The transportation of lactic acid in tumor cells is facilitated by solute transporters such as SLC16A1 (monocarboxylic acid transporter 1, MCT1), SLC16A7 (monocarboxylic acid transporter 2, MCT2), and SLC16A3 (monocarboxylic acid transporter 4, MCT4), which play a role in maintaining the balance of intracellular energy and pH [59, 60]. The gene discussed is SLC16A7; the disease is neoplasm.