Immune Checkpoint Inhibition as Single Therapy for Synchronous Cancers Exhibiting Hypermutation: An IRRDC Study

Two targets with one arrow: #Immunotherapy as single treatment for synchronous RRD #glioblastoma and #metastatic cancers.

Functional Precision Medicine Identifies New Therapeutic Candidates for Medulloblastoma

Medulloblastoma is among the most common malignant brain tumors in children. Recent studies have identified at least four subgroups of the disease that differ in terms of molecular characteristics and patient outcomes. Despite this heterogeneity, most patients with medulloblastoma receive similar therapies, including surgery, radiation, and intensive chemotherapy. Although these treatments prolong survival, many patients still die from the disease and survivors suffer severe long-term side effects from therapy. We hypothesize that each patient with medulloblastoma is sensitive to different therapies and that tailoring therapy based on the molecular and cellular characteristics of patients' tumors will improve outcomes. To test this, we assembled a panel of orthotopic patient-derived xenografts (PDX) and subjected them to DNA sequencing, gene expression profiling, and high-throughput drug screening. Analysis of DNA sequencing revealed that most medulloblastomas do not have actionable mutations that point to effective therapies. In contrast, gene expression and drug response data provided valuable information about potential therapies for every tumor. For example, drug screening demonstrated that actinomycin D, which is used for treatment of sarcoma but rarely for medulloblastoma, was active against PDXs representing Group 3 medulloblastoma, the most aggressive form of the disease. Functional analysis of tumor cells was successfully used in a clinical setting to identify more treatment options than sequencing alone. These studies suggest that it should be possible to move away from a one-size-fits-all approach and begin to treat each patient with therapies that are effective against their specific tumor. SIGNIFICANCE: These findings show that high-throughput drug screening identifies therapies for medulloblastoma that cannot be predicted by genomic or transcriptomic analysis.

Abstract IA11: Overcoming immune evasion in pediatric brain tumors

Many immunotherapies act by enhancing T-cell killing of tumor cells. Cytotoxic T cells recognize antigens presented by class I major histocompatibility complex (MHC-I) proteins on tumor cells. Our studies suggest that medulloblastomas and high-grade gliomas lacking the p53 tumor suppressor do not express surface MHC-I and are therefore resistant to immune rejection. Mechanistically, this is because p53 regulates expression of the peptide transporter Tap1 and the aminopeptidase Erap1, which are required for MHC-I trafficking to the cell surface. Treatment with tumor necrosis factor or lymphotoxin beta receptor agonist rescues expression of Erap1, Tap1, and MHC-I on p53 mutant tumor cells. In vivo, TNF treatment prolongs survival and markedly augments the efficacy of the immune checkpoint inhibitor anti-PD-1. These studies identify p53 as a key regulator of immune evasion in vivo and suggest that TNF could be used to enhance sensitivity of p53-mutant tumors to immunotherapy.

Citation Format: Alexandra Garancher, Hiromichi Suzuki, Svasti Haricharan, Meher B. Masihi, Jessica M. Rusert, Paula S. Norris, Florent Carrette, Megan M. Romero, Sorana A. Morrissy, Patryk Skowron, Florence M.G. Cavalli, Hamza Farooq, Vijay Ramaswamy, Alaide Morcavallo, Jacob J. Henderson, James M. Olson, Yoon-Jae Cho, Xiao-Nan Li, Louis Chesler, Marco A. Marra, Oren J. Becher, Linda M. Bradley, Carl F. Ware, Michael D. Taylor, Robert J. Wechsler-Reya. Overcoming immune evasion in pediatric brain tumors [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr IA11.

Tumor necrosis factor overcomes immune evasion in p53-mutant medulloblastoma

Many immunotherapies act by enhancing the ability of cytotoxic T cells to kill tumor cells. Killing depends on T cell recognition of antigens presented by class I major histocompatibility complex (MHC-I) proteins on tumor cells. In this study, we showed that medulloblastomas lacking the p53 tumor suppressor do not express surface MHC-I and are therefore resistant to immune rejection. Mechanistically, this is because p53 regulates expression of the peptide transporter Tap1 and the aminopeptidase Erap1, which are required for MHC-I trafficking to the cell surface. In vitro, tumor necrosis factor (TNF) or lymphotoxin-β receptor agonist can rescue expression of Erap1, Tap1 and MHC-I on p53-mutant tumor cells. In vivo, low doses of TNF prolong survival and synergize with immune checkpoint inhibitors to promote tumor rejection. These studies identified p53 as a key regulator of immune evasion and suggest that TNF could be used to enhance sensitivity of tumors to immunotherapy.

