In this study, the expression of BCRP in SP cells was significantly higher than that in non-SP cells, suggesting that radiation-resistance may be associated with the expression of BCRP in SP cells; however, the radiotherapy resistance mechanism of endometrial cancer stem cells (e.g., the relationship between radiation resistance and the cell cycle/signaling pathway) needs further study. This evidence concerns the gene ABCG2 and endometrial cancer.