Cutting the root:the next generation of T cells engagers against cancer stem cells to overcome drug resistance in triple-negative breast cancer

Triple-negative breast cancer(TNBC)is the most difficult type of breast cancer to treat.TNBC is defined by the lack of expression of three receptors:estrogen receptor(ER);progesterone receptor(PR);and human epidermal growth factor receptor 2(HER2).Chemotherapy is currently first-line treatment for TNBC;however,due to the high heterogeneity of TNBC,most patients eventually develop chemotherapy resistance,which is associated with a poor prognosisl-2.Emerging immune checkpoint blockade(ICB)therapies have been shown to have promising therapeutic efficacy in treating solid tumors.A phase III clinical trial reported that the combination of ICB and chemotherapy lengthened progression-free survival in patients with metastatic PD-L1+TNBC3;however,most patients had primary resistance or acquired resistance to ICB.Thus,the intrinsic mechanisms underlying ICB resistance are still under investigation4.