Search

This study aimed to provide comprehensive diagnostic and candidate analyses in a pediatric rare disease cohort through the Genomic Answers for Kids program.Extensive analyses of 960 families with suspected genetic disorders included short-read exome sequencing and short-read genome sequencing (srGS); PacBio HiFi long-read genome sequencing (HiFi-GS); variant calling for single nucleotide variants (SNV), structural variant (SV), and repeat variants; and machine-learning variant prioritization. Structured phenotypes, prioritized variants, and pedigrees were stored in PhenoTips database, with data sharing through controlled access the database of Genotypes and Phenotypes.Diagnostic rates ranged from 11% in patients with prior negative genetic testing to 34.5% in naive patients. Incorporating SVs from genome sequencing added up to 13% of new diagnoses in previously unsolved cases. HiFi-GS yielded increased discovery rate with4-fold more rare coding SVs compared with srGS. Variants and genes of unknown significance remain the most common finding (58% of nondiagnostic cases).Computational prioritization is efficient for diagnostic SNVs. Thorough identification of non-SNVs remains challenging and is partly mitigated using HiFi-GS sequencing. Importantly, community research is supported by sharing real-time data to accelerate gene validation and by providing HiFi variant (SNV/SV) resources from1000 human alleles to facilitate implementation of new sequencing platforms for rare disease diagnoses.

Figure S1

Purpose: To investigate the safety, dose-limiting toxicities, and pharmacokinetics of the smoothened inhibitor vismodegib in children with refractory or relapsed medulloblastoma.Experimental design: Initially, vismodegib was administered daily at 85 mg/m2 and escalated to 170 mg/m2. The study was then revised to investigate a flat-dosing schedule of 150 mg for patients with small body surface area (BSA, 0.67–1.32 m2) or 300 mg for those who were larger (BSA, 1.33–2.20 m2). Pharmacokinetics were performed during the first course of therapy, and the right knees of all patients were imaged to monitor bone toxicity. Immunohistochemical analysis was done to identify patients with Sonic Hedgehog (SHH)-subtype medulloblastoma.Results: Thirteen eligible patients were enrolled in the initial study: 6 received 85 mg/m2 vismodegib, and 7 received 170 mg/m2. Twenty eligible patients were enrolled in the flat-dosing part of the study: 10 at each dosage level. Three dose-limiting toxicities were observed, but no drug-related bone toxicity was documented. The median (range) vismodegib penetration in the cerebrospinal fluid (CSF) was 0.53 (0.26–0.78), when expressed as a ratio of the concentration of vismodegib in the CSF to that of the unbound drug in plasma. Antitumor activity was seen in 1 of 3 patients with SHH-subtype disease whose tumors were evaluable, and in none of the patients in the other subgroups.Conclusions: Vismodegib was well tolerated in children with recurrent or refractory medulloblastoma; only two dose-limiting toxicities were observed with flat dosing. The recommended phase II study dose is 150 or 300 mg, depending on the patient's BSA. Clin Cancer Res; 19(22); 6305–12. ©2013 AACR.

Astrocytes are present in Shh type MB

Nestin expression in Hh type MB

Simvastatin inhibits MB cell proliferation in Ptch1+/- mice.

Gene sets and pathways with selective enrichment among MB subtypes

Supplementary figure legend

The intermediate filament protein Nestin serves as a biomarker for stem cells and has been used to identify subsets of cancer stem–like cells. However, the mechanistic contributions of Nestin to cancer pathogenesis are not understood. Here, we report that Nestin binds the hedgehog pathway transcription factor Gli3 to mediate the development of medulloblastomas of the hedgehog subtype. In a mouse model system, Nestin levels increased progressively during medulloblastoma formation, resulting in enhanced tumor growth. Conversely, loss of Nestin dramatically inhibited proliferation and promoted differentiation. Mechanistic investigations revealed that the tumor-promoting effects of Nestin were mediated by binding to Gli3, a zinc finger transcription factor that negatively regulates hedgehog signaling. Nestin binding to Gli3 blocked Gli3 phosphorylation and its subsequent proteolytic processing, thereby abrogating its ability to negatively regulate the hedgehog pathway. Our findings show how Nestin drives hedgehog pathway–driven cancers and uncover in Gli3 a therapeutic target to treat these malignancies. Cancer Res; 76(18); 5573–83. ©2016 AACR.

