Curcumin treatment increased apoptosis in scleroderma lung fibroblast (SLF) but not in normal lung fibroblast (NLF), because protein kinase C (PKC) and heme oxygenase 1 (HO-1) and glutathione-S-transferase P1 (GST P1) are not active in SLF. Here, GSTP1 is linked to scleroderma.