Previously we observed that hiPSC‐derived cardiomyocytes from doxorubicin sensitive patients exhibit lower mitochondrial amount compared to hiPSC‐CMs from patients that did not develop DIC.[9] To investigate whether lower mitochondrial levels correlated to severe DIC toxicity, with patients written consent, we recruited cancer patients (n = 11) and collected 8 mL of whole blood prior to their anthracycline chemotherapy and monitored their heart failure biomarkers (BNP [early heart failure], cTnT and cTnI [late heart failure]). The gene discussed is TNNI3; the disease is heart failure.