PARP1-DNA co-condensation drives DNA repair site assembly to prevent disjunction of broken DNA ends.

DNA double-strand breaks (DSBs) are repaired at DSB sites. How DSB sites assemble and how broken DNA is prevented from separating is not understood. Here we uncover that the synapsis of broken DNA is mediated by the DSB sensor protein poly(ADP-ribose) (PAR) polymerase 1 (PARP1). Using bottom-up biochemistry, we reconstitute functional DSB sites and show that DSB sites form through co-condensation of PARP1 multimers with DNA. The co-condensates exert mechanical forces to keep DNA ends together and become enzymatically active for PAR synthesis. PARylation promotes release of PARP1 from DNA ends and the recruitment of effectors, such as Fused in Sarcoma, which stabilizes broken DNA ends against separation, revealing a finely orchestrated order of events that primes broken DNA for repair. We provide a comprehensive model for the hierarchical assembly of DSB condensates to explain DNA end synapsis and the recruitment of effector proteins for DNA damage repair.

Reliability and accuracy of single-molecule FRET studies for characterization of structural dynamics and distances in proteins.

Single-molecule Förster-resonance energy transfer (smFRET) experiments allow the study of biomolecular structure and dynamics in vitro and in vivo. We performed an international blind study involving 19 laboratories to assess the uncertainty of FRET experiments for proteins with respect to the measured FRET efficiency histograms, determination of distances, and the detection and quantification of structural dynamics. Using two protein systems with distinct conformational changes and dynamics, we obtained an uncertainty of the FRET efficiency ≤0.06, corresponding to an interdye distance precision of ≤2 Å and accuracy of ≤5 Å. We further discuss the limits for detecting fluctuations in this distance range and how to identify dye perturbations. Our work demonstrates the ability of smFRET experiments to simultaneously measure distances and avoid the averaging of conformational dynamics for realistic protein systems, highlighting its importance in the expanding toolbox of integrative structural biology.

Phase-separating RNA-binding proteins form heterogeneous distributions of clusters in subsaturated solutions.

Macromolecular phase separation is thought to be one of the processes that drives the formation of membraneless biomolecular condensates in cells. The dynamics of phase separation are thought to follow the tenets of classical nucleation theory, and, therefore, subsaturated solutions should be devoid of clusters with more than a few molecules. We tested this prediction using in vitro biophysical studies to characterize subsaturated solutions of phase-separating RNA-binding proteins with intrinsically disordered prion-like domains and RNA-binding domains. Surprisingly, and in direct contradiction to expectations from classical nucleation theory, we find that subsaturated solutions are characterized by the presence of heterogeneous distributions of clusters. The distributions of cluster sizes, which are dominated by small species, shift continuously toward larger sizes as protein concentrations increase and approach the saturation concentration. As a result, many of the clusters encompass tens to hundreds of molecules, while less than 1% of the solutions are mesoscale species that are several hundred nanometers in diameter. We find that cluster formation in subsaturated solutions and phase separation in supersaturated solutions are strongly coupled via sequence-encoded interactions. We also find that cluster formation and phase separation can be decoupled using solutes as well as specific sets of mutations. Our findings, which are concordant with predictions for associative polymers, implicate an interplay between networks of sequence-specific and solubility-determining interactions that, respectively, govern cluster formation in subsaturated solutions and the saturation concentrations above which phase separation occurs.

Advancing Use of DEXA Scans to Quantitatively and Qualitatively Evaluate Lateral Spinal Curves, for Preliminary Identification of Adolescent Idiopathic Scoliosis.

Dual-energy X-ray absorptiometry (DEXA) scan is an emerging screening method for identifying likely adolescent idiopathic scoliosis (AIS). Using DEXA in an unbiased population sample (the Raine Study), we aimed to report the inter-rater reliability and minimal detectable change (MDC95) for scoliosis curve angle measurement, identify likely AIS prevalence, and the concordance between reported AIS diagnosis and DEXA-identified likely AIS. Scoliosis curve angles were measured using the modified Ferguson method on DEXA scans (n = 1238) at age 20 years. For curve angle inter-rater reliability, two examiners measured angles (6-40°) on 41 scans. Likely, AIS was determined with quantitative and qualitative criteria (modified Ferguson angles ≥ 10° and expert review of spinal curves).The inter-rater reliability for scoliosis curve angle measurement was good-excellent (ICC: 0.82; 95% CI: 0.71-0.89; p < 0.001), and MDC95 was 6.2°. The prevalence of likely AIS was 2.1% (26/1238). Diagnosis of AIS was reported despite little or no scoliosis curve (< 3.8°) for 20 participants (1.6%), and diagnosis of AIS was not reported despite scoliosis curve ≥ 10° for 11 participants (0.9%). Results support the use of modified Ferguson method to measure scoliosis curve angles on DEXA. There is potential utility for using a combination of quantitative measurement and qualitative criteria to evaluate DEXA images, to identify likely AIS for reporting prevalence. Without formal school screening, the analysis of DEXA in this population sample suggested that relying on current health professional diagnosis alone could result in 2.5% of this cohort being at risk of false positive diagnosis or delay in necessary management due to non-diagnosis of AIS.

