Nursing mothers are excluded Pregnant and nursing mothers are excluded from this study. Pregnant or nursing mothers are excluded Pregnant women are excluded from this study; nursing mothers should stop breastfeeding to be eligible Pregnant women, nursing mothers or women of child-bearing potential who are unwilling to use medically accepted methods of contraception Pregnant women are excluded from this study; in nursing mothers, breastfeeding should be discontinued Pregnant women and breastfeeding mothers are excluded Pregnant women or nursing mothers Pregnant and nursing mothers are excluded from this study Study drug must not be administered to pregnant women or nursing mothers Pregnant women or nursing mothers Pregnant women or nursing mothers Pregnant women or nursing mothers Pregnant women, nursing mothers or women of child-bearing potential who are unwilling to use medically accepted methods of contraception Pregnant women or nursing mothers are not eligible for this trial; patients of child bearing potential must use adequate contraception Pregnant or nursing mothers Breastfeeding mothers must agree to discontinue nursing if the mother is treated with selinexor Pregnant women or nursing mothers are not eligible for this trial; patients of child bearing potential must use adequate contraception Pregnant women or nursing mothers Pregnant women and nursing mothers Breastfeeding mothers Pregnancy and/or nursing mothers Pregnant or nursing mothers Pregnant women are excluded from this study; breastfeeding should be discontinued by nursing mothers who agree to participate in the study Breastfeeding mothers are not eligible Pregnant women/lactating mothers Pregnancy or nursing mothers Pregnant women or nursing mothers are not eligible for this trial. Patients of child bearing potential must use adequate contraception (contraceptive pill, or intrauterine device ((IUD)), or two mechanical barriers).