As the samples analyzed consist predominantly (but not solely) of fully differentiated non-dividing cardiomyocytes, this suggests that spaceflight activates p21- and Myc-related pathways to regulate cell growth, cardiomyocyte function, and potentially cardiomyopathy, although complex interactions such as these remain to be elucidated. This evidence concerns the gene CDKN1A and cardiomyopathy.