SLC16A1 and cancer: Lactate intake through MCT1 acts as a paracrine signaling agent that generates a pseudohypoxic response in oxidized cancer cells where it not only leads to HIF- 1α but also HIF-2α stabilization and HIF-2 activation after oxidation to pyruvate and pyruvate-mediated inhibition of proguanidin hydroxylase (PHD) (Lu et al., 2005; Perez-Escuredo et al., 2016a).