WEE1 and cancer: Inhibition of Wee1 releases tumor cells from DNA-damage-induced arrest at the G2/M boundary, so that unrepaired DNA damage may be taken into mitosis (M phase); as cancer cells show higher levels of endogenous damage than normal cells, as well as exhibiting loss of one or more DDR capabilities, this is predicted to preferentially enhance cancer cell death through mitotic catastrophe compared with normal cells [2, 9].