FAS and leukemia: In GVL mouse models, where mice were injected with the murine leukemia cell line L1210 or P815 two days before bone marrow transplantation, mice receiving BM from FasL-deficient mice survived significantly longer than mice transplanted with BM from perforin-deficient mice, indicating that the perforin pathway is more important for the GVL effect than the fas/fas ligand pathway (22).