WEE1 and neoplasm: Natural chemopreventive agents are relatively safe for normal cells, but they can induce tumor apoptosis through different pathways, such as the cell proliferation pathway (cyclin D1 and c-myc), cell survival pathway (Bcl-2, Bcl-xL, cFLIP, XIAP, and c-IAP1), caspase activation pathway (caspase-8, -3, and -9), tumor suppressor pathway (p53 and p21), death receptor pathway (DR4 and DR5), mitochondrial pathways, and protein kinase pathway (JNK, Akt, and AMPK) [42], as has been demonstrated in several clinical trials [43].