Alternatively, or in addition, the experimental induction of PTP4A1 by TGFβ in NHDF lines suggests that increased levels of TGFβ in the pro-fibrotic milieu of SSc skin, together with enhanced endogenous TGFβ sensitivity of SSc fibroblasts, might underlie the overexpression of PTP4A1 in early SSc skin stages and SSc fibroblasts5, 46, 47. This evidence concerns the gene PTP4A1 and systemic sclerosis.