HIF1A and neoplasm: Succinate can promote M2 polarization of macrophages by binding to the succinate receptor 1.196 In the tumor environment, succinate could be produced and released by tumor cells, and via interacting with succinate receptor 1 to activate phosphoinositide-3-kinase/protein kinase B pathway and upregulate HIF-1α, inducing macrophage polarization, and enhancing tumor cell metastasis.197 Besides, succinate can mediate the progress of inflammation.