In the three treatment groups, the antitumor engineered strain EcN (Tum 5-p53) expressing the Tum 5-p53 fusion protein was significantly superior to the EcN (Tum-5) expressing the Tum-5 protein alone and EcN (p53) expressing the p53 protein alone (P < 0.05), whereas the therapeutic effect of EcN (Tum-5) on human hepatocellular carcinoma SMMC-7721 was slightly higher than that of EcN (p53) (P < 0.05) (Fig. 5a and b). Here, TP53 is linked to hepatocellular carcinoma.