TOP2B and heart failure: Our finding that phenylalanine induces TOP2β‐mediated DSBs is consistent with the reports that transcription is overactivated in failing hearts [146, 147], TOP2β‐induced DSBs are responsible for cardiotoxicity induced by DNA damaging agents [148], and elevated serum phenylalanine triggers heart failure [65] and cardiac aging [66] and its supplementation decreases lifespan in Caenorhabditis elegans [149].