European Society for Medical Oncology (ESMO) suggests measuring BNP to evaluate cardiotoxicity during and after radiotherapy for breast cancer patients.[35] BNP measurement should be performed in patients with risk factors for cardiac damage, in those who receive high doses to the heart despite modern technology.[36–39] According to follow up of breast cancer patients, BNP is a potential biomarker to heart damage, and is recommended to detect gradually for a long time. The gene discussed is NPPB; the disease is breast cancer.