SLC16A1 and cancer: While the first generation MCT inhibitors were not clinically viable, owing to a lack of MCT specificity and associated toxicity (Marchiq and Pouysségur, 2015), a potent, second generation MCT1 inhibitor from AstraZeneca, AZD3965, has shown anticancer effects in a variety of cancer cell lines (Bola et al., 2014; Polanski et al., 2014) and treatment of tumors in vivo reduced tumor growth and increased sensitivity to radiation (Bola et al., 2014).