We used karyotyping, fluorescence in situ hybridization (FISH), Southern blotting, and RT-PCR in order to analyze prospectively 77 @entity1 (less than 1 year of age) with @entity981 for the occurrence of 11q23/ @entity11626 rearrangements and/or other @entity2008 . Out of the 69 informative samples we found an 11q23/ @entity11626 rearrangement in 42 cases (61%). Regarding only pro-B @entity981 cases, the incidence of 11q23/ @entity11626 rearranged cases, however, reached more than 90% The @entity1 were treated within the therapy studies @entity981 -BFM90, @entity981 -BFM95 and CoALL-05-92. For @entity1 with an adequate follow-up of 4 years the event-free survival of the 11q23/ @entity11626 -positive and 11q23/ @entity11626 -negative group was 0.2 or 0.64, respectively (P = 0.024). The monoclonal antibody 7.1. (moab 7.1) does not react with normal hematopoetic precursors or mature blood cells but was shown to specifically react with leukemic cells bearing a rearrangement of chromosome 11q23 or the @entity11626 gene, respectively. We, therefore, specifically addressed the question whether the reactivity of moab 7.1, as determined by flow cytometry, may substitute for molecular testing of an 11q23/ @entity11626 rearrangement in this cohort of @entity1 ALLs. Reactivity of moab 7.1 indicated a 11q23/ @entity11626 rearrangement with a specificity of 100%. However, five of the 11q23/ @entity11626 -positive cases did not react with moab 7.1 indicating a sensitivity of 84% only. Three of these five moab 7.1-negative but 11q23/ @entity11626 -positive cases could be identified by their unique expression pattern of CD65s and/or @entity5824 . Thus, 95% of all 11q23/ @entity11626 -positive @entity981 cases in infancy may be identified by flow cytometry based on their expression of @entity5824 , CD65s and/or moab 7.1.

XXXX @entity981 - combined cytogenetic, immunophenotypical and molecular analysis of 77 cases.

@entity1 :: ('9606', 'Species') :: ['patients', 'infants', 'infant'] @entity981 :: ('MESH:D054198', 'Disease') :: ['ALL', 'acute lymphoblastic leukemia'] @entity11626 :: ('4297', 'Gene') :: ['MLL'] @entity5824 :: ('2526', 'Gene') :: ['CD15'] @entity2008 :: ('MESH:D002869', 'Disease') :: ['cytogenetic abnormalities']
@entity1 :: (9606,Species) :: ['Infant']
