RESUMO
We report on two patients with myeloid disorders and complex karyotypes including a dicentric chromosome, dic(17;20)(p11.2;q11.2), resulting in the loss of most of 17p and 20q. The presence of the centromeres of chromosomes 17 and 20 in the dic(17;20), as well as the loss of TP53, were confirmed by fluorescence in situ hybridization. Deletions of 17p and 20q are recurrent abnormalities in hematologic disorders, particularly myelodysplastic syndrome and acute myeloid leukemia). However, a dic(17;20) is an uncommon finding. According to the few reports in the literature, dic(17;20) is associated with an unfavorable prognosis. The key mechanism might be the loss of TP53 as well as other tumor suppressor genes in 20q that may have a critical role in tumor genesis.
Assuntos
Leucemia Mieloide/genética , Síndromes Mielodisplásicas/genética , Doença Aguda , Idoso , Antineoplásicos/uso terapêutico , Feminino , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Leucemia Mieloide/diagnóstico , Leucemia Mieloide/tratamento farmacológico , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/diagnóstico , Síndromes Mielodisplásicas/tratamento farmacológicoRESUMO
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.