PDF file - 156K, Supplementary Fig. S1. Concentration-time plots of the first 72 hours after administration of the first vismodegib dose during Course 1 to the patients in the initial cohort: 6 received 85 mg/m2 (Figure A & B), and 7 received 170 mg/m2 (Figure C &D). Plasma concentrations of total vismodegib (A, C) and unbound vismodegib (B, D) were measured. Supplementary Fig S2. The relation between total vismodegib plasma concentrations and alpha-1-acid glycoprotein (AAGP) plasma concentrations in pediatric patients. The scatter plot includes all data from patients treated in this study. The solid line represents the best-fit line from linear regression analysis (R2= 0.38).

Purpose: The role of cholesterol biosynthesis in hedgehog pathway activity and progression of hedgehog pathway medulloblastoma (Hh-MB) were examined in vivo. Statins, commonly used cholesterol-lowering agents, were utilized to validate cholesterol biosynthesis as a therapeutic target for Hh-MB.Experimental Design: Bioinformatic analysis was performed to evaluate the association between cholesterol biosynthesis with hedgehog group medulloblastoma in human biospecimens. Alterations in hedgehog signaling were evaluated in medulloblastoma cells after inhibition of cholesterol biosynthesis. The progression of endogenous medulloblastoma in mice was examined after genetic blockage of cholesterol biosynthesis in tumor cells. Statins alone, or in combination with vismodegib (an FDA-approved Smoothened antagonist), were utilized to inhibit medulloblastoma growth in vivo.Results: Cholesterol biosynthesis was markedly enhanced in Hh-MB from both humans and mice. Inhibition of cholesterol biosynthesis dramatically decreased Hh pathway activity and reduced proliferation of medulloblastoma cells. Statins effectively inhibited medulloblastoma growth in vivo and functioned synergistically in combination with vismodegib.Conclusions: Cholesterol biosynthesis is required for Smoothened activity in the hedgehog pathway, and it is indispensable for the growth of Hh-MB. Targeting cholesterol biosynthesis represents a promising strategy for treatment of Hh-MB. Clin Cancer Res; 24(6); 1375–88. ©2018 AACR.

Astrocytes, the most abundant type of glial cells in the brain, play critical roles in supporting neuronal development and brain function. Although astrocytes have been frequently detected in brain tumors, including medulloblastoma (MB), their functions in tumorigenesis are not clear. Here, we demonstrate that astrocytes are essential components of the MB tumor microenvironment. Tumor-associated astrocytes (TAA) secrete the ligand sonic hedgehog (Shh), which is required for maintaining MB cell proliferation despite the absence of its primary receptor Patched-1 (Ptch1). Shh drives expression of Nestin in MB cells through a smoothened-dependent, but Gli1-independent mechanism. Ablation of TAA dramatically suppresses Nestin expression and blocks tumor growth. These findings demonstrate an indispensable role for astrocytes in MB tumorigenesis and reveal a novel Ptch1-independent Shh pathway involved in MB progression. Cancer Res; 77(23); 6692–703. ©2017 AACR.

Supplementary figure legend

PDF file - 104K, Supplementary Table S1. Vismodegib Dosing Strategy Supplementary Table S2. Commonly Reported Adverse Events According to Grade Supplementary Table S3. Pharmacokinetics of Unbound Vismodegib in Pediatric Patients with Medulloblastoma

