Acceleration of electrons in the plasma wakefield of a proton bunch

High-energy particle accelerators have been crucial in providing a deeper understanding of fundamental particles and the forces that govern their interactions. To increase the energy of the particles or to reduce the size of the accelerator, new acceleration schemes need to be developed. Plasma wakefield acceleration^1–5, in which the electrons in a plasma are excited, leading to strong electric fields (so called ‘wakefields’), is one such promising acceleration technique. Experiments have shown that an intense laser pulse^6–9 or electron bunch^10,11 traversing a plasma can drive electric fields of tens of gigavolts per metre and above—well beyond those achieved in conventional radio-frequency accelerators (about 0.1 gigavolt per metre). However, the low stored energy of laser pulses and electron bunches means that multiple acceleration stages are needed to reach very high particle energies^5,12. The use of proton bunches is compelling because they have the potential to drive wakefields and to accelerate electrons to high energy in a single acceleration stage¹³. Long, thin proton bunches can be used because they undergo a process called self-modulation^14–16, a particle–plasma interaction that splits the bunch longitudinally into a series of high-density microbunches, which then act resonantly to create large wakefields. The Advanced Wakefield (AWAKE) experiment at CERN^17–19 uses high-intensity proton bunches—in which each proton has an energy of 400 gigaelectronvolts, resulting in a total bunch energy of 19 kilojoules—to drive a wakefield in a ten-metre-long plasma. Electron bunches are then injected into this wakefield. Here we present measurements of electrons accelerated up to two gigaelectronvolts at the AWAKE experiment, in a demonstration of proton-driven plasma wakefield acceleration. Measurements were conducted under various plasma conditions and the acceleration was found to be consistent and reliable. The potential for this scheme to produce very high-energy electron bunches in a single accelerating stage²⁰ means that our results are an important step towards the development of future high-energy particle accelerators^21,22.

Electron acceleration to very high energies is achieved in a single step by injecting electrons into a ‘wake’ of charge created in a 10-metre-long plasma by speeding long proton bunches.

Intradural extramedullary granular cell tumour in a cat

A 7-year-old domestic shorthair cat was evaluated for progressive paraparesis, inability to jump, a paralysed tail and inability to void the bladder. Neurologic examination was consistent with a L4-S3 localisation. Survey radiographs of the lumbar vertebral column revealed L4-L7 vertebral body remodelling. A pre-contrast T1-weighted hyperintense, diffusely enhancing intradural lesion extending from L4 to S1 vertebral bodies was detected by MRI. Large, mesenchymal, round-to-polygonal cells arranged in nests or sheets were found on histologic examination at post mortem. These cells were characterised by abundant intracytoplasmic PAS-positive, diastase-resistant granules and positive immunoexpression of vimentin, S-100, neuron-specific enolase and desmin. This is the first report of a spinal granular cell tumour in a cat.

Analyses of germline variants associated with ovarian cancer survival identify functional candidates at the 1q22 and 19p12 outcome loci

We previously identified associations with ovarian cancer outcome at five genetic loci. To identify putatively causal genetic variants and target genes, we prioritized two ovarian outcome loci (1q22 and 19p12) for further study. Bioinformatic and functional genetic analyses indicated that MEF2D and ZNF100 are targets of candidate outcome variants at 1q22 and 19p12, respectively. At 19p12, the chromatin interaction of a putative regulatory element with the ZNF100 promoter region correlated with candidate outcome variants. At 1q22, putative regulatory elements enhanced MEF2D promoter activity and haplotypes containing candidate outcome variants modulated these effects. In a public dataset, MEF2D and ZNF100 expression were both associated with ovarian cancer progression-free or overall survival time. In an extended set of 6,162 epithelial ovarian cancer patients, we found that functional candidates at the 1q22 and 19p12 loci, as well as other regional variants, were nominally associated with patient outcome; however, no associations reached our threshold for statistical significance (p<1×10-5). Larger patient numbers will be needed to convincingly identify any true associations at these loci.

