Prognostic significance of cytogenetic abnormalities of chromosome arm 12p in childhood acute lymphoblastic leukemia

Dicentric Translocation (9;12) in Acute Lymphoblastic Leukemia: A Chromosomal Abnormality with an Excellent Prognosis?

“…All the series published so far, except one (8), have observed excellent results in patients with dicentric translocation (9;12). Heerema et al (8) showed no differences in event-free survival of the 12 patients with dicentric translocation (9;12) compared to those patients lacking a 12p abnormality. Outcomes for the patients with aberrations in both 12p homologues appeared better than those lacking 12p abnormalities.…”

“…It usually occurs with a lower count of leukocytes at diagnosis and a discrete predominance in males (1,2). Table I lists the different pediatric series published to date, in which the survival of these patients approaches 100% (1)(2)(3)(4)(5)(6)(7)(8). Patients with this alteration show a very good response to…”

Spectral karyotyping and interphase FISH reveal abnormalities not detected by conventional G‐banding

“…Ten cases (14%) had rearrangements of the short arm on chromosome 12 other than the TEL/ AML1 fusion. Around 10% of all leukemias have previously been reported to have cytogenetically visible abnormalities of 12p (8). Reciprocal translocations involving 12p and a number of other chromosomal bands have been identified by karyotypic analyses.…”

“…On the other hand, high hyperdiploidy (52-60 chromosomes) is associated with a favourable outcome. The prognosis in patients with TEL/AML1 fusion seems to vary depending on the treatment protocols, and recent studies have reported late relapses in this group of patients (4,(6)(7)(8)(9)(10)(11)(12). Ideal methods for the cytogenetic characterisation of abnormalities in ALL should allow the identification of different risk categories in order to avoid over-treatment and to identify patients that would benefit from more intensive therapy.…”