Purpose:Here, we examined the role of leukotrienes, well-known inflammatory mediators, in the tumorigenesis of hedgehog pathway-associated medulloblastoma, and tested the efficacies of antagonists of leukotriene biosynthesis in medulloblastoma treatment.Experimental Design: We examined the leukotriene levels in medulloblastoma cells by ELISA. We next tested whether leukotriene synthesis in medulloblastoma cells relied on activation of hedgehog pathway, or the presence of hedgehog ligand secreted by astrocytes. We then investigated whether leukotriene mediated hedgehog-induced Nestin expression in tumor cells. The functions of leukotriene in tumor cell proliferation and tumor growth in medulloblastoma were determined through knocking down 5-lipoxygenase (a critical enzyme for leukotriene synthesis) by shRNAs, or using 5-lipoxygenase–deficient mice. Finally, the efficacies of antagonists of leukotriene synthesis in medulloblastoma treatment were tested in vivo and in vitro.Results:Leukotriene was significantly upregulated in medulloblastoma cells. Increased leukotriene synthesis relied on hedgehog ligand secreted by astrocytes, a major component of medulloblastoma microenvironment. Leukotriene stimulated tumor cells to express Nestin, a cytoskeletal protein essential for medulloblastoma growth. Genetic blockage of leukotriene synthesis dramatically suppressed medulloblastoma cell proliferation and tumor growth in vivo. Pharmaceutical inhibition of leukotriene synthesis markedly repressed medulloblastoma cell proliferation, but had no effect on proliferation of normal neuronal progenitors. Moreover, antagonists of leukotriene synthesis exhibited promising tumor inhibitory efficacies on drug-resistant medulloblastoma.Conclusions:Our findings reveal a novel signaling pathway that is critical for medulloblastoma cell proliferation and tumor progression, and that leukotriene biosynthesis represents a promising therapeutic target for medulloblastoma treatment.

Table S1

PDF file - 2MB, Supplementary Fig. S1. Menin interacts directly with PRMT5.Supplementary Fig. S2. Men1 is completely excised in Men1l/l;Ubc9CreER mice after treatment with tamoxifen (4OHT). Supplementary Fig. S3. Gene Set Enrichment Analysis (GSEA) of control Men1l/l and Men1-excised islets. Supplementary Fig. S4. Menin recruits PRMT5 and its histone methylation mark, H4R3m2s, to the Gas1 promoter. Supplementary Fig. S5. Ectopic expression of PRMT5, and either wild type or mutant menin in HEK293 cells used for co-immunoprecipitation and histone methyltransferase (HMT) assays. Supplementary Fig. S6. Islet area and fasting insulin levels in Men1l/l; RipCre mice treated with either control solution or GDC 0449.Supplementary Fig. S7. Menin interacts with PRMT5, but not PRMT7. Menin was ectopically expressed in HEK293 cells, and menin immunoprecipitates were immunoblotted with either anti-PRMT5 or -PRMT7 antibodies.

PDF file - 147KB

NG2 expression in Snf5F/F p53L/L GFAP-Cre mutant brain tissue.

Multiple endocrine neoplasia type 1 (MEN1) is an inherited tumor syndrome that includes susceptibility to pancreatic islet tumors. This syndrome results from mutations in the MEN1 gene, encoding menin. Although menin acts as an oncogenic cofactor for mixed lineage leukemia (MLL) fusion protein–mediated histone H3 lysine 4 methylation, the precise basis for how menin suppresses gene expression and proliferation of pancreatic beta cells remains poorly understood. Here, we show that menin ablation enhances Hedgehog signaling, a proproliferative and oncogenic pathway, in murine pancreatic islets. Menin directly interacts with protein arginine methyltransferase 5 (PRMT5), a negative regulator of gene transcription. Menin recruits PRMT5 to the promoter of the Gas1 gene, a crucial factor for binding of Sonic Hedgehog (Shh) ligand to its receptor PTCH1 and subsequent activation of the Hedgehog signaling pathway, increases repressive histone arginine symmetric dimethylation (H4R3m2s), and suppresses Gas1 expression. Notably, MEN1 disease-related menin mutants have reduced binding to PRMT5, and fail to impart the repressive H4R3m2s mark at the Gas1 promoter, resulting in its elevated expression. Pharmacologic inhibition of Hedgehog signaling significantly reduces proliferation of insulinoma cells, and expression of Hedgehog signaling targets including Ptch1, in MEN1 tumors of mice. These findings uncover a novel link between menin and Hedgehog signaling whereby menin/PRMT5 epigenetically suppresses Hedgehog signaling, revealing it as a target for treating MEN1 tumors. Cancer Res; 73(8); 2650–8. ©2013 AACR.

