found that the accumulated succinate in SDH-deficient tumor cells not only upregulates HIF-1A expression via the activation of the intracellular PI3K/Akt signaling pathway but also contributes to tumor invasion by activating macrophage surface SUCNR-1, subsequently inducing M1 polarization and promoting a malignant tumor phenotype (75, 78). This evidence concerns the gene SUCNR1 and neoplasm.