To verify whether HFn-DOX could make feasible the therapeutic combination of TZ and DOX in the management of HER2+ BC, we analyzed heart tissue of mice treated with placebo, TZ, DOX, HFn-DOX, and with the combination of HFn-DOX + TZ and DOX + TZ in order to find typical morphological mitochondrial alteration due to cardiotoxicity. This evidence concerns the gene ERBB2 and breast cancer.