The sonic hedgehog (Shh) pathway is activated in ∼30% of human medulloblastoma resulting in increased expression of downstream target genes. In about half of these cases, this has been shown to be a consequence of mutations in regulatory genes within the pathway, including Ptc1, Smo, and Sufu. However, for some tumors, no mutations have been detected in known pathway genes. This suggests that either mutations in other genes promote tumorigenesis or that epigenetic alterations increase pathway activity in these tumors. Here, we report that 3% to 4% of mice lacking either one or both functional copies of Cxcr6 develop medulloblastoma. Although CXCR6 is not known to be involved in Shh signaling, tumors derived from Cxcr6 mutant mice expressed Shh pathway target genes including Gli1, Gli2, Ptc2, and Sfrp1, indicating elevated pathway activity. Interestingly, the level of Ptc1 expression was decreased in tumor cells although two normal copies of Ptc1 were retained. This implies that reduced CXCR6 function leads to suppression of Ptc1 thereby increasing Smoothened function and promoting tumorigenesis. We used a direct transplant model to test the sensitivity of medulloblastoma arising in Cxcr6 mutant mice to a small-molecule inhibitor of Smoothened (HhAntag). We found that transplanted tumors were dramatically inhibited in mice treated for only 4 days with HhAntag. These findings suggest that HhAntag may be effective against tumors lacking mutations in known Shh pathway genes. [Cancer Res 2007;67(8):3871–7]

Supplementary Table 1 from Shh Pathway Activity Is Down-Regulated in Cultured Medulloblastoma Cells: Implications for Preclinical Studies

Malignant rhabdoid tumors arise in several anatomic locations and are associated with poor outcomes. In the brain, these tumors are known as atypical teratoid/rhabdoid tumors (AT/RT). While genetically engineered models for malignant rhabdoid tumors exist, none of them recapitulate AT/RT, for which preclinical models remain lacking. In the majority of AT/RT, LOH occurs at the genetic locus SNF5 (Ini1/BAF47/Smarcb1), which functions as a subunit of the SWI/SNF chromatin-remodeling complex and a tumor suppressor in familial and sporadic malignant rhabdoid tumors. Therefore, we generated mice in which Snf5 was ablated specifically in nestin-positive and/or glial fibrillary acid protein (GFAP)-positive progenitor cells of the developing central nervous system (CNS). Snf5 ablation in nestin-positive cells resulted in early lethality that could not be rescued by loss of p53. However, Snf5 ablation in GFAP-positive cells caused a neurodegenerative phenotype exacerbated by p53 loss. Notably, these double mutants exhibited AT/RT development, associated with an earlier failure in granule neuron migration in the cerebellum, reduced neuronal projections in the hippocampus, degeneration of the corpus callosum, and ataxia and seizures. Gene expression analysis confirmed that the tumors that arose in Snf5/p53 mutant mice were distinct from other neural tumors and most closely resembled human AT/RT. Our findings uncover a novel role for Snf5 in oligodendrocyte generation and survival, and they offer evidence of the first genetically engineered mouse model for AT/RT in the CNS. Cancer Res; 75(21); 4629–39. ©2015 AACR.

Supplementary Figure Legend from Shh Pathway Activity Is Down-Regulated in Cultured Medulloblastoma Cells: Implications for Preclinical Studies

Gene expression profiling indicates that the Sonic Hedgehog (Shh) pathway is active in ∼30% of human medulloblastomas, suggesting that it could provide a useful therapeutic target. Previously, we showed that spontaneous medulloblastomas in Ptc1+/−p53−/− mice could be eradicated by treatment with a small-molecule inhibitor (HhAntag) of Smoothened (Smo). Here, we compared the responses of mouse medulloblastoma cells propagated in flank allografts, either directly or after culture in vitro, to HhAntag. We found that Shh pathway activity was suppressed in medulloblastoma cells cultured in vitro and it was not restored when these cells were transplanted into the flank of nude mice. The growth of these transplanted tumor cells was not inhibited by treatment of mice with doses of HhAntag that completely suppressed Smo activity. Interestingly, tumor cells transplanted directly into the flank maintained Smo activity and were sensitive to treatment with HhAntag. These findings indicate that propagation of tumor cells in culture inhibits Smo activity in a way that cannot be reversed by transplantation in vivo, and they raise concerns about the use of cultured tumor cells to test the efficacy of Shh pathway inhibitors as anticancer therapies. (Cancer Res 2006; 66(8): 4215-22)

Description of additional methods and procedures used in the study.

