MR inhibitor (e.g., eplerenone, canrenone, spironolactone) use can be supportive in breast cancer chemotherapy, as it was proven to reduce cardiotoxicity and cardiovascular mortality of patients treated with anthracyclines—By reducing fibrosis, extracellular matrix turnover and myocardial collagen content and leading to better left ventricle parameters, notably lesser decrease of LVEF (left ventricular ejection fraction). This evidence concerns the gene NR3C2 and breast carcinoma.