Notably, we also found that neither high concentrations of exogenous soluble FasL (up to 100 ng/ml) nor soluble TRAIL (up to 50 ng/ml) could induce apoptosis of OCI-AML3 cells (while similar concentrations were able to cause cell death on non-AML cell lines), further suggesting against a role for FasL/TRAIL receptor ligation in mediating CTL-induced AML killing (Supplementary Fig. 4D). This evidence concerns the gene FASLG and acute myeloid leukemia.