MicroRNAs as prognostic markers in indolent primary cutaneous B-cell lymphoma.

Indolent primary cutaneous B-cell lymphoma is a group of malignant lymphomas comprising marginal zone B-cell lymphoma and centrofollicular B-cell lymphoma. Relapse rate of these tumors is close to 40%, and identifying those patients who are likely to progress remains a challenge. The aim of this study was to characterize the microRNA (miRNA) expression profile of a series of primary cutaneous B-cell lymphomas and correlate with histological and clinical findings. We studied a series of 68 patients with primary cutaneous B-cell lymphomas (30 cutaneous marginal-zone B-cell lymphomas and 38 primary cutaneous centrofollicular lymphomas). A set of 11 miRNAs associated with the differentiation stage of B cells was quantified by real-time PCR, using RNA extracted from formalin-fixed, paraffin-embedded tissue diagnostic samples. Relevant clinical variables were retrieved in a subset of 57 patients (28 cutaneous marginal zone B-cell lymphomas and 29 primary cutaneous centrofollicular lymphomas). miR-150 was upregulated in cutaneous marginal zone B-cell lymphomas relative to primary cutaneous centrofollicular lymphoma samples (false discovery rate <0.05). miR-155 and miR-150 expression levels were associated with progression-free survival in a univariate Cox regression analysis (P<0.1). After stratification by histological subtype, low-expression levels of miR-155 and miR-150 were both associated with shorter progression-free survival only in primary cutaneous marginal zone B-cell lymphomas cases (log-rank test, P<0.05). In summary, miRNA expression analysis can be used as a tool for diagnosis and outcome prognosis in indolent primary cutaneous B-cell lymphoma.

A high-throughput study in melanoma identifies epithelial-mesenchymal transition as a major determinant of metastasis.

Metastatic disease is the primary cause of death in cutaneous malignant melanoma (CMM) patients. To understand the mechanisms of CMM metastasis and identify potential predictive markers, we analyzed gene-expression profiles of 34 vertical growth phase melanoma cases using cDNA microarrays. All patients had a minimum follow-up of 36 months. Twenty-one cases developed nodal metastatic disease and 13 did not. Comparison of gene expression profiling of metastatic and nonmetastatic melanoma cases identified 243 genes with a >2-fold differential expression ratio and a false discovery rate of <0.2 (206 up-regulated and 37 down-regulated). This set of genes included molecules involved in cell cycle and apoptosis regulation, epithelial-mesenchymal transition (EMT), signal transduction, nucleic acid binding and transcription, protein synthesis and degradation, metabolism, and a specific group of melanoma- and neural-related proteins. Validation of these expression data in an independent series of melanomas using tissue microarrays confirmed that the expression of a set of proteins included in the EMT group (N-cadherin, osteopontin, and SPARC/osteonectin) were significantly associated with metastasis development. Our results suggest that EMT-related genes contribute to the promotion of the metastatic phenotype in primary CMM by supporting specific adhesive, invasive, and migratory properties. These data give a better understanding of the biology of this aggressive tumor and may provide new prognostic and patient stratification markers in addition to potential therapeutic targets.

Neuronal specific regulatory elements in apolipoprotein E gene proximal promoter.

Systemic and local changes in apolipoprotein E (ApoE) quantity have been related with Alzheimer's and other neurodegenerative diseases, showing the relevance of maintaining physiological ApoE levels. However, APOE transcription has not been extensively studied in neural cells. In this report, we study the transcriptional activity of different APOE proximal promoter regions and their binding to nuclear proteins from human neural (astrocytoma and neuroblastoma) and peripheral (hepatoma and lymphoma) cell lines. We define several regions with a negative regulatory effect in all the cells and a region with a strong positive activity in neuroblastoma cells. Additionally, we show that the -219T/G polymorphism produces variations in APOE transcriptional activity, with the G allele showing higher activity.

Managing a biobank network.

Today's biomedical research of excellence is mainly seen as a global phenomenon around the study of large series of samples organized with well-defined and detailed criteria regarding the identification of patients, with the specific information required in each case. This justifies the growing interest in developing cooperative networks of biobanks to minimize biases arising from heterogeneity in the quality of biological samples by means of protocols for procedures, development of common quality assurance policies, and promotion of collaborative environments. This article focuses on some basic aspects of biobank networking, including design and management. It does not try to be an exhaustive analysis but a preliminary approach to the topic, based on the author's expertise in biobank networking in Spain.

Functional signatures identified in B-cell non-Hodgkin lymphoma profiles.

Gene-expression profiling in B-cell lymphomas has provided crucial data on specific lymphoma types, which can contribute to the identification of essential lymphoma survival genes and pathways. In this study, the gene-expression profiling data of all major B-cell lymphoma types were analyzed by unsupervised clustering. The transcriptome classification so obtained, was explored using gene set enrichment analysis generating a heatmap for B-cell lymphoma that identifies common lymphoma survival mechanisms and potential therapeutic targets, recognizing sets of coregulated genes and functional pathways expressed in different lymphoma types. Some of the most relevant signatures (stroma, cell cycle, B-cell receptor (BCR)) are shared by multiple lymphoma types or subclasses. A specific attention was paid to the analysis of BCR and coregulated pathways, defining molecular heterogeneity within multiple B-cell lymphoma types.

A TAP2 genotype associated with Alzheimer's disease in APOE4 carriers.

Sporadic Alzheimer's disease (AD) appears to be the consequence of the interaction between combinations of genes and environmental factors. Binding with the transporter associated with antigen processing (TAP) is thought to be the main way in which herpes simplex virus type 1 (HSV-1) evades immune surveillance. Several TAP gene polymorphisms were examined and a TAP2 SNP (rs241448) associated with AD found in two independent case-control samples, especially in carriers of the APOE4 allele. These findings are consistent with the hypothesis that human genetic variants facilitating the access of HSV-1 to the brain might result in susceptibility to AD.