107 research outputs found
Late-Stage Metastatic Melanoma Emerges through a Diversity of Evolutionary Pathways
Understanding the evolutionary pathways to metastasis and resistance to immune-checkpoint inhibitors (ICI) in melanoma is critical for improving outcomes. Here, we present the most comprehensive intrapatient metastatic melanoma dataset assembled to date as part of the Posthumous Evaluation of Advanced Cancer Environment (PEACE) research autopsy program, including 222 exome sequencing, 493 panel-sequenced, 161 RNA sequencing, and 22 single-cell whole-genome sequencing samples from 14 ICI-treated patients. We observed frequent whole-genome doubling and widespread loss of heterozygosity, often involving antigen-presentation machinery. We found KIT extrachromosomal DNA may have contributed to the lack of response to KIT inhibitors of a KIT-driven melanoma. At the lesion-level, MYC amplifications were enriched in ICI nonresponders. Single-cell sequencing revealed polyclonal seeding of metastases originating from clones with different ploidy in one patient. Finally, we observed that brain metastases that diverged early in molecular evolution emerge late in disease. Overall, our study illustrates the diverse evolutionary landscape of advanced melanoma.SIGNIFICANCE: Despite treatment advances, melanoma remains a deadly disease at stage IV. Through research autopsy and dense sampling of metastases combined with extensive multiomic profiling, our study elucidates the many mechanisms that melanomas use to evade treatment and the immune system, whether through mutations, widespread copy-number alterations, or extrachromosomal DNA.See related commentary by Shain, p. 1294. This article is highlighted in the In This Issue feature, p. 1275.</p
Genomic architecture and evolution of clear cell renal cell carcinomas defined by multiregion sequencing
Clear cell renal carcinomas (ccRCCs) can display intratumor heterogeneity (ITH). We applied multiregion exome sequencing (M-seq) to resolve the genetic architecture and evolutionary histories of ten ccRCCs. Ultra-deep sequencing identified ITH in all cases. We found that 73â75% of identified ccRCC driver aberrations were subclonal, confounding estimates of driver mutation prevalence. ITH increased with the number of biopsies analyzed, without evidence of saturation in most tumors. Chromosome 3p loss and VHL aberrations were the only ubiquitous events. The proportion of C>T transitions at CpG sites increased during tumor progression. M-seq permits the temporal resolution of ccRCC evolution and refines mutational signatures occurring during tumor development
Tracking genomic cancer evolution for precision medicine: The Lung TRACERx Study
The importance of intratumour genetic and functional heterogeneity is increasingly recognised as a driver of cancer progression and survival outcome. Understanding how tumour clonal heterogeneity impacts upon therapeutic outcome, however, is still an area of unmet clinical and scientific need. TRACERx (TRAcking non-small cell lung Cancer Evolution through therapy [Rx]), a prospective study of patients with primary non-small cell lung cancer (NSCLC), aims to define the evolutionary trajectories of lung cancer in both space and time through multiregion and longitudinal tumour sampling and genetic analysis. By following cancers from diagnosis to relapse, tracking the evolutionary trajectories of tumours in relation to therapeutic interventions, and determining the impact of clonal heterogeneity on clinical outcomes, TRACERx may help to identify novel therapeutic targets for NSCLC and may also serve as a model applicable to other cancer types
Late-Stage Metastatic Melanoma Emerges through a Diversity of Evolutionary Pathways
UNLABELLED: Understanding the evolutionary pathways to metastasis and resistance to immune-checkpoint inhibitors (ICI) in melanoma is critical for improving outcomes. Here, we present the most comprehensive intrapatient metastatic melanoma dataset assembled to date as part of the Posthumous Evaluation of Advanced Cancer Environment (PEACE) research autopsy program, including 222 exome sequencing, 493 panel-sequenced, 161 RNA sequencing, and 22 single-cell whole-genome sequencing samples from 14 ICI-treated patients. We observed frequent whole-genome doubling and widespread loss of heterozygosity, often involving antigen-presentation machinery. We found KIT extrachromosomal DNA may have contributed to the lack of response to KIT inhibitors of a KIT-driven melanoma. At the lesion-level, MYC amplifications were enriched in ICI nonresponders. Single-cell sequencing revealed polyclonal seeding of metastases originating from clones with different ploidy in one patient. Finally, we observed that brain metastases that diverged early in molecular evolution emerge late in disease. Overall, our study illustrates the diverse evolutionary landscape of advanced melanoma. SIGNIFICANCE: Despite treatment advances, melanoma remains a deadly disease at stage IV. Through research autopsy and dense sampling of metastases combined with extensive multiomic profiling, our study elucidates the many mechanisms that melanomas use to evade treatment and the immune system, whether through mutations, widespread copy-number alterations, or extrachromosomal DNA. See related commentary by Shain, p. 1294. This article is highlighted in the In This Issue feature, p. 1275
Deterministic Evolutionary Trajectories Influence Primary Tumor Growth: TRACERx Renal.
