The most common examples are the transgenic mice expressing oncogenes, such as MYC (c-Myc) or CTNNB1 (β-catenin), and mice with mutation/deletion of several genes such as PDGF, TGFβ1, NEMO, TAK1, A1AT (α1-antitrypsin), or PTEN. Experimental evidence suggests that tumor suppressor genes also play an important role in HCC response to anticancer drugs. This evidence concerns the gene PTEN and hepatocellular carcinoma.