A direct comparison of CellSearch and ISET for circulating tumour-cell detection in patients with metastatic carcinomas

Abstract

Background:Circulating tumour cells (CTCs) can provide information on patient prognosis and treatment efficacy. However, there is no universal method to detect CTC currently available. Here, we compared the performance of two CTC detection systems based on the expression of the EpCAM antigen (CellSearch assay) or on cell size (ISET assay).Methods:Circulating tumour cells were enumerated in 60 patients with metastatic carcinomas of breast, prostate and lung origins using CellSearch according to the manufacturer's protocol and ISET by studying cytomorphology and immunolabelling with anti-cytokeratin or lineage-specific antibodies.Results:Concordant results were obtained in 55% (11 out of 20) of the patients with breast cancer, in 60% (12 out of 20) of the patients with prostate cancer and in only 20% (4 out of 20) of lung cancer patients.Conclusion:Our results highlight important discrepancies between the numbers of CTC enumerated by both techniques. These differences depend mostly on the tumour type. These results suggest that technologies limiting CTC capture to EpCAM-positive cells, may present important limitations, especially in patients with metastatic lung carcinoma.

Sequential Tracking of PD-L1 Expression and RAD50 Induction in Circulating Tumor and Stromal Cells of Lung Cancer Patients Undergoing Radiotherapy

“…2). Being that PDCTCs have been shown to be the same CTC population of cells isolated by the CellSearch Ò CTC System, these numbers are on par with previous reports (7)(8)(9)15). The CellSearch system isolates CTCs in patients with NSCLC ranging from approximately 0% to 5% positivity in stage III NSCLC and 21% to 32% in stage IV (7-9, 15).…”

“…Although PDCTCs are the subtype of CTCs isolated using the CellSearch platform, it is uncommon in patients with NSCLC and thus of limited value here. EMTCTCs are more prevalent in NSCLC (6)(7)(8)(9)16) with 49% of all our T0 samples containing an EMTCTC, greatly expanding the utility of blood as a surrogate to tissue biopsies in NSCLC. CAMLs were the most prevalent, with 81% of our patients with NSCLC having CAMLs in circulation at baseline and 100% after induction of treatment.…”

“…Recently, we have identified a prevalent CStC subtype, cancerassociated macrophage-like cells (CAMLs), using a nonaffinity microfiltration-based method that captures both CTCs and CAMLs and allows for parallel analysis of these cancer-specific circulating cell subtypes (1,(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). CAMLs are recently defined circulating myeloid-derived stromal cells, found in all the stages of invasive malignancy and in various solid malignancies [e.g., breast, prostate, non-small cell lung carcinoma (NSCLC), and pancreatic; refs.…”

Critical issues in the clinical application of liquid biopsy in non-small cell lung cancer

“…EMT CTCs are documented in NSCLC (76), and low numbers of CTCs are observed with epithelial marker-dependent methods (13,33). Indeed, methods based on physical properties (48,49,53) or PCR-based methods (32), usually detect higher numbers of CTCs in lung cancer. However, so far, the FDA-cleared CellSearch ® assay, enriching and counting EpCAM+ CTCs (Table 1) has proved to identify 20-40% of CTC positive metastatic NSCLC patients (32,33,48,57).…”

Post-Genomics Nanotechnology Is Gaining Momentum: Nanoproteomics and Applications in Life Sciences

“…This technology detects circulating tumor cells in blood samples for early diagnosis of cancer. The technology relies upon incubating the blood sample with ferrofluids that consist of a magnetic core surrounded by a polymeric layer coated with EpCAM antibodies for capturing cells (Farace et al, 2011).…”