Anti-PD-L1 antibody direct activation of macrophages contributes to a radiation-induced abscopal response in glioblastoma

BACKGROUND

Most glioblastomas recur near prior radiation treatment sites. Future clinical success will require achieving and optimizing an "abscopal effect," whereby unirradiated neoplastic cells outside treatment sites are recognized and attacked by the immune system. Radiation combined with anti-programmed cell death ligand 1 (PD-L1) demonstrated modest efficacy in phase II human glioblastoma clinical trials, but the mechanism and relevance of the abscopal effect during this response remain unknown.

METHODS

We modified an immune-competent, genetically driven mouse glioma model (forced platelet derived growth factor [PDGF] expression + phosphatase and tensin homolog loss) where a portion of the tumor burden is irradiated (PDGF) and another unirradiated luciferase-expressing tumor (PDGF + luciferase) is used as a readout of the abscopal effect following systemic anti-PD-L1 immunotherapy. We assessed relevance of tumor neoepitope during the abscopal response by inducing expression of epidermal growth factor receptor variant III (EGFRvIII) (PDGF + EGFRvIII). Statistical tests were two-sided.

RESULTS

Following radiation of one lesion, anti-PD-L1 immunotherapy enhanced the abscopal response to the unirradiated lesion. In PDGF-driven gliomas without tumor neoepitope (PDGF + luciferase, n = 8), the abscopal response occurred via anti-PD-L1 driven, extracellular signal-regulated kinase-mediated, bone marrow-derived macrophage phagocytosis of adjacent unirradiated tumor cells, with modest survival implications (median survival 41 days vs radiation alone 37.5 days, P = 0.03). In PDGF-driven gliomas with tumor neoepitope (PDGF + EGFRvIII, n = 8), anti-PD-L1 enhanced abscopal response was associated with macrophage and T-cell infiltration and increased survival benefit (median survival 36 days vs radiation alone 28 days, P = 0.001).

CONCLUSION

Our results indicate that anti-PD-L1 immunotherapy enhances a radiation- induced abscopal response via canonical T-cell activation and direct macrophage activation in glioblastoma.

Expansile duraplasty and obex exploration compared with bone-only decompression for Chiari malformation type I in children: retrospective review of outcomes and complications

OBJECTIVE

While a select population of pediatric patients with Chiari malformation type I (CM-I) remain asymptomatic, some patients present with tussive headaches, neurological deficits, progressive scoliosis, and other debilitating symptoms that necessitate surgical intervention. Surgery entails a variety of strategies to restore normal CSF flow, including increasing the posterior fossa volume via bone decompression only, or bone decompression with duraplasty, with or without obex exploration. The indications for duraplasty and obex exploration following bone decompression remain controversial. The objective of this study was to describe an institutional series of pediatric patients undergoing surgery for CM-I, performed by a single neurosurgeon. For patients presenting with a syrinx, the authors compared outcomes following bone-only decompression with duraplasty only and with duraplasty including obex exploration. Clinical outcomes evaluated included resolution of syrinx, scoliosis, presenting symptoms, and surgical complications.

METHODS

A retrospective review was conducted of the medical records of 276 consecutive pediatric patients with CM-I operated on at a single institution between 2001 and 2015 by the senior author. Imaging findings of tonsillar descent, associated syrinx (syringomyelia or syringobulbia), basilar invagination, and clinical assessment of CM-I-attributable symptoms and scoliosis were recorded. In patients presenting with a syrinx, clinical outcomes, including syrinx resolution, symptom resolution, and impact on scoliosis progression, were compared for three surgical groups: bone-only/posterior fossa decompression (PFD), PFD with duraplasty (PFDwD), and PFD with duraplasty and obex exploration (PFDwDO).

RESULTS

PFD was performed in 25% of patients (69/276), PFDwD in 18% of patients (50/276), and PFDwDO in 57% of patients (157/276). The mean follow-up was 35 ± 35 months. Nearly half of the patients (132/276, 48%) had a syrinx. In patients presenting with a syrinx, PFDwDO was associated with a significantly higher likelihood of syrinx resolution relative to PFD only (HR 2.65, p = 0.028) and a significant difference in time to symptom resolution (HR 2.68, p = 0.033). Scoliosis outcomes did not differ among treatment groups (p = 0.275). Complications were not significantly higher when any duraplasty (PFDwD or PFDwDO) was performed following bone decompression (p > 0.99).

