Leveraging big data of immune checkpoint blockade response identifies novel potential targets.

BACKGROUND: The development of immune checkpoint blockade (ICB) has changed the way we treat various cancers. While ICB produces durable survival benefits in a number of malignancies, a large proportion of treated patients do not derive clinical benefit. Recent clinical profiling studies have shed light on molecular features and mechanisms that modulate response to ICB. Nevertheless, none of these identified molecular features were investigated in large enough cohorts to be of clinical value. MATERIALS AND METHODS: Literature review was carried out to identify relevant studies including clinical dataset of patients treated with ICB [anti-programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1), anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4) or the combination] and available sequencing data. Tumor mutational burden (TMB) and 37 previously reported gene expression (GE) signatures were computed with respect to the original publication. Biomarker association with ICB response (IR) and survival (progression-free survival/overall survival) was investigated separately within each study and combined together for meta-analysis. RESULTS: We carried out a comparative meta-analysis of genomic and transcriptomic biomarkers of IRs in over 3600 patients across 12 tumor types and implemented an open-source web application (predictIO.ca) for exploration. TMB and 21/37 gene signatures were predictive of IRs across tumor types. We next developed a de novo GE signature (PredictIO) from our pan-cancer analysis and demonstrated its superior predictive value over other biomarkers. To identify novel targets, we computed the T-cell dysfunction score for each gene within PredictIO and their ability to predict dual PD-1/CTLA-4 blockade in mice. Two genes, F2RL1 (encoding protease-activated receptor-2) and RBFOX2 (encoding RNA-binding motif protein 9), were concurrently associated with worse ICB clinical outcomes, T-cell dysfunction in ICB-naive patients and resistance to dual PD-1/CTLA-4 blockade in preclinical models. CONCLUSION: Our study highlights the potential of large-scale meta-analyses in identifying novel biomarkers and potential therapeutic targets for cancer immunotherapy.

A phase II study of axitinib (AG-013736) in patients with incurable adenoid cystic carcinoma.

BACKGROUND: Recurrent/metastatic adenoid cystic carcinoma (ACC) is an incurable disease with no standard treatments. The majority of ACCs express the oncogenic transcription factor MYB (also c-myb), often in the context of a MYB gene rearrangement. This phase II trial of the tyrosine kinase inhibitor (TKI) axitinib (Pfizer) tested the hypothesis that targeting pathways activated by MYB can be therapeutically effective for ACC. PATIENTS AND METHODS: This is a minimax two-stage, phase II trial that enrolled patients with incurable ACC of any primary site. Progressive or symptomatic disease was required. Patients were treated with axitinib 5 mg oral twice daily; dose escalation was allowed. The primary end point was best overall response (BOR). An exploratory analysis correlating biomarkers to drug benefit was conducted, including next-generation sequencing (NGS) in 11 patients. RESULTS: Thirty-three patients were registered and evaluable for response. Fifteen patients had the axitinib dose increased. Tumor shrinkage was achieved in 22 (66.7%); 3 (9.1%) had confirmed partial responses. Twenty-five (75.8%) patients had stable disease, 10 of whom had disease stability for >6 months. The median progression-free survival (PFS) was 5.7 months (range 0.92-21.8 months). Grade 3 axitinib-related toxicities included hypertension, oral pain and fatigue. A trend toward superior PFS was noted with the MYB/NFIB rearrangement, although this was not statistically significant. NGS revealed three tumors with 4q12 amplification, producing increased copies of axitinib-targeted genes PDGFR/KDR/KIT. Two 4q12 amplified patients achieved stable disease for >6 months, including one with significant tumor reduction and the longest PFS on study (21.8 months). CONCLUSIONS: Although the primary end point was not met, axitinib exhibited clinical activity with tumor shrinkage achieved in the majority of patients with progressive disease before trial enrollment. Analysis of MYB biomarkers and genomic profiling suggests the hypothesis that 4q12 amplified ACCs are a disease subset that benefit from TKI therapy.

Outcomes for patients with papillary thyroid cancer who do not undergo prophylactic central neck dissection.

BACKGROUND: The role of prophylactic central neck dissection (CND) in the management of papillary thyroid cancer (PTC) is controversial. This report describes outcomes of an observational approach in patients without clinical evidence of nodal disease in PTC. METHODS: All patients who had surgery between 1986 and 2010 without CND for PTC were identified. All patients had careful clinical assessment of the central neck during preoperative and perioperative evaluation, with any suspicious nodal tissue excised for analysis. The cohort included patients in whom lymph nodes had been removed, but no patient had undergone a formal neck dissection. Recurrence-free survival (RFS), central neck RFS and disease-specific survival (DSS) were calculated using the Kaplan-Meier method. RESULTS: Of 1798 patients, 397 (22.1 per cent) were men, 1088 (60.5 per cent) were aged 45 years or more, and 539 (30.0 per cent) had pT3 or pT4 disease. Some 742 patients (41.3 per cent) received adjuvant treatment with radioactive iodine. At a median follow-up of 46 months the 5-year DSS rate was 100 per cent. Five-year RFS and central neck RFS rates were 96.6 and 99.1 per cent respectively. CONCLUSION: Observation of the central neck is safe and should be recommended for all patients with PTC considered before and during surgery to be free of central neck metastasis.

