PTPN1 and Duchenne muscular dystrophy: Importantly, the down-regulation of PTPN1/2 expression during differentiation and the concomitant up-regulation of STAT3 phosphorylation appear to be dysregulated in DMD MuSCs, suggesting that PTPN1/2 may be a viable target to restore pro-myogenic STAT3 signaling in DMD MuSCs.