The top ten clues to understand the origin of chronic lymphocytic leukemia (CLL)

The malignant transformation potential of the oncogene STYK1/NOK at early lymphocyte development in transgenic mice

B-cell Chronic Lymphocytic Leukemia (B-CLL) is a malignancy caused by the clonal expansion of mature B lymphocytes bearing a CD5+CD19+ (B1) phenotype. However, the origin of B-CLL remains controversial. We showed previously that STYK1/NOK transgenic mice develop a CLL-like disease. Using this model system in this study, we attempt to define the stage of CLL initiation. Here, we show that the phenotype of STYK1/NOK-induced B-CLL is heterogeneous. The expanded B1 lymphocyte pool was detected within peripheral lymphoid organs and was frequently associated with the expansions of memory B cells. Despite this immunophenotypic heterogeneity, suppression of B cell development at an early stage consistently occurred within the bone marrow (BM) of STYK1/NOK-tg mice. Overall, we suggest that enforced expression of STYK1/NOK in transgenic mice might significantly predispose BM hematopoietic stem cells (HSCs) towards the development of B-CLL.

The dual role of complement in cancers, from destroying tumors to promoting tumor development

Complement is an important branch of innate immunity; however, its biological significance goes far beyond the scope of simple nonspecific defense and involves a variety of physiological functions, including the adaptive immune response. In this review, to unravel the complex relationship between complement and tumors, we reviewed the high diversity of complement components in cancer and the heterogeneity of their production and activation pathways. In the tumor microenvironment, complement plays a dual regulatory role in the occurrence and development of tumors, affecting the outcomes of the immune response. We explored the differential expression levels of various complement components in human cancers via the Oncomine database. The gene expression profiling interactive analysis (GEPIA) tool and Kaplan-Meier plotter (K-M plotter) confirmed the correlation between differentially expressed complement genes and tumor prognosis. The tumor immune estimation resource (TIMER) database was used to statistically analyze the effect of complement on tumor immune infiltration. Finally, with a view to the role of complement in regulating T cell metabolism, complement could be a potential target for immunotherapies. Targeting complement to regulate the antitumor immune response seems to have potential for future treatment strategies. However, there are still many complex problems, such as who will benefit from this therapy and how to select the right therapeutic target and determine the appropriate drug concentration. The solutions to these problems depend on a deeper understanding of complement generation, activation, and regulatory and control mechanisms.

Follicular lymphoma (FL): Immunological tolerance theory in FL

The ultimate cause of follicular lymphoma (FL) remains unknown. Remarkably, almost nothing is known about immunological tolerance mechanisms that might contribute to FL development. Immunological tolerance mechanisms, like other stimuli, also induce persistent changes of B cell receptors that induce genetic instability and molecular aberrations promoting the development of a neoplasm. Using the same method as Burnet, we provide a new perspective taking advantage of the comparison of a normal linear B cell differentiation process and FL development within the framework of clonal selection theory. We propose that FL is a malignancy of cells that acquire both translocation t(14;18) and self-BCR, inducing them to proliferate and mature, resistant to negative selection. Additional genetic damage induced by non-apoptotic tolerance mechanisms, such as receptor editing, may transform a self-reactive B cell with t(14;18) into an FL. The result of tolerogenic mechanisms and genetic aberrations is the survival of FL B cell clones with similar markers and homogenous gene expression signatures despite the different stages of maturation at which the molecular damage occurs. To antagonize further growth advantage due to self-antigen recognition and chronic activation of tolerance mechanisms in the apoptosis-resistant background of FL B cells, inhibitors of BCR signaling may be promising therapeutic options.

A functional variant that affects exon-skipping and protein expression of SP140 as genetic mechanism predisposing to multiple sclerosis

Several variants in strong linkage disequilibrium (LD) at the SP140 locus have been associated with multiple sclerosis (MS), Crohn's disease (CD) and chronic lymphocytic leukemia (CLL). To determine the causal polymorphism, we have integrated high-density data sets of expression quantitative trait loci (eQTL), using GEUVADIS RNA sequences and 1000 Genomes genotypes, with MS-risk variants of the high-density Immunochip array performed by the International Multiple Sclerosis Genetic Consortium (IMSGC). The variants most associated with MS were also correlated with a decreased expression of the full-length RNA isoform of SP140 and an increase of an isoform lacking exon 7. By exon splicing assay, we have demonstrated that the rs28445040 variant was the causal factor for skipping of exon 7. Western blots of peripheral blood mononuclear cells from MS patients showed a significant allele-dependent reduction of the SP140 protein expression. To confirm the association of this functional variant with MS and to compare it with the best-associated variant previously reported by GWAS (rs10201872), a case-control study including 4384 MS patients and 3197 controls was performed. Both variants, in strong LD (r(2) = 0.93), were found similarly associated with MS [P-values, odds ratios: 1.9E-9, OR = 1.35 (1.22-1.49) and 4.9E-10, OR = 1.37 (1.24-1.51), respectively]. In conclusion, our data uncover the causal variant for the SP140 locus and the molecular mechanism associated with MS risk. In addition, this study and others previously reported strongly suggest that this functional variant may be shared with other immune-mediated diseases as CD and CLL.