Muscles express motor patterns of non-innervating neural networks by filtering broad-band input.

We describe three slow muscles that responded to low-frequency modulation of a high-frequency neuronal input and, consequently, could express the motor patterns of neural networks whose neurons did not directly innervate the muscles. Two of these muscles responded to different frequency components present in the same input, and as a result each muscle expressed the motor pattern of a different, non-innervating, neural network. In an analogous manner, the distinct dynamics of the multiple intracellular processes that most cells possess may allow each process to respond to, and hence differentiate among, specific frequency ranges present in broad-band input.

Selective use of radioactive iodine (RAI) in thyroid cancer: No longer "one size fits all".

A remarkable, evidence-based trend toward de-escalation has reformed the practice of radioactive iodine (RAI) administration for thyroid cancer patients. Updated guidelines have supported both decreased RAI doses for select populations, as well as expanded definitions of low-risk and intermediate-risk patients that may not require RAI. Correspondingly, there is now increased flexibility for hemithyroidectomy without need for RAI, and relaxed TSH suppression targets for low-risk thyroidectomy patients. Clinical judgment remains indispensable where multiple risk factors co-exist that individually are not indications for RAI. This is especially salient in intermediate-risk patients with a less than excellent response to therapy, determined through thyroglobulin and ultrasound surveillance. Such judgment, however, may lead to patterns of inappropriate RAI practices or overuse with little benefit to the patient and unnecessary harm. A multidisciplinary, risk-adapted approach is ever more important and obliges the surgeon to understand the likelihood that their patients will receive RAI. The risks and benefits of RAI, its evolved role in contemporary guidelines, and current patterns of use among endocrinologists are reviewed, as well as the practical implications for thyroid surgeons.

Genetic determinants at the interface of cancer and neurodegenerative disease.

It has been hypothesized that oncogenesis and neurodegeneration may share common mechanistic foundations. Recent evidence now reveals a number of genes in which alteration leads to either carcinogenesis or neurodegeneration, depending on cellular context. Pathways that have emerged as having critical roles in both cancer and neurodegenerative disease include those involving genes such as PARK2, ATM, PTEN, PTPRD, and mTOR. A number of mechanisms have been implicated, and commonly affected cellular processes include cell cycle regulation, DNA repair, and response to oxidative stress. For example, we have recently shown that the E3 ubiquitin ligase PARK2 is mutated or deleted in many different human malignancies and helps drive loss on chromosome 6q25.2-27, a genomic region frequently deleted in cancers. Mutation in PARK2 is also the most common cause of juvenile Parkinson's disease. Mutations in PARK2 result in an upregulation of its substrate cyclin E, resulting in dysregulated entry into the cell cycle. In neurons, this process results in cell death, but in cycling cells, the result is a growth advantage. Thus, depending on whether the cell affected is a dividing cell or a post-mitotic neuron, responses to these alterations may differ, ultimately leading to varying disease phenotypes. Here, we review the substantial data implicating specific genes in both cancer and neurodegenerative disease.

Techniques for early diagnosis and management of cervicofacial necrotising fasciitis.

BACKGROUND: Cervicofacial necrotising fasciitis carries high rates of morbidity and mortality, and is not often initially suspected due to its rarity and misleadingly innocuous presentation. We propose an algorithm for the timely diagnosis and management of cervicofacial necrotising fasciitis. METHODS: Retrospective review of seven patients ultimately diagnosed with cervicofacial necrotising fasciitis. RESULTS: In these seven patients, common presenting symptoms included sore throat, fever and neck pain. On initial examination and imaging, only three had obvious findings. One patient's diagnosis was facilitated via a bedside cut-down procedure. Six patients underwent surgical debridement. Four required tracheotomy, and five wounds closed via secondary intention. There were two deaths. CONCLUSION: The severity of cervical necrotising fasciitis and its rapid spread necessitate early diagnosis and timely surgical management. The presentation often appears benign. A high index of clinical suspicion should be maintained in cases of neck cellulitis with nonspecific clinical findings, especially in diabetic or otherwise immunocompromised patients. A normal computed tomography scan does not rule out necrotising fasciitis. A cut-down procedure may be critical to early diagnosis in some cases.

