Abstract P2-01-07: Isolation of viable CTCs from leukapharesis product with parsortix system enables subsequent culture

Abstract

Abstract Background: Solid tumors are constantly releasing circulating tumor cells (CTCs) into the circulatory system. They are genotypically and phenotypically different from the primary tumor. Especially viable CTCs can be of high interest to obtain further therapeutically relevant information. Their extremely low frequency is one of the main limiting factors to use them for further characterization. To overcome this challenge we tested to isolate viable CTCs from diagnostic leukapharesis (DLA) products obtained from breast cancer patients. Material/methods: 16 DLA samples and matched peripheral blood (PB) samples of metastasized breast cancer patients were collected and CTC numbers were determined by CellSearch® analysis. Viable cells were enriched from DLA product with Parsortix system. Genomic DNA of single cultured CTCs was isolated and amplified by whole genome amplification. Array-based comparative genomic hybridization of single cells was performed to analyze for genomic aberrations. Resulting profiles were compared to genomic aberration profiles of CTCs isolated before in vitro culture. Results: CTCs were detected in ten PB and matched DLA samples and in three more DLA samples whose corresponding blood samples were CTC-negative. CTC number per ml was increased by an average of 22.5 fold. Parsortix was optimized to enrich tumor cells from DLA product while keeping them best viable. An enrichment rate of 67.7% ± 11.3% and a harvesting rate of 65.3% ± 9.7% were determined with spiked MCF7 cells. We could grow viable CTCs from three out of eight CTC positive DLA samples from metastasized patients as determined by immune fluorescence analysis. The growing cells harbor genomic anomalies confirming their malignant origin. Most aberrations are widely identical to the aberrations detected in uncultured CTCs. Conclusions: DLA provides greater numbers of viable CTCs which can be enriched with Parsortix system in order to enable their in vitro cultivation. This workflow will allow functional studies. Citation Format: Neubauer H, Franken A, Driemel C, Lampignano R, Behrens B, Reinhardt F, Niederacher D, Stoecklein NH, Fischer JC, Fehm T. Isolation of viable CTCs from leukapharesis product with parsortix system enables subsequent culture [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-01-07.