In harmony with the essentiality of MCT4 for tumor growth, several studies indicate that expression of the hypoxia-inducible monocarboxylate transporter MCT4 is increased in tumors and its expression correlates with clinical outcome, thus it may serve as a valuable prognostic factor (Witkiewicz et al., 2012; Doyen et al., 2014; Baek et al., 2014). The gene discussed is SLC16A3; the disease is neoplasm.