Phase II open-label randomized multi-centre study of neoadjuvant olaparib in patients (pts) with platinum sensitive (PS) relapsed high grade serous ovarian cancer (OC): The NEO trial

TPS5608

Background: Olaparib is a PARP inhibitor with clinical benefit in relapsed OC, especially in pts with germline BRCA1/2 mutation ( gBRCA). Study 19 (NCT00753545) found a progression free survival (PFS) gain from maintenance olaparib, post chemotherapy for PS relapse. Olaparib treatment in gBRCA OC pts relapsing post ≥ 3 prior chemotherapy regimens gave a response rate (RR) of 46% in the PS subgroup (Study 42; NCT01078662). Efficacy of olaparib may extend to OC with homologous recombination DNA repair pathway deficiency (HRD); susceptible to synthetic lethality from PARP inhibition. NEO [NCT02489006] is a window of opportunity study to assess tumor heterogeneity and the pharmacodynamic effects of olaparib given prior to surgery in PS OC, analyse the tumor genomic landscape pre and post olaparib, and assess for predictive biomarkers beyond BRCA mutation. Methods: This phase 2 study enrols pts with high grade serous OC, primary peritoneal or fallopian tube cancer with a progression free interval of ≥6 months and sensitive to their last line of platinum therapy. Pts must be suitable for secondary debulking surgery and agree to pre-operative tumour biopsy. All pts receive olaparib tablets 300mg po bid for 6 ± 2 weeks pre-surgery. Post-operatively, pts are randomised 1:1 to olaparib or 6 cycles of platinum-based chemotherapy followed by maintenance olaparib. The primary endpoint is the degree of PAR and PARP-1 inhibition in the blood and tumor following pre-operative olaparib in PS relapsed OC. Clinical efficacy is assessed by RR (RECIST 1.1), CA125, PFS and PFS2. Translational studies include next generation sequencing HRD panel to assess for somatic and germline mutations including RAD51B/C/D, PPM1D, FANCM, BRIP1, PALB2 and BARD1; evaluation of gene expression change in tumor tissue pre and post olaparib; assessment for resistance mechanisms and impact of heterogeneity. Circulating tumor DNA measured weekly pre-surgery is assessed for its prognostic value, alone and compared with CA125. The study will enrol 50-70 pts with estimated accrual of 3 pts/month across multiple sites, and opened at Princess Margaret Cancer Centre in 7/2016. Clinical trial information: NCT02489006.

Prevalence and Risk Factors for Presumptive Ascending/Descending Myelomalacia in Dogs after Thoracolumbar Intervertebral Disk Herniation

Background

Ascending/descending myelomalacia (ADMM) is a severe complication of thoracolumbar intervertebral disk herniation (TL‐IVDH) in dogs.

Hypothesis/Objectives

To investigate the prevalence and risk factors for ADMM in nonambulatory dogs with surgically treated TL‐IVDH.

Animals

Six‐hundred and fifty‐two client‐owned dogs evaluated for TL‐IVDH that underwent decompressive spinal surgery.

Methods

Retrospective medical record review from February 2007 through December 2015.

Results

Thirteen dogs developed ADMM, with an overall prevalence of 2.0%. The prevalence of ADMM was 0% in dogs with neurological signs graded 1 or 2 at admission or before magnetic resonance imaging (MRI) or surgical procedures, 0.6% in dogs with neurological signs graded 3, 2.7% in dogs with neurological signs graded 4, and 14.5% in dogs with neurological signs graded 5. Age (<5.8 years), neurological status (grade 5), site of disk herniation (L5‐L6), duration of clinical signs before becoming nonambulatory (<24 hours), detection of intramedullary T2‐weighted (T2W) hyperintensity, and a T2 length ratio >4.57 were significant risk factors in the univariate analysis for development of ADMM.

Conclusions and Clinical Importance

The factors identified in this study may be useful for the prediction of ADMM. Multicenter studies with a higher number of dogs with ADMM are required to confirm these data.

