Our current study demonstrate that genes involved in myogenesis (i.e., Pax7 and Myod) and muscle function (i.e., Myh1 and Pdk4), as well as miR-486, a regulator of myogenesis (16, 30), are uniquely dysregulated in skeletal muscles based on breast cancer subtype and mutation pattern. This evidence concerns the gene MYH1 and breast cancer.