This study showed that mRNA levels of several ECM molecules such as TGF-β1, myostatin, collagen I and VI, MMP-2, TIMP-1, and TIMP-2 were significantly higher whereas no significant differences were noticeable in mRNA levels of MMP-9 and TIMP-3 in DMD myotubes compared to normal myotubes (Zanotti et al., 2007). Here, MMP9 is linked to Duchenne muscular dystrophy.