ESR1 and breast cancer: In breast cancer in vitro experiments, palmatine treatment at concentrations ranging from 0.5–100 μg/mL on human estrogen receptor-positive breast cancer cell lines (MCF-7, T47D, and ZR-75–1) and normal human mammary epithelial cells (MCF-10A) revealed IC50 values between 5.126 and 5.805 μg/mL, with dose-dependent inhibition of cancer cell proliferation but minimal effects on normal mammary epithelial cells (Grabarska et al., 2021).