A systematic review on clinical adaptive radiotherapy for head and neck cancer.

INTRODUCTION: Head and neck cancer (HNC) patients' anatomy may undergo significant changes during radiotherapy (RT). This potentially affects dose distribution and compromises conformity between planned and delivered dose. Adaptive radiotherapy (ART) is a promising technique to overcome this problem but requires a significant workload. This systematic review aims to estimate the clinical and dosimetric benefits of ART using prospective data. MATERIAL AND METHODS: A search on PubMed and Web of Science according to the PRISMA guidelines was made on Feb 6, 2023. Search string used was: 'adaptive radiotherapy head neck cancer'. English language filter was applied. All studies were screened for inclusion on title and abstract, and the full text was read and discussed in the research group in case of uncertainty. Inclusion criteria were a prospective ART strategy for HNC investigating clinical or dosimetric outcomes. RESULTS: A total of 1251 articles were identified of which 15 met inclusion criteria. All included studies were published between 2010 and 2023 with a substantial diversity in design, endpoints, and nomenclature. The number of patients treated with ART was small with a median of 20 patients per study (range 4 to 86), undergoing 1-2 replannings. Mean dose to the parotid glands was reduced by 0.4-7.1 Gy. Maximum dose to the spinal cord was reduced by 0.5-4.6 Gy. Only five studies reported clinical outcome and disease control was excellent. Data on toxicity were ambiguous with some studies indicating reduced acute toxicity and xerostomia, while others found reduced quality of life in patients treated with ART. CONCLUSION: The literature on clinical ART in HNC is limited. ART is associated with small reductions in doses to organs at risk, but the influence on toxicity and disease control is uncertain. There is a clear need for larger, prospective trials with a well-defined control group.

Long-term outcome after Bascom's cleft-lift procedure under tumescent local analgesia for pilonidal sinus disease: a cohort study.

AIM: Bascom's cleft-lift procedure for pilonidal sinus disease under tumescent local analgesia is feasible and well tolerated with favourable short-term outcomes. We aimed to assess the 10-year treatment success rate after cleft-lift under tumescent local analgesia. METHOD: This was a single-centre cohort study based on prospectively registered perioperative data and survey data with additional data from electronic medical records. The cleft-lift procedure was performed under tumescent local analgesia in a day-surgical setting at a tertiary referral hospital between 1 July 2008 and 31 March 2014. The primary outcome was the 10-year risk treatment success defined as complete wound healing within 180 days of surgery or no recurrence assessed with competing risk analyses. Secondary outcomes were time to complete wound healing, persistent pain and cosmetic satisfaction. RESULTS: Two hundred patients with complex pilonidal sinus disease were included. Indication was incomplete wound healing after pilonidal sinus surgery in 43 (21.5%) patients, recurrence after previous intervention in 78 (39.0%) or moderate to complex sinuses assessed by a consultant surgeon in 79 (39.5%). One hundred and ninety-five patients had complete wound healing within 180 days with a median time of 29 days (interquartile range 16-47). The cumulative risk of 10-year recurrence was 11.3% (95% CI 6.2%-16.4%) with a median follow-up time of 8.5 (1.0-10.7) years. Treatment success was 86.1% (95% CI 80.6%-91.5%). No significant predictors were associated with recurrence, and 90% of patients experienced no persistent pain. CONCLUSION: Cleft-lift performed under tumescent local analgesia has an acceptable 10-year treatment failure rate, making the method feasible in a day-surgery setting.

Enhanced Solid-State Fluorescence of Flavin Derivatives by Incorporation in the Metal-Organic Frameworks MIL-53(Al) and MOF-5.