Primer sequences of qRT-PCR.

Supplementary Figure S1 from Shh Pathway Activity Is Down-Regulated in Cultured Medulloblastoma Cells: Implications for Preclinical Studies

Legends for Supplemental Figures S1-S5 and Supplemental Table S1.

Supplementary Figure 1 and Tables 1-2 from Medulloblastomas Derived from Cxcr6 Mutant Mice Respond to Treatment with a Smoothened Inhibitor

Summary Tumor-associated macrophages (TAMs) play an important role in tumor immunity and comprise of subsets that have distinct phenotype, function, and ontology. Transcriptomic analyses of human medulloblastoma, the most common malignant pediatric brain cancer, showed that medulloblastomas (MBs) with activated sonic hedgehog signaling (SHH-MB) have significantly more TAMs than other MB subtypes. Therefore, we examined MB-associated TAMs by single-cell RNA sequencing of autochthonous murine SHH-MB at steady state and under two distinct treatment modalities: molecular-targeted inhibitor and radiation. Our analyses reveal significant TAM heterogeneity, identify markers of ontologically distinct TAM subsets, and show the impact of brain microenvironment on the differentiation of tumor-infiltrating monocytes. TAM composition undergoes dramatic changes with treatment and differs significantly between molecular-targeted and radiation therapy. We identify an immunosuppressive monocyte-derived TAM subset that emerges with radiation therapy and demonstrate its role in regulating T cell and neutrophil infiltration in MB.

A rapid, low-cost, sensitive, multi-cancer early detection (MCED) test would be transformational in the diagnostics field. Earlier cancer detection can increase survival rates and quality of life of patients. An effective test must accurately identify the small proportion of patients with typically non-specific symptoms who have cancer. Such symptoms do not easily segregate by organ system, necessitating a multi-cancer approach. In this large-scale study (n = 2094 patients) we applied the Dxcover® Cancer Liquid Biopsy to differentiate cancer against non-cancer patients, as well as organ specific tests to identify cancers of the brain, breast, colorectal, kidney, lung, ovary, pancreas, and prostate. The test uses Fourier transform infrared (FTIR) spectroscopy to analyze all macromolecules in a minute volume of patient serum, and machine learning algorithms to build a classifier of the resultant spectral profiles to detect cancer. This approach can be fine-tuned to maximize either sensitivity or specificity depending on the requirements from different healthcare systems and cancer diagnostic pathways. The cancer v asymptomatic non-cancer classification detected 64% of stage I cancers when specificity was 99% (overall sensitivity 56%). When tuned for higher sensitivity, this model identified 99% of stage I cancers (while specificity was 58%). When examining cancer against all non-cancer (including symptomatic patients), the sensitivity-tuned model enabled 90% sensitivity with 61% specificity, with detection rates of 93% for stage I, 84% for stage II, 92% for stage III and 95% for stage IV. For organ specific cancer classifiers, area under the receiver operating characteristic (ROC) curve values were calculated for all cancers: brain (0.90), breast (0.75), colorectal (0.91), kidney (0.91), lung (0.91), ovarian (0.86), pancreatic (0.85) and prostate (0.86). Cancer treatment is more effective when given earlier and this low-cost strategy can facilitate the requisite earlier diagnosis.

