Improving the yield of circulating tumour cells facilitates molecular characterisation and recognition of discordant HER2 amplification in breast cancer

Abstract

BACKGROUND: Circulating tumour cells (CTCs) offer a non-invasive approach to obtain and characterise metastatic tumour cells, but their usefulness has been limited by low CTC yields from conventional isolation methods. METHODS: To improve CTC yields and facilitate their molecular characterisation we compared the Food and Drug Administrationapproved CellSearch Epithelial Kit (CEK) to a simplified CTC capture method, CellSearch Profile Kit (CPK), on paired blood samples from patients with metastatic breast (n ¼ 75) and lung (n ¼ 71) cancer. Molecular markers including Human Epidermal growth factor Receptor 2 (HER2) were evaluated on CTCs by fluorescence in situ hybridisation (FISH) and compared to patients' primary and metastatic cancer. RESULTS: The median cell count from patients with breast cancer using the CPK was 117 vs 4 for CEK (Po0.0001). Lung cancer samples were similar; CPK: 145 cells vs CEK:4 cells (Po0.0001). Recovered CTCs were relatively pure (60 -70%) and were evaluable by FISH and immunofluorescence. A total of 10 of 30 (33%) breast cancer patients with HER2-negative primary and metastatic tissue had HER2-amplified CTCs. CONCLUSION: The CPK method provides a high yield of relatively pure CTCs, facilitating their molecular characterisation. Circulating tumour cells obtained using CPK technology demonstrate that significant discordance exists between HER2 amplification of a patient's CTCs and that of the primary and metastatic tumour.

ApoStream™, a new dielectrophoretic device for antibody independent isolation and recovery of viable cancer cells from blood

“…7 In addition, monitoring the response of circulating breast cancer cells to adjuvant chemotherapy allowed detection of patients at risk of early relapse. 9,10 CTCs are rare cells present in the blood in numbers as low as one CTC per 10 6 -10 7 leukocytes, which makes their capture and detection very challenging. The techniques currently used for CTC capture include immunomagnetic separation, 6,8 membrane filters, 11,12 and micro-electro-mechanical system (MEMS) chips.…”

Detection of circulating tumor cells: Clinical relevance of a novel metastatic tumor marker

“…nearly 98% of patients with hEr2-positive primary and metastatic cancers had ctcs expressing elevated levels of hEr2. however, 33% of patients, in whom the primary cancer was hEr2-negative, had ctcs that were hEr2-positive (44). this suggests that hEr2 expression by ctcs may provide the rationale for individually targeted hEr2 therapy (80,82,83).…”

“…tively, from two different patient groups (44,45). new ctc-chip micro-fluidic technology showed a 10-to 100-fold improvement in ctc yield from patient samples over the cellSearch system (44). however, this method needs further validation using large numbers of clinical samples.…”

“…genetic and molecular analysis of these rare cells may provide a novel tool for evaluating their biological and clinical relevance. tively, from two different patient groups (44,45). new ctc-chip micro-fluidic technology showed a 10-to 100-fold improvement in ctc yield from patient samples over the cellSearch system (44).…”

Minimal Residual Disease and Circulating Tumor Cells in Breast Cancer

“…Because of the availability of anti-HER2 agents, HER2 expression was studied on DTCs [71][72][73] and CTCs [33,42,55,59,66,[74][75][76][77][78] (Table 2) and was correlated with HER2 expression on the primary tumor. In most studies, HER2 expression on DTCs/CTCs is more prevalent in women with HER2-positive BC than in women with HER2-negative BC in both non-metastatic and metastatic settings.…”