The Selection Strategy for Circulating Tumor Cells (CTCs) Isolation and Enumeration: Technical Features, Methods, and Clinical Applications

Abstract

The key aim of the proposed chapter is to provide readers a brief description for the most important parts of the field of circulating tumor cells (CTCs): the core techniques, including negative and positive selection-based CTC isolation, and the differences between them. Most importantly, we will also review the clinical applications and important findings in clinical trials. The evidence-based review will not only help clinicians use CTCs to predict recurrence and foresee the disease-related outcomes but also to inspire the researchers in this field to conduct further investigations.

The change in circulating tumor cells before and during concurrent chemoradiotherapy is associated with survival in patients with locally advanced head and neck cancer

“…The methodology we used, compared to the only FDA‐approved device, Cellsearch, showed a similar recovery rate and a better detection rate in late‐stage cancer settings . Most importantly, CTC testing based on the negative selection strategy has more chances to save cells with no CKs or EpCAM expressions . Those cells are possibly undergoing epithelial‐mesenchymal transformation, pushing cancer to grow, evolve, and probably leading to poor outcomes in patients with cancer.…”

A Prognostic Model Based on Circulating Tumour Cells is Useful for Identifying the Poorest Survival Outcome in Patients with Metastatic Colorectal Cancer

“…Furthermore, two large-scale meta-analysis studies, which included 3094 patients in the first study and 1329 patients in the second study, showed that the detection of CTCs correlated with a poor prognosis for CRC patients. 26 , 27 In addition, the optimal cut-off value of the number of CTCs for the prognostic value in patients positive for CTCs was undetermined 28 . Furthermore, only approximately one-third of the patients had detectable CTCs, and the discrimination of survival differences among those patients who were negative for CTCs was impossible.…”

Emerging on‐chip electrokinetic based technologies for purification of circulating cancer biomarkers towards liquid biopsy: A review

“…In addition, the immunoaffinity assay is expensive, labor-intensive, and subject to large variability in the recovery rate (9-90%) mainly due to the variability in expression of surface markers [13,72]. Therefore, negative selection methods are developed to avoid some of the major disadvantages of the positive selection method, such as losing non-EpCAM CTCs and a relatively poor recovery rate [79]. In this approach, red blood cells are lysed followed by a CD45 (a common antigen of leukocytes) immuno-depletion process to remove leukocytes.…”

“…Therefore, all CTCs, either epithelial marker positive or negative, can be fully recovered, which makes the number of isolated CTCs larger than those by the positive method [75]. However, the background cells in negatively isolated samples are often mixed with numerous white blood cells and red blood cells, and hence, prohibit the downstream molecular analysis [79]. Therefore, more efficient and reliable methods are required for CTCs isolation.…”