Moreover, HRE-containing oncolytic adenoviruses (H5CmTERT-Ad and H5CmTERT-Ad/TRAIL) showed markedly higher cell killing efficacy during hypoxia than normoxia [normoxia vs. hypoxia; P < 0.05 or P < 0.01 for U87MG (0.5 MOI), P < 0.05 for U251N (0.2 MOI), respectively], indicating that HRE inserted upstream of a cancer-specific promoter can give hypoxia responsiveness to (and enhance the potency of) an oncolytic adenovirus. The gene discussed is TNFSF10; the disease is cancer.