Two members of this family, MCT1 and MCT4, are upregulated in several cancers, including breast, colorectal, lung, kidney, and glioblastoma (Doherty and Cleveland, 2013; Doyen et al., 2014), and function to regulate lactate transport across the plasma membrane (Halestrap, 2013; Marchiq and Pouysségur, 2015). The gene discussed is SLC16A1; the disease is cancer.