CONCLUSIONS

In this series of pediatric patients with CM-I, patients presenting with a syrinx who underwent expansile duraplasty with obex exploration had a significantly greater likelihood of syrinx and symptom resolution, without increased risk of CSF-related complications, compared to those who underwent bone-only decompression.

Teaching the Emergency Neurologic Life Support Course at Two Major Hospitals in Phnom Penh, Cambodia

OBJECTIVE

To determine the effect of offering a subset of the Emergency Neurological Life Support (ENLS) course modules on provider knowledge and self-reported confidence in acute management of neurocritically ill patients in a low-middle income country (LMIC).

METHODS

Eight ENLS modules were provided by in-person lecture using English to Khmer translated slides and a medical translator to physicians and nurses of 2 hospitals in Phnom Penh, Cambodia in May 2019. Providers included emergency, neurology, neurologic surgery, and general intensive care. Demographics, pre- and postcourse knowledge of ENLS content areas, and pre- and postcourse confidence in managing neurocritically ill patients were assessed. Data were pooled across both hospitals for analysis.

RESULTS

A total of 57 health care providers were approached for participation: 52 (25 physicians, 27 nurses) participated; 45 completed all study instruments. Pre- and postcourse knowledge scores showed no significant differences between providers. Postcourse, 37/45 (82.2%) participants reported that the content had prepared them for acute management of neurocritically ill patients. Satisfaction with module content ranged from 77.8%-80.0% per module. For the 8 modules, a majority of participants agreed that course material had provided them with knowledge and skills to provide acute care for patients' neurologic emergencies (68.4%-88.6%).

CONCLUSIONS

Provision of ENLS course module content increased LMIC provider self-reported knowledge and confidence in acute management of neurocritically ill patients immediately postcourse. Tailoring ENLS course presentation to a particular LMIC setting warrants additional investigation, as does the effect of ENLS course training on neurocritically ill patient outcomes in the LMIC setting.

Tobacco use, immunosuppressive, chronic pain, and psychiatric conditions are prevalent in women with symptomatic mesh complications undergoing mesh removal surgery

Purpose

To identify demographic and clinical characteristics of patients with symptomatic pelvic floor mesh complications who underwent mesh removal at our academic medical center. The secondary goal was to determine patient-reported outcomes after mesh removal.

Materials and Methods

We conducted a retrospective review of consecutive patients from 2011-2016 undergoing removal of mesh graft for treatment of symptomatic mesh-related complications. Patient demographics, comorbidities, symptoms, and mesh factors were evaluated. Outcomes after explant were determined by the Patient Global Impression of Improvement and a Likert satisfaction scale.

Results

One hundred fifty-six symptomatic patients underwent complete or partial pelvic floor mesh removal during the study period. Mid-urethral slings comprised 86% of explanted mesh grafts. Mesh exposure or erosion was identified in 72% of patients. Eighty-one percent of patients presented with pain, and 35% reported pain in the absence of exposure or erosion. Pre-operative comorbidities included psychiatric disease (54.5%), chronic pain (34.0%), irritable bowel syndrome (20.5%) and fibromyalgia (9.6%). Forty-three percent of patients reported current or past tobacco use. At mean follow-up of 14 months, 68% of responding patients reported improvement on the Patient Global Impression of Improvement after surgery.

Conclusions

This research identified tobacco use, and psychiatric, immunosuppressive, and chronic pain conditions as prevalent in this cohort of patients undergoing mesh removal. Surgical removal can improve presenting symptoms, including for patients with pain in the absence of other indications.

