However, at very high viral doses and an extended period of infection, Ad5WS1 also caused some CPE, albeit only to a very small extent, in BFTC-905 and TSGH-8301 cells with wild-type p53. Studies along this line demonstrated that E1B-deleted adenovirus can infect tumour cells with functional p53 at higher viral doses, while kill those carrying nonfunctional p53 at much lower doses in hepatocellular carcinoma and lung cancer cell lines (Vollmer et al, 1999; You et al, 2000). The gene discussed is TP53; the disease is hepatocellular carcinoma.