For example, lactate-induced GPR81 activation activates the transcription factor TEAD by reducing intracellular cAMP levels, further mediating the programmed death-ligand 1 (PD-L1) promoter activation and increase of PD-L1 protein levels in lung cancer, which confirms the key role of lactate in modulating cancer cells to evade immune surveillance [37]. This evidence concerns the gene HCAR1 and cancer.