The flavin derivatives 10-methyl-isoalloxazine (MIA) and 6-fluoro-10-methyl-isoalloxazine (6F-MIA) were incorporated in two alternative metal-organic frameworks, (MOFs) MIL-53(Al) and MOF-5. We used a post-synthetic, diffusion-based incorporation into microcrystalline MIL-53 powders with one-dimensional (1D) pores and an in-situ approach during the synthesis of MOF-5 with its 3D channel network. The maximum amount of flavin dye incorporation is 3.9 wt% for MIA@MIL-53(Al) and 1.5 wt% for 6F-MIA@MIL-53(Al), 0.85 wt% for MIA@MOF-5 and 5.2 wt% for 6F-MIA@MOF-5. For the high incorporation yields the probability to have more than one dye molecule in a pore volume is significant. As compared to the flavins in solution, the fluorescence spectrum of these flavin@MOF composites is broadened at the bathocromic side especially for MIA. Time-resolved spectroscopy showed that multi-exponential fluorescence lifetimes were needed to describe the decays. The fluorescence-weighted lifetime of flavin@MOF of 4 ± 1 ns also corresponds to those in solution but is significantly prolonged compared to the solid flavin dyes with less than 1 ns, thereby confirming the concept of "solid solutions" for dye@MOF composites. The fluorescence quantum yield (ΦF) of the flavin@MOF composites is about half of the solution but is significantly higher compared to the solid flavin dyes. Both the fluorescence lifetime and quantum yield of flavin@MOF decrease with the flavin loading in MIL-53 due to the formation of various J-aggregates. Theoretical calculations using plane-wave and QM/MM methods are in good correspondence with the experimental results and explain the electronic structures as well as the photophysical properties of crystalline MIA and the flavin@MOF composites. In the solid flavins, π-stacking interactions of the molecules lead to a charge transfer state with low oscillator strength resulting in aggregation-caused quenching (ACQ) with low lifetimes and quantum yields. In the MOF pores, single flavin molecules represent a major population and the computed MIA@MOF structures do not find π-stacking interactions with the pore walls but only weak van-der-Waals contacts which reasons the enhanced fluorescence lifetime and quantum yield of the flavins in the composites compared to their neat solid state. To analyze the orientation of flavins in MOFs, we measured fluorescence anisotropy images of single flavin@MOF-5 crystals and a static ensemble flavin@MIL53 microcrystals, respectively. Based on image information, anisotropy distributions and overall curve of the time-resolved anisotropy curves combined with theoretical calculations, we can prove that all fluorescent flavins species have a defined and rather homogeneous orientation in the MOF framework. In MIL-53, the transition dipole moments of flavins are orientated along the 1D channel axis, whereas in MOF-5 we resolved an average orientation that is tilted with respect to the cubic crystal lattice. Notably, the more hydrophobic 6F-MIA exhibits a higher degree order than MIA. The flexible MOF MIL-53(Al) was optimized essentially to the experimental large-pore form in the guest-free state with QuantumEspresso (QE) and with MIA molecules in the pores the structure contracted to close to the experimental narrow-pore form which was also confirmed by PXRD. In summary, the incorporation of flavins in MOFs yields solid-state materials with enhanced rigidity, stabilized conformation, defined orientation and reduced aggregations of the flavins, leading to increased fluorescence lifetime and quantum yield as controllable photo-luminescent and photo-physical properties.

A comprehensive analysis of RAS-effector interactions reveals interaction hotspots and new binding partners.

RAS effectors specifically interact with GTP-bound RAS proteins to link extracellular signals to downstream signaling pathways. These interactions rely on two types of domains, called RAS-binding (RB) and RAS association (RA) domains, which share common structural characteristics. Although the molecular nature of RAS-effector interactions is well-studied for some proteins, most of the RA/RB-domain-containing proteins remain largely uncharacterized. Here, we searched through human proteome databases, extracting 41 RA domains in 39 proteins and 16 RB domains in 14 proteins, each of which can specifically select at least one of the 25 members in the RAS family. We next comprehensively investigated the sequence-structure-function relationship between different representatives of the RAS family, including HRAS, RRAS, RALA, RAP1B, RAP2A, RHEB1, and RIT1, with all members of RA domain family proteins (RASSFs) and the RB-domain-containing CRAF. The binding affinity for RAS-effector interactions, determined using fluorescence polarization, broadly ranged between high (0.3 µM) and very low (500 µM) affinities, raising interesting questions about the consequence of these variable binding affinities in the regulation of signaling events. Sequence and structural alignments pointed to two interaction hotspots in the RA/RB domains, consisting of an average of 19 RAS-binding residues. Moreover, we found novel interactions between RRAS1, RIT1, and RALA and RASSF7, RASSF9, and RASSF1, respectively, which were systematically explored in sequence-structure-property relationship analysis, and validated by mutational analysis. These data provide a set of distinct functional properties and putative biological roles that should now be investigated in the cellular context.