Activation of P2X7 and P2Y11 purinergic receptors inhibits migration and normalizes tumor-derived endothelial cells via cAMP signaling

Purinergic signaling is involved in inflammation and cancer. Extracellular ATP accumulates in tumor interstitium, reaching hundreds micromolar concentrations, but its functional role on tumor vasculature and endothelium is unknown. Here we show that high ATP doses (>20 μM) strongly inhibit migration of endothelial cells from human breast carcinoma (BTEC), but not of normal human microvascular EC. Lower doses (1–10 mm result ineffective. The anti-migratory activity is associated with cytoskeleton remodeling and is significantly prevented by hypoxia. Pharmacological and molecular evidences suggest a major role for P2X7R and P2Y11R in ATP-mediated inhibition of TEC migration: selective activation of these purinergic receptors by BzATP mimics the anti-migratory effect of ATP, which is in turn impaired by their pharmacological or molecular silencing. Downstream pathway includes calcium-dependent Adenilyl Cyclase 10 (AC10) recruitment, cAMP release and EPAC-1 activation. Notably, high ATP enhances TEC-mediated attraction of human pericytes, leading to a decrease of endothelial permeability, a hallmark of vessel normalization. Finally, we provide the first evidence of in vivo P2X7R expression in blood vessels of murine and human breast carcinoma. In conclusion, we have identified a purinergic pathway selectively acting as an antiangiogenic and normalizing signal for human tumor-derived vascular endothelium.

Giant Cell Osteosarcoma in the Calvarium of a Cat

Feline primary osteosarcomas involving the skull are extremely rare. When they occur, orbit, mandible, and maxilla are the most common sites. Microscopically, scattered multinucleated giant cells (MGCs) are not an uncommon occurrence in osteosarcoma (OSC), but they are generally in low number. Only in a rare variant, the giant cell-rich OSC, are MGCs the prevalent cell type. Although osteoclast and osteoblast origin have been postulated in human and veterinary literature, the origin of MGCs in osteosarcomas is poorly understood. This report describes a giant cell-rich OSC in the calvarium of a 13-year-old spayed female shorthair cat. The animal exhibited a range of neurologic signs, including left circling, compulsive gait, lack of proprioception, and bilateral absence of menace reaction, with indication of left forebrain involvement. Gross lesions were characterized by a multilobate, spherical mass located in the left calvarium, compressing the left forebrain. Histologically, the tumor was characterized by scattered nests of MGCs separated by small bundles of pleomorphic, fusate to polygonal cells. Between spindle cells, osteoid was very sparse and arranged in thin strands. immunohistochemical stains for vimentin were positive, with no detectable cellular staining for cytokeratin, S-100 protein, or Class II major histocompatibility complex. Ultrastructurally, MGCs contained profiles of rough endoplasmic reticulum; no lysosomes were observed. The origin of MGCs in osteosarcoma remains obscure, and our results confirm their ambiguous identity.

Abstract PR16: Computational modeling of serous ovarian carcinoma dynamics: Implications for screening and therapy

High-grade serous ovarian carcinoma (HG-SOC) is the most common subtype of ovarian cancer and has the worst prognosis. There is intense controversy on whether the temporal order of cytoreductive surgery and chemotherapy affects treatment outcome, with the main options being primary debulking surgery with adjuvant chemotherapy (PDS) versus neo-adjuvant chemotherapy with interval debulking surgery (NACT). Although some studies report that PDS-treated patients survive significantly longer than those receiving NACT, other reports showed no significant difference patient outcome. To address this question in an unbiased way, we used computational modeling and simulated HG-SOC progression dynamics with different treatments.

We developed a mathematical framework to predict the evolution of chemotherapy resistance, and populated our model with clinical data from nearly 300 patients receiving PDS or NACT from multiple institutes. After estimating the rates of proliferation and mutation of carcinoma cells, we determined that most HG-SOC patients likely harbor chemotherapy-resistant cancer cells at diagnosis. Furthermore, we predicted the effects of PDS and NACT on the number of sensitive and resistant cells, as well as patient survival following treatment, and found that our model closely recapitulated clinical observations in both training and test sets. Based on our results, we predict that PDS with optimal debulking (&lt;1mm residual tumor) has the potential to be curative because surgery can sometimes remove all chemo-resistant cells, while adjuvant chemotherapy depletes the remaining chemo-sensitive cells. By contrast, NACT is unlikely to cure the disease because it depletes chemo-sensitive cells that can mark the location of accompanying “passenger” chemo-resistant cells. Our model also predicts that PDS should have a better outcome than NACT, when controlled for residual tumor size.

