FLT3LG and central nervous system cancer: After their success in preclinical models showing that FLT3L delivered by adenovirus vectors is sufficient to induce DC activation and prolong overall survival [52], a phase I clinical trial to test the safety of the combination of two adenoviral vectors expressing FLT3L and herpes simplex virus type 1 thymidine kinase (HSV1-TK) in patients with high-grade gliomas showed that the strategy is well tolerated and resulted in encouraging results [53].