Plasma ctDNA Monitoring of a PTCH1-Mutant Metastatic Adult Medulloblastoma Showing a Durable Benefit With Vismodegib.

Adult medulloblastoma (MB) is a rare disease affecting 0.6 persons per million adults over 19 years of age. The SHH-activated/TP53-wild type is the most common subtype, accounting for 60% of adult MBs, being characterized by mutations in PTCH1, SMO, or the TERT promoter. Several small studies demonstrate objective but short-lived responses to SMO inhibitors such as vismodegib or sonidegib. Like other oncogene-addicted solid tumors, detection of the corresponding drivers through liquid biopsy could aid in the molecular diagnosis and monitoring of the disease through less invasive procedures. However, most studies have only evaluated cerebrospinal fluid as the ctDNA reservoir, and very limited evidence exists on the role of liquid biopsy in plasma in patients with primary central nervous system tumors, including MB. We present the case of a 26-year-old patient with a recurrent MB, in which next-generation sequencing (FoundationOne CDx) revealed a mutation in PTCH1, allowing the patient to be treated with vismodegib in second line, resulting in a durable benefit lasting for 1 year. Using an in-house digital PCR probe, the PTCH1 mutation could be tracked in ctDNA during treatment with first-line chemotherapy and while on treatment with vismodegib, demonstrating a precise correlation with the radiological and clinical behavior of the disease.

Exploring genetic alterations in circulating tumor DNA from cerebrospinal fluid of pediatric medulloblastoma.

Medulloblastoma (MB) is the most common type of brain malignancy in children. Molecular profiling has become an important component to select patients for therapeutic approaches, allowing for personalized therapy. In this study, we successfully identified detectable levels of tumor-derived cell-free DNA (cfDNA) in cerebrospinal fluid (CSF) samples of patients with MB. Furthermore, cfDNA from CSF can interrogate for tumor-associated molecular clues. MB-associated alterations from CSF, tumor, and post-chemotherapy plasma were compared by deep sequencing on next-generation sequencing platform. Shared alterations exist between CSF and matched tumor tissues. More alternations were detected in circulating tumor DNA from CSF than those in genomic DNA from primary tumor. It was feasible to detect MB-associated mutations in plasma of patients treated with chemotherapy. Collectively, CSF supernatant can be used to monitor genomic alterations, as a superior technique as long as tumor-derived cfDNA can be isolated from CSF successfully.

A Multi-institutional Comparative Analysis of Proton and Photon Therapy-Induced Hematologic Toxicity in Patients With Medulloblastoma.

PURPOSE: This multi-institutional retrospective study sought to examine the hematologic effects of craniospinal irradiation (CSI) in pediatric patients with medulloblastoma using proton or photon therapy. METHODS AND MATERIALS: Clinical and treatment characteristics were recorded for 97 pediatric patients with medulloblastoma who received CSI without concurrent chemotherapy or with concurrent single-agent vincristine from 2000 to 2017. Groups of 60 and 37 patients underwent treatment with proton-based and photon-based therapy, respectively. Overall survival was determined by Kaplan-Meier curves with log-rank test. Comparisons of blood counts at each timepoint were conducted using multiple t tests with Bonferroni corrections. Univariate and multivariate analyses of time to grade ≥3 hematologic toxicity were performed with Cox regression analyses. RESULTS: Median age of patients receiving proton and photon CSI was 7.5 years (range, 3.5-22.7 years) and 9.9 years (range, 3.6-19.5 years), respectively. Most patients had a diagnosis of standard risk medulloblastoma, with 86.7% and 89.2% for the proton and photon cohorts, respectively. Median total dose to involved field or whole posterior fossa was 54.0 Gy/Gy relative biological effectiveness (RBE) and median CSI dose was 23.4 Gy/Gy(RBE) (range, 18-36 Gy/Gy[RBE]) for both cohorts. Counts were significantly higher in the proton cohort compared with the photon cohort in weeks 3 to 6 of radiation therapy (RT). Although white blood cell counts did not differ between the 2 cohorts, patients receiving proton RT had significantly higher lymphocyte counts throughout the RT course. Similar results were observed when excluding patients who received vertebral body sparing proton RT or limiting to those receiving 23.4 Gy. Only photon therapy was associated with decreased time to grade ≥3 hematologic toxicity on univariate and multivariable analyses. No difference in overall survival was observed, and lymphopenia did not predict survival. CONCLUSIONS: Patients who receive CSI using proton therapy experience significantly decreased hematologic toxicity compared with those receiving photon therapy.