Nonmicroradical Resection Margin as a Predictor of Recurrence in Patients With Stage III Colon Cancer Undergoing Complete Mesocolic Excision: A Prospective Cohort Study.

BACKGROUND: The prognostic value of the present definition of microradicality in colon cancer is poorly understood, especially considering the vast influence it has in rectal cancer prognosis. OBJECTIVE: This study aimed to investigate whether the risk of recurrence after complete mesocolic excision for stage III colon cancer is associated with the distance from tumor tissue to resection margin and whether the location of the involved margin is of any significance. DESIGN: A prospective cohort of patients was stratified into 2 groups to distinguish between direct margin invasion (0-mm resection margin) and a ≤1-mm resection margin without direct invasion or 3 groups to distinguish between the location of margin involvement (lateral tumor resection margin, central vascular ligation margin, and nonperitonealized mesocolic resection margin). Patients with microradical resections were used as a control group. SETTINGS: We included all patients undergoing elective complete mesocolic excision for International Union Against Cancer stage III colon cancer at Nordsjællands Hospital between January 1, 2008, and December 31, 2016. PATIENTS: A total of 276 patients met all inclusion criteria and none of the exclusion criteria. MAIN OUTCOME MEASURES: Primary outcome was risk of recurrence after 3.2 years. RESULTS: A total of 41 patients (15%) had a nonmicroradical resection. The 3.2-year cumulative incidence of recurrence for a 0-mm margin was 43% and 24% for a ≤1-mm margin without direct invasion, corresponding with an HR of 4.3 (p = 0.0146) and 1.3 (p = 0.474). The location of the involved margin showed no significant differences. LIMITATIONS: This was a single-center study containing a limited number of patients with a nonmicroradical resection with a risk of type II error. CONCLUSIONS: We found no increased risk of recurrence for a ≤1-mm margin without direct invasion, indicating that the present classification of microradicality might not be justified if an intact posterior mesocolic fascia without invasion of tumor tissue is present. See Video Abstract at http://links.lww.com/DCR/B625. MARGEN DE RESECCIN NO MICRORRADICAL COMO PREDICTOR DE RECURRENCIA EN PACIENTES CON CNCER DE COLON EN ESTADIO III SOMETIDOS A ESCISIN MESOCLICA COMPLETA UN ESTUDIO DE COHORTE PROSPECTIVO: ANTECEDENTES:El valor pronóstico de la definición actual de microrradicalidad en el cáncer de colon es poco conocido, especialmente considerando la gran influencia que tiene en el pronóstico del cáncer de recto.OBJETIVO:Este estudio tiene como objetivo investigar si el riesgo de recurrencia después de la escisión mesocólica completa (CME) para el cáncer de colon en estadio III está asociado con la distancia desde el tejido tumoral hasta el margen de resección y si la localización del margen afectado tiene alguna importancia.DISEÑO:Una cohorte prospectiva de pacientes se estratificó en dos grupos para distinguir entre la invasión del margen directo (margen de resección de 0 mm) y un margen de resección ≤1 mm sin invasión directa, o tres grupos para distinguir entre la localización de la afectación del margen (resección lateral del margen del tumor, margen de ligadura vascular central y margen de resección mesocólica no peritonizada). Los pacientes con resecciones microrradicales se utilizaron como grupo control.ENTORNO CLÍNICO:Incluimos a todos los pacientes sometidos a CME electiva por cáncer de colon en estadio III de la UICC en el Hospital Nordsjællands, Dinamarca, entre el 1 de enero de 2008 y el 31 de diciembre de 2016.PACIENTES:Un total de 276 pacientes cumplieron todos los criterios de inclusión y ninguno de los criterios de exclusión.PRINCIPALES MEDIDAS DE RESULTADO:El resultado primario fue el riesgo de recurrencia después de 3 · 2 años.RESULTADOS:Un total de 41 (15%) pacientes tuvieron una resección no microrradical. La incidencia acumulada de recurrencia a los 3,2 años para un margen de 0 mm fue del 43% y del 24% para un margen ≤1 mm sin invasión directa, lo que corresponde a un cociente de riesgo de 4,3 (p = 0,0146) y 1,3 (p = 0,474) respectivamente. La localización del margen afectado no mostró diferencias significativas.LIMITACIONES:Estudio unicéntrico con un número limitado de pacientes con resección no microrradical con riesgo de error tipo II.CONCLUSIONES:No encontramos un mayor riesgo de recurrencia para un margen ≤1 mm sin invasión directa, lo que indica que la clasificación actual de microrradicalidad podría no estar justificada si está presente una fascia mesocólica posterior intacta sin invasión del tejido tumoral. Consulte Video Resumen en http://links.lww.com/DCR/B625. (Traducción-Dr Yazmin Berrones-Medina).

