Presence of leukemic clone-specific immunoglobulin heavy chain rearrangements in neonatal blood spots of children with B-cell precursor acute lymphoblastic leukemia.

Our study confirms that a large proportion of childhood BCP-ALL originates in utero, regardless of the molecular subtype defined by chromosomal aberrations. The observed trend toward younger age at diagnosis in Guthrie card-positive versus Guthrie card-negative patients implies that the age at diagnosis depends on the presence of preleukemic clone at birth, as well as on the timing of postnatal transforming genetic events.