We characterized and compared ECM protein changes occurring during tumor development in the PDGFC Tg mouse model, a model of HCC associated with fibrosis and angiogenesis [4] and in the Pten null mouse model, a model of liver tumors of mixed cholangio- and hepatocytic features [6]–[8], [17]. The gene discussed is PDGFC; the disease is hepatocellular carcinoma.