RESUMEN
A 12-year-old male with pre-B-cell acute lymphoblastic leukemia with cryptic BCR/ABL rearrangement underwent sex-mismatched allogeneic bone marrow transplantation (allo-BMT). Contradictory results were provided by various chimerism analyses 3 months later. Y-chromosome-specific quantitative polymerase chain reaction and sex chromosome-specific interphase fluorescence in situ hybridization (i-FISH) showed complete donor chimerism. Analysis of autosomal short tandem repeats (A-STR), BCR/ABL i-FISH test, and X-STR haplotype indicated relapse. Metaphase-FISH and combined BCR/ABL and sex chromosome-specific i-FISH patterns revealed loss of the Y-chromosome and duplication of the X-chromosome in the host cells. Sex chromosome changes after allo-BMT can cause significant difficulties in chimerism analysis.
Asunto(s)
Trasplante de Médula Ósea , Quimera , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/terapia , Análisis para Determinación del Sexo , Niño , Cromosomas Humanos X/genética , Cromosomas Humanos Y/genética , Proteínas de Fusión bcr-abl/genética , Humanos , Hibridación Fluorescente in Situ , Masculino , Reacción en Cadena de la Polimerasa , Leucemia-Linfoma Linfoblástico de Células Precursoras B/diagnóstico , Secuencias Repetidas en Tándem/genética , Trasplante Homólogo , Resultado del TratamientoRESUMEN
Detecting balanced translocations using tissue sections plays an important diagnostic role in cases of hematological malignancies. Manual scoring is often problematic due to truncation and overlapping of nuclei. Reports have described automated analysis using primarily tile sampling. The aim of this study was to investigate an automated fluorescent in situ hybridization analysis method using grid sampling on tissue sections, and compare the performance of dual-fusion (DF) and break-apart (BA) probes in this setting. Ten follicular, 10 mantle cell lymphoma, and 10 translocation-negative samples were used to set the threshold of false positivity using IGH/CCND1, IGH/BCL-2 DF, and IGH BA probes. The cut-off distances of red and green signals to define fusion signals were 0.5, 1.0, and 1.2 mum for the IGH/CCND1, IGH/BCL-2 DF, and IGH BA probes, respectively. The mean false positivity of grid units was 5.3, 11.4, and 28.1%, respectively. Ten to 14 additional samples analyzed blindly and were correctly classified using each probe. Discriminating positive and negative samples using automated analysis and grid sampling was possible with each probe, although different definitions of fusion signals were required due to the different physical distances between the DNA probes. Using the DF probes resulted in lower false positivity, which was less affected by signal numbers per grid units.
Asunto(s)
Hibridación Fluorescente in Situ/instrumentación , Hibridación Fluorescente in Situ/métodos , Linfoma/metabolismo , Parafina/química , Translocación Genética , Automatización , Sondas de ADN , Reacciones Falso Positivas , Colorantes Fluorescentes/química , Técnicas Histológicas , Humanos , Ganglios Linfáticos/patología , Adhesión en Parafina , Sensibilidad y EspecificidadRESUMEN
Bone marrow specimens from 185 patients with plasma cell disorders (PCD) were investigated by fluorescence in situ hybridization (FISH) in order to determine the temporal sequence of cytogenetic aberrations. In 25 cases combined FISH analysis has also been performed at single cell level. Clonal evolution was observed in 16% of cases. The Δ13 was preceded by t(4;14)(p16;q32) and t(14;16)(q32;q23) translocations. Deletion of p53 gene was a secondary aberration compared to Δ13 and t(11;14)(q13;q32) translocation. In 22% of all cases with recurrent IGH translocation, this aberration was presented only in a subset of purified plasma cells questioning its initiating role.