In this relatively large, single-center, retrospective analysis evaluating cardiac biomarkers in patients with breast cancer, the following was observed: (1) anthracycline recipients had higher values of NT-proBNP than non-recipients; (2) increasing time between breast cancer diagnosis and serum collection was associated with higher NT-proBNP values; and (3) sST2 and galectin-3 did not differ between anthracycline recipients and non-recipients. This evidence concerns the gene NPPB and breast cancer.