CDKN1A and cardiac hypertrophy: For example, upregulating p21Cip1/Waf1 was found to be associated with the inhibition of cardiomyocyte hypertrophy via a cardiac-restricted protein, called CHAMP (cardiac helicase activated by MEF2 protein) during prenatal and postnatal development of the heart [44], while a downregulation of p21Cip1/Waf1 was found in aortic constriction-induced cardiac hypertrophy in adult hearts [9], which was supported by a recent study showing that p21Cip1/Waf1 protects cardiac hypertrophy [10].