Sensing acidification of ECM, carcinoma cells increase expression of the lactate/H+ symporter monocarboxylate transporter (MCT) family, consisting of MCT1, MCT2, MCT3, and MCT4 (Kim et al., 2015), where, MCT1 and MCT4 contribute to cancer malignancy by shuttling lactate within tumor, which serves as a respiratory fuel in tumor metabolism (Gao et al., 2015). The gene discussed is SLC16A7; the disease is neoplasm.