A study in the United States analyzed the distribution of xenobiotic detoxification gene alleles of GSTM1  (insertion/deletion) , GSTT1  (insertion/deletion), and  GSTP1  (Ala114Val) genes among 173 child patients and registered the association of a functional allele of GSTM1  and a rare genotype of GSTP1  (Val114/Val114) with pediatric astrocytoma [21]. Here, GSTM1 is linked to childhood astrocytic tumor.