Distinct patterns of novel gene mutations in poor-prognostic stereotyped subsets of chronic lymphocytic leukemia: the case of SF3B1 and subset #2.

Recent studies have revealed recurrent mutations of the NOTCH1, SF3B1 and BIRC3 genes in chronic lymphocytic leukemia (CLL), especially among aggressive, chemorefractory cases. Nevertheless, it is currently unknown whether their presence may differ in subsets of patients carrying stereotyped B-cell receptors and also exhibiting distinct prognoses. Here, we analyzed the mutation status of NOTCH1, SF3B1 and BIRC3 in three subsets with particularly poor prognosis, that is, subset #1, #2 and #8, aiming to explore links between genetic aberrations and immune signaling. A remarkably higher frequency of SF3B1 mutations was revealed in subset #2 (44%) versus subset #1 and #8 (4.6% and 0%, respectively; P<0.001). In contrast, the frequency of NOTCH1 mutations in subset #2 was only 8%, lower than the frequency observed in either subset #1 or #8 (19% and 14%, respectively; P=0.04 for subset #1 versus #2). No associations were found for BIRC3 mutations that overall were rare. The apparent non-random association of certain mutations with stereotyped CLL subsets alludes to subset-biased acquisition of genomic aberrations, perhaps consistent with particular antigen/antibody interactions. These novel findings assist in unraveling specific mechanisms underlying clinical aggressiveness in poor-prognostic stereotyped subsets, with far-reaching implications for understanding their clonal evolution and implementing biologically oriented therapy.

450K-array analysis of chronic lymphocytic leukemia cells reveals global DNA methylation to be relatively stable over time and similar in resting and proliferative compartments.

In chronic lymphocytic leukemia (CLL), the microenvironment influences gene expression patterns; however, knowledge is limited regarding the extent to which methylation changes with time and exposure to specific microenvironments. Using high-resolution 450K arrays, we provide the most comprehensive DNA methylation study of CLL to date, analyzing paired diagnostic/follow-up samples from IGHV-mutated/untreated and IGHV-unmutated/treated patients (n=36) and patient-matched peripheral blood and lymph node samples (n=20). On an unprecedented scale, we revealed 2239 differentially methylated CpG sites between IGHV-mutated and unmutated patients, with the majority of sites positioned outside annotated CpG islands. Intriguingly, CLL prognostic genes (for example, CLLU1, LPL, ZAP70 and NOTCH1), epigenetic regulator (for example, HDAC9, HDAC4 and DNMT3B), B-cell signaling (for example, IBTK) and numerous TGF-ß and NF-κB/TNF pathway genes were alternatively methylated between subgroups. Contrary, DNA methylation over time was deemed rather stable with few recurrent changes noted within subgroups. Although a larger number of non-recurrent changes were identified among IGHV-unmutated relative to mutated cases over time, these equated to a low global change. Similarly, few changes were identified between compartment cases. Altogether, we reveal CLL subgroups to display unique methylation profiles and unveil methylation as relatively stable over time and similar within different CLL compartments, implying aberrant methylation as an early leukemogenic event.

A functionally distinct TATA box required for late progression through the Epstein-Barr virus life cycle.

During EBV infection, lytic DNA replication activates late gene expression in trans via an uncharacterized pathway. In this study, we mapped the target of this regulatory cascade to a variant TATA box (TATTAAA) and the 3' flanking region within the core promoter of the BcLF1 gene. The inherent late activity of this core promoter is, surprisingly, disrupted by a heterologous enhancer, suggesting that late gene expression is regulated through core promoter sequences located in a transcriptionally inert environment.

Caveats in interpreting and applying pharmacoeconomic data.

Cautions in the interpretation and application of pharmacoeconomic data are discussed. Cost containment is driving outcomes research and can cause pharmacoeconomic study methods to be manipulated to support preordained conclusions. The usual tactic is to adopt a narrow perspective in assessing benefits and costs. For example, many calculations ignore financial and physical pain borne by the patient. Before the results of any pharmacoeconomic analysis are embraced, the perspective adopted should be carefully examined. Each provider must look at a product or service from all relevant angles and in the context of its own standards. Although outcomes research may indeed make it possible to provide high-quality care for less money in the long term, in the short term these studies are devoted largely to the goal of spending less, even if some patients may suffer. In such circumstances, legal issues unavoidably arise. Principal among them is tort liability, the risk of being deemed negligent either in providing care or in obtaining informed consent. Any topic pressing enough to be included in outcomes research agendas and debates is going to require decisions that consider (1) the positions of national medical specialty societies, (2) the relevant catchment area or other defining cohort, (3) the specific institution, and (4) the professionals practicing in that institution. The inhouse professional who disagrees with rationing can become a credible whistle blower, and the judiciary may go to extraordinary lengths to empower patients, even without whistle blowers. Complete honesty in obtaining informed consent can help avoid legal actions. Pharmacoeconomic research can be useful in describing value for money spent. It is important to remember, however, that perspective matters in any analysis and that honesty is vital in policymaking and in sharing information with patients.

The impact of healthcare reform proposals on radiology practice.

Current healthcare reform proposals (especially the Clinton administration's Health Security Act) are daunting in their detail, scope and possible effect on radiology--daunting, but crucial for understanding the immediate future of the profession. Ms. Cahill reveals some of the most important proposed changes, the context within which they are framed and their implications.

The appearance of fluorescein-labelled lymphocytes in lymph following in vitro or in vivo labelling: the route of lymphocyte recirculation through mesenteric lymph nodes.

Fluorescein isothiocyanate (FITC) has been used to study lymphocyte migration in sheep. After being labelled in vitro with FITC, lymphocytes migrated from blood into lymph at the same rate and with the same recovery as lymphocytes labelled with with the radioisotope 51chromium. The in vivo labelling of mesenteric lymph nodes (MLN) with FITC resulted in high numbers of labelled lymphocytes appearing in prescapular lymph. However, the appearance of the FITC-labelled lymphocytes in the prescapular lymph could be prevented by cannulating the main intestinal lymph duct prior to the in vivo labelling procedure. It was concluded that lymphocytes labelled in vivo within the MLN required an intact lymphatic system to reach the blood circulation and did not enter the venous circulation directly from the MLN.