Quercetin can: directly bind to the BH3 structural domain of BCL-2 and B-cell lymphoma-extra large (BCL-XL)proteins [48], thereby inhibiting their anti-apoptotic activity; stimulate the expression of pro-apoptotic genes such as BAX, BCL-2 associated agonist of cell death (BAD), and apoptotic protease activating factor 1(Apaf-1) [49]; increase the release of cytochrome C from the mitochondria into the cytoplasm [50]; and promote the activation of caspase-9 and caspase-3 [50,51,52] from the mitochondria-induced apoptosis pathway to induce apoptosis in tumor cells. This evidence concerns the gene APAF1 and neoplasm.