The Crk and CrkL adaptor proteins have SH2 and SH3 domains and play essential overlapping, as well as distinct, roles in many biological processes, ranging from cell structure and motility to proliferation. Conditional ablation of both Crk and CrkL in neuronal progenitor cells, using a Nestin-Cre transgene, resulted in severe defects in postnatal eye development, including progressive eye closure, lens rupture, and retinal malformation. These phenotypes were not observed in the presence of a single wild-type allele of either Crk or CrkL. We found that the lens in knockout mice started to rupture and disintegrate between postnatal days 7 and 12, although the structure of the retina was relatively well maintained. As the lens deteriorated further, the outer nuclear layer in the posterior of the retina enlarged and developed ruffles. Cre recombination occurred in the lens and retina of the knockout mice. Furthermore, the posterior lens capsule of the knockout mouse was thinner at postnatal days 0.5 and 3, suggesting that the defective lens capsule caused rupturing of the lens near the posterior pole. These results indicate that Crk and CrkL play essential overlapping roles in postnatal lens development.

Background Diagnostic delays impact the quality of life and survival of patients with brain tumors. Earlier and expeditious diagnoses in these patients are crucial to reduce the morbidities and mortalities associated with brain tumors. A simple, rapid blood test that can be administered easily in a primary care setting to efficiently identify symptomatic patients who are most likely to have a brain tumor would enable quicker referral to brain imaging for those who need it most. Methods Blood serum samples from 603 patients were prospectively collected and analyzed. Patients either had non-specific symptoms that could be indicative of a brain tumor on presentation to the Emergency Department, or a new brain tumor diagnosis and referral to the neurosurgical unit, NHS Lothian, Scotland. Patient blood serum samples were analyzed using the Dxcover® Brain Cancer liquid biopsy. This technology utilizes infrared spectroscopy combined with a diagnostic algorithm to predict the presence of intracranial disease. Results Our liquid biopsy approach reported an area under the receiver operating characteristic curve of 0.8. The sensitivity-tuned model achieves a 96% sensitivity with 45% specificity (NPV 99.3%) and identified 100% of glioblastoma multiforme patients. When tuned for a higher specificity, the model yields a sensitivity of 47% with 90% specificity (PPV 28.4%). Conclusions This simple, non-invasive blood test facilitates the triage and radiographic diagnosis of brain tumor patients while providing reassurance to healthy patients. Minimizing time to diagnosis would facilitate the identification of brain tumor patients at an earlier stage, enabling more effective, less morbid surgical and adjuvant care.

Purpose: Here, we examined the role of leukotrienes, well-known inflammatory mediators, in the tumorigenesis of hedgehog pathway-associated medulloblastoma, and tested the efficacies of antagonists of leukotriene biosynthesis in medulloblastoma treatment. Experimental Design: We examined the leukotriene levels in medulloblastoma cells by ELISA. We next tested whether leukotriene synthesis in medulloblastoma cells relied on activation of hedgehog pathway, or the presence of hedgehog ligand secreted by astrocytes. We then investigated whether leukotriene mediated hedgehog-induced Nestin expression in tumor cells. The functions of leukotriene in tumor cell proliferation and tumor growth in medulloblastoma were determined through knocking down 5-lipoxygenase (a critical enzyme for leukotriene synthesis) by shRNAs, or using 5-lipoxygenase–deficient mice. Finally, the efficacies of antagonists of leukotriene synthesis in medulloblastoma treatment were tested in vivo and in vitro. Results: Leukotriene was significantly upregulated in medulloblastoma cells. Increased leukotriene synthesis relied on hedgehog ligand secreted by astrocytes, a major component of medulloblastoma microenvironment. Leukotriene stimulated tumor cells to express Nestin, a cytoskeletal protein essential for medulloblastoma growth. Genetic blockage of leukotriene synthesis dramatically suppressed medulloblastoma cell proliferation and tumor growth in vivo. Pharmaceutical inhibition of leukotriene synthesis markedly repressed medulloblastoma cell proliferation, but had no effect on proliferation of normal neuronal progenitors. Moreover, antagonists of leukotriene synthesis exhibited promising tumor inhibitory efficacies on drug-resistant medulloblastoma. Conclusions: Our findings reveal a novel signaling pathway that is critical for medulloblastoma cell proliferation and tumor progression, and that leukotriene biosynthesis represents a promising therapeutic target for medulloblastoma treatment.

