ESR1 and breast cancer: Many peptides that effectively reverse breast cancer resistance have been explored, such as The 8-mer peptide derived from β-fetoprotein inhibits the growth of tamoxifen-resistant estrogen receptor-positive breast cancer cells (Bennett et al., 2002), and Membrane-Lytic Peptide (Chen C. H. et al., 2022), Acid-Sensitive Peptide (Sheng et al., 2015), RanGTP inhibitory peptide (RAN-IP) (Haggag et al., 2020).