Dysmetabolic Circulating Tumor Cells Are Prognostic in Metastatic Breast Cancer

Abstract

Circulating tumor cells (CTCs) belong to a heterogeneous pool of rare cells, and a unequivocal phenotypic definition of CTC is lacking. Here, we present a definition of metabolically-altered CTC (MBA-CTCs) as CD45-negative cells with an increased extracellular acidification rate, detected with a single-cell droplet microfluidic technique. We tested the prognostic value of MBA-CTCs in 31 metastatic breast cancer patients before starting a new systemic therapy (T0) and 3–4 weeks after (T1), comparing results with a parallel FDA-approved CellSearch (CS) approach. An increased level of MBA-CTCs was associated with: i) a shorter median PFS pre-therapy (123 days vs. 306; p < 0.0001) and during therapy (139 vs. 266 days; p = 0.0009); ii) a worse OS pre-therapy (p = 0.0003, 82% survival vs. 20%) and during therapy (p = 0.0301, 67% survival vs. 38%); iii) good agreement with therapy response (kappa = 0.685). The trend of MBA-CTCs over time (combining data at T0 and T1) added information with respect to separate evaluation of T0 and T1. The combined results of the two assays (MBA and CS) increased stratification accuracy, while correlation between MBA and CS was not significant, suggesting that the two assays are detecting different CTC subsets. In conclusion, this study suggests that MBA allows detection of both EpCAM-negative and EpCAM-positive, viable and label-free CTCs, which provide clinical information apparently equivalent and complementary to CS. A further validation of proposed method and cut-offs is needed in a larger, separate study.

Clinical relevance of the combined analysis of circulating tumor cells and anti-tumor T-cell immunity in metastatic breast cancer patients

“…The study was conducted at the IRCCS-CRO Aviano-National Cancer Institute and approved by the Institutional Review Board with number IRB-12-2014 ( 32 ). Informed and written consent was obtained from all patients and healthy donors before their enrolment, and their clinico-pathological information was recorded.…”

“…A detailed description of the procedure employed for the enrichment and identification of CTCs with a metabolism-based assay (MBA) has been published previously ( 32 ). Briefly, peripheral blood samples (2.5 ml) were drawn into K2-EDTA Vacutainer tubes (Becton Dickinson).…”

“…On these grounds, the present study aimed at investigating the association of the anti-tumor activity of circulating T-cells and the level of CTCs before and after treatment in a cohort of mBC patients and to evaluate their potential predictive and prognostic role. For this cohort, we previously reported that an increased level of dysmetabolic CTCs, as detected by a new CTC assay developed by our group, was associated with a worst prognosis and that tracking CTC dynamic over time improved patient stratification ( 32 ). With the final goal to further improve the predictive and prognostic definition of mBC patients, here we investigated the clinical relevance of integrating CTC data with T-cell responses against BC associated antigens and the variations of TCR repertoire assessed in the peripheral blood.…”

Liquid Biopsy as a Tool for the Diagnosis, Treatment, and Monitoring of Breast Cancer

“…This review identified 16 studies that assessed the presence of CTCs and their use as predictive biomarkers for treatment response or relapse. These studies associated a high CTC count with shorter progression-free survival (PFS), DFS and/or OS [ 79 , 80 , 81 , 82 , 83 , 84 ], resistance to different therapies [ 80 , 84 , 85 ], worse outcome [ 82 , 84 , 85 ], disease relapse [ 82 , 85 ], and metastasis [ 86 ]. Some studies have also evaluated CTC counts with different phenotypes, such as mesenchymal CTCs (mCTCs) and epithelial CTCs (eCTCs).…”

Metabolic Constrains Rule Metastasis Progression

“…Coherently, the upregulation of the same gene represents an efficient strategy to identify metastatic prostate cancer patients [188]. The high glycolytic metabolism has also been proven to result into a high lactate production, which was indeed used in devices aimed at CTC isolation [189,190]. Ultimately, a work from Aceto and colleagues conducted in CTCs derived from breast cancer patients pointed out a significant hyperactivation of the ATP metabolic process and amino acid metabolism [191].…”