We also have recently demonstrated that SLC7A5 and SLC3A2 singularly are associated with poor prognosis, particularly in the luminal-B subtype of breast cancer [11,12]; however, studies addressing the clinical significance of the SLC7A5/SLC3A2 complex in ER+ breast cancer and the efficacy of endocrine treatment remain lacking. Here, SLC7A5 is linked to breast cancer.