Inactivation of GPX4 leads to the accumulation of lipid peroxides, which destroys the cell membrane and ultimately causes cell death.[12, 13] Previous studies have reported that RSL3 could successfully inhibit the development of breast cancer.[14] However, it remains unclear whether RSL3 encapsulated in hydrogels can also effectively suppress breast cancer and exert anticancer effects in a sustained release manner. The gene discussed is GPX4; the disease is breast cancer.