Polymorphisms: GSTO1*A140D (C419A; rs4925), GSTO2*N142D (A424G; rs156697)Main findings:- no association between allele frequency or genotypes of GSTO1*A140D and GSTO2*N142G variants and Pre-B ALL risk; - significant reverse correlation with Pre-B ALL risk, for 140AA/142DD or 140DD/142NN combination genotypes. This evidence concerns the gene GSTO2 and acute lymphoblastic leukemia.