A high number of losses in 13q14 chromosome band is associated with a worse outcome and biological differences in patients with B-cell chronic lymphoid leukemia.

BACKGROUND: Among patients with B-cell chronic lymphoid leukemia, those with 13q14 deletion have a favorable outcome. However, whether the percentage of cells with 13q- influences the prognosis or the biological characteristics of this disease is unknown. We analyzed the clinico-biological characteristics and outcome of patients with B-cell chronic lymphoid leukemia with loss of 13q as the sole cytogenetic aberration. DESIGN AND METHODS: Three hundred and fifty patients with B-cell chronic lymphoid leukemia were studied. Clinical data were collected and fluorescence in situ hybridization and molecular studies were carried out. In addition, a gene expression profile was obtained by microarray-based analysis. RESULTS: In 109 out of the 350 cases (31.1%) loss of 13q was the sole cytogenetic aberration at diagnosis. In the subgroup of patients with 80% or more of cells with loss of 13q (18 cases), the overall survival was 56 months compared with not reached in the 91 cases in whom less than 80% of cells had loss of 13q (p< 0.0001). The variables included in the multivariate analysis for overall survival were the percentage of losses of 13q14 (p=0.001) and B symptoms (p=0.007). The time to first therapy in the group with 80% or more vs. less than 80% of losses was 38 months vs. 87 months, respectively (p=0.05). In the multivariate analysis the variables selected were unmutated status of IgV(H) (p=0.001) and a high level of beta(2)microglobulin (p=0.003). Interestingly, these differences regarding overall survival and time to first therapy were also present when other cut-offs were considered. The gene expression profile of patients with a high number of losses in 13q14 showed a high proliferation rate, downregulation of apoptosis-related genes, and dysregulation of genes related to mitochondrial functions. CONCLUSIONS: Patients with B-cell chronic lymphoid leukemia with a high number of losses in 13q14 as the sole cytogenetic aberration at diagnosis display different clinical and biological features: short overall survival and time to first therapy as well as more proliferation and less apoptosis. A quantification of the number of cells showing a genetic abnormality should, therefore, be included in the study of the prognostic factors of B-cell chronic lymphoid leukemia.

aCGH-MAS: analysis of aCGH by means of multiagent system.

There are currently different techniques, such as CGH arrays, to study genetic variations in patients. CGH arrays analyze gains and losses in different regions in the chromosome. Regions with gains or losses in pathologies are important for selecting relevant genes or CNVs (copy-number variations) associated with the variations detected within chromosomes. Information corresponding to mutations, genes, proteins, variations, CNVs, and diseases can be found in different databases and it would be of interest to incorporate information of different sources to extract relevant information. This work proposes a multiagent system to manage the information of aCGH arrays, with the aim of providing an intuitive and extensible system to analyze and interpret the results. The agent roles integrate statistical techniques to select relevant variations and visualization techniques for the interpretation of the final results and to extract relevant information from different sources of information by applying a CBR system.

TET2 overexpression in chronic lymphocytic leukemia is unrelated to the presence of TET2 variations.

TET2 is involved in a variety of hematopoietic malignancies, mainly in myeloid malignancies. Most mutations of TET2 have been identified in myeloid disorders, but some have also recently been described in mature lymphoid neoplasms. In contrast to the large amount of data about mutations of TET2, some data are available for gene expression. Moreover, the role of TET2 in chronic lymphocytic leukemia (CLL) is unknown. This study analyzes both TET2 expression and mutations in 48 CLL patients. TET2 expression was analyzed by exon arrays and quantitative real-time polymerase chain reaction (qRT-PCR). Next-generation sequencing (NGS) technology was applied to investigate the presence of TET2 variations. Overexpression of TET2 was observed in B-cell lymphocytes from CLL patients compared with healthy donors (P = 0.004). In addition, in CLL patients, an overexpression of TET2 was also observed in the clonal B cells compared with the nontumoral cells (P = 0.002). However, no novel mutations were observed. Therefore, overexpression of TET2 in CLL seems to be unrelated to the presence of genomic TET2 variations.

Molecular characterization of chronic lymphocytic leukemia patients with a high number of losses in 13q14.

BACKGROUND: Patients with chronic lymphocytic leukemia and 13q deletion as their only FISH abnormality could have a different outcome depending on the number of cells displaying this aberration. Thus, cases with a high number of 13q- cells (13q-H) had both shorter overall survival and time to first therapy. The goal of the study was to analyze the genetic profile of 13q-H patients. DESIGN AND METHODS: A total of 102 samples were studied, 32 of which served as a validation cohort and five were healthy donors. RESULTS: Chronic lymphocytic leukemia patients with higher percentages of 13q- cells (>80%) showed a different level of gene expression as compared to patients with lower percentages (<80%, 13q-L). This deregulation affected genes involved in apoptosis and proliferation (BCR and NFkB signaling), leading to increased proliferation and decreased apoptosis in 13q-H patients. Deregulation of several microRNAs, such as miR-15a, miR-155, miR-29a and miR-223, was also observed in these patients. In addition, our study also suggests that the gene expression pattern of 13q-H cases could be similar to the patients with 11q- or 17p-. CONCLUSIONS: This study provides new evidence regarding the heterogeneity of 13q deletion in chronic lymphocytic leukemia patients, showing that apoptosis, proliferation as well as miRNA regulation are involved in cases with higher percentages of 13q- cells.

Factores pronósticos en la leucemia linfocítica crónica / Prognostic factors in chronic lymphocytic leukemia

La leucemia linfocítica crónica (LLC) es una hemopatía maligna heterogénea, en parte por las características genéticas de sus células. Si bien los sistemas de Binet y Rai continúan siendo los índices más utilizados para establecer el pronóstico, no predicen el curso individual en estadios iniciales. En este sentido, los nuevos factores pronósticos bioquímicos, la generalización del uso de las técnicas de hibridación in situ fluorescente (FISH), la determinación del estado mutacional del gen VH y la expresión de CD38 y ZAP-70, entre otros, han producido un gran avance en el estudio de los factores pronósticos. Las alteraciones citogenéticas estudiadas mediante FISH identifican grupos con pronóstico favorable (13q- y citogenética normal) y desfavorable (11q- y 17p-) y el estudio de las mutaciones somáticas de VH ponen de manifiesto que los pacientes con patrón no mutado presentan características clínico citogenéticas y pronósticas desfavorables, con una buena correlación con la expresión de ZAP-70 y una mayor tendencia a citogenéticas de mal pronóstico. Aun así, la importancia clínica de estas alteraciones presenta algunas controversias y quedan por definir aspectos pronósticos de algunas alteraciones citogenéticas menos frecuentes. En los últimos años, el estudio de nuevos marcadores moleculares así como la secuenciación del genoma de la LLC y los avances en la bioinformática y robótica han producido una revolución en el estudio de esta enfermedad...