Orthogonal Comparison of Four Plasma NGS Tests With Tumor Suggests Technical Factors are a Major Source of Assay Discordance.

Purpose: Discordance between plasma and tumor variant calling has been attributed primarily to tumor heterogeneity, whereas technical variables remain largely unexplored.

Materials And Methods: To measure these variables, we tested four next-generation sequencing (NGS) gene panel assays for mutations in circulating tumor DNA (ctDNA) using replicate sets of 24 plasma samples and compared the results with matched tumor-normal tissue pairs.

Results: Our orthogonal approach identified false-negative (FN) and false-positive (FP) variants with high confidence and revealed substantial variability among the ctDNA assays, with a range of sensitivity (38% to 89%) and positive predictive value (36% to 80%).

Comparative analysis of primary relapse/refractory DLBCL identifies shifts in mutation spectrum.

Current understanding of the mutation spectrum of relapsed/refractory (RR) tumors is limited. We performed whole exome sequencing (WES) on 47 diffuse large B cell lymphoma (DLBCL) tumors that persisted after R-CHOP treatment, 8 matched to primary biopsies. We compared genomic alterations from the RR cohort against two treatment-naïve DLBCL cohorts (n=112).

Acquired Resistance to the Mutant-Selective EGFR Inhibitor AZD9291 Is Associated with Increased Dependence on RAS Signaling in Preclinical Models.

Resistance to targeted EGFR inhibitors is likely to develop in EGFR-mutant lung cancers. Early identification of innate or acquired resistance mechanisms to these agents is essential to direct development of future therapies. We describe the detection of heterogeneous mechanisms of resistance within populations of EGFR-mutant cells (PC9 and/or NCI-H1975) with acquired resistance to current and newly developed EGFR tyrosine kinase inhibitors, including AZD9291.

Interneuronal transfer of human tau between Lamprey central neurons in situ.

The mechanisms by which tau-containing lesions are propagated between adjacent and synaptically interconnected parts of the brain are a potentially important but poorly understood component of human tauopathies such as Alzheimer's disease, Pick's disease, and corticobasal degeneration. Since the utility of currently available transgenic models for studying intercellular aspects of tauopathy is limited by their broad patterns of tau expression in the central nervous system, we used an in situ tauopathy model that replicates tau-induced cytodegeneration in identified neurons on a tau-negative background to determine whether tau secretion or interneuronal transfer might play a role in lesion propagation. We found that the N-terminal half of tau is required for tau secretion and is efficiently exported to the extracellular space and adjacent neurons at relatively low levels of overexpression.

Dietary supplementation with S-adenosyl methionine delays the onset of motor neuron pathology in a murine model of amyotrophic lateral sclerosis.

The full range of causative factors in Amyotrophic lateral sclerosis (ALS) remains elusive, but oxidative stress is recognized as a contributing factor. Mutations in Cu/Zn superoxide dismutase 1 (SOD-1), associated with familial ALS, promote widespread oxidative damage. Mice-expressing G93A mutant human SOD-1 mice display multiple pathological changes characteristic of ALS and are therefore useful for therapeutic development.

The nature of extracellular iron influences iron acquisition by Mycobacterium tuberculosis residing within human macrophages.

We have reported that Mycobacterium tuberculosis residing within the phagosomes of human monocyte-derived macrophages (MDM) can acquire Fe from extracellular transferrin (TF) and sources within the MDM. In the lung, Fe is also bound to lactoferrin (LF) and low-molecular-weight chelates. We therefore investigated the ability of intraphagosomal M.

Intraphagosomal Mycobacterium tuberculosis acquires iron from both extracellular transferrin and intracellular iron pools. Impact of interferon-gamma and hemochromatosis.

Mycobacterium tuberculosis multiplies within the macrophage phagosome and requires iron for growth. We examined the route(s) by which intracellular M. tuberculosis acquires iron.