Medulloblastoma during pregnancy: Hormone-mediated association? Report of 2 cases.

OBJECTIVE: To report two rare cases of medulloblastoma in pregnant patients and a review of the literature. MATERIAL AND METHODS: Report of patients diagnosed with medulloblastoma during their pregnancies, who were treated with surgery and adjuvant therapy. We also reviewed other cases reported in the literature and the association made with hormonal receptors. RESULTS: Brain tumors in coincidence with pregnancy are unusual, and the incidence of medulloblastoma in pregnancy is still rarer. We found 8 cases of medulloblastomas diagnosed during pregnancy. Reports suggest that hormonal changes and increases in the levels of growth factors and angiogenic factors during pregnancy influence the rate of growth of brain tumors (not only medulloblastomas but also meningiomas or glial tumors). CONCLUSIONS: The uniqueness of these cases is their rarity. The symptoms are usually masked by the symptoms of pregnancy. At present, there is still little evidence regarding the pathogenesis and treatment of medulloblastoma in pregnancy.

Metabolic Fingerprinting on Synthetic Alloys for Medulloblastoma Diagnosis and Radiotherapy Evaluation.

Diagnostics is the key in screening and treatment of cancer. As an emerging tool in precision medicine, metabolic analysis detects end products of pathways, and thus is more distal than proteomic/genetic analysis. However, metabolic analysis is far from ideal in clinical diagnosis due to the sample complexity and metabolite abundance in patient specimens. A further challenge is real-time and accurate tracking of treatment effect, e.g., radiotherapy. Here, Pd-Au synthetic alloys are reported for mass-spectrometry-based metabolic fingerprinting and analysis, toward medulloblastoma diagnosis and radiotherapy evaluation. A core-shell structure is designed using magnetic core particles to support Pd-Au alloys on the surface. Optimized synthetic alloys enhance the laser desorption/ionization efficacy and achieve direct detection of 100 nL of biofluids in seconds. Medulloblastoma patients are differentiated from healthy controls with average diagnostic sensitivity of 94.0%, specificity of 85.7%, and accuracy of 89.9%, by machine learning of metabolic fingerprinting. Furthermore, the radiotherapy process of patients is monitored and a preliminary panel of serum metabolite biomarkers is identified with gradual changes. This work will lead to the application-driven development of novel materials with tailored structural design and establishment of new protocols for precision medicine in near future.

Proteome and miRNome profiling of microvesicles derived from medulloblastoma cell lines with stem-like properties reveals biomarkers of poor prognosis.

Primary central nervous system (CNS) tumors are the most common deadly childhood cancer. Several patients with medulloblastoma experience local or metastatic recurrences after standard treatment, a condition associated with very poor prognosis. Current neuroimaging techniques do not accurately detect residual stem-like medulloblastoma cells promoting tumor relapses. In attempt to identify candidate tumor markers that could be circulating in blood or cerebrospinal (CSF) fluid of patients, we evaluated the proteome and miRNome content of extracellular microvesicles (MVs) released by highly-aggressive stem-like medulloblastoma cells overexpressing the pluripotent factor OCT4A. These cells display enhanced tumor initiating capability and resistance to chemotherapeutic agents. A common set of 464 proteins and 10 microRNAs were exclusively detected in MVs of OCT4A-overexpressing cells from four distinct medulloblastoma cell lines, DAOY, CHLA-01-MED, D283-MED, and USP13-MED. The interactome mapping of these exclusive proteins and miRNAs revealed ERK, PI3K/AKT/mTOR, EGF/EGFR, and stem cell self-renewal as the main oncogenic signaling pathways altered in these aggressive medulloblastoma cells. Of these MV cargos, four proteins (UBE2M, HNRNPCL2, HNRNPCL3, HNRNPCL4) and five miRNAs (miR-4449, miR-500b, miR-3648, miR-1291, miR-3607) have not been previously reported in MVs from normal tissues and in CSF. These proteins and miRNAs carried within MVs might serve as biomarkers of aggressive stem-like medulloblastoma cells to improve clinical benefit by helping refining diagnosis, patient stratification, and early detection of relapsed disease.

