Specifically, prior studies found lower NRG-1 levels in patients with severe coronary artery disease (CAD) and those developing cardiotoxicity with trastuzumab.29,30 In the current study, we likewise noted lower NRG-1β values in patients who developed a decline in LVEF over the full course of trastuzumab therapy. Here, NRG1 is linked to coronary artery disorder.