Finally, we evaluated the potential benefits of early diagnosis of naive or relapsed HG-SOC. We recapitualted the clinical finding that CA125-based earlier diagnosis of relapsed cancer does not improve survival compared to physical-symptom-based diagnosis. We also predict that more sensitive detection methods (such as ctDNA-based diagnosis) are unlikely to improve survival post-relapse with current chemotherapy, because earlier diagnosis does not decrease the number of chemo-resistant cells, which are already enriched at recurrence. By contrast, our model predicts that with sufficiently sensitive assays, early detection of treatment-naive HG-SOC could improve survival time and increase chance of cure.

This abstract is also presented as Poster B19.

Citation Format: Shengqing Gu, Stephanie Lheureux, Azin Sayad, Liat Hogen Ben-David, Iryna Vyarvelska, Paulina Cybulska, Marcus Bernardini, Barry Rosen, Amit Oza, Benjamin G. Neel. Computational modeling of serous ovarian carcinoma dynamics: Implications for screening and therapy. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr PR16.

Abstract B2-06: Computational modeling of serous ovarian carcinoma dynamics: Implications for screening and therapy

High-grade serous ovarian carcinoma (HG-SOC) is the most common subtype of ovarian cancer and has the worst prognosis. There is intense controversy on whether the temporal order of cytoreductive surgery and chemotherapy affects treatment outcome, with the main options being primary debulking surgery with adjuvant chemotherapy (PDS) versus neo-adjuvant chemotherapy with interval debulking surgery (NACT). Although some studies report that PDS-treated patients survive significantly longer than those receiving NACT, other reports showed no significant difference in patient outcome. To address this question in an unbiased way, we used computational modeling and simulated HG-SOC progression dynamics with different treatments.

We developed a mathematical framework to predict the evolution of chemotherapy resistance, and populated our model with survival data from &gt;300 patients receiving PDS or NACT. After estimating the rates of proliferation and mutation of carcinoma cells, we determined that most HG-SOC patients likely harbor chemotherapy-resistant cancer cells at diagnosis. Furthermore, we predicted the effects of PDS and NACT on the number of sensitive and resistant cells, as well as patient survival following treatment, and found that our model closely recapitulated clinical observations in both training and test sets. Based on our results, we predict that PDS with optimal debulking (&lt;1mm residual tumor) has the potential to be curative because surgery can sometimes remove all chemo-resistant cells, while adjuvant chemotherapy depletes the remaining chemo-sensitive cells. By contrast, NACT is unlikely to cure the disease because it depletes chemo-sensitive cells that can mark the location of accompanying “passenger” chemo-resistant cells. Moreover, NACT results in extensive enrichment of chemo-resistant cells before surgery, but the deposits of such cells are typically too small to be visualized at eventual surgery. Our model also predicts that PDS should have a better outcome than NACT, when controlled for residual tumor size.

Finally, we evaluated the potential benefits of early diagnosis of naïve or relapsed HG-SOC. We recapitulated the clinical finding that CA125-based earlier diagnosis of relapsed cancer does not improve survival. We also predict that more sensitive detection methods (such as ctDNA-based diagnosis) are unlikely to improve survival post-relapse with current chemotherapy, because earlier diagnosis does not decrease the number of chemo-resistant cells, which are already enriched at recurrence. By contrast, our model predicts that with sufficiently sensitive assays, early detection could improve survival time and increase chances of cure.

Citation Format: Shengqing Gu, Stephanie Lheureux, Azin Sayad, Liat Frida Hogen, Iryna Vyarvelska, Paulina Cybulska, Marcus Bernardini, Barry Rosen, Amit Oza, Benjamin G. Neel. Computational modeling of serous ovarian carcinoma dynamics: Implications for screening and therapy. [abstract]. In: Proceedings of the AACR Special Conference on Computational and Systems Biology of Cancer; Feb 8-11 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 2):Abstract nr B2-06.

