Comprehensive cross-platform comparison of methods for non-invasive EGFR mutation testing : results of the RING observational trial.

Abstract Several platforms for noninvasive EGFR testing are currently used in the clinical setting with sensitivities ranging from 30% to 100%. Prospective studies evaluating agreement and sources for discordant results remain lacking. Herein, seven methodologies including two next-generation sequencing (NGS)-based methods, three high-sensitivity PCR-based platforms, and two FDA-approved methods were compared using 72 plasma samples, from EGFR-mutant non-small-cell lung cancer (NSCLC) patients progressing on a first-line tyrosine kinase inhibitor (TKI). NGS platforms as well as high-sensitivity PCR-based methodologies showed excellent agreement for EGFR-sensitizing mutations (K = 0.80-0.89) and substantial agreement for T790M testing (K = 0.77 and 0.68, respectively). Mutant allele frequencies (MAFs) obtained by different quantitative methods showed an excellent reproducibility (intraclass correlation coefficients 0.86-0.98). Among other technical factors, discordant calls mostly occurred at mutant allele frequencies (MAFs) ≤ 0.5%. Agreement significantly improved when discarding samples with MAF ≤ 0.5%. EGFR mutations were detected at significantly lower MAFs in patients with brain metastases, suggesting that these patients risk for a false-positive result. Our results support the use of liquid biopsies for noninvasive EGFR testing and highlight the need to systematically report MAFs. Keywords: NGS; circulating free DNA; epidermal growth factor receptor; non-small-cell lung cancer; osimertinib; tyrosine kinase inhibitor

Developmental Reaction Norms for Water Stressed Seedlings of Succulent Cacti

Succulent cacti are remarkable plants with capabilities to withstand long periods of drought. However, their adult success is contingent on the early seedling stages, when plants are highly susceptible to the environment. To better understand their early coping strategies in a challenging environment, two developmental aspects (anatomy and morphology) in Polaskia chichipe and Echinocactus platyacanthus were studied in the context of developmental reaction norms under drought conditions. The morphology was evaluated using landmark based morphometrics and Principal Component Analysis, which gave three main trends of the variation in each species. The anatomy was quantified as number and area of xylem vessels. The quantitative relationship between morphology and anatomy in early stages of development, as a response to drought was revealed in these two species. Qualitatively, collapsible cells and collapsible parenchyma tissue were observed in seedlings of both species, more often in those subjected to water stress. These tissues were located inside the epidermis, resembling a web of collapsible-cell groups surrounding turgid cells, vascular bundles, and spanned across the pith. Occasionally the groups formed a continuum stretching from the epidermis towards the vasculature. Integrating the morphology and the anatomy in a developmental context as a response to environmental conditions provides a better understanding of the organism's dynamics, adaptation, and plasticity

Histological sections and schematic representations of <i>Echinocactus platycanthus</i> hypocotyls.

<p>Transversal sections were obtained 3–4 mm above the base of the shoot. <b>A</b>: Seedling of a Control treatment. <b>B</b> Seedling of a Stress treatment. <b>C</b> Vascular bundle area showing details of the collapsible cells and areas of collapsible tissue. <b>D</b>: Section of parenchyma showing turgid cells next to collapsed cells. <b>E–F</b>: Schematic representation of B,C respectively: turgid cells in green, collapsed cells in grey, xylem cells in red, and phloem cells in blue. <b>A–B</b>: Bright field microscopy; <b>C–D</b>: Phase contrast microscopy. White arrows show a turgid cell, black arrows show groups of collapsible cells. Scale bar 100 µm. CO: cortex; PI: pith; VB: vascular bundle.</p

Quantification of the morphology and the anatomy in cacti seedlings.

<p><b>A–C</b>: The morphology of <i>Polaskia chichipe</i> expressed as PC_Pol. <b>D–E</b>: The number and area of xylem vessels in <i>Polaskia chichipe</i>. <b>F–H</b>: The morphology of <i>Echinocactus platyacanthus</i> represented as PC_Ech. <b>I–J</b>: The number and area of vessels in <i>Echinocactus platyacanthus</i>. <b>D–E</b>,<b>I–J</b>: Significant PCs from the regression <i>y_i</i> = β_PC1+β_PC2+β_PC3+ε_i are highlighted. * p<0.5, *** p<0.0005. Error bars represent standard error. DAG: days after germination.</p

Morphometric analysis of seedling shape and size.

<p><b>A,B</b>: 30-point template to capture the shape of both <i>Polaskia chichipe</i> and <i>Echinocactus platyacanthus</i> seedlings. Open circles correspond to primary landmarks which are placed on recognizable features of the seedlings (base, cotyledonary areoles, and apex); filled circles correspond to secondary landmarks evenly spaced between primary landmarks. <b>C</b>: Example of the 30-point model template fitted onto a photographed seedling. <b>D</b>: Principal Component Analysis of <i>Polaskia chichipe</i> (PCA_Pol) and <i>Echinocactus platyacanthus</i> (PCA_Ech) seedlings. Mean shapes with and without procrustes for size are shown. SD: Standard deviation. PC1_Pol shows elongation of the apex with size effects.</p

Seroprevalence and immunological memory against SARS-CoV-2 in lung cancer patients: the SOLID study.

At present, we did not find any articles that studied seroprevalence and its persistence several months later in lung cancer patients in the setting of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Most patients with coronavirus disease 2019 (COVID-19) go on to develop antibodies (Abs) against viral proteins. However, it is not known how long these Abs last nor whether cancer treatments could affect the duration of immune response. This prospective, longitudinal, multicenter serological study in the setting of SARS-CoV-2 infection was carried out in 50 Spanish hospitals. Eligibility criterion was the diagnosis of any lung cancer. The determination of anti-SARS-CoV-2 IgG Abs was performed by qualitative immuno-enzymatic assay using enzyme-linked immunosorbent assay (ELISA) kit from NovaLisa whose Abs target the recombinant antigen N of the nucleocapsid of SARS-CoV-2. The first Ab determination was performed between April 21 and June 3, 2020. The second Ab determination was performed in all previously seropositive patients, between September 10 and November 20, 2020. Study objectives were to prospectively determine seroprevalence in unselected lung cancer patients during the first wave of the pandemic; the persistence of immunity; protection or lack thereof against reinfection; and the influence of treatments on maintenance or loss of immunity. Of 1,500 patients, 128 were seropositive, overall prevalence of 8.5% seropositivity [95% confidence interval (CI): 7.2-10.1%]. Seventy-five percent were in active cancer treatment. Forty-seven point seven percent of IgG positive participants had experienced a symptomatic illness suspected of being infected with SARS-CoV-2 (95% CI: 38.8-56.6%). A second determination was performed on average 4.5 months later [interquartile range (IQR), 4.0-5.0 months] and obtained for 104 of the initially seropositive patients (81%), it could not be obtained in 24 patients, the majority due to death caused by disease progression (73%). In the second determination, IgG was not detected in 30.8% of patients. The severity of the infection, the need for hospitalization (P=0.032) and the presence of symptoms at diagnosis (P=0.02) were associated with persistence of immunity in the second determination. No variables or treatments received were associated with Abs loss. Immunity against SARS-CoV-2 does not appear to be compromised by treatment and persists beyond 4 months. Neither do mortality rates appear to be particularly high in this unselected population. ClinicalTrials.gov identifier: NCT04407143