The evolutionary features of clear-cell renal cell carcinoma (ccRCC) have not been systematically studied to date. We analyzed 1,206 primary tumor regions from 101 patients recruited into the multi-center prospective study, TRACERx Renal. We observe up to 30 driver events per tumor and show that subclonal diversification is associated with known prognostic parameters. By resolving the patterns of driver event ordering, co-occurrence, and mutual exclusivity at clone level, we show the deterministic nature of clonal evolution. ccRCC can be grouped into seven evolutionary subtypes, ranging from tumors characterized by early fixation of multiple mutational and copy number drivers and rapid metastases to highly branched tumors with >10 subclonal drivers and extensive parallel evolution associated with attenuated progression. We identify genetic diversity and chromosomal complexity as determinants of patient outcome. Our insights reconcile the variable clinical behavior of ccRCC and suggest evolutionary potential as a biomarker for both intervention and surveillance
Effect of a Perioperative, Cardiac Output-Guided Hemodynamic Therapy Algorithm on Outcomes Following Major Gastrointestinal Surgery A Randomized Clinical Trial and Systematic Review
Importance: small trials suggest that postoperative outcomes may be improved by the use of cardiac output monitoring to guide administration of intravenous fluid and inotropic drugs as part of a hemodynamic therapy algorithm.Objective: to evaluate the clinical effectiveness of a perioperative, cardiac outputâguided hemodynamic therapy algorithm.Design, setting, and participants: OPTIMISE was a pragmatic, multicenter, randomized, observer-blinded trial of 734 high-risk patients aged 50 years or older undergoing major gastrointestinal surgery at 17 acute care hospitals in the United Kingdom. An updated systematic review and meta-analysis were also conducted including randomized trials published from 1966 to February 2014.Interventions: patients were randomly assigned to a cardiac outputâguided hemodynamic therapy algorithm for intravenous fluid and inotrope (dopexamine) infusion during and 6 hours following surgery (n=368) or to usual care (n=366).Main outcomes and measures: the primary outcome was a composite of predefined 30-day moderate or major complications and mortality. Secondary outcomes were morbidity on day 7; infection, critical careâfree days, and all-cause mortality at 30 days; all-cause mortality at 180 days; and length of hospital stay.Results: baseline patient characteristics, clinical care, and volumes of intravenous fluid were similar between groups. Care was nonadherent to the allocated treatment for less than 10% of patients in each group. The primary outcome occurred in 36.6% of intervention and 43.4% of usual care participants (relative risk [RR], 0.84 [95% CI, 0.71-1.01]; absolute risk reduction, 6.8% [95% CI, ?0.3% to 13.9%]; P?=?.07). There was no significant difference between groups for any secondary outcomes. Five intervention patients (1.4%) experienced cardiovascular serious adverse events within 24 hours compared with none in the usual care group. Findings of the meta-analysis of 38 trials, including data from this study, suggest that the intervention is associated with fewer complications (intervention, 488/1548 [31.5%] vs control, 614/1476 [41.6%]; RR, 0.77 [95% CI, 0.71-0.83]) and a nonsignificant reduction in hospital, 28-day, or 30-day mortality (intervention, 159/3215 deaths [4.9%] vs control, 206/3160 deaths [6.5%]; RR, 0.82 [95% CI, 0.67-1.01]) and mortality at longest follow-up (intervention, 267/3215 deaths [8.3%] vs control, 327/3160 deaths [10.3%]; RR, 0.86 [95% CI, 0.74-1.00]).Conclusions and relevance: in a randomized trial of high-risk patients undergoing major gastrointestinal surgery, use of a cardiac outputâguided hemodynamic therapy algorithm compared with usual care did not reduce a composite outcome of complications and 30-day mortality. However, inclusion of these data in an updated meta-analysis indicates that the intervention was associated with a reduction in complication rate
The Origins of AGN Obscuration: The 'Torus' as a Dynamical, Unstable Driver of Accretion
Multi-scale simulations have made it possible to follow gas inflows onto
massive black holes (BHs) from galactic scales to the accretion disk. When
sufficient gas is driven towards the BH, gravitational instabilities
generically form lopsided, eccentric disks that propagate inwards. The lopsided
stellar disk exerts a strong torque on the gas disk, driving inflows that fuel
rapid BH growth. Here, we investigate whether the same gas disk is the 'torus'
invoked to explain obscured AGN. The disk is generically thick and has
characteristic ~1-10 pc sizes and masses resembling those required of the
torus. The scale heights and obscured fractions of the predicted torii are
substantial even in the absence of strong stellar feedback providing the
vertical support. Rather, they can be maintained by strong bending modes and
warps excited by the inflow-generating instabilities. Other properties commonly
attributed to feedback processes may be explained by dynamical effects:
misalignment between torus and host galaxy, correlations between local SFR and
turbulent gas velocities, and dependence of obscured fractions on AGN
luminosity or SFR. We compare the predicted torus properties with observations
of gas surface density profiles, kinematics, scale heights, and SFR densities
in AGN nuclei, and find that they are consistent. We argue that it is not
possible to reproduce these observations and the observed column density (N_H)
distribution without a clumpy gas distribution, but allowing for clumping on
small scales the predicted N_H distribution is in good agreement with
observations from 10^20-27 cm^-2. We examine how N_H scales with galaxy and AGN
properties, and find that AGN feedback may be necessary to explain some trends
with luminosity and/or redshift. The torus is not merely a bystander or passive
fuel source for accretion, but is itself the mechanism driving accretion.Comment: 20 pages, 10 figures, accepted to MNRAS (matches accepted version
Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources
Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based
on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30
to 857 GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency
coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual
shocks, each in their own phase of development, shape the radio spectra as they move in the relativistic jet. The SEDs presented in this paper
were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the
spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed,
with an emphasis on proper, physical modelling of the synchrotron bump using multiple components. Planck ERCSC data also suggest that the
original accelerated electron energy spectrum could be much harder than commonly thought, with power-law index around 1.5 instead of the
canonical 2.5. The implications of this are discussed for the acceleration mechanisms effective in blazar shocks. Furthermore in many cases the
Planck data indicate that gamma-ray emission must originate in the same shocks that produce the radio emission
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