ESR1 and breast cancer: Specificity of TANs to TROP2+ breast cancer cells shows the potential of the TAN prototype nanoformulation as an exclusive hybrid nanoparticle for breast cancer targeting, irrespective of their expression of EsR, PR and HER.30,55 Our data suggest that tetravalent inclusions of TAN can lethally target the cancer cell and its subcellular entities leading to necrosis.