Nasal vestibule squamous cell carcinoma: a population-based cohort study from DAHANCA.

BACKGROUND: Cancer of the nasal vestibule is a rare type of malignancy dominated by squamous cell carcinoma (SCC), and with poor survival. The treatment is either radiotherapy, surgery or a combination of both. Previous studies have shown a 5-year disease-specific survival of 74% and overall survival (OS) of 50%.Our objective was to describe the consecutive cohort of patients diagnosed with SCC of the nasal vestibule in Denmark from 2008 until 2018 and evaluate prognostic factors and treatment outcome using locoregional failure (LRF), disease-specific mortality (DSM), and OS as endpoints. METHODS: All patients diagnosed with SCC of the nasal vestibule from 2008 until 2018 were identified in the nationwide clinical database, DAHANCA and were followed for LRF and death (DSM and OS) until March 2021. OS was analysed using Kaplan-Meier estimator, and cumulative incidence of LRF and DSM were analysed using the Aalen-Johansen estimator. Analysis of prognostic factors was performed using Cox proportional hazard models. RESULTS: A total of 162 patients were identified. The median age was 71 years and 54% were male. Disease stage at the time of diagnosis were stage I (70%), II (17%), III (2%) and IV (11%). Curatively intended treatment was performed in 146 patients (90%), of which treatment failure occurred in 42 patients (29%). Most failures occurred at the primary tumour site (64%). Cancer Patient Pathways recommended time to treatment was fulfilled in 71% of patients. The 5-year OS and DSM in patients treated with curative intent were 65% and 11%, respectively. Stage was a significant independent prognostic factor. No difference in LRF, DSM or OS were shown between the applied treatments. CONCLUSIONS: Stage is the main independent prognostic factor, and failure most commonly appear at the primary tumour site.

Unraveling multi-state molecular dynamics in single-molecule FRET experiments. II. Quantitative analysis of multi-state kinetic networks.

Single-molecule Förster Resonance Energy Transfer (smFRET) experiments are ideally suited to resolve the structural dynamics of biomolecules. A significant challenge to date is capturing and quantifying the exchange between multiple conformational states, mainly when these dynamics occur on the sub-millisecond timescale. Many methods for quantitative analysis are challenged if more than two states are involved, and the appropriate choice of the number of states in the kinetic network is difficult. An additional complication arises if dynamically active molecules coexist with pseudo-static molecules in similar conformational states with undistinguishable Förster Resonance Energy Transfer (FRET) efficiencies. To address these problems, we developed a quantitative integrative analysis framework that combines the information from FRET-lines that relate average fluorescence lifetimes and intensities in two-dimensional burst frequency histograms, fluorescence decays obtained by time-correlated single-photon-counting, photon distribution analysis of the intensities, and fluorescence correlation spectroscopy. Individually, these methodologies provide ambiguous results for the characterization of dynamics in complex kinetic networks. However, the global analysis approach enables accurate determination of the number of states, their kinetic connectivity, the transition rate constants, and species fractions. To challenge the potential of smFRET experiments for studying multi-state kinetic networks, we apply our integrative framework using a set of synthetic data for three-state systems with different kinetic connectivity and exchange rates. Our methodology paves the way toward an integrated analysis of multiparameter smFRET experiments that spans all dimensions of the experimental data. Finally, we propose a workflow for the analysis and show examples that demonstrate the usefulness of this toolkit for dynamic structural biology.

Unraveling multi-state molecular dynamics in single-molecule FRET experiments. I. Theory of FRET-lines.