Genetic testing for cancer risk: a population survey on attitudes and intention

<b>Objective:</b> Genetic testing for cancer risk will shortly enter medical practice. Our intent was to increase the understanding of the public’s attitudes towards and potential demand for genetic testing. <b>Methods:</b> We conducted a random-digit-dial survey of 1,450 adults in Washington State to assess the public’s attitudes toward genetic testing for cancer risk and to investigate correlates of intention to be tested for breast cancer risk (women) and prostate cancer risk (men). No specific genes were mentioned, as the intent of the survey was to understand the general interest in screening for genetic risks. The survey addressed familiarity with genetic testing, intention to be tested for breast or prostate cancer risk (when tests become available), benefits and risks associated with genetic tests, and who should have access to test results. <b>Results:</b> Most respondents expressed the intention to be tested for breast or prostate cancer risk (women 76%, men 83%). Most women (83%) and men (74%) would give the results to their primary care physician, but fewer believed that the test results should be available to their employer (women 5%, men 9%), their health insurer (women 32%, men 31%), or family members (women 42%, men 43%). Over 60% worried that discrimination could arise from genetic testing. Correlates of intention to be tested for breast cancer (women) included a family history of breast cancer, lower education, poor health, a history of mammography screening, and more physician visits in the past year. Among men, correlates of intention to test for prostate cancer included higher income, previous cancer diagnosis, a history of PSA screening, and more physician visits in the past year. Respondents who strongly believed in the benefits of genetic testing, who perceived themselves at greater risk for having a gene that increases risk, or who were less worried about discrimination expressed greater intent to be tested. <b>Conclusions:</b> Our survey suggests that the demand for genetic tests for cancer risk may be high, although confidentiality of test results is a major concern. Health care providers, genetic counselors, and research institutions should prepare strategies and policies for genetic testing and counseling as these tests enter general medical practice.

Women's interest in genetic testing for breast cancer susceptibility may be based on unrealistic expectations

We report on results of an interview study assessing women's attitudes toward and hypothetical interest in genetic susceptibility testing for breast cancer. Data are from 246 interviews with women of varying ethnicity (African American, European American, Native American, and Ashkenazi Jewish), family history of breast cancer (negative, positive, and borderline), and educational level. Semistructured interviews included questions on general health beliefs; attitudes, experiences, and concerns about breast cancer; and hypothetical interest in genetic testing. Influence of specific test characteristics was assessed with 14 Likert scales varying negative and positive predictive value, timing of disease, possible medical interventions following a positive result. Results reported include both statistical and qualitative analysis. We found that women had a high level of interest in testing which, in general, did not vary by ethnicity, level of education, or family history. Interest in testing appeared to be shaped by an exaggerated sense of vulnerability to breast cancer, limited knowledge about genetic susceptibility testing, and generally positive views about information provided through medical screening. However, study participants were most interested in a test that didn't exist (high positive predictive value followed by effective, noninvasive, preventive therapy) and least interested in the test that does exist (less than certain positive predictive value, low negative predictive value, and limited, invasive, and objectionable therapeutic options). Our data suggest that without a careful counseling process, women could easily be motivated toward interest in a test which will not lead to the disease prevention they are seeking.

Attitudes and interest in genetic testing for breast and ovarian cancer susceptibility in diverse groups of women in western Washington

OBJECTIVES

This paper examines the knowledge, opinions, and predictors of interest in genetic testing for breast cancer risk in a demographically diverse group of women in western Washington who participated in a randomized controlled trial (RCT) of breast cancer risk counseling methods.

MATERIALS AND METHODS

Four groups of women were surveyed, all with some family history of breast cancer: (a) 307 white women; (b) 36 African-American women; (c) 87 lesbian/bisexual women; and (d) 113 Ashkenazi Jewish women. As part of the baseline questionnaire for the RCT, participants were asked about their familiarity with genetic testing for breast cancer risk, their interest in such testing and opinions of it, and actions they anticipated based on test results.

RESULTS

Women in all four groups favored ready access to testing, believed the decision to be tested should be a personal choice, believed that genetic test results should stay confidential, and were not greatly concerned that this might not be possible. Women anticipated using such genetic test results to increase the frequency of various breast cancer screening methods (in all four groups, > 69% would increase mammogram frequency, > 85% would increase clinician exam, and > 92% would increase breast self exam). Women overwhelmingly rejected prophylactic surgery as a preventive measure (in all > 80% probably or definitely would not consider it). Significant predictors of interest in genetic testing for cancer risk included perceived risk, cancer worry, and beliefs about access to testing.