Lymph node central necrosis on computed tomography as predictor of extracapsular spread in metastatic head and neck squamous cell carcinoma: pilot study.

OBJECTIVE: This study aimed (1) to investigate the relationship between the presence of lymph node central necrosis, viewed on pre-operative computed tomography imaging, and the occurrence of histopathologically determined metastatic lymph node extracapsular spread and (2) to determine whether a larger scale study would be valuable. MATERIALS AND METHODS: Pre-operative computed tomography scans, surgical records and post-operative histopathological analysis results were reviewed for 19 consecutive neck dissections performed in 17 patients with head and neck squamous cell carcinoma. RESULTS: A total of 20/26 (77 per cent) lymph nodes with central necrosis had extracapsular spread on histopathological analysis. Twenty of 21 (95 per cent) lymph nodes with extracapsular spread had central necrosis on pre-operative computed tomography. Thirty-four of 40 (85 per cent) lymph nodes without extracapsular spread had no evidence of central necrosis on computed tomography. Only three of 12 (25 per cent) patients with lymph node central necrosis identified on pre-operative computed tomography were found to have actual necrosis on final histopathological analysis. CONCLUSIONS: Lymph node central necrosis viewed on pre-operative computed tomography scans is a useful indicator of metastatic lymph node extracapsular spread, with a sensitivity of 95 per cent, a specificity of 85 per cent, a positive predictive value of 69 per cent and a negative predictive value of 98 per cent. Lymph node diameter is not a sensitive indicator of extracapsular spread.

3D reconstruction and manufacture of real abdominal aortic aneurysms: from CT scan to silicone model.

Abdominal aortic aneurysm (AAA) can be defined as a permanent and irreversible dilation of the infrarenal aorta. AAAs are often considered to be an aorta with a diameter 1.5 times the normal infrarenal aorta diameter. This paper describes a technique to manufacture realistic silicone AAA models for use with experimental studies. This paper is concerned with the reconstruction and manufacturing process of patient-specific AAAs. 3D reconstruction from computed tomography scan data allows the AAA to be created. Mould sets are then designed for these AAA models utilizing computer aided designcomputer aided manufacture techniques and combined with the injection-moulding method. Silicone rubber forms the basis of the resulting AAA model. Assessment of wall thickness and overall percentage difference from the final silicone model to that of the computer-generated model was performed. In these realistic AAA models, wall thickness was found to vary by an average of 9.21%. The percentage difference in wall thickness recorded can be attributed to the contraction of the casting wax and the expansion of the silicone during model manufacture. This method may be used in conjunction with wall stress studies using the photoelastic method or in fluid dynamic studies using a laser-Doppler anemometry. In conclusion, these patient-specific rubber AAA models can be used in experimental investigations, but should be assessed for wall thickness variability once manufactured.

Muscle response to changing neuronal input in the lobster (Panulirus interruptus) stomatogastric system: spike number- versus spike frequency-dependent domains.

We aimed to determine the neuronal parameters controlling the contraction of slowly contracting, non-twitch ("tonic") muscles driven by rhythmic neuronal activity. These muscles are almost completely absent in mammals but are common in lower vertebrates and invertebrates. Slow muscles are often believed to function primarily in tonic motor patterns. However, previous research and data presented here indicate that slow muscles are also driven by rhythmic neuronal inputs. In rapidly contracting "twitch" muscles, motor unit force is believed to be primarily determined by motor neuron spike frequency. What determines slow muscle output is less well understood. We present a simple model that suggests that when motor neuron burst duration is brief compared with muscle summation time, spike number, not spike frequency, determines slow muscle contraction amplitude. We present analyses that distinguish between spike number and spike frequency dependence in two slow muscles in the lobster stomatogastric system. Our analysis shows that, functionally, one muscle is spike number dependent, whereas the other is primarily spike frequency dependent. Thus, both of these parameters can determine slow muscle output. To predict the movements elicited by neuronal activity in preparations in which slow muscles are common, it may be necessary to determine spike number versus spike frequency dependence for each muscle. Spike number dependence couples motor neuron burst duration and spike frequency in that changing either parameter alone alters spike number (and hence muscle contraction amplitude). Neural networks innervating spike number-dependent muscles may therefore have specific properties to compensate for the complexity intrinsic to spike number coding.

Mechanisms underlying stabilization of temporally summated muscle contractions in the lobster (Panulirus) pyloric system.