Abstract LB-307: Computational modeling of serous ovarian carcinoma dynamics: Implications for screening and therapy

High-grade serous ovarian carcinoma (HG-SOC) is the most common subtype of ovarian cancer and has the worst prognosis. There is intense controversy on whether the temporal order of cytoreductive surgery and chemotherapy affects treatment outcome, with the main options being primary debulking surgery with adjuvant chemotherapy (PDS) versus neo-adjuvant chemotherapy with interval debulking surgery (NACT). Although some studies report that PDS-treated patients survive significantly longer than those receiving NACT, other reports showed no significant difference in patient outcome. To address this question in an unbiased way, we used computational modeling to simulate HG-SOC progression dynamics with different treatments.

We adapted a mathematical framework to predict the evolution of chemotherapy resistance, and populated our model with survival data from &gt;300 patients receiving PDS or NACT. After estimating the mutation rate of carcinoma cells and cancer cell number at diagnosis, we determined that most HG-SOC patients likely harbor chemotherapy-resistant cancer cells at diagnosis. Furthermore, we predicted the effects of PDS and NACT on the number of sensitive and resistant cells, as well as patient survival following treatment, and found that our model closely recapitulated clinical observations in both training and test sets. Based on our results, we predict that PDS with optimal debulking (&lt;1mm residual tumor) has the potential to be curative because surgery can sometimes remove all chemo-resistant cells, while adjuvant chemotherapy depletes the remaining chemo-sensitive cells. By contrast, NACT is unlikely to cure the disease because neo-adjuvant chemotherapy depletes chemo-sensitive cells that can mark the location of accompanying “passenger” chemo-resistant cells. As a result, it leads to extensive enrichment of chemo-resistant cells before surgery, but the deposits of such cells are typically too small to be visualized at eventual surgery. Our model also predicts that PDS should have a better outcome than NACT, when controlled for residual tumor size.

Finally, we evaluated the potential benefits of early diagnosis of naïve or relapsed HG-SOC. We recapitulated the clinical finding that CA125-based earlier diagnosis of relapsed cancer does not improve survival. We also predict that more sensitive detection methods (such as ctDNA-based diagnosis) are unlikely to improve survival post-relapse with current chemotherapy, because earlier diagnosis does not decrease the number of chemo-resistant cells, which are already enriched at recurrence. By contrast, our model predicts that with sufficiently sensitive assays, early detection could improve survival time and increase chances of cure.

Note: This abstract was not presented at the meeting.

Citation Format: Shengqing Gu, Liat Hogen, Stephanie Lheureux, Azin Sayad, Iryna Vyarvelska, Paulina Cybulska, Marcus Bernardini, Barry Rosen, Amit Oza, Benjamin G. Neel. Computational modeling of serous ovarian carcinoma dynamics: Implications for screening and therapy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-307. doi:10.1158/1538-7445.AM2015-LB-307

Technical update on tissue morcellation during gynaecologic surgery: its uses, complications, and risks of unsuspected malignancy

OBJECTIVE

To review the use of tissue morcellation in minimally invasive gynaecological surgery.

OUTCOMES

Morcellation may be used in gynaecological surgery to allow removal of large uterine specimens, providing women with a minimally invasive surgical option. Adverse oncologic outcomes of tissue morcellation should be mitigated through improved patient selection, preoperative investigations, and novel techniques that minimize tissue dispersion.

