RESUMEN

About 30% of T cell acute lymphoblastic leukemias (T-ALL) carry TAL1 gene aberrations. In the majority of cases (approximately 25%), this concerns a submicroscopic deletion of approximately 90 kb in chromosome region 1p32, which deletes the coding regions of the SIL gene and the untranslated region of the TAL1 gene, thereby placing the TAL1 gene under control of the SIL promoter region. Translocation (1;14)(p32;q11) involving the TAL1 gene occurs at a much lower frequency (3%), whereas some other rare variant translocations have been described as well. In this study we developed a set of TAL1 FISH probes based on the split-signal FISH principle that enables detection of both types of TAL1 gene aberrations in single test. For this purpose, one probe was designed downstream of the TAL1 gene (TAL1-D) and the second probe in the region upstream of the TAL1 gene, partly covering the SIL gene (SIL-U). We show that this split-signal FISH probe set allows reliable detection of the unaffected SIL-TAL1 gene region with a fusion signal, SIL-TAL1 fusion genes with loss of the SIL-U signal, and TAL1 gene translocations with a split-signal, independent of the involved partner gene.

Asunto(s)

Proteínas Bacterianas/genética , Proteínas de Unión al ADN/genética , Leucemia-Linfoma de Células T del Adulto/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteínas Proto-Oncogénicas , Translocación Genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Rotura Cromosómica , Cromosomas Humanos Par 1/genética , Eliminación de Gen , Biblioteca de Genes , Secuencias Hélice-Asa-Hélice , Humanos , Hibridación Fluorescente in Situ , Cariotipificación , Leucemia-Linfoma de Células T del Adulto/inmunología , Proteínas de Fusión Oncogénica/genética , Reacción en Cadena de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sensibilidad y Especificidad , Proteína 1 de la Leucemia Linfocítica T Aguda , Factores de Transcripción/genética