Efectos endocrinológicos tardíos del tratamiento oncológico en supervivientes de meduloblastoma / Endocrinological late effects of oncologic treatment on survivors of medulloblastoma

INTRODUCCIÓN: La radioterapia, quimioterapia y la cirugía empleada en el tratamiento de los tumores cerebrales tienen efectos en el eje hipotálamo-hipofisario y pueden resultar en disfunción endocrina hasta en el 96% de los casos. PACIENTES Y MÉTODO: Estudio retrospectivo y descriptivo en pacientes diagnos ticados de meduloblastoma sometidos a tratamiento con quimio y radioterapia en los últimos 20 años en un hospital terciario. Se analizan variables edad, sexo, peso, talla, índice de masa corporal (IMC) al final del seguimiento, estadio de maduración sexual, niveles séricos de TSH y T4 libre, ACTH/cortisol e IGF-1, FSH, LH, estradiol, testosterona, perfil lipídico (colesterol total) y prueba de función dinámica de hormona de crecimiento. RESULTADOS: Muestra total de 23 pacientes. El déficit de hormona de crecimiento es la secuela más frecuente (82 %) seguido de disfunción ti roidea (44,8%) y disfunción puberal (24,1%). Solo se diagnosticó un caso de diabetes insípida y 2 casos de déficit de corticotrofina. CONCLUSIONES: El seguimiento a largo plazo de los supervivientes de meduloblastoma tratados con quimio y radioterapia revela una prevalencia muy alta de disfun ción endocrina, particularmente de deficiencia de hormona del crecimiento y de hipotiroidismo. Creemos oportuna la monitorización y el seguimiento a largo plazo de estos pacientes con el fin de garantizar un manejo terapéutico adecuado de aquellas disfunciones tratables.

INTRODUCTION: Radiation therapy, chemotherapy, and surgery used to treat brain tumors have effects on the hy pothalamic-pituitary-adrenal axis and can result in endocrine dysfunction in up to 96% of cases. PATIENTS Y METHOD: Retrospective and descriptive study in patients diagnosed with medulloblasto ma who underwent treatment with chemo and radiotherapy in the last 20 years in a tertiary hospital. The variables analyzed were age, sex, weight, height, body mass index (BMI) at the end of follow-up, sexual maturity stage, serum levels of TSH and free T4, ACTH/cortisol and IGF-1, FSH, LH, estradiol, testosterone, lipid profile (total cholesterol), and growth hormone dynamic function test. RESULTS: Total sample of 23 patients. Growth hormone deficiency is the most frequent sequelae (82%) fo llowed by thyroid dysfunction (44.8%), and disorders of puberty (24.1%). Only one case of diabetes insipidus and two cases of corticotropin deficiency were diagnosed. CONCLUSIONS: Long-term follow- up of medulloblastoma survivors treated with chemo and radiotherapy reveals a very high prevalence of endocrine dysfunction, especially growth hormone deficiency and hypothyroidism. We believe that monitoring and long-term follow-up of these patients is necessary in order to ensure adequate therapeutic management of those treatable dysfunctions.

Pilot study of DNA methylation-derived neutrophil-to-lymphocyte ratio and survival in pediatric medulloblastoma.

INTRODUCTION: Methylation-derived neutrophil-to-lymphocyte ratio (mdNLR) has been identified as a potential prognostic biomarker of outcomes in various cancers. We evaluated the prognostic value of blood-derived mdNLR within a retrospective cohort of pediatric medulloblastoma patients. MATERIALS AND METHODS: DNA methylation was measured in archival peripheral blood samples collected on 56 pediatric medulloblastoma patients. Hazard ratios (HR) and 95% confidence intervals (CI) for the association between mdNLR and survival were evaluated using Cox proportional hazard models. RESULTS: Compared to patients who were alive at last follow-up (n = 43), the mean mdNLR value was slightly higher in deceased patients (n = 13) (12.3 vs. 5.2,P = 0.163). Elevated log-transformed mdNLR was suggestively associated with an increased likelihood of death in unadjusted models (HR=1.43, 95%CI: 0.92-2.22) and significantly associated with mortality in adjusted models (HR=1.61, 95%CI: 1.01-2.58). DISCUSSION: Future work is warranted to investigate the relationship between mdNLR outcomes in specific pediatric medulloblastoma molecular subgroups.