Conformational dynamics of biomolecules are of fundamental importance for their function. Single-molecule studies of Förster Resonance Energy Transfer (smFRET) between a tethered donor and acceptor dye pair are a powerful tool to investigate the structure and dynamics of labeled molecules. However, capturing and quantifying conformational dynamics in intensity-based smFRET experiments remains challenging when the dynamics occur on the sub-millisecond timescale. The method of multiparameter fluorescence detection addresses this challenge by simultaneously registering fluorescence intensities and lifetimes of the donor and acceptor. Together, two FRET observables, the donor fluorescence lifetime τD and the intensity-based FRET efficiency E, inform on the width of the FRET efficiency distribution as a characteristic fingerprint for conformational dynamics. We present a general framework for analyzing dynamics that relates average fluorescence lifetimes and intensities in two-dimensional burst frequency histograms. We present parametric relations of these observables for interpreting the location of FRET populations in E-τD diagrams, called FRET-lines. To facilitate the analysis of complex exchange equilibria, FRET-lines serve as reference curves for a graphical interpretation of experimental data to (i) identify conformational states, (ii) resolve their dynamic connectivity, (iii) compare different kinetic models, and (iv) infer polymer properties of unfolded or intrinsically disordered proteins. For a simplified graphical analysis of complex kinetic networks, we derive a moment-based representation of the experimental data that decouples the motion of the fluorescence labels from the conformational dynamics of the biomolecule. Importantly, FRET-lines facilitate exploring complex dynamic models via easily computed experimental observables. We provide extensive computational tools to facilitate applying FRET-lines.

Dynamics of the nucleosomal histone H3 N-terminal tail revealed by high precision single-molecule FRET.

Chromatin compaction and gene accessibility are orchestrated by assembly and disassembly of nucleosomes. Although the disassembly process was widely studied, little is known about the structure and dynamics of the disordered histone tails, which play a pivotal role for nucleosome integrity. This is a gap filling experimental FRET study from the perspective of the histone H3 N-terminal tail (H3NtT) of reconstituted mononucleosomes. By systematic variation of the labeling positions we monitored the motions of the H3NtT relative to the dyad axis and linker DNA. Single-molecule FRET unveiled that H3NtTs do not diffuse freely but follow the DNA motions with multiple interaction modes with certain permitted dynamic transitions in the µs to ms time range. We also demonstrate that the H3NtT can allosterically sense charge-modifying mutations within the histone core (helix α3 of histone H2A (R81E/R88E)) resulting in increased dynamic transitions and lower rate constants. Those results complement our earlier model on the NaCl induced nucleosome disassembly as changes in H3NtT configurations coincide with two major steps: unwrapping of one linker DNA and weakening of the internal DNA - histone interactions on the other side. This emphasizes the contribution of the H3NtT to the fine-tuned equilibrium between overall nucleosome stability and DNA accessibility.

Fundamental photophysics of isomorphic and expanded fluorescent nucleoside analogues.

Fluorescent nucleoside analogues (FNAs) are structurally diverse mimics of the natural essentially non-fluorescent nucleosides which have found numerous applications in probing the structure and dynamics of nucleic acids as well as their interactions with various biomolecules. In order to minimize disturbance in the labelled nucleic acid sequences, the FNA chromophoric groups should resemble the natural nucleobases in size and hydrogen-bonding patterns. Isomorphic and expanded FNAs are the two groups that best meet the criteria of non-perturbing fluorescent labels for DNA and RNA. Significant progress has been made over the past decades in understanding the fundamental photophysics that governs the spectroscopic and environmentally sensitive properties of these FNAs. Herein, we review recent advances in the spectroscopic and computational studies of selected isomorphic and expanded FNAs. We also show how this information can be used as a rational basis to design new FNAs, select appropriate sequences for optimal spectroscopic response and interpret fluorescence data in FNA applications.

Sinonasal cancer in Denmark 2008-2015: a population-based phase-4 cohort study from DAHANCA.

BACKGROUND: Sinonasal cancer is considered a rare disease with poor survival. Its treatment has changed profoundly in recent years, primarily following the introduction of intensity-modulated radiation therapy (IMRT) and minimally invasive endoscopic surgery. Danish national guidelines on treatment of patients diagnosed with sinonasal carcinoma were introduced in 2007. The aim of this phase-4 study was to assess the effect of the implementation of guidelines by describing treatment outcomes in a consecutive nationwide cohort. METHODS: All patients diagnosed with sinonasal carcinoma in Denmark from 2008 to 2015 were identified in the nationwide clinical database, DAHANCA, and were followed until May 2020. Overall survival (OS) was analysed using Kaplan-Meier estimator. Cumulative incidence of locoregional failure (LRF) and disease-specific mortality (DSM) were analysed using the Aalen-Johansen estimator. Competing risks were death from other causes (DSM) and distant failure and death (LRF). Analysis of prognostic factors was performed using Cox proportional hazard analysis. Start of follow-up was time of diagnosis. The results are presented as estimates with 95% confidence intervals (95% CIs). RESULTS: A total of 331 patients were identified. Curatively intended treatment was performed in 264 patients (80%). Non-compliance with treatment guidelines was registered in 24 patients (9%). Non-compliance was associated with LRF (hazard ratio [HR], 2.0 [95% CI: 1.1-3.5]). Among patients qualified for curative treatment, failure occurred in 109 patients (41%), primarily at the primary tumour site (81%). Anatomical tumour site and disease stage were independent prognostic factors. The 5-year OS was 56% in patients treated with curative intent, and a combined treatment strategy showed reduced LRF (HR, 0.53 [95% CI: 0.30-0.92]) in a multivariate analysis. CONCLUSIONS: Guideline compliance and a combined treatment approach reduced the incidence of LRF and thereby increased OS. Our results confirm those of international studies. Treatment of sinonasal carcinoma remains a challenge that requires multidisciplinary team coordination.