Muscles are the final effectors of behavior. The neural basis of behavior therefore cannot be completely understood without a description of the transfer function between neural output and muscle contraction. To this end, we have been studying muscle contraction in the well-investigated lobster pyloric system. We report here the mechanisms underlying stabilization of temporally summating contractions of the very slow dorsal dilator muscle in response to motor nerve stimulation with trains of rhythmic shock bursts at a physiological intraburst spike frequency (60 Hz), physiological cycle periods (0.5-2 s), and duty cycles from 0.1 to 0.8. For temporal summation to stabilize, the rise and relaxation amplitudes of the phasic contractions each burst induces must equalize as the rhythmic train continues. Stabilization could occur by changes in rise duration, rise slope, plateau duration, and/or relaxation slope. We demonstrate a generally applicable method for quantifying the relative contribution changes in these characteristics make to contraction stabilization. Our data show that all characteristics change as contractions stabilize, but their relative contribution differs depending on stimulation cycle period and duty cycle. The contribution of changes in rise duration did not depend on period or duty cycle for the 1-, 1.5-, and 2-s period regimes, contributing approximately 30% in all cases; but for the 0.5-s period regime, changes in rise duration increased from contributing 25% to contributing 50% as duty cycle increased from 0.1 to 0.8. At all cycle periods decreases in rise slope contributed little to stabilization at small duty cycles but increased to contributing approximately 80% at high duty cycles. The contribution of changes in plateau duration decreased in all cases as duty cycle increased; but this decrease was greater in long cycle period regimes. The contribution of changes in relaxation slope also decreased in all cases as duty cycle increased; but for this characteristic, the decrease was greatest in fast cycle period regimes, and in these regimes at high duty cycles these changes opposed contraction stabilization. Exponential fits to contraction relaxations showed that relaxation time constant increased with total contraction amplitude; this increase presumably underlies the decreased relaxation slope magnitude seen in high duty cycle, fast cycle period regimes. These data show that changes in no single contraction characteristic can account for contraction stabilization in this muscle and suggest that predicting muscle response in other systems in which slow muscles are driven by rapidly varying neuronal inputs may be similarly complex.

Muscle response to changing neuronal input in the lobster (Panulirus interruptus) stomatogastric system: slow muscle properties can transform rhythmic input into tonic output.

Slow, non-twitch muscles are widespread in lower vertebrates and invertebrates and are often assumed to be primarily involved in posture or slow motor patterns. However, in several preparations, including some well known invertebrate "model" preparations, slow muscles are driven by rapid, rhythmic inputs. The response of slow muscles to such inputs is little understood. We are investigating this issue with a slow stomatogastric muscle (cpv1b) driven by a relatively rapid, rhythmic neural pattern. A simple model suggests that as cycle period decreases, slow muscle contractions show increasing intercontraction temporal summation and at steady state consist of phasic contractions overlying a tonic contracture. We identify five components of these contractions: total, average, tonic, and phasic amplitudes, and percent phasic (phasic amplitude divided by total amplitude). cpv1b muscle contractions induced by spontaneous rhythmic neural input in vitro consist of phasic and tonic components. Nerve stimulation at varying cycle periods and constant duty cycle shows that a tonic component is always present, and at short periods the muscle transforms rhythmic input into almost completely tonic output. Varying spike frequency, spike number, and cycle period show that frequency codes total, average, and tonic amplitudes, number codes phasic amplitude, and period codes percent phasic. These data suggest that tonic contraction may be a property of slow muscles driven by rapid, rhythmic input, and in these cases it is necessary to identify the various contraction components and their neural coding. Furthermore, the parameters that code these components are interdependent, and control of slow muscle contraction is thus likely complex.

Derivation of aquatic screening benchmarks for 1,2-dibromoethane.

Ethylene dibromide (1,2-dibromoethane or EDB) was primarily used in the United States as an additive in leaded gasoline and as a soil and grain fumigant for worm and insect control until it was banned in 1983. Historical releases of EDB have resulted in detectable EDB in groundwater and drinking wells, and recently concentrations up to 16 microg/L were detected in ground water at two fuel spill plumes in the vicinity of the Massachusetts Military Reservation Base on Cape Cod, Massachusetts. Because the ground water in this area is used to flood cranberry bogs for the purposes of harvesting, the U.S. Air Force sponsored the development of aquatic screening benchmarks for EDB. Acute toxicity tests with Pimephales promelas (fathead minnow), Daphnia magna, and Ceriodaphnia dubia were conducted to provide data needed for development of screening benchmarks. Using a closed test-system to prevent volatilization of EDB, the 48-h LC50S (concentration that kills 50% of the test organisms) for P. promelas, D. magna, and C. dubia were 4.3 mg/L, 6.5 mg/L, and 3.6 mg/L, respectively. The screening benchmark for aquatic organisms, derived as the Tier II chronic water quality criteria, is 0.031 mg EDB/L. The sediment screening benchmark, based on equilibrium partitioning, is 2.45 mg EDB/kg of organic carbon in the sediment. The screening benchmarks developed here are an important component of an ecological risk assessment, during which perhaps hundreds of chemicals must be evaluated for their potential to cause ecological harm.