Monocarboxylate Transporters 1-4 in NSCLC: MCT1 Is an Independent Prognostic Marker for Survival

Introduction: Monocarboxylate transporters (MCTs) 1-4 are lactate transporters crucial for cancers cells adaption to upregulated glycolysis. Herein, we aimed to explore their prognostic impact on disease-specific survival (DSS) in both cancer and tumor stromal cells in NSCLC. Methods: Tissue micro arrays (TMAs) were constructed, representing both cancer and stromal tumor tissue from 335 unselected patients diagnosed with stage I-IIIA NSCLC. Immunohistochemistry was used to evaluate the expression of MCT1-4. Results: In univariate analyses; down arrow MCT1 (P = 0.021) and up arrow MCT4 (P = 0.027) expression in cancer cells, and up arrow MCT1 (P = 0.003), down arrow MCT2 (P = 0.006), down arrow MCT3 (P = 0.020) expression in stromal cells correlated significantly with a poor DSS. In multivariate analyses; down arrow MCT1 expression in cancer cells (HR: 1.9, CI 95%: 1.3-2.8, P = 0.001), down arrow MCT2 (HR: 2.4, CI 95%: 1.5-3.9, P<0.001), down arrow MCT3 (HR: 1.9, CI 95%: 1.1-3.5, P = 0.031) and up arrow MCT1 expression in stromal cells (HR: 1.7, CI 95%: 1.1-2.7, P = 0.016) were significant independent poor prognostic markers for DSS. Conclusions: We provide novel information of MCT1 as a candidate marker for prognostic stratification in NSCLC. Interestingly, MCT1 shows diverging, independent prognostic impact in the cancer cell and stromal cell compartments.