A prospective cohort study of confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy evaluating SARS-CoV-2 antibodies in maternal and umbilical cord blood and SARS-CoV-2 in vaginal swabs.

INTRODUCTION: Evidence about the consequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in pregnancy is rapidly increasing; however, data on antibody response and risk of transmission during pregnancy and delivery are still limited. The aim of this study was to evaluate if SARS-CoV-2 is detectable in vaginal swabs and whether antibodies against SARS-CoV-2 are present in maternal and umbilical cord blood of pregnant women with confirmed SARS-CoV-2. MATERIAL AND METHODS: A single-unit prospective cohort study in Denmark including pregnant women with SARS-CoV-2 infection confirmed by a pharyngeal swab between August 20, 2020, and March 1, 2021, who gave birth during the same period. All patients admitted to the maternity ward and antepartum clinic were screened for SARS-CoV-2 infection. A maternal blood sample and vaginal swabs were collected at inclusion. If included antepartum, these samples were repeated intrapartum when an umbilical cord blood sample was also collected. Swabs were analyzed for SARS-CoV-2 and blood samples were analyzed for SARS-CoV-2 total antibodies. Placental and neonatal swabs as well as placental histopathological examinations were performed on clinical indications. RESULTS: We included 28 women, of whom four had serious maternal or fetal outcomes including one case of neonatal death. Within the first 8 days after confirmed SARS-CoV-2 infection, SARS-CoV-2 was detectable in two vaginal swabs (2/28) and SARS-CoV-2 antibodies were detected in 1 of 13 women. From 16 days after confirmed infection, antibodies were observed in 19 of 21 of women. Antibodies in cord blood were not detected during the first 16 days after confirmed infection (n = 7). However, from 26 days, antibodies were present in 16 of 17 cord blood samples of seropositive mothers. Placental examination in two cases of severe fetal outcomes preceded by reduced fetal movements revealed SARS-CoV-2 in swabs and severe histopathological abnormalities. CONCLUSIONS: SARS-CoV-2 was detected in only 2 of 28 vaginal swabs within 8 days after confirmed infection in pregnant women. Our data suggest that maternal seroconversion occurs between days 8 and 16, whereas antibodies in cord blood of seropositive mothers were present in the majority from 26 days after confirmed infection. Additional data are needed regarding timing of seroconversion for the mother and appearance of antibodies in cord blood.

5-year outcome after complete mesocolic excision for right-sided colon cancer: a population-based cohort study.