CONCLUSIONS

These data will be of interest to health care providers, payers, public health professionals, legislators, and others as they consider issues associated with population testing for susceptibility to common diseases such as breast cancer.

Testing for inherited susceptibility to breast cancer: a survey of informed consent forms for BRCA1 and BRCA2 mutation testing

The identification of genetic mutations linked to breast cancer has made it possible to test for the genetic predisposition to this disease. However, though this test may provide certain benefits, there are also potential risks involved with the testing process, including social and economic considerations. In light of these potential risks, we sought to determine what information individuals are receiving in the informed decision making process. To learn the minimal amount of information the actual testees receive, we obtained 10 informed consent forms from seven different testing facilities. These testing centers include the major sources of BRCA1 and BRCA2 mutation testing in the United States at this time. We analyzed the content of these forms by developing content categories and scoring them appropriately. We found all ten forms discussed in varying ways and to varying degrees the purpose of genetic testing, limitations of the test, implications of both positive and negative results, and confidentiality procedures; most, but not all, addressed various psychological and insurance risks. Overall, the forms demonstrated substantial variation in content and organization, underlining the need for more discussion and research on the purpose, nature, and effectiveness of informed consent forms for this type of genetic test.

The advent of the "unpatients'

Predictive diagnosis by molecular methods will change the scientific basis of prognostics. At the same time, it will change the ethical dimensions of the relation among patients, their doctors and other providers of care.

Ethics and the Human Genome Project

This article provides an overview of ethical issues in genetic testing and screening as they are currently considered in relationship to the Human Genome Project. Previous landmark reports and policy recommendations on genetic testing and screening are briefly described. The goals and research interests of the joint National Institutes of Health/Department of Energy Ethical, Legal, and Social Working Group of the Human Genome Project are outlined. To provide an example of one method by which ethical issues in genetics may be addressed, the ethical framework and practical aspects of a clinical ethics research project at the University of Washington, Seattle, are described. Finally, future directions for the study of ethical and social issues related to genetic testing and screening programs are suggested.

Concerted evolution of primate alpha satellite DNA. Evidence for an ancestral sequence shared by gorilla and human X chromosome alpha satellite

To understand evolutionary events in the formation of higher-order repeat units in alpha satellite DNA, we have examined gorilla sequences homologous to human X chromosome alpha satellite. In humans, alpha satellite on the X chromosome is organized as a tandemly repeated, 2.0 x 10(3) base-pairs (bp) higher-order repeat unit, operationally defined by the restriction enzyme BamHI. Each higher-order repeat unit is composed of 12 tandem approximately 171 base-pair monomer units that have been classified into five distinct sequence homology groups. BamHI-digested gorilla genomic DNA hybridized with the cloned human 2 x 10(3) bp X alpha satellite repeat reveals three bands of sizes approximately 3.2 x 10(3), 2.7 x 10(3) and 2 x 10(3) bp. Multiple copies of all three repeat lengths have been isolated and mapped to the centromeric region of the gorilla X chromosome by fluorescence in situ hybridization. Long-range restriction mapping using pulsed-field gel electrophoresis shows that the 2.7 x 10(3) and 3.2 x 10(3) bp repeat arrays exist as separate but likely neighboring arrays on the gorilla X, each ranging in size from approximately 200 x 10(3) to 500 x 10(3) bp, considerably smaller than the approximately 2000 x 10(3) to 4000 x 10(3) bp array found on human X chromosomes. Nucleotide sequence analysis has revealed that monomers within all three gorilla repeat units can be classified into the same five sequence homology groups as monomers located within the higher-order repeat unit on the human X chromosome, suggesting that the formation of the five distinct monomer types predates the divergence of the lineages of contemporary humans and gorillas. The order of 12 monomers within the 2 x 10(3) and 2.7 x 10(3) bp repeat units from the gorilla X chromosome is identical with that of the 2 x 10(3) bp repeat unit from the human X chromosome, suggesting an ancestral linear arrangement and supporting hypotheses about events largely restricted to single chromosome types in the formation of alpha satellite higher-order repeat units.

