Evaluation of Monocarboxylate Transporter 4 ( MCT4) Expression and Its Prognostic Significance in Circulating Tumor Cells From Patients With Early Stage Non-Small-Cell Lung Cancer

Monocarboxylate transporter 4 ( can influence the amount of lactate in the tumor microenvironment and further control cancer cell proliferation, migration, and angiogenesis. We investigated for the first time the expression of in circulating tumor cells (CTCs) derived from early stage Non-Small Cell Lung Cancer patients (NSCLC) and whether this is associated with clinical outcome. A highly sensitive RT-qPCR assay for quantification of transcripts was developed and validated and applied to study expression in CTC isolated through the Parsortix size-dependent microfluidic device from 53 and 9 peripheral blood (PB) samples of NSCLC patients at baseline (pre-surgery) and at relapse, respectively, as well as the "background noise" was evaluated using peripheral blood samples from 10 healthy donors (HD) in exactly the same way as patients. was differentially expressed between HD and NSCLC patients. Overexpression of was detected in 14/53 (26.4%) and 3/9 (33.3%) patients at baseline and at progression disease (PD), respectively. The expression levels of was found to increase in CTCs at the time of relapse. Kaplan-Meier analysis showed that the overexpression of was significantly ( = 0.045) associated with progression-free survival (median: 12.5 months, range 5-31 months). overexpression was observed at a high frequency in CTCs from early NSCLC patients supporting its role in metastatic process. investigated as clinically relevant tumor biomarker characterizing tumor aggressiveness and its potential value as target for cancer therapy. We are totally convinced that overexpression in CTCs merits further evaluation as a non-invasive circulating tumor biomarker in a large and well-defined cohort of patients with NSCLC.