TNF superfamily cytokines overcome immune evasion in medulloblastoma

Many immunotherapies act by enhancing T cell killing of tumor cells. CD8+ cytotoxic T cells recognize antigens presented by class I major histocompatibility complex (MHC-I) proteins on tumor cells. Here we show that medulloblastomas lacking the p53 tumor suppressor do not express surface MHC-I and are therefore resistant to immune rejection. Mechanistically, this is because p53 regulates expression of the peptide transporter Tap1 and the aminopeptidase Erap1, which are required for MHC-I trafficking to the cell surface. Treatment with tumor necrosis factor (TNF) or lymphotoxin beta receptor agonist (LTβRag) rescues expression of Erap1, Tap1 and MHC-I on p53-mutant tumor cells. In vivo, TNF treatment prolongs survival and markedly augments the efficacy of the immune checkpoint inhibitor anti-PD-1. These studies identify p53 as a key regulator of immune evasion in vivo, and suggest that TNF could be used to enhance sensitivity of p53-mutant tumors to immunotherapy.

Rare but Recurrent ROS1 Fusions Resulting From Chromosome 6q22 Microdeletions are Targetable Oncogenes in Glioma

PURPOSE

Gliomas, a genetically heterogeneous group of primary central nervous system tumors, continue to pose a significant clinical challenge. Discovery of chromosomal rearrangements involving kinase genes has enabled precision therapy, and improved outcomes in several malignancies.

EXPERIMENTAL DESIGN

Positing that similar benefit could be accomplished for patients with brain cancer, we evaluated The Cancer Genome Atlas (TCGA) glioblastoma dataset. Functional validation of the oncogenic potential and inhibitory sensitivity of discovered ROS1 fusions was performed using three independent cell-based model systems, and an in vivo murine xenograft study.

RESULTS

In silico analysis revealed previously unreported intrachromosomal 6q22 microdeletions that generate ROS1-fusions from TCGA glioblastoma dataset. ROS1 fusions in primary glioma and ependymoma were independently corroborated from MSK-IMPACT and Foundation Medicine clinical datasets. GOPC-ROS1 is a recurrent ROS1 fusion in primary central nervous system (CNS) tumors. CEP85L-ROS1 and GOPC-ROS1 are transforming oncogenes in cells of astrocytic lineage, and amenable to pharmacologic inhibition with several ROS1 inhibitors even when occurring concurrently with other cancer hotspot aberrations frequently associated with glioblastoma. Oral monotherapy with a brain-permeable ROS1 inhibitor, lorlatinib, significantly prolonged survival in an intracranially xenografted tumor model generated from a ROS1 fusion-positive glioblastoma cell line.

CONCLUSIONS

Our findings highlight that CNS tumors should be specifically interrogated for these rare intrachromosomal 6q22 microdeletion events that generate actionable ROS1 fusions. ROS1 fusions in primary brain cancer may be amenable for clinical intervention with kinase inhibitors, and this holds the potential of novel treatment paradigms in these treatment-refractory cancer types, particularly in glioblastoma.

Functional validation of the oncogenic cooperativity and targeting potential of tuberous sclerosis mutation in medulloblastoma using a MYC-amplified model cell line

Medulloblastoma is the most common malignant brain tumor of childhood. To identify targetable vulnerabilities, we employed inhibitor screening that revealed mTOR inhibitor hypersensitivity in the MYC-overexpressing medulloblastoma cell line, D341. Concomitant exome sequencing unveiled an uncharacterized missense mutation, TSC2^A415V , in these cells. We biochemically demonstrate that the TSC2^A415V mutation is functionally deleterious, leading to shortened half-life and proteasome-mediated protein degradation. These data suggest that MYC cooperates with activated kinase pathways, enabling pharmacologic intervention in these treatment refractory tumors. We propose that identification of activated kinase pathways may allow for tailoring targeted therapy to improve survival and treatment-related morbidity in medulloblastoma.

Trends in joint arthroplasty litigation over five years: the British experience

INTRODUCTION

Increasing numbers of joint arthroplasty are performed in Britain. While associated complications are well documented, it is not known which of those initiate malpractice claims.

