Pretreatment with ciprofloxacin had no effect on TGFβ-induced phosphorylation of Smad3 or Smad1 in both SSc and healthy cells, suggesting that the antifibrotic effects of ciprofloxacin are not mediated through the TGFβ/Smad pathway (Fig. 3C). The gene discussed is SMAD1; the disease is systemic sclerosis.