Although, the functional significance of Myh6 in breast cancer cells is unknown, these studies do provide a model of how BPA may down-regulate Myh6. Given that neonatal cardiomyocytes express functional estrogen receptors [23] it is plausible that hormone mediated pathways drive the BPA induced inhibition of Myh6 expression observed in our study. This evidence concerns the gene ESR1 and breast cancer.