METHOD

A five-year period was assessed for trends to highlight areas for further improvement in patient information and surgical management.

RESULTS

The National Health Service paid out almost £14 million for 598 claims. Forty per cent of this was for legal costs. The number of claims increased over time while the rate of successful claims decreased.

CONCLUSIONS

A failure to consent adequately and to adhere to policies and standard practice can result in a successful malpractice claim. Protecting patients intraoperatively and maintaining high technical expertise while implementing policies and obtaining informed consent decreases the litigation burden.

Manifestation of spin selection rules on the quantum tunneling of magnetization in a single-molecule magnet

We present low temperature magnetometry measurements on a new Mn3 single-molecule magnet in which the quantum tunneling of magnetization (QTM) displays clear evidence for quantum mechanical selection rules. A QTM resonance appearing only at high temperatures demonstrates tunneling between excited states with spin projections differing by a multiple of three. This is dictated by the C3 molecular symmetry, which forbids pure tunneling from the lowest metastable state. Transverse field resonances are understood by correctly orienting the Jahn-Teller axes of the individual manganese ions and including transverse dipolar fields. These factors are likely to be important for QTM in all single-molecule magnets.

High-frequency microstrip cross resonators for circular polarization electron paramagnetic resonance spectroscopy

In this article we discuss the design and implementation of a novel microstrip resonator which allows absolute control of the microwaves polarization degree for frequencies up to 30 GHz. The sensor is composed of two half-wavelength microstrip line resonators, designed to match the 50 Omega impedance of the lines on a high dielectric constant GaAs substrate. The line resonators cross each other perpendicularly through their centers, forming a cross. Microstrip feed lines are coupled through small gaps to three arms of the cross to connect the resonator to the excitation ports. The control of the relative magnitude and phase between the two microwave stimuli at the input ports of each line allows for tuning the degree and type of polarization of the microwave excitation at the center of the cross resonator. The third (output) port is used to measure the transmitted signal, which is crucial to work at low temperatures, where reflections along lengthy coaxial lines mask the signal reflected by the resonator. Electron paramagnetic resonance spectra recorded at low temperature in an S=5/2 molecular magnet system show that 82% fidelity circular polarization of the microwaves is achieved over the central area of the resonator.

On-chip integration of high-frequency electron paramagnetic resonance spectroscopy and Hall-effect magnetometry

A sensor that integrates high-sensitivity micro-Hall effect magnetometry and high-frequency electron paramagnetic resonance spectroscopy capabilities on a single semiconductor chip is presented. The Hall-effect magnetometer (HEM) was fabricated from a two-dimensional electron gas GaAsAlGaAs heterostructure in the form of a cross, with a 50 x 50 microm2 sensing area. A high-frequency microstrip resonator is coupled with two small gaps to a transmission line with a 50 Omega impedance. Different resonator lengths are used to obtain quasi-TEM fundamental resonant modes in the frequency range 10-30 GHz. The resonator is positioned on top of the active area of the HEM, where the magnetic field of the fundamental mode is largest, thus optimizing the conversion of microwave power into magnetic field at the sample position. The two gaps coupling the resonator and transmission lines are engineered differently--the gap to the microwave source is designed to optimize the loaded quality factor of the resonator (Q<or=150) while the gap for the transmitted signal is larger. This latter gap minimizes losses and prevents distortion of the resonance while enabling measurement of the transmitted signal. The large filling factor of the resonator permits sensitivities comparable to that of high-quality factor resonant cavities. The integrated sensor enables measurement of the magnetization response of micron scale samples upon application of microwave fields. In particular, the combined measurement of the magnetization change and the microwave power under cw microwave irradiation of single crystal of molecular magnets is used to determine of the energy relaxation time of the molecular spin states. In addition, real-time measurements of the magnetization dynamics upon application of fast microwave pulses are demonstrated.

The Parker Flex-Tip™ tracheal tube makes endotracheal intubation with the Bullard laryngoscope easier and faster

BACKGROUND

The Bullard laryngoscope can be useful in management of difficult airway. When the endotracheal tube is advanced over the original Bullard laryngoscope stylet, the endotracheal tube sometimes makes contact with structures around the vocal cords, especially the right arytenoids. A similar problem also occurs with flexible fibreoptic intubation and it has been shown that use of the Parker Flex-Tip tube usually resolves the problem. In this study we tested our hypothesis that use of the Parker Flex-Tip tube might improve endotracheal tube passage with the Bullard laryngoscope.

