An essential initial objective was to define the minimal Rad51 promoter element that retained the robust transcriptional activity and tumor selectivity of the intact promoter, since the full length Rad51 promoter reported by Gorbunova and colleagues is over 6.5 kb in length [18] and exceeds the insert capacity for many adenoviral vectors [20], [21]. The gene discussed is RAD51; the disease is neoplasm.