BACKGROUND: The benefits of extensive lymph node dissection as performed in complete mesocolic excision are still debated, although recent studies have shown an association with improved long-term outcomes. However, none of these studies had an intention-to-treat design or aimed to show a causal effect; therefore in this study, we aimed to estimate the causal oncological treatment effects of complete mesocolic excision on right-sided colon cancer. METHODS: We did a population-based cohort study involving prospective data collected from four hospitals in Denmark. We compared the oncological outcome data of patients at one centre performing central lymph node dissection and vascular division after almost complete exposure of the proximal part of the superior mesenteric vein (ie, the complete mesocolic excision group) with three other centres performing conventional resections with unstandardised and limited lymph node dissection (ie, non-complete mesocolic excision; control group). We included data for all patients in the Capital Region of Denmark undergoing elective curative-intent right-sided colon resections for stages I-III colon cancer, as categorised by the Union for International Cancer Control (UICC; 5th edition), from June 1, 2008, to Dec 31, 2013. Patients were followed-up for 5·2 years after surgery. The primary outcome was the cumulative incidence of recurrence after 5·2 years of surgery. Inverse probability of treatment weighting and competing risk analyses were used to estimate the possible causal effects of complete mesocolic excision. This study is registered with ClinicalTrials.gov, number NCT03754075. FINDINGS: 1069 patients (813 in the control group and 256 in the complete mesocolic excision group) underwent curative-intent elective surgery for right-sided colon cancer during the study period. None of the patients were lost to follow-up regarding survival or recurrence status, and consequently no patient was censored in the analyses. The 5·2-year cumulative incidence of recurrence was 9·7% (95% CI 6·3-13·1) in the complete mesocolic excision group compared with 17·9% (15·3-20·5) in the control group, and the absolute risk reduction of complete mesocolic excision after 5·2 years was 8·2% (95% CI 4·0-12·4; p=0·00015). In the control group, 145 (18%) of 813 patients were diagnosed with a recurrence and 281 (35%) died during follow-up, whereas in the complete mesocolic excision group 25 (10%) of 256 patients were diagnosed with a recurrence and 75 (29%) died during follow-up. INTERPRETATION: This study shows a causal treatment effect of central mesocolic lymph node excision on risk of recurrence after resection for right-sided colon adenocarcinoma. Complete mesocolic excision has the potential to reduce the risk of recurrence and improve long-term outcome after resection for all UICC stages I-III of right-sided colon adenocarcinomas. FUNDING: The Tvergaard Fund, Helen Rude Fund, Krista and Viggo Petersen Fund, Olga Bryde Nielsen Fund, and Else and Mogens Wedell-Wedellsborg Fund.

Intratumor heterogeneity of PD-L1 expression in head and neck squamous cell carcinoma.

Intratumor heterogeneity may contribute to the ambiguous clinical results on PD-L1 status as a predictor for immunotherapy response in patients with HNSCC. This decreases the utility of PD-L1 expression from single tumour biopsies as a predictive biomarker. In this prospective study, intratumor heterogeneity of PD-L1 expression in HNSCC was investigated with both Tumour Proportion Score (TPS) and Combined Positive Score (CPS). Thirty-three whole surgical specimens from 28 patients with HNSCC were included. PD-L1 expression in six random core biopsies from each surgical specimen was used to assess the concordance between multiple biopsies and the negative predictive value of a single negative core biopsy. With 1% cut off, 36% of the specimens were concordant with TPS and 52% with CPS. With a 50% cut-off value the concordance was 70% with TPS and 55% with CPS. Defining a tumour as positive if just a single-one of the biopsies was positive, the negative predictive value (NPV) of a single negative core biopsy was 38.9 and 0% (1% cut off), and 79.9% and 62.8% (50% cut off) for TPS and CPS, respectively. In conclusion, PD-L1 positivity varies markedly within the tumour, both with TPS and CPS, challenging the utility of this biomarker.

Comparing the patients' subjective experiences of acute side effects during radiotherapy for head and neck cancer with four different patient-reported outcomes questionnaires.

Background: The systematic use of a Patient-Reported Outcome (PRO) as symptom monitoring during cancer treatment and follow-up has the potential to increase symptom awareness, secure timely management of side effects, improve health-related quality of life and improve data quality. This study was conducted to identify the patients' experience during chemoradiotherapy for squamous cell carcinoma of the head and neck (HNSCC) and to investigate how these symptoms correspond with different PRO questionnaires. Material and methods: Semi-structured interviews on acute side effects were performed until saturation with HNSCC patients treated with high-dose radiotherapy (RT) ± concomitant chemotherapy. The symptoms were thematically grouped in organ classes in accordance with Medical Dictionary for Regulatory Activities (MedDRA). PRO questionnaires validated for patients with HNSCC during RT were identified in the literature and were compared to the patients' symptoms. Results: Thirteen patients were interviewed. The most frequently mentioned symptoms were oral pain, decreased appetite, dysphagia, dry mouth, fatigue and hoarseness, in order of frequency. A comparison between the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire for Head and Neck Cancer (EORTC QLQ-H&N35), the Functional Assessment of Cancer Therapy General and Head and Neck (FACT-H&N), the M.D. Anderson Symptom Inventory Head and Neck questionnaire (MDASI-HN), selected items from the Patient-Reported Outcomes Version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) and the symptoms described by the patients showed that the PROs do not cover the same symptoms, and no specific questionnaire covers all patient's experiences. Conclusion: We find, that questionnaires applied in the field of PRO among patients with HNSCC undergoing RT may not fully comprise the experiences of patients and we recommend, that experiences of patients must be included in the design of trials involving PRO, in order to decrease the likelihood of missing out reports of acute side effects.