Accelerated growth of hemangioblastoma in pregnancy: the role of proangiogenic factors and upregulation of hypoxia-inducible factor (HIF) in a non-oxygen-dependent pathway.

Hemangioblastomas (HBs) are benign, highly vascular tumors, often characterized by loss of function of the von Hippel-Lindau (vHL) gene. They are the most common central nervous system tumor observed in vHL syndrome. Loss of function of the vHL gene creates a "pseudo-hypoxic" state, causing overactivation of hypoxia-inducible factor (HIF) and vascular endothelial growth factor (VEGF)-related pathways. In some cases, HBs can rapidly increase in size during pregnancy to then present acutely, which most frequently occurs after the 20th gestational week. These changes in size usually occur from enlargement of the cystic component of the HB. Due to their preferred location in the posterior fossa near critical structures as well as along the spinal cord, such cases can present with severe neurological deficits, requiring urgent surgical intervention in a multidisciplinary setting. However, the reasons for this acute flare-up during pregnancy remain poorly understood, as are the reasons why this occurs in only a subset of tumors. Unveiling the etiology for this clinical scenario can affect the treatment of HBs, as it will contribute to the understanding of the pathophysiology of such a transformation from a quiescent lesion to a symptomatic one, not only in the setting of pregnancy. Identifying the correct triggers and the conditions initiating and mediating this switch will enable us to develop preventive medications which should allow us to keep the tumor in its quiescent phase. In this pathophysiological review, we investigate the association between HB growth and pregnancy based on an analysis > 40 such published cases. We suggest that the proangiogenic state of pregnancy is the leading etiology for this striking association, and to support the argument, we discuss its potential impact on HIF overexpression in a non-hypoxic manner through activation of the PI3K/Akt/mTOR pathway by proangiogenic factors. Specifically, we discuss the involvement of placental growth factor (PlGF) and its receptor vascular endothelial growth factor receptor 1 (VEGFR-1) in various pathologic processes that can lead to the formation and growth of peritumoral edema and cysts, which are the primary causes for the development of any symptoms in HB. Both PlGF and VEGFR-1 are expressed at increased levels during pregnancy, and both have been reported as part of various pathological processes, including angiogenesis and tumorigenesis. The unique feature that both do essentially not show any significant negative impact on regular physiological processes makes them attractive therapeutic targets since very little side effects are expected. Further research into the effects of anti-PlGF or anti-VEGFR-1 therapy in HB is therefore recommended.

Endocrinological late effects of oncologic treatment on survivors of medulloblastoma. / Efectos endocrinológicos tardíos del tratamiento oncológico en supervivientes de meduloblastoma.

INTRODUCTION: Radiation therapy, chemotherapy, and surgery used to treat brain tumors have effects on the hy pothalamic-pituitary-adrenal axis and can result in endocrine dysfunction in up to 96% of cases. PATIENTS AND METHOD: Retrospective and descriptive study in patients diagnosed with medulloblasto ma who underwent treatment with chemo and radiotherapy in the last 20 years in a tertiary hospital. The variables analyzed were age, sex, weight, height, body mass index (BMI) at the end of follow-up, sexual maturity stage, serum levels of TSH and free T4, ACTH/cortisol and IGF-1, FSH, LH, estradiol, testosterone, lipid profile (total cholesterol), and growth hormone dynamic function test. RESULTS: Total sample of 23 patients. Growth hormone deficiency is the most frequent sequelae (82%) fo llowed by thyroid dysfunction (44.8%), and disorders of puberty (24.1%). Only one case of diabetes insipidus and two cases of corticotropin deficiency were diagnosed. CONCLUSIONS: Long-term follow- up of medulloblastoma survivors treated with chemo and radiotherapy reveals a very high prevalence of endocrine dysfunction, especially growth hormone deficiency and hypothyroidism. We believe that monitoring and long-term follow-up of these patients is necessary in order to ensure adequate therapeutic management of those treatable dysfunctions.

