Constitutive overexpression of Erbb2 results in an enlarged heart characterized by extensive cardiomyocyte hypertrophy, dedifferentiation and proliferation, whereas transient induction of ERBB2 promotes cardiomyocyte dedifferentiation and regeneration after myocardial infarction (D’Uva et al., 2015). The gene discussed is ERBB2; the disease is myocardial infarction.