 t(12;21)(p13;q22)[ETV6-RUNX1] is the most common chromosomal translocation in childhood acute lymphoblastic leukemia, and it can often be backtracked to Guthrie cards supporting prenatal initiation and high levels of circulating t(12;21)-positive cells at birth.     ///    Prevalence of t(12;21)[ETV6-RUNX1]-positive cells in healthy neonates.. 