Tenascin-C (TN-C) is an extracellular matrix glycoprotein [6] that is not expressed in normal adult hearts but is expressed in various myocardial diseases such as acute myocarditis [7–9], dilated cardiomyopathy [10], myocardial infarction [11], and myocardial hibernation [12]. The gene discussed is TNC; the disease is acute myocarditis.