Indeed, we found that knockdown of SLC7A5 and SLC3A2 expression increase the sensitivity of breast cancer cells to tamoxifen, which suggests that targeting co-expression of the SLC7A5/SLC3A2 complex might be a potential therapeutic approach to improve the efficacy of endocrine therapy in ER+/HER2− early breast cancer. The gene discussed is SLC7A5; the disease is breast cancer.