RESUMEN
Deletion 20q is a recurrent abnormality in myeloid malignancies. In our previous study, we identified fusion of the additional sex combs-like 1 (ASXL1) and teashirt zinc finger homeobox 2 genes in a patient with myelodysplastic syndrome. The objective of this study was to determine the frequency of ASXL1 breakpoints in a cohort of 36 patients with deletion 20q as the sole cytogenetic aberration. A combination of molecular cytogenetic methods was used to confirm ASXL1 gene alterations in 19 of the 36 patients, and the determination of ASXL1 gene changes in patients with deletion 20q revealed clinical and prognostic impacts.
Asunto(s)
Deleción Cromosómica , Cromosomas Humanos Par 20/genética , Síndromes Mielodisplásicos/genética , Proteínas Represoras/genética , Análisis Citogenético , HumanosRESUMEN
BACKGROUND: Low-grade gliomas represent a heterogeneous group of primary brain malignancies. The current diagnostics of these tumors rely strongly on histological classification. With the development of molecular cytogenetic methods several genetic markers were described, contributing to a better distinction of glial subtypes. The aim of this study was to assess the frequency of acquired chromosomal aberrations in lowgrade gliomas and to search for new genomic changes associated with higher risk of tumor progression. PATIENTS AND METHODS: We analysed biopsy specimens from 41 patients with histological dia-gnosis of low-grade glioma using interphase fluorescence in situ hybridization (IâFISH) and single nucleotide polymorphism (SNP) array techniques (19 females and 22 males, medium age 42 years). RESULTS: Besides notorious and most frequent finding of combined deletion of 1p/â19q (81.25% patients) several other recurrent aberrations were described in patients with oligodendrogliomas: deletions of p and q arms of chromosome 4 (25% patients), deletions of the short arms of chromosome 9 (18.75% patients), deletions of the long arms of chromosome 13 and monosomy of chromosome 18 (18.75% patients). In bio-psy specimens from patients with astrocytomas, we often observed deletion of 1p (24% patients), amplification of the long arms of chromosome 7 (16% patients), deletion of the long arm of chromosome 13 (20% patients), segmental uniparental disomy (UPD) of the short arms of chromosome 17 (60% patients) and deletion of the long arms of chromosome 19 (28% patients). In one patient we detected a shuttered chromosome 10 resulting from chromothripsis. CONCLUSION: Using a combination of IâFISH and SNP array, we detected not only known chromosomal changes but also new or less frequent recur-rent aberrations. Their role in cancerâ cell progression and their impact on lowâgrade gliomas classification remains to be elucidated in a larger cohort of patients.
Asunto(s)
Neoplasias Encefálicas/genética , Aberraciones Cromosómicas , Eliminación de Gen , Glioma/genética , Adulto , Astrocitoma/genética , Astrocitoma/patología , Neoplasias Encefálicas/patología , Femenino , Glioma/patología , Humanos , Hibridación Fluorescente in Situ , Masculino , Persona de Mediana Edad , Oligodendroglioma/genética , Oligodendroglioma/patologíaRESUMEN
In oligodendroglial brain tumours, losses of chromosomal material of the short arm of chromosome 1 and long arm of chromosome 19 have been shown to predict responsiveness to chemotherapy and prolonged patients' survival. Therefore, the correct diagnosis of these genetic alterations in tumours of oligodendroglial origin is particularly important. To detect deletions of 1p36 and/or 19q13.3 in oligodendroglial cells we used dual-colour I-FISH with locus-specific DNA probes. I-FISH was performed on isolated whole cell nuclei, prepared from fresh non-fixed tumour tissue samples resuspended in media and processed using a standard cytogenetic procedure, thus bypassing the problem of nuclear truncation. We examined 16 patients with histologically proved oligodendrogliomas (5x oligodendroglioma, 9x anaplastic oligodendroglioma, 2x anaplastic oligoastrocytoma). The results of molecular cytogenetic analyses were correlated with morphological and clinical findings. Molecular cytogenetic analyses were successful in 15 patients and, due to a non-adequate tissue specimen, were uninformative in one patient only. Combined deletions 1p36/19q13 were proved in 13 patients. However, in six of them additional genetic alterations typical for high-grade astrocytoma were found, which could have negative influence on the prognosis. One patient had isolated deletion of 1p36 and another had a normal genetic pattern without any chromosomal alterations. In summary, I-FISH on isolated cell nuclei is a powerful tool for detecting chromosomal aberrations in tumour cells. A systematic molecular cytogenetic analysis may advance diagnosis, prognostic stratification, and targeted treatment of patients with brain tumours.
Asunto(s)
Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/genética , Hibridación Fluorescente in Situ , Interfase/fisiología , Oligodendroglioma/diagnóstico , Oligodendroglioma/genética , Adulto , Anciano , Núcleo Celular/metabolismo , Aberraciones Cromosómicas , Cromosomas Humanos Par 11/genética , Cromosomas Humanos Par 7/genética , Cromosomas Humanos Par 9/genética , Sondas de ADN/metabolismo , Femenino , Genoma Humano/genética , Humanos , Masculino , Persona de Mediana Edad , PronósticoRESUMEN
Morphological examination is the routine first step in the diagnosis of hematological malignancies, including chronic lymphocytic leukemia (CLL). Atypical cell morphology according to the FAB criteria is known to herald disease progression. Several years ago, it was proposed that FAB morphology at diagnosis had a considerable prognostic impact. However, this proposal has not been widely adopted in practice. Thus we questioned the prognostic value of the morphological examination, which was performed retrospectively in 88 patients out of our 110 institutional registry patients (70 males and 40 females, median age 57 yrs) with CLL at diagnosis. We related the results to the more modern prognostic markers. Atypical FAB morphology was shown to correlate with IgVH gene mutation status, trisomy of chromosome 12 and deletion of 17p detected either by conventional G-banding or by fluorescence in situ hybridization (FISH) analysis. The correlation of FAB morphology with CD38 antigen expression or with the histopathological pattern of bone marrow infiltration was not significant. Overall survival (OS) data were available for 84 morphologically examined patients. The patients with atypical morphology (64 patients) had a significantly shorter OS (103 months) than the 20 patients presenting with typical CLL morphology (237 months; p=0.03). Only the mutation status of IgVH genes correlated more closely with OS (p=0.002). Of note, there was no leukemia-related death within "unmutated" cases who had typical FAB morphology (p=0.14), and vice versa, the mutation status had a significant prognostic impact within the morphologically atypical cases (p=0.01). Thus FAB morphology and the mutation status may yield complementary prognostic information. OS was affected both by the presence of cytogenetic aberrations (p=0.03) - most adversely by deletions of 17p and 11q, and by CD38 expression (p=0.003). We conclude that careful examination of peripheral blood smears according to FAB is a simple, cheap and valuable tool in the first-line assessment of prognosis of CLL patients and should not be overlooked even in 3rd millennium when more sophisticated prognostic markers are at hand. This ought to be confirmed in larger prospective studies with multivariate analysis of data.