Purpose: FAS is a cell surface receptor involved in apoptotic signal transmission. Deregulation of this pathway results in down-regulation of apoptosis and subsequent persistence of a malignant clone. A single nucleotide polymorphism resulting in guanine-to-adenine transition in the FAS promoter region (position -1377) is thought to reduce stimulatoryprotein 1 transcription factor binding and decrease FAS expression. Previous work has shown increased risk of developing acute myeloid leukemia (AML) in adult patients with a variant allele at this site. The same authors have shown that the presence of an adenine residue rather than a guanine residue at -1,377 bp significantly attenuates transcription factor stimulatory protein 1 binding and may contribute to a reduction in FAS expression and ultimatelyto the enrichment of apoptosis-resistant clones in AML. We hypothesized that FAS genotype by altering susceptibility to apoptosis might affect outcome of childhood AML therapy. Experimental Design: Four hundred forty-four children treated for de novo AML on a uniform protocol were genotyped for FAS 1377. Results: There were no significant differences in overall survival, event-free survival, treatment- related mortality, or relapse rate between patients with FAS 1377GG genotype versus 1377GA/ 1377AA genotypes. Conclusions: FAS 1377 genotype does not alter outcome of de novo AML in children.