Characterization of circulating tumor cells in breast cancer patients by spiral microfluidics

Circulating tumor cells (CTCs) have important application prospects in the early diagnosis, treatment evaluation, and prognostic prediction of tumors. In this study, we enrolled a total of 65 patients with different stages and molecular subtypes of breast cancer and isolated and enriched for CTCs from peripheral blood using the ClearCell FX1 platform, which is based on a label-free spiral microfluidic method. The ClearCell platform can successfully isolate CTCs from peripheral blood with different detection rates in breast cancer patients. We also compared the difference between the ClearCell and CellSearch platforms for isolating CTCs. To further determine the genetic information of CTCs, we performed single-cell whole-exome sequencing (WES) in three CTCs isolated from one patient. The sequencing results indicated the presence of a few hundreds of single-nucleotide variants (SNVs) in each CTC, with only 16 SNVs being shared by all three CTCs. These shared SNVs may have a crucial impact on the development of breast cancer. Here, we report, for the first time, the complete process and results of performing single-cell WES on CTCs isolated by the ClearCell FX1 platform.