XPO1 and breast carcinoma: Other natural inhibitors of XPO1 include anguinomycins, isolated from Streptomyces species with selective cytotoxicity to transformed cells (77), and goniothalamin, obtained from Goniothalamus macrophyllus. Goniothalamin has been reported to induce G2/M phase cell cycle arrest and apoptosis in breast cancer cells (78,79).