The present invention found that lasofoxifene is an antagonist of ER-α36. It not only inhibits the growth of ER-α36 positive lung, colon and gastric cancers, and also it can inhibit the growth of acquired or de novo tamoxifen-resistant MCF-7 cells. Our finding also provides methods and compositions for treating cancer comprising lasofoxifene alone or in combination with at least one other agent selected from the group consisting of gefitinib and/or trastuzumab or functional equivalent thereof, and an inhibitor in hormonal or epidermal growth factor signal transduction pathways.