Patterns of intra- and interarray sequence variation in alpha satellite from the human X chromosome: evidence for short-range homogenization of tandemly repeated DNA sequences

A number of processes, such as sequence conversion, unequal crossingover, and molecular drive, have been postulated to explain the homogenization of tandemly repeated DNA families. To investigate the nature and extent of such processes in the alpha satellite family of centromeric DNA, we determined the nucleotide sequence of approximately 700 bp from each of 40 representative alpha satellite repeats from six sources of human X chromosomes, obtaining a total of approximately 28 kb of sequence data. Sequence divergence among the repeats examined was low, with an average pairwise difference of approximately 1%. Pairwise comparisons of all repeats indicate that the degree of similarity for those repeats in physical proximity (within approximately 15 kb) of each other is significantly greater than that for randomly located repeats, from either the same or different X chromosomes, suggesting that the mechanisms predicted to homogenize these arrays are effectively short-range in action. Analysis of individual patterns of sequence variation allows the assignment of haplotypes for five high-copy-number diagnostic positions and reveals distinct positions of equilibrium and disequilibrium within the repeat. These analyses address hypotheses about the origin of the observed patterns of variation throughout alpha satellite evolution.

Regional localization of the TIMP gene on the human X chromosome. Extension of a conserved synteny and linkage group on proximal Xp

The gene encoding a tissue inhibitor of metallo-proteinases, TIMP, has previously been shown to be X-linked in both the human and mouse genomes. We have used a series of somatic cell hybrids segregating translocation and deletion X chromosomes to map the TIMP gene on the human X chromosome. In combination with previous data, the gene can be assigned to Xp11.23----Xp11.4. Genetic linkage analyses demonstrate that TIMP is linked to the more distal ornithine transcarbamylase (OTC) locus at a distance of about 22 centimorgans. The data are consistent with the conclusion that TIMP maps to a conserved synteny and linkage group on the proximal short arm of the human X chromosome and on the pericentric region of the mouse X chromosome, including loci for synapsin-1, a member of the raf oncogene family, OTC, and TIMP.

Molecular analysis of a polymorphic domain of alpha satellite from the human X chromosome

Alpha satellite DNA, a diverse family of tandemly repeated DNA sequences located at the centromeric region of each human chromosome, is organized in a highly chromosome-specific manner and is characterized by a high frequency of restriction-fragment-length polymorphism. To examine events underlying the formation and spread of these polymorphisms within a tandem array, we have cloned and sequenced a representative copy of a polymorphic array from the X chromosome and compared this polymorphic copy with the predominant higher-order repeat form of X-linked alpha satellite. Sequence data indicate that the polymorphism arose by a single base mutation that created a new restriction site (for HindIII) in the sequence of the predominant repeat unit. This variant repeat unit, marked by the new HindIII site, was subsequently amplified in copy number to create a polymorphic domain consisting of approximately 500 copies of the variant repeat unit within the X-linked array of alpha satellite. We propose that a series of intrachromosomal recombination events between misaligned tandem arrays, involving multiple rounds of either unequal crossing-over or sequence conversion, facilitated the spread and fixation of this variant HindIII repeat unit.

Chromosome-specific alpha satellite DNA from human chromosome 1: hierarchical structure and genomic organization of a polymorphic domain spanning several hundred kilobase pairs of centromeric DNA

The human alpha satellite repetitive DNA family is organized as distinct chromosome-specific subsets localized to the centromeric region of each chromosome. Here, we report he isolation and characterization of cloned repeat units which define a hierarchical subset of alpha satellite on human chromosome 1. This subset is characterized by a 1.9-kb higher-order repeat unit which consists of 11 tandem approximately 171-bp alpha satellite monomer repeat units. The higher-order repeat unit is itself tandemly repeated, present in at least 100 copies at the centromeric region of chromosome 1. Using pulsed-field gel electrophoresis we estimate the total array length of these tandem sequences at the centromere of chromosome 1 to be several hundred kilobase pairs. Under conditions of high stringency, the higher-order repeat probe hybridizes specifically to chromosome 1 and can be used to detect several associated restriction fragment length DNA polymorphisms. As such, this probe may be useful for molecular and genetic analyses of the centromeric region of human chromosome 1.

RFLP detected by an X-linked cDNA encoding erythroid-potentiating activity/tissue inhibitor of metalloproteinase (EPA/TIMP)

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