 TEL-AML1 (ETV6-RUNX1) fusion gene which is formed prenatally in 1% of the newborns, is a common genetic abnormality in childhood Bcell precursor acute lymphoblastic leukemia.     ///    "In other words, out of a hundred children born with TEL-AML1 only one child is at risk for leukemia development, which means that TEL-AML1 fusion gene is not sufficient for overt leukemia. "    ///    Mitotic crossover promotes leukemogenesis in children born with TEL-AML1 via the generation of loss of heterozygosity at 12p.. 