A recent study found that the markers of muscle regeneration (Pax-7, Myf-5, MyoD and myogenia) and the numbers of Pax-7+/Myf-5- SCs in the vastus lateralis of sarcopenic COPD patients were decreased, while markers of muscle injury and the myostatin level were increased (86). The gene discussed is MSTN; the disease is chronic obstructive pulmonary disease.