METHODS

Forty patients scheduled for elective anaesthesia were randomly assigned into group ST (standard tube) or Group PT (Parker Flex-Tip tube). The time taken to achieve successful endotracheal tube placement after obtaining the best laryngeal view, the number of attempts at intubation and the incidences of successful intubation at first attempt and of re-direction of the Bullard laryngoscope during intubation were recorded. Unpaired t-test and chi2-test were employed and P < 0.05 was considered significant.

RESULTS

Use of the Parker Flex-Tip tube reduced the time required for successful endotracheal tube placement after the best laryngeal view was obtained from 14 +/- 6 to 6 +/- 2 s (P < 0.01). It also reduced the incidence of requirement for re-direction of the Bullard laryngoscope during intubation from 10/19 to 1/19 (P < 0.01). The incidence of successful intubation at the first attempt (18/19 vs. 15/19) was higher in the PT group but the difference was not statistically significant.

CONCLUSIONS

During intubation with the Bullard laryngoscope, use of the Parker Flex-Tip tube is associated with more rapid success and a lower incidence of re-direction of the Bullard laryngoscope during endotracheal intubation when compared to a standard endotracheal tube.

Perceptions of orthopaedic surgeons regarding hepatitis C viral transmission: a questionnaire survey

INTRODUCTION

Occupationally acquired hepatitis C viral infection is an important issue in surgery since there are no known vaccines or effective prophylaxis.

MATERIALS AND METHODS

An anonymous questionnaire survey was performed to determine the attitudes and perception of risks of occupational acquired hepatitis C viral transmission in orthopaedic surgeons.

RESULTS

A total of 763 questionnaires were posted to orthopaedic surgeons with various subspecialty interests and 261 surgeons responded (34.2%). Of respondents, 117 (47%) had sustained sharps injuries in the previous 12 months. Only 82 surgeons (33%) always reported such injuries, although 208 (84%) expressed concerns of occupationally acquired hepatitis C viral transmission. Orthopaedic surgeons were mostly unaware of the true prevalence of hepatitis C in high-risk groups, such as intravenous drug abusers.

CONCLUSIONS

Greater awareness of all aspects of hepatitis C infection and its risks to the practice of surgery is required. Further debate is necessary on the role of routine testing of surgeons and patients.

Difficult Airway Society guidelines for management of the unanticipated difficult intubation

Problems with tracheal intubation are infrequent but are the most common cause of anaesthetic death or brain damage. The clinical situation is not always managed well. The Difficult Airway Society (DAS) has developed guidelines for management of the unanticipated difficult tracheal intubation in the non-obstetric adult patient without upper airway obstruction. These guidelines have been developed by consensus and are based on evidence and experience. We have produced flow-charts for three scenarios: routine induction; rapid sequence induction; and failed intubation, increasing hypoxaemia and difficult ventilation in the paralysed, anaesthetised patient. The flow-charts are simple, clear and definitive. They can be fully implemented only when the necessary equipment and training are available. The guidelines received overwhelming support from the membership of the DAS.

DISCLAIMER

It is not intended that these guidelines should constitute a minimum standard of practice, nor are they to be regarded as a substitute for good clinical judgement.

The use of paraglossal straight blade laryngoscopy in difficult tracheal intubation

In 10 cases of unexpected difficult tracheal intubation using the Macintosh laryngoscope blade, the larynx could not be seen. In each case, a good view was achieved using the Miller blade lateral to the tongue, which enabled tracheal intubation under direct vision. The results achieved using narrow, low-profile straight laryngoscope blades with this technique are reviewed. The improved view obtained with this technique is a consequence of reduced tongue compression as compared with the Macintosh technique. This leads both to an improved line of sight, and to a reduced risk of backward displacement of the tongue and epiglottis. In addition, the molar or retromolar variation of the technique reduces the intrusion of maxillary structures into the line of sight, so that a better view of the larynx is achieved for a given degree of soft tissue compression. Paraglossal straight blade laryngoscopy may have an advantage over use of the Macintosh technique when intubation proves unexpectedly difficult. It is perhaps time to question standard teaching about the role of the curved blade in such patients or, more particularly, whether the technique of laryngoscopy as currently taught is optimal. The paraglossal straight blade technique needs to be practised in routine intubation before it can be used with confidence in difficult cases.