Development and validation of a sensitive LC MS/MS method for the measurement of the checkpoint kinase 1 inhibitor prexasertib and its application in a cerebral microdialysis study.

LC MS/MS methods to measure prexasertib in mouse plasma and Ringer's solution containing 0.5% BSA (Ringer's/BSA) were developed and validated. Liquid-liquid extraction with tert-butyl methyl ether was used to extract prexasertib from mouse plasma and Ringer's/BSA. Reverse phase chromatography with gradient elution was performed to separate prexasertib from the endogenous interference in the matrix, followed by MS detection using positive ion MRM mode. The initial calibration curve for mouse plasma samples ranged from 1 to 500 ng/ml, and after validation of that curve and use in a preliminary study another calibration curve (0.2-200 ng/ml) was created to enable the quantitation of prexasertib at lower concentrations. The method described was precise and accurate with %CV in precision studies of ≤ 6.7% and accuracies within 95.0-110% of nominal target concentration across all concentrations tested for both matrices. This validated method was successfully applied in the analysis of prexasertib in mouse plasma and dialysate samples collected during a cerebral microdialysis study.

Pre-operative neutrophil count and neutrophil-lymphocyte count ratio (NLCR) in predicting the histological grade of paediatric brain tumours: a preliminary study.

INTRODUCTION: The neutrophil-lymphocyte count ratio (NLCR) is an established prognostic marker for renal, lung and colorectal carcinomas and has been suggested to be predictive of histological grade and outcome in adult intracranial tumours. The purpose of this study was to determine whether a correlation of the pre-operative neutrophil count (NC) and NLCR with the final histological grade exists in paediatric intracranial tumours. METHODS: A retrospective analysis was undertaken at a single centre. Patients less than 18 years old at the time of surgery who underwent tumour-related procedures from 2006 to 2015 were included. Patients with recurrent tumours, previous bone marrow transplant and metastases were excluded. Pre-operative full blood counts (FBC), collected before the diagnosis of intracranial pathology and before administration of steroids, were matched with histological diagnosis for each patient. Post-operative FBC was also recorded, together with survival data where applicable. RESULTS: A total of 116 patients (74 male, 42 female; mean age, 8 ± 0.9 years) with a diagnosis of primary intracranial tumours had pre-operative FBC that could be matched to final histological grade. Pre-operative NC and NLCR were higher with increasing grade of tumour: grade 1 (NC 4.29 109/l, NLCR 2.26), grade 2 (NC 4.59 109/l, NLCR 2.38), grade 3 (NC 5.67 109/l, NLCR 2.72) and grade 4 (NC 6.59 109/l, NLCR 3.31). Patients with WHO grade 1 and 2 tumours pooled together had a lower NC (4.37 95% CI ± 0.67 109/l) compared to WHO grade 3 and 4 patients (6.41 95% CI ± 0.99 109/l, p = 0.0013). The NLCR was lower in grade 1 and 2 tumours (2.29 ± 0.59) (compared to grade 3 and 4 tumours; 3.20 ± 0.76) but this did not reach significance (p = 0.069). The subgroup of patients with pilocytic astrocytoma had a significantly lower NC when compared to patients with high-grade tumours (p = 0.005). Medulloblastoma and supratentorial PNET subgroups had significantly higher NC compared to the low-grade group (p = 0.033, p = 0.002). Post-operative NC was significantly higher in the high-grade tumours (p = 0.034), but no difference was observed for NLCR (p = 0.28). CONCLUSIONS: No evidence exists to support the correlation of pre-operative NC or NLCR to histological diagnosis in paediatric intracranial tumours. Our results indicate that a higher pre-operative NC/NLCR correlates with a higher histological grade of tumour. This suggests that immunological mechanisms may be involved in the pathogenesis of paediatric brain tumours, and a further prospective study is required to substantiate and expand these findings.

Pre-treatment lymphopenia and indication of tumor-induced systemic immunosuppression in medulloblastoma.

