Potential Targets and Biomarkers of Radionuclide Therapy in Breast Cancer

In recent years, multidisciplinary treatment strategies have profoundly improved drug responses and survival outcomes of breast cancer (BC) patients. However, there is an urgent need for novel therapies for BC patients who are heavily treated or develop resistance to conventional treatment regimens. Radionuclide therapy (RT) and targeted radionuclide therapy (TRT) have emerged as paradigm-shifting therapeutic approaches for BC, which enable functions of both imaging and localised treatment. They utilise radionuclides that can selectively bind to biomarkers overexpressing on BC cells, allowing precise delivery and localised tumour irradiation. Moreover, several types of radionuclides possess 'cross-fire' effects that result in the eradication of neighbouring tumour cells lacking the biomarker expression. In the current review, we summarise the potential biomarkers for the development of RT and TRT that can be employed in the treatment of BC, including receptor markers of ER, PR and HER2, together with other markers of Trop2, PD-1, EGFR, GRPR and PSMA.