RESUMEN
Fluorescence in situ hybridization (FISH) analysis in a case of infant acute monocytic leukemia M5 revealed a complex rearrangement between chromosomes 10 and 11, leading to the disruption of the MLL gene. Using two painting probes for chromosomes 10 and 11 and a specific probe for the MLL gene localized on 11q23, we observed a paracentric inversion of the 11q13-q23 fragment translocated to 10p12. Molecular analysis showed that AF10 localized on 10p12 was the fusion partner gene of MLL in this rearrangement (10;11). This report underlined the usefulness of FISH and molecular techniques in identifying complex rearrangements.
Asunto(s)
Inversión Cromosómica , Cromosomas Humanos Par 10/ultraestructura , Cromosomas Humanos Par 11/ultraestructura , Proteínas de Unión al ADN/genética , Leucemia Monocítica Aguda/genética , Proteínas de Fusión Oncogénica/genética , Proto-Oncogenes , Factores de Transcripción/genética , Translocación Genética , Trasplante de Médula Ósea , Cromosomas Humanos Par 10/genética , Cromosomas Humanos Par 11/genética , N-Metiltransferasa de Histona-Lisina , Humanos , Hibridación Fluorescente in Situ , Lactante , Masculino , Proteína de la Leucemia Mieloide-Linfoide , Translocación Genética/genéticaRESUMEN
Medulloblastoma is the most frequent malignant brain tumor of the posterior fossa in children. As prognostic factors for this disease are not well-established, it seemed important to identify genetic features in these tumors. We present data provided by recent studies on conventional cytogenetic, molecular cytogenetic and molecular genetic in correlation with prognosis in these tumors.
Asunto(s)
Neoplasias Infratentoriales/genética , Meduloblastoma/genética , Niño , Aberraciones Cromosómicas , Cromosomas Humanos Par 17/genética , Amplificación de Genes , Humanos , Hibridación Fluorescente in Situ , Neoplasias Infratentoriales/patología , Cariotipificación , Meduloblastoma/patología , PronósticoRESUMEN
To draw the cytogenetic profile of childhood and adult acute megakaryoblastic leukemia (M7), the Groupe Français de Cytogénétique Hématologique collected 53 cases of M7 (30 children and 23 adults). Compared to other acute myeloid leukemias, M7 is characterized by a higher incidence of abnormalities, a higher complexity of karyotypes, and a different distribution of abnormalities among children and adults. Nine cytogenetic groups were identified: normal karyotypes (group 1), patients with Down syndrome (group 2), numerical abnormalities only (group 3), t(1;22)(p13;q13) or OTT-MAL transcript (group 4), t(9;22)(q34;q11) (group 5), 3q21q26 (group 6), -5/del(5q) or -7/del(7q) or both (group 7), i(12)(p10) (group 8), and other structural changes (group 9). Groups 1, 2, 3, and 4 were exclusively composed of children (except one adult in group 3), whereas groups 5, 6, 7, and 8 were mainly made up of adults. The main clinical and hematologic features of these groups were described. No new recurrent abnormality was identified, but mapping of all breakpoints allowed us to specify several possible hot spots of rearrangement: 17q22-23, 11q14-21, 21q21-22, and 16q21-22-23. Although 90.5% of cases had no documented antecedent hematologic disorder or exposure to chemotherapy or radiotherapy, the morphologic and the cytogenetic findings indicated that M7 might be a secondary leukemia more often than suggested by preceding history, particularly among adults. The concurrent analyses of morphologic and cytogenetic data also led us to assume that the initial precursor involved might be more immature in adult than in childhood M7.