The presence of tumor-induced systemic immune suppression, including lymphopenia, has been recognized in adult patients with glioblastoma for several decades, and pre-treatment neutrophil-to-lymphocyte count ratio (NLCR) is associated with inferior clinical outcome in patients with glioblastoma. Whether tumor-induced systemic immune suppression is also present in children with malignant brain tumors is not known. We performed a retrospective analysis of pretreatment neutrophil and lymphocyte counts in pediatric patients with medulloblastoma (MB) compared to a control group of children with posterior fossa pilocytic astrocytoma (PA). Compared to the control group, we observed statistically significantly lower absolute lymphocyte counts (ALCs) and higher NLCRs in the medulloblastoma group. Our findings suggest the presence of tumor-induced systemic immune suppression in MB patients already present at the time of diagnosis, with potential implications for the development of immune therapies in this population.

Regulatory T cell subsets in patients with medulloblastoma at diagnosis and during standard irradiation and chemotherapy (PBTC N-11).

BACKGROUND: We evaluated circulating levels of immunosuppressive regulatory T cells (Tregs) and other lymphocyte subsets in patients with newly diagnosed medulloblastoma (MBL) undergoing surgery compared to a control cohort of patients undergo craniectomy for correction of Chiari malformation (CM) and further determined the impact of standard irradiation and chemotherapy on this cell population. METHODS: Eligibility criteria for this biologic study included age 4-21 years, patients with CM undergoing craniectomy (as non-malignant surgical controls) and receiving dexamethasone for prevention of post-operative nausea, and those with newly diagnosed posterior fossa tumors (PFT) undergoing surgical resection and receiving dexamethasone as an anti-edema measure. Patients with confirmed MBL were also followed for longitudinal blood collection and analysis during radiotherapy and chemotherapy. RESULTS: A total of 54 subjects were enrolled on the study [22-CM, 18-MBL, and 14-PFT]. Absolute number and percentage Tregs (defined as CD4+CD25+FoxP3+CD127low/-) at baseline were decreased in MBL and PFT compared to CM [p = 0.0016 and 0.001, respectively). Patients with MBL and PFT had significantly reduced overall CD4+ T cell count (p = 0.0014 and 0.0054, respectively) compared to those with CM. Radiation and chemotherapy treatment in patients with MBL reduced overall lymphocyte counts; however, within the CD4+ T cell compartment, Tregs increased during treatment but gradually declined post therapy. CONCLUSIONS: Our results demonstrate that patients with MBL and PFT exhibit overall reduced CD4+ T cell counts at diagnosis but not an elevated proportion of Tregs. Standard treatment exacerbates lymphopenia in those with MBL while enriching for immunosuppressive Tregs over time.

Impact of acute hematological toxicity on treatment interruptions during cranio-spinal irradiation in medulloblastoma: a tertiary care institute experience.

To analyze treatment interruptions due to acute hematological toxicity in patients of medulloblastoma receiving cranio-spinal irradiation (CSI). Prospectively collected data from case records of 52 patients of medulloblastoma treated between 2011 and 2014 was evaluated. Blood counts were monitored twice a week during CSI. Spinal irradiation was interrupted for patients with ≥grade 2 hematological toxicity and resumed after recovery to grade 1 level (TLC >3000; platelet count >75,000). Treatment interruptions and hematological toxicity were analyzed. Median age was 11 years. All patients received adjuvant CSI of 36 Gy, followed by boost of 18 Gy to posterior fossa, at 1.8 Gy per fraction. Concurrent chemotherapy was not given. Adjuvant chemotherapy was given after CSI for high risk patients. Spinal fields were interrupted in 73.1% of patients. Cause of first interruption was leucopenia in 92.1%, thrombocytopenia in 2.6%, and both in 5.3%. Median number of fractions at first interruption was 8, with 25% of interruptions in first week. Median duration for hematological recovery after nadir was 5 days for leucopenia and 3 days for thrombocytopenia. Half of the patients had at least 2 interruptions, and 19% subsequently developed grade 3 toxicity. On multivariate analysis, significant correlation with duration of delay was observed for pre-treatment haemoglobin, number of fractions at first interruption, grade and duration of recovery of leucopenia. Acute hematological toxicity with CSI is frequently under-reported. Patients with low pre-treatment hemoglobin, early onset leucopenia, profound leucopenia and prolonged recovery times are at a higher risk of having protracted courses of irradiation. Frequent monitoring of blood counts and timely interruption of spinal fields of irradiation at grade 2 level of hematological toxicity minimizes the risk of grade 3 and grade 4 toxicity, while reducing the interruptions in irradiation of the gross tumour bed.

