ESR1 and breast cancer: Various breast cancer cell lines have been used to demonstrate a dose-dependent response to CBD, including estrogen-receptor (ER)-positive cells (MCF-7, ZR-75-1, T47D), ER-negative cells (MDA-MB-231, MDA-MB-468, and SK-BR3), and triple-negative breast cancer (TNBC) cells (SUM159, 4T1up, MVT-1, and SCP2) [67,83,84,85,86,87,88].