Point of Care Liquid Biopsy for Cancer Treatment-Early Experience from a Community Center.

Liquid biopsy is rapidly becoming an indispensable tool in the oncologist's arsenal; however, this technique remains elusive in a publicly funded healthcare system, and real-world evidence is needed to demonstrate utility and feasibility. Here, we describe the first experience of an in-house point of care liquid biopsy program at a Canadian community hospital. A retrospective review of consecutive cases that underwent plasma-based next-generation sequencing (NGS) was conducted.

The Role of Local Therapy for Oligo-Progressive Disease in Oncogene-Addicted Non-Small-Cell Lung Cancer.

Purpose: We first described the role of local radiation therapy (LT) for oligoprogressive disease (OPD) on targeted therapy in 2012. Here, we present an updated and larger data set and extend the analysis beyond EGFR and ALK.

Methods: A retrospective review of patients with metastatic NSCLC harboring V600E mutations, or rearrangements, who had OPD on respective tyrosine-kinase inhibitor (TKI) and treated with LT was performed.

Oncogene Overlap Analysis of Circulating Cell-free Tumor DNA to Explore the Appropriate Criteria for Defining MET Copy Number-Driven Lung Cancer.

Introduction: Defining clinically relevant MET amplification levels in non-small cell lung cancer (NSCLC) remains challenging. We hypothesize that oncogene overlap and MET amplicon size decline with increase in MET plasma copy number (pCN), thus enriching for MET-dependent states.

Patients And Methods: We interrogated cell-free DNA NGS results of 16,782 patients with newly diagnosed advanced NSCLC to identify those with MET amplification as reported using Guardant360.

Association of anticoagulant use with clinical outcomes from crizotinib in ALK- and ROS1-rearranged advanced non-small cell lung cancers: A retrospective analysis of PROFILE 1001.

Background: ROS1- and ALK-rearranged advanced NSCLCs are associated with increased thromboembolic risk. We hypothesized that a prothrombotic phenotype offers an evolutionary advantage to subsets of these cancers. The impact of this phenotype could alter outcomes from targeted therapy.

Managing Central Nervous System Spread of Lung Cancer: The State of the Art.

Brain metastases (BrM) are common in both non-small-cell lung cancer and small-cell lung cancer. Substantial progress in BrM management has occurred in the past decade related to advances in both radiation and medical oncology. Recent and ongoing radiation trials have focused on increasing the candidacy for focal therapy of BrM with stereotactic radiosurgery; reducing the toxicity and improving patient selection for whole brain radiotherapy; and, in small-cell lung cancer, evaluating brain magnetic resonance imaging surveillance without prophylactic cranial irradiation, hippocampal avoidance in prophylactic cranial irradiation and whole brain radiotherapy, and the role of upfront stereotactic radiosurgery for BrM.

Particle-Hole Symmetry and the Fractional Quantum Hall Effect in the Lowest Landau Level.

We report on detailed experimental studies of a high-quality heterojunction insulated-gate field-effect transistor (HIGFET) to probe the particle-hole symmetry of the fractional quantum Hall effect (FQHE) states about half-filling in the lowest Landau level. The HIGFET is specially designed to vary the density of a two-dimensional electronic system under constant magnetic fields. We find in our constant magnetic field, variable density measurements that the sequence of FQHE states at filling factors ν=1/3,2/5,3/7… and its particle-hole conjugate states at filling factors 1-ν=2/3,3/5,4/7… have a very similar energy gap.

Spin transition in the ν=8/3 fractional quantum Hall effect.

We present here the results from a density dependent study of the activation energy gaps of the fractional quantum Hall effect states at Landau level fillings ν=8/3 and 7/3 in a series of high quality quantum wells. In the density range from 0.5×10(11) to 3×10(11) cm(-2), the 7/3 energy gap increases monotonically with increasing density, supporting its ground state being spin polarized.

Enhancement of the ν = 5/2 fractional quantum Hall state in a small in-plane magnetic field.

Using a 50-nm-width ultraclean GaAs/AlGaAs quantum well, we have studied the Landau level filling factor ν=5/2 fractional quantum Hall effect in a perpendicular magnetic field B∼1.7  T and determined its dependence on tilted magnetic fields. Contrary to all previous results, the 5/2 resistance minimum and the Hall plateau are found to strengthen continuously under an increasing tilt angle 0<θ<25° (corresponding to an in-plane magnetic field 0 View Article and Find Full Text PDF

Termination of two-dimensional metallic conduction near the metal-insulator transition in a Si/SiGe quantum well.

We report in this Letter our recent low-temperature transport results in a Si/SiGe quantum well with moderate peak mobility. An apparent metal-insulating transition is observed. Within a small range of densities near the transition, the conductivity σ displays a nonmonotonic temperature dependence.

Impact of disorder on the 5/2 fractional quantum Hall state.

We compare the energy gap of the ν = 5/2 fractional quantum Hall effect state obtained in conventional high mobility modulation-doped quantum-well samples with those obtained in high quality GaAs transistors (heterojunction insulated gate field-effect transistors). We are able to identify the different roles that long-range and short-range disorders play in the 5/2 state and observe that the long-range potential fluctuations are more detrimental to the strength of the 5/2 state than short-range potential disorder.

