MPO and breast cancer: We have discussed the available evidence on three “classical biomarkers” (troponins, NPs, and LVEF/strain changes), five “emerging biomarkers” (SNPs, miRNAs, MPO, Gal-3, and MMPs), several “other biomarkers” (inflammatory, NLR, metabolism, PBMCs, IgE, CRP, and GDF-15), and provided a list of numerous newly investigated biomarkers in the field of precision medicine for the assessment of CTRCD in breast cancer patients.