Several animal models have been developed in the past decades namely APCmin (adenomatous polyposis coli), AOM (azoxymethane), MNU (N-methyl-N-nitrosourea), MMR (mismatch repair), TGF-β, (transforming growth factor-beta) xenograft, and the non-murine zebrafish models of human colorectal cancer (CRC) disease [23]. The gene discussed is TGFB1; the disease is colorectal cancer.