The included studies investigated MT’s effects in a wide array of breast cancer cell lines, including triple-negative breast cancer (TNBC) cells such as MDA-MB-231, BT474, MDA-MB-468, HCC-1806, and BT20; ER+/PR+ breast cancer cell lines such as MCF-7, T47-D, and Bcap-37; HER2+ cell lines such as SK-BR-3; and the murine breast cancer cell line 4T1. The gene discussed is ESR1; the disease is triple-negative breast carcinoma.