Observation of reentrant phases induced by short-range disorder in the lowest Landau level of Al{x}Ga{1-x}As/Al{0.32}Ga{0.68}as heterostructures.

We report the observation of a reentrant quantum Hall effect in the lowest Landau level between filling factors of 2/3 and 3/5 in a Al{x}Ga{1-x}As/Al{0.32}Ga{0.68}As heterostructure sample with x=0.

Observation of a pinning mode in a Wigner solid with ν=1/3 fractional quantum Hall excitations.

We report the observation of a resonance in the microwave spectra of the real diagonal conductivities of a two-dimensional electron system within a range of ∼ ± 0.015 from filling factor ν = 1/3. The resonance is remarkably similar to resonances previously observed near integer ν, and is interpreted as the collective pinning mode of a disorder-pinned Wigner solid phase of e/3-charged carriers.

Pinning-mode resonance of a Skyrme crystal near Landau-level filling factor ν=1.

Microwave pinning-mode resonances found around integer quantum Hall effects, are a signature of crystallized quasiparticles or holes. Application of in-plane magnetic field to these crystals, increasing the Zeeman energy, has negligible effect on the resonances just below Landau-level filling ν=2, but increases the pinning frequencies near ν=1, particularly for smaller quasiparticle or hole densities. The charge dynamics near ν=1, characteristic of a crystal order, are affected by spin, in a manner consistent with a Skyrme crystal.

Scaling in plateau-to-plateau transition: a direct connection of quantum hall systems with the Anderson localization model.

The quantum Hall-plateau transition was studied at temperatures down to 1 mK in a random alloy disordered high mobility two-dimensional electron gas. A perfect power-law scaling with kappa=0.42 was observed from 1.

Observation of a fractional quantum hall state at nu = 1/4 in a wide GaAs quantum well.

We report the observation of an even-denominator fractional quantum Hall state at nu = 1/4 in a high quality, wide GaAs quantum well. The sample has a quantum well width of 50 nm and an electron density of n(e) = 2.55 x 10(11) cm(-2).

Pinning mode resonances of 2D electron stripe phases: effect of an in-plane magnetic field.

We study the anisotropic pinning-mode resonances in the rf conductivity spectra of the stripe phase of 2D electron systems around a Landau level filling of 9/2, in the presence of an in-plane magnetic field B(ip). The polarization along which the resonance is observed switches as B(ip) is applied, consistent with the reorientation of the stripes. The resonance frequency, a measure of the pinning interaction between the 2D electron systems and disorder, increases with B(ip).

Observation of pinning mode of stripe phases of 2D systems in high Landau levels.

We study the radio-frequency diagonal conductivities of the anisotropic stripe phases of higher Landau levels near half-integer fillings. In the hard direction, in which larger dc resistivity occurs, the spectrum exhibits a striking resonance, while in the orthogonal, easy direction, no resonance is discernible. The resonance is interpreted as a pinning mode of the stripe phase.

Anisotropic modification of the effective hole g factor by electrostatic confinement.

We investigate effects of lateral confinement on spin splitting of energy levels in 2D hole gases grown on [311] GaAs. We found that lateral confinement enhances anisotropy of spin splitting relative to the 2D gas for both confining directions. Unexpectedly, the effective g factor does not depend on the 1D energy level number N for B parallel[01[over ]1] while it has strong N dependence for B parallel[2[over ]33].

Pinning modes and interlayer correlation in high-magnetic-field bilayer Wigner solids.

We report studies of pinning mode resonances in the low total Landau filling (nu) Wigner solid of a series of bilayer hole samples with negligible interlayer tunneling and with varying interlayer separation d. Comparison of states with equal layer densities (p,p) to single layer states (p,0) produced in situ by biasing, indicates that there is interlayer quantum correlation in the solid at small d. Also, the resonance frequency at small d is decreased just near nu = 1/2 and 2/3, indicating the importance in the solid of correlations related to those in the fractional quantum Hall effects.

Disappearance of metal-like behavior in GaAs two-dimensional holes below 30 mK.

The zero-field temperature dependence of the resistivity of two-dimensional holes is observed to exhibit two qualitatively different characteristics for a fixed carrier density for which only the metallic behavior of the so-called metal-insulator transition is anticipated. As T is lowered from 150 to 0.5 mK, the sign of the derivative of the resistivity with respect to T changes from being positive to negative when the temperature is lowered below approximately 30 mK and the resistivity continuously rises with cooling down to 0.

Astability and negative differential resistance of the Wigner solid.

We report spontaneous narrow band oscillations in the high field Wigner solid. These oscillations are similar to the recently seen and yet unexplained oscillations in the reentrant integer quantum Hall states. The current-voltage characteristic has a region of negative differential resistance in the current biased setup and it is hysteretic in the voltage biased setup.

Intervalley gap anomaly of two-dimensional electrons in silicon.

We report here a systematic study of the energy gaps at the odd-integer quantum Hall states nu = 3 and 5 under tilted magnetic (B) fields in a high quality Si two-dimensional electron system. Out of the coincidence region, the valley splitting is independent of the in-plane fields. However, the nu = 3 valley gap differs by about a factor of 3 (Deltav approximately 0.