These were probably because certain amounts of OAd-tAIB-Luc infected the tumor cells even in the presence of anti-Ad5 antibodies, although the infection efficiencies of OAd-tAIB-Luc were lower in the presence of the low titers of anti-Ad5 antibodies than in the naïve serum-pre-injected mice. The gene discussed is PSEN2; the disease is infection.