RESUMO
Fluorescence in situ hybridization (FISH) analysis of the bone marrow of a 24-year-old man diagnosed with acute promyelocytic leukemia (APL) revealed a variant pattern with one fusion signal instead of the typical two fusions expected with the probe set used. The combined FISH and conventional chromosome analyses suggested that two subsequent translocations had occurred in this patient involving the same chromosomes 15 and 17. As the prognostic outcome in APL is strictly associated with the presence of a PML/RARA fusion, it is useful and necessary to perform both cytogenetic and FISH analyses of a variant t(15;17) to determine the status of the PML/RARA fusion.
Assuntos
Aberrações Cromossômicas , Cromossomos Humanos Par 15/genética , Cromossomos Humanos Par 17/genética , Leucemia Promielocítica Aguda/genética , Proteínas de Neoplasias/genética , Proteínas de Fusão Oncogênica/genética , Translocação Genética/genética , Adulto , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Leucemia Promielocítica Aguda/patologia , Masculino , Proteínas de Neoplasias/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Células Tumorais CultivadasRESUMO
We present a case of del(14)(q21) as a sole abnormality in a 4-year-old boy diagnosed with precursor B-cell acute lymphoblastic leukemia (pre-B ALL). To our knowledge, this is the first case of isolated del(14)(q21) in pre-B ALL. Two pretreatment bone marrow samples obtained 5 days apart were analyzed by cytogenetics. The G-banded karyotypes of the two samples were similar, differing only in the ratio of normal/abnormal metaphases detected. Both samples showed a del(14)(q21) as the only abnormality. Fluorescence in situ hybridization performed using the probes TEL/AML1 and immunoglobulin heavy chain (IGH) showed no fusion involving the TEL and AML1 genes and only a single IGH signal in 20% of the interphase cells analyzed.
