It was also noticeable that the TGF-β/Smad3 pathway was highly activated in both normal and DM1 myoblasts at differentiation day 0, which was consistent with the previous reports that the activation of TGF-β involved pathway inhibited differentiation but induced quiescence of myoblasts (Rathbone et al., 2011). This evidence concerns the gene SMAD3 and myotonic dystrophy type 1.