Negative Enrichment and Isolation of Circulating Tumor Cells from Cryopreserved Blood Fractions for Whole Genome Amplification.

The presence and frequency of circulating tumor cells (CTCs) in the peripheral blood of many cancer types, including breast cancer, can be an indicator of later metastasis. Assessing their molecular features may be useful in understanding the mechanisms behind metastasis. However, CTCs are very rare and require quick processing in order to preserve viability. Here, we describe a method to enrich and isolate single CTCs from the cryopreserved blood fractions of patients with breast cancer, to allow for delayed isolation. This protocol includes immunomagnetic depletion to enrich for CTCs followed by single-cell isolation using the DEPArray NxT™. Whole-genome amplification of isolated CTCs allows for many downstream applications to be performed, such as shallow whole genome sequencing for copy number analysis or quantitative polymerase chain reaction (qPCR) for genomic analyses.