Diffuse large B-cell lymphoma with combined TP53 mutation and MIR34A methylation: Another “double hit” lymphoma with very poor outcome?

MiR34A, B and C have been implicated in lymphomagenesis, but information on their role in normal CD19+ B-cells (PBL-B) and de novo diffuse large B-cell lymphoma (DLBCL) is limited.We show that in normal and activated B-cells miR34A-5p plays a dominant role compared to other miR34 family members. Only miR34A-5p is expressed in PBL-B, and significantly induced in activated B-cells and reactive lymph nodes. In PBL-B, the MIR34A and MIR34B/C promoters are unmethylated, but the latter shows enrichment for the H3K4me3/H3K27me3 silencing mark.Nine de novo DLBCL cases (n=150) carry both TP53 mutation and MIR34A methylation (“double hit”) and these patients have an exceedingly poor prognosis with a median survival of 9.4 months (P<0.0001), while neither TP53 mutation, MIR34A or MIR34B/C promoter methylation alone (“single hit”) influence on survival. The TP53/MIR34A “double-hit” is an independent negative prognostic factor for survival (P=0.0002). In 2 DLBCL-cell lines with both TP53 mutation and promoter methylation of MIR34A, miR34A-5p is upregulated by 5-aza-2''deoxycytidine. Thus, the TP53/MIR34A “double hit” characterizes a very aggressive subgroup of DLBCL, which may be treatable with epigenetic therapy prior to or in combination with conventional immunochemotherapy.     

Needs and concerns of patients in isolation care units - learnings from COVID-19: A reflection

With strict measures in place to contain the spread of coronavirus disease 2019, many have been isolated as suspected or confirmed cases. Being isolated causes much inconvenience for the patients and family. Patients' and next-of-kins’ needs and concerns during isolation will be shared together with suggestions for key process improvements. Our hospital’s Senior Patient Experience Managers contact all patients admitted to the isolation wards on a daily basis to provide some form of support. Common issues raised were gathered and strategies to help with their needs and concerns were discussed. Being in isolation is a challenging period for both patients and family. Nonetheless, we can implement measures to mitigate against the adverse effects of isolation. Patient education, effective and efficient means of communication, close monitoring for signs of distress and anxiety, and early intervention could help patients cope better with the whole isolation experience. Nursing management may want to consider implementing the measures shared in the article to manage patient’s stress while not compromising on staff safety.     

Structural Basis for Activation of G‐Protein‐Coupled Receptors

Abstract: Our understanding of how G‐protein‐coupled receptors (GPCRs) operate at the molecular level has been considerably improved over the last few years. The application of advanced biophysical techniques as well as the availability of high‐resolution structural information has allowed insight both into conformational changes accompanying GPCR activation and the underlying molecular mechanism governing transition of the receptor between its active and inactive states. Using the β₂‐adrenergic receptor as a model system we have obtained evidence for an evolutionary conserved activation mechanism where disruption of intramolecular interactions between TM3 and TM6 leads to a major conformational change of TM6 relative to the rest of the receptor. This conclusion was based on experiments in which environmentally sensitive, sulfhydryl‐reactive fluorophores were site‐selectively incorporated into wild‐type and mutant β₂‐adrenergic receptors purified from Sf‐9 insect cells. Our studies have also raised important questions regarding kinetics of receptors activation. These questions should be addressed in the future by application of techniques that will allow for simultaneous measurement of conformational changes and receptor activation. At the current stage we are exploring the possibility of reaching this goal by direct in situ labeling of the β₂‐adrenergic receptor in Xenopus Laevis oocytes with conformationally sensitive fluorescent probes and parallel detection of receptor activation by co‐expression with the cAMP sensitive Cl^? channel CFTR (cystic fibrosis transmembrane conductance regulator) and electrophysiological measurements.     

Cell-of-origin determined by both gene expression profiling and immunohistochemistry is the strongest predictor of survival in patients with diffuse large B-cell lymphoma

The tumor cells in diffuse large B-cell lymphomas (DLBCL) are considered to originate from germinal center derived B-cells (GCB) or activated B-cells (ABC). Gene expression profiling (GEP) is preferably used to determine the cell of origin (COO). However, GEP is not widely applied in clinical practice and consequently, several algorithms based on immunohistochemistry (IHC) have been developed. Our aim was to evaluate the concordance of COO assignment between the Lymph2Cx GEP assay and the IHC-based Hans algorithm, to decide which model is the best survival predictor. Both GEP and IHC were performed in 359 homogenously treated Swedish and Danish DLBCL patients, in a retrospective multicenter cohort. The overall concordance between GEP and IHC algorithm was 72%; GEP classified 85% of cases assigned as GCB by IHC, as GCB, while 58% classified as non-GCB by IHC, were categorized as ABC by GEP. There were significant survival differences (overall survival and progression-free survival) if cases were classified by GEP, whereas if cases were categorized by IHC only progression-free survival differed significantly. Importantly, patients assigned as non-GCB/ABC both by IHC and GEP had the worst prognosis, which was also significant in multivariate analyses. Double expression of MYC and BCL2 was more common in ABC cases and was associated with a dismal outcome. In conclusion, to determine COO both by IHC and GEP is the strongest outcome predictor to identify DLBCL patients with the worst outcome.     

Population data of 23 Y chromosome STR loci for the five major human subpopulations of Ghana

In this study, 268 samples for unrelated males belonging to the five major human subpopulation groups in Ghana (Akan, Ewe, Mole-Dagbon, Ga-Dangme and Guang) were genetically characterised for 23 Y chromosome short tandem repeat (STR) loci using the Powerplex® Y23 STR kit. A total of 263 complete haplotypes were recorded of which 258 were unique. The haplotype diversity, discriminating capacity and match probability for the pooled population data were 0.9998, 0.9627 and 0.0039, respectively. The pairwise genetic distance (RST) for the Ghanaian datasets and other reference populations deposited in the Y-STR Haplotype Reference Database (YHRD) were estimated and mapped using multidimensional scaling (MDS) plot. The Guang and Ewe were significantly different from the Akan, Mole-Dagbon and Ga-Dangme. However, the five Ghanaian datasets were all plotted close together with other African populations in the MDS data mapping.