Coagulation and angiogenic gene expression profiles are defined by molecular subgroups of medulloblastoma: evidence for growth factor-thrombin cross-talk.

BACKGROUND: The coagulation system becomes activated during progression and therapy of high-grade brain tumors. Triggering tissue factor (F3/TF) and thrombin receptors (F2R/PAR-1) may influence the vascular tumor microenvironment and angiogenesis irrespective of clinically apparent thrombosis. These processes are poorly understood in medulloblastoma (MB), in which diverse oncogenic pathways define at least four molecular disease subtypes (WNT, SHH, Group 3 and Group 4). We asked whether there is a link between molecular subtype and the network of vascular regulators expressed in MB. METHODS: Using R2 microarray analysis and visualization platform, we mined MB datasets for differential expression of vascular (coagulation and angiogenesis)-related genes, and explored their link to known oncogenic drivers. We evaluated the functional significance of this link in DAOY cells in vitro following growth factor and thrombin stimulation. RESULTS: The coagulome and angiome differ across MB subtypes. F3/TF and F2R/PAR-1 mRNA expression are upregulated in SHH tumors and correlate with higher levels of hepatocyte growth factor receptor (MET). Cultured DAOY (MB) cells exhibit an up-regulation of F3/TF and F2R/PAR-1 following combined SHH and MET ligand (HGF) treatment. These factors cooperate with thrombin, impacting the profile of vascular regulators, including interleukin 1ß (IL1B) and chondromodulin 1 (LECT1). CONCLUSIONS: Coagulation pathway sensors (F3/TF, F2R/PAR-1) are expressed in MB in a subtype-specific manner, and may be functionally linked to SHH and MET circuitry. Thus coagulation system perturbations may elicit subtype/context-specific changes in vascular and cellular responses in MB.

Oncogenes and the coagulation system--forces that modulate dormant and aggressive states in cancer.

Cancers arise and progress genetically amidst profound perturbations of the microenvironmental and systemic homeostasis. This includes the coagulation system, which is a part of the vascular milieu (niche) that remains under the control of molecular events occurring within the cancer cell genome. Thus, activation of several prototypic oncogenic pathways, such as RAS, EGFR, HER2, MET, SHH and loss of tumor suppressors (PTEN, TP53) alter the expression, activity and vesicular release of coagulation effectors, as exemplified by tissue factor (TF). The cancer-specific determinants of coagulopathy are also illustrated by the emerging link between the expression profiles of coagulation-related genes (coagulome) in glioblastoma multiforme (GBM), medulloblastoma (MB) and possibly other cancers and molecular subtypes of these respective tumors. The state of the coagulome is consequential for growth, metastasis and angiogenesis of established tumors, but could potentially also affect dormant cancer cells. For example, TF expression may trigger awakening of dormant glioma cells in mice in a manner involving recruitment of vascular and inflammatory cells, and resulting in lasting changes in the cancer cell genome and epigenome. Thus, coagulation system effectors could act as both targets and (indirect) inducers of genetic tumor progression, and a better understanding of this link may hold new diagnostic and therapeutic opportunities.

Successful large-volume leukapheresis for hematopoietic stem cell collection in a very-low-weight brain tumor infant with coagulopathy.

Peripheral apheresis has become a safe procedure to collect hematopoietic stem cells, even in pediatric patients and donors. However, the apheresis procedure for small and sick children is more complicated due to difficult venous access, relatively large extracorporeal volume, toxicity of citrate, and unstable hemostasis. We report a small and sick child with refractory medulloblastoma, impaired liver function, and coagulopathy after several major cycles of cisplatin-based chemotherapy. She successfully received large-volume leukapheresis for hematopoietic stem cell collection, although the patient experienced severe coagulopathy during the procedures. Health care providers should be alert to this potential risk.