prostate cancer

Abstract

Abstract Circulating tumor cells (CTCs) which disseminate from the primary tumor site have been found to be a major source of metastatic tumor. However, CTCs are heterogeneous and most CTC DNA is fragmented due to apoptosis. To better understand the molecular pathogenesis of metastasis, it is imperative to obtain single, non-apoptotic CTCs and investigate the genetic concordance between primary tumor cells, CTCs and metastatic tumor cells. Due to the abundance of normal cells present in the blood and in tumor tissue, isolation of single tumor cells or pure cell populations of these cells is extremely difficult. The DEPArray platform is designated to collect single CTCs after Cell-Search enrichment, and to sort pure intact tumor cells from formalin-fixed, paraffin-embedded (FFPE) tissues. Taking advantage of this technology, we have isolated single CTCs from prostate cancer patients. Whole genome amplification was performed and genomes with high integrity were used to evaluate the hotspot mutations in PIK3CA. For comparison, we also made single cell suspensions from FFPE tissue blocks of primary tumors and metastatic tumor in lymph nodes from the same patients. Immunofluorescence staining for cytokeratin (CK) and vimentin (Vim) was performed, followed by isolation of pure tumor cells (CK+), stromal cells (Vim+) and double-positive cells (CK+/Vim+) from both primary tumor and lymph node samples. We plan to do genetic analysis on these cells and compare the results to determine the genetic concordance between primary tumor cells, CTCs and metastatic tumor cells. By using the DEPArray, we have successfully isolated single CTCs, and populations of tumor cells, stromal cells and double-positive cells from primary and metastatic tumors. We will present new data on the genetic concordance between these cells, which will provide new insight into our understanding of metastasis in prostate cancer. Citation Format: Lixin Yang, Linling Chen, Yafan Wang, Jeremy Jones, Yun Yen, Sofia Loera, Raju Pillai, Peiguo Chu, Dennis Weisenburger. Characterization of genetic concordance between primary tumor cells, circulating tumor cells, and metastatic tumor cells from patients with prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4880. doi:10.1158/1538-7445.AM2015-4880