The value of skeletal scintigraphy in predicting the need for revision surgery in total knee replacement

We have reviewed the results of 99mtech-netium-methylene diphosphonate (Tc-MDP) bone scintigrams performed on patients following total knee arthroplasty. In addition, 67gallium (Ga) citrate scintigrams were carried out sequentially on 29 patients. Three groups of patients were identified: those with asymptomatic knees (undergoing scans for other reasons); those with aseptic or septic loosening; and those with pain without radiologic evidence of loosening. There was good correlation between the results of the scans and the final outcome. We conclude that sequential 99mTc-MDP and 67Ga citrate scintigrams are useful for demonstrating the presence of aseptic and septic loosening in knee prostheses, and pain with a normal scan appearance is probably not due to loosening or infection.

Abortion caused by Brucella abortus biovar 1 in a free-ranging bison (Bison bison) from Yellowstone National Park

A near-term aborted bison (Bison bison) fetus was collected near Old Faithful geyser in Yellowstone National Park, Wyoming (USA). On necropsy, the fetus liver had a small capsular tear, and there was a small quantity of blood in the peritoneal cavity. Microscopic lesions included mild, purulent bronchopneumonia and mild, multifocal, interstitial pneumonia. Brucella abortus biovar 1 was isolated from fetal abomasal contents, lung, and heart blood.

The management of an old fused hip after the occurrence of paraplegia

Two patients are reported who suffered traumatic paraplegia, and had a long-standing fused hip joint. Both required an excision (Girdlestone) arthroplasty to allow them to sit and one, who made a late but substantial neurological recovery, eventually underwent a total hip replacement. Both suffered thromboembolic and urinary complications. These may not have occurred if the procedures had been carried out earlier. Early mobilisation of the hip joint is recommended in these circumstances.

The epidemiology of fractures and fracture-dislocations of the cervical spine

A total of 717 fractures and fracture-dislocations of the cervical spine occurred in 657 patients in a 13-year period. Injury was commonest in the third decade of life. The levels most frequently injured were the second, fifth, and sixth. Injuries of the first and second cervical vertebrae commonly occurred together, and injuries involving the upper and lower cervical spine in the same individual occurred in 9 per cent of patients with fractures of C1 and C2. Odontoid fractures were the most frequent fractures in patients over 70 years of age, and formed the majority of fractures in patients over 80 years of age. It is recommended that if a fracture of the upper cervical spine is seen on radiographs, another fracture in the upper or lower cervical spine should be excluded. Patients aged 70 years and above who complain of neck pain after trauma should be suspected of having an odontoid fracture, until proven otherwise.

Burns management and junior staff--what do they know?

This study examines the ability of junior doctors to initiate the management of burned patients. One hundred and twenty-four junior doctors were assessed using a questionnaire. Eighty per cent of the sample had had undergraduate lectures on the subject and 43 per cent had experience of managing patients with major burns. Despite this only 3 per cent could correctly carry out all the steps necessary to estimate the fluid requirements of a burned patient. Theoretical knowledge of the 'Rule of Nines' was adequate but 10 per cent of the sample made mathematical errors when supplied with a burns formula and the appropriate values. We suggest that postgraduate instruction be given to junior staff and that burns charts include details of a burns formula and an illustrative example of the calculation required.

Carpometacarpal dislocation. An easily missed diagnosis

We have reviewed 21 cases of dorsal dislocation of carpometacarpal joints. In 15 of them the diagnosis was missed when they were first seen in an accident and emergency department. General swelling may obscure the characteristic clinical deformity and routine radiographs may not show the displacement clearly. It is recommended that a true lateral radiograph of the hand be requested when this injury is suspected.

Influence of anaesthetic technique on postoperative pain. A comparison of anaesthetic supplementation with halothane and with phenoperidine

Fifty male patients undergoing elective surgery for duodenal ulcer received either phenoperidine or halothane 0.5% for the supplementation of anaesthesia. The patients in the phenoperidine group required the first postoperative dose of analgesic later and had lower pain scores in the first 2 h after operation. In the course of the 1st, 2nd and 3rd days, the two groups of patients showed a similar pattern after operation with regard to pain scores, vital capacity impairment and oxygen tension measurements.