Deletions of the derivative chromosome 9 do not account for the poor prognosis associated with Philadelphia-positive acute lymphoblastic leukemia

The Philadelphia (Ph) translocation t(9;22)(q34;q11) is found in 15% to 25% of adults and 3% to 5% of children with acute lymphoblastic leukemia (ALL)[1][1] and identifies patients with a particularly poor prognosis.[2][2] The Ph translocation is also the hallmark of chronic myeloid leukemia (CML),