Diagnostic delays impact the quality of life and survival of patients with brain tumors. Earlier and expeditious diagnoses in these patients are crucial to reducing the morbidities and mortalities associated with brain tumors. A simple, rapid blood test that can be administered easily in a primary care setting to efficiently identify symptomatic patients who are most likely to have a brain tumor would enable quicker referral to brain imaging for those who need it most. Blood serum samples from 603 patients were prospectively collected and analyzed. Patients either had non-specific symptoms that could be indicative of a brain tumor on presentation to the Emergency Department, or a new brain tumor diagnosis and referral to the neurosurgical unit, NHS Lothian, Scotland. Patient blood serum samples were analyzed using the Dxcover® Brain Cancer liquid biopsy. This technology utilizes infrared spectroscopy combined with a diagnostic algorithm to predict the presence of intracranial disease. Our liquid biopsy approach reported an area under the receiver operating characteristic curve of 0.8. The sensitivity-tuned model achieves a 96% sensitivity with 45% specificity (NPV 99.3%) and identified 100% of glioblastoma multiforme patients. When tuned for a higher specificity, the model yields sensitivity of 47% with 90% specificity (PPV 28.4%). This simple, non-invasive blood test facilitates the triage and radiographic diagnosis of brain tumor patients, while providing reassurance to healthy patients. Minimizing time to diagnosis would facilitate identification of brain tumor patients at an earlier stage, enabling more effective, less morbid surgical and adjuvant care. Citation Format: James M. Cameron, Paul M. Brennan, Georgios Antoniou, Holly J. Butler, Loren Christie, Justin J.A. Conn, Tom Curran, Ewan Gray, Mark G. Hegarty, Michael Jenkinson, Daniel Orringer, David S. Palmer, Alexandra Sala, Benjamin R. Smith, Matthew J. Baker. Clinical validation of a spectroscopic liquid biopsy for early detection of brain cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5922.

The Hedgehog (Hh) pathway plays an indispensable role in bone development and genetic activation of the pathway results in medulloblastoma (MB), the most common malignant brain tumor in children. Inhibitors of Hh pathway (such as vismodegib and sonedigib), which are used to treat MB, cause irreversible defects in bone growth in young children. Cholesterol is required for the activation of the Hh pathway, and statins, inhibitors of cholesterol biosynthesis, suppress MB growth by repressing Hh signaling in tumor cells. Here, we investigate the role of cholesterol biosynthesis in the proliferation and Hh signaling in chondrocytes, and examine the bone development in mice after statin treatment. Statins significantly inhibited MB growth in young mice, but caused no defects in bone development. Conditional deletion of NADP steroid dehydrogenase-like (NSDHL), an enzyme necessary for cholesterol biosynthesis, suppressed cholesterol synthesis in chondrocytes, and disrupted the growth plate in mouse femur and tibia, indicating the important function of intracellular cholesterol in bone development. Hh pathway activation and the proliferation of chondrocytes were inhibited by statin treatment in vitro; however, statins did not impair bone growth in vivo due to insufficient penetration into the bone. Our studies reveal a critical role of cholesterol in bone development, and support the utilization of statins for treatment of MB as well as other Hh pathway-associated malignancies.

Objectives To prepare for the predicted surge of patients with COVID-19 in Southeast Michigan, the US Department of Veterans Affairs Ann Arbor Healthcare System engineered, built, and staffed a 12-bed intensive care unit (ICU) from the existing postanesthesia care unit (PACU). Observations Considerations including floor planning, reversal of airflow, strict airborne precautions, sealing off a dedicated nursing station, and developing an infection control plan in an open care unit. A staffing model was created that included anesthesiologist intensivists, advanced practice providers, residents, certified registered nurse anesthetists, and perioperative nurses working alongside ICU trained nurses. Challenges arose in infection control, communication, mechanical ventilation using anesthesia machines, providing renal replacement therapy, and maintaining patient privacy in an open unit. Conclusions This article describes the setup, challenges, and solutions that allowed the creation of the PACU-ICU to help serve veterans and civilians during a time of unprecedented strain on the health care system due to COVID-19.