To confirm the effect of 5FU, anti-PrP antibody, or cetuximab on CRC progression, we initially assessed the tumor size after treatment with 5FU, anti-PrP antibody (5 or 50 mg), or cetuximab (50 mg/kg) twice a week in an SNU-C5/WT xenograft model and investigated the level of PrPC in serum (Figure 6A–D). The gene discussed is PRNP; the disease is colorectal carcinoma.