EVIDENCE

Published literature was retrieved through searches of PubMed and Medline in the spring of 2014 using appropriate controlled vocabulary (leiomyomsarcoma, uterine neoplasm, uterine myomectomy, hysterectomy) and key words (leiomyoma, endometrial cancer, uterine sarcoma, leiomyosarcoma, morcellation, and MRI). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date limits but results were limited to English or French language materials. Searches were updated on a regular basis and incorporated in the guideline to August 2014. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of evidence in this document was rated using the criteria described in the report of the Canadian Task Force on Preventive Health Care. (Table 1) BENEFITS, HARMS, AND COSTS: Gynaecologists may offer women minimally invasive surgery and this may involve tissue morcellation and the use of a power morcellator for specimen retrieval. Women should be counselled that in the case of unexpected uterine sarcoma or endometrial cancer, the use of a morcellator is associated with increased risk of tumour dissemination. Appropriate training and safe practices should be in place before offering tissue morcellation. SUMMARY STATEMENTS: 1. Uterine sarcomas may be difficult to diagnose preoperatively. The risk of an unexpected uterine sarcoma following surgery for presumed benign uterine leiomyoma is approximately 1 in 350, and the rate of leiomyosarcoma is 1 in 500. (II-2) This risk increases with age. (II-2) 2. An unexpected uterine sarcoma treated by primary surgery involving tumour disruption, including morcellation of the tumour, has the potential for intra-abdominal tumour-spread and a worse prognosis. (II-2) 3. Uterus-sparing surgery remains a safe option for patients with symptomatic leiomyomas who desire future fertility. (II-1) RECOMMENDATIONS: 1. Techniques for morcellation of a uterine specimen vary, and physicians should consider employing techniques that minimize specimen disruption and intra-abdominal spread. (III-C) 2. Each patient presenting with uterine leiomyoma should be assessed for the possible presence of malignancy, based on her risk factors and preoperative imaging, although the value of these is limited. (III-C) 3. Preoperative endometrial biopsy and cervical assessment to avoid morcellation of potentially detectable malignant and premalignant conditions is recommended. (II-2A) 4. Hereditary cancer syndromes that increase the risk of uterine malignancy should be considered a contraindication to uncontained uterine morcellation. (III-C) 5. Uterine morcellation is contraindicated in women with established or suspected cancer. (II-2A) If there is a high index of suspicion of a uterine sarcoma prior to surgery, patients should be advised to proceed with a total abdominal hysterectomy, bilateral salpingectomy, and possible oophorectomy. (II-2C) A gynaecologic oncology consultation should be obtained. 6. Tissue morcellation techniques require appropriate training and experience. Safe practice initiatives surrounding morcellation technique and the use of equipment should be implemented at the local level. (II-3B) 7. Morcellation is an acceptable option for retrieval of benign uterine specimens and may facilitate a minimally invasive surgical approach, which is associated with decreased perioperative risks. Each patient should be counselled about the possible risks associated with the use of morcellation, including the risks associated with underlying malignancy. (III-C).

The impacts of neoadjuvant chemotherapy and of debulking surgery on survival from advanced ovarian cancer

OBJECTIVES

Women with advanced ovarian cancer are treated with chemotherapy either before (neoadjuvant) or after surgery (primary debulking). The goal is to leave no residual disease post-surgery; for women treated with primary debulking surgery this has been associated with an improvement in survival. It has not been shown that the survival advantage conferred by having no residual disease post-surgery is present for women who receive neoadjuvant chemotherapy.

METHODS

We reviewed the records of 326 women with stage IIIc or IV serous ovarian cancer. We determined if they received neoadjuvant chemotherapy or primary debulking surgery and we measured the extent of residual disease post-surgery. We estimated seven-year survival rates for women after various treatments.

RESULTS

Women who had neoadjuvant chemotherapy were more likely to have no residual disease than women who had primary debulking surgery (50.1% versus 41.5%; p=0.03) but they experienced inferior seven-year survival (8.6% versus 41%; p<0.0001). Among women who had primary debulking surgery, those with no residual disease had much better seven-year survival than women who had any residual disease (73.6% versus 21.0%; p<0.0001). Women who had no residual disease after debulking surgery and who received intraperitoneal chemotherapy had a seven-year survival of 90%.

CONCLUSIONS

Neoadjuvant chemotherapy should be reserved for ovarian cancer patients who are not candidates for primary debulking surgery. Among women with no residual disease after primary debulking surgery, intraperitoneal chemotherapy extends survival.