The expression levels of several proteins, namely epidermal growth factor receptor (EGFR), collagen type I alpha 1 chain (COL1A1), matrix metalloproteinase-9 (MMP9), matrix metalloproteinase-2 (MMP2), phosphor-mothers against decapentaplegic homolog 2 (ph-SMAD2), Vimentin (Vim), transforming growth factor-beta1 (TGF-β1), alpha-smooth muscle actin (α-SMA), and connective tissue growth factor (CTGF) involved in the induction and progression of liver fibrosis and in the regulation of signal transduction were analyzed by Western blotting. The gene discussed is SMAD2; the disease is Hepatic fibrosis.