Research
Print page Print page
Switch language
The Capital Region of Denmark - a part of Copenhagen University Hospital
Published

Cryopreservation of Circulating Tumor Cells for Enumeration and Characterization

Research output: Contribution to journalJournal articleResearchpeer-review

DOI

  1. Optimized Biobanking Procedures for Preservation of RNA in Tissue: Comparison of Snap-Freezing and RNAlater-Fixation Methods

    Research output: Contribution to journalJournal articleResearchpeer-review

  1. A simple clinical assessment is superior to systematic triage in prediction of mortality in the emergency department

    Research output: Contribution to journalJournal articleResearchpeer-review

  2. Feasibility of single-cell analysis of model cancer and foetal cells in blood after isolation by cell picking

    Research output: Contribution to journalJournal articleResearchpeer-review

  3. Triage for selection to colonoscopy?

    Research output: Contribution to journalJournal articleResearchpeer-review

  4. Clean Colorectum at Diagnostic Colonoscopy: Subsequent Detection of Extracolonic Malignancies by Plasma Protein Biomarkers?

    Research output: Contribution to journalJournal articleResearchpeer-review

View graph of relations

BACKGROUND: A blood sample containing circulating tumor cells (CTCs) may serve as a surrogate for metastasis in invasive cancer. Cryopreservation will provide new opportunities in management of clinical samples in the laboratory and allow collection of samples over time for future analysis of existing and upcoming cancer biomarkers.

METHODS: Blood samples from healthy volunteers were spiked with high (∼500) and low (∼50) number of tumor cells from culture. The samples were stored at -80C with cryopreservative dimethyl sulfoxide mixed with Roswell Park Memorial Institute 1640 medium. Flow cytometry tested if cryopreservation affected specific biomarkers regularly used to detect CTCs, i.e. cytokeratin (CK) and epithelial cell adhesion molecule (EpCAM) and white blood cell specific lymphocyte common antigen (CD45). After various time intervals (up to 6 months), samples were thawed and tumor cell recovery (enumeration) was examined. Clinical samples may differ from cell line studies, so the cryopreservation protocol was tested on 17 patients with invasive breast cancer and tumor cell recovery was examined. Two blood samples were drawn from each patient.

RESULTS: Biomarkers, CK, CD45, and EpCAM, were not affected by the freezing and thawing procedures. Cryopreserved samples (n = 2) spiked with a high number of tumor cells (∼500) had a ∼90% recovery compared with the spiked fresh samples. In samples spiked with lower numbers of tumor cells (median = 43 in n = 5 samples), the recovery was 63% after cryopreservation (median 27 tumor cells), p = 0.03. With an even lower number of spiked tumor cells (median = 3 in n = 8 samples), the recovery rate of tumor cells after cryopreservation did not seem to be affected (median = 8), p = 0.09. Time of cryopreservation did not affect recovery. When testing the effect of cryopreservation on enumeration in clinical samples, no difference was observed in the number of CTCs between the fresh and the cryopreserved samples based on n = 17 pairs, p = 0.83; however, the variation was large. This large variation was confirmed by clinically paired fresh samples (n = 64 pairs), where 95% of the samples (<30 CTCs) vary in number up to ±15 CTCs, p = 0.18.

CONCLUSIONS: A small loss of CTCs after cryopreservation may be expected; however, cryopreservation of CTCs for biomarker characterization for clinical applications seems promising.

Original languageEnglish
JournalBiopreservation and Biobanking
Volume14
Issue number4
Pages (from-to)330-7
ISSN1947-5535
DOIs
Publication statusPublished - 2016

ID: 46402432