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Contains fulltext : 290144.pdf (Publisher’s version ) (Open Access)

Item does not contain fulltext, The clinical presentation of patients with slow-flow vascular malformations is very heterogeneous. High clinical burden and subsequent reduced health-related quality of life is something they have in common. There is an unmet medical need for these patients for whom regular treatments like surgery and embolization are either insufficient or technically impossible. Sirolimus has been reported to be effective and overall well-tolerated in most patients. However, the main limitation of sirolimus is the reported high toxicity, especially when target levels of 10-15 ng/mL are being used. We report the results of a phase IIB single-arm open-label clinical trial consisting of 68 (67 in the challenge phase and 68 in the rechallenge phase) evaluable patients (children n = 33 and adults n = 35) demonstrating that treatment with low sirolimus target levels (4-10 ng/mL) is effective in 79.1% of the patients. When sirolimus treatment was stopped, the majority of patients experienced a recurrence of symptoms, supporting prolonged or even lifelong treatment requirement. Adults experienced a higher baseline pain score compared with children, having an estimated marginal mean of 6.2 versus 4.1, p < 0.05; however, they showed a similar decrease to children. Furthermore, the pediatric population experienced less often a sirolimus-related grade I-IV adverse event (35.9% vs. 64.1%, p > 0.05) compared with adults. Additionally, response rates were higher in children compared with adults (93.8% vs. 65.7%, p < 0.05), and children responded faster (28 vs. 91 days, p < 0.05). These results suggest benefits of sirolimus in patients with slow-flow vascular malformations and support its initiation as young as possible.

Contains fulltext : 292754.pdf (Publisher’s version ) (Open Access), INTRODUCTION: Vascular malformations are rare congenital anomalies of the vascular system, which can involve the capillaries, veins, arteries, lymphatics, or a combination of vessel types. Patients with vascular malformations experience an impaired health-related quality of life (HRQoL) because of their symptoms (e.g., pain, swelling, and bleeding) and psychosocial distress. Sirolimus is an effective drug used in the medical treatment of these patients; however, relatively little is known about the effect of sirolimus on specific changes in the HRQoL domains and its magnitude. METHODS: The magnitude of change (effect size) following intervention is more informative to clinical practitioners than statistically significant but clinically unimportant changes; therefore, this study aimed to examine the magnitude and meaningfulness of change in the HRQoL of children and adults with vascular malformations following sirolimus treatment using low target levels. RESULTS: In total, 50 patients with vascular malformations (19 children, 31 adults) were included in this study. These patients experienced a lower HRQoL than the general population, with the adults reporting a significantly lower score in almost all domains. A 6-month sirolimus treatment improved the HRQoL in 29 patients, including 77.8% of the children (Pediatric Quality of Life Inventory score [PedsQL]) and 57.7% of the adults (Short Form 36 [SF-36]). The effect sizes of sirolimus for each SF-36/PedsQL domain ranged from 0.19 to 1.02. The clinically relevant moderate magnitude of changes was seen in the domains of the children's reports: "Physical functioning" and "Social functioning" and in the domains of the parent reports: "Social functioning," "School functioning," and "Psychosocial." A high-magnitude change was seen in the domains "Emotional functioning" and "Psychosocial" in the children's reports and "Physical functioning" in the parent reports. In addition, the moderate magnitude of changes was also seen i

01 juli 2023, Item does not contain fulltext, Sirolimus is an antiproliferative and immunosuppressive compound inhibiting the mTOR pathway, which is often activated in congenital low-flow vascular malformations. Studies have demonstrated the efficacy of sirolimus for this disease. Studies in kidney transplant patients suggest that genetic variants can influence these pharmacokinetic parameters. Therefore, a systematic literature search was performed to gain insight into pharmacogenetic studies with sirolimus. Most studies investigated CYP3A4 and CYP3A5, with inconsistent results. No pharmacogenetic studies focusing on sirolimus have been performed for low-flow vascular malformations. We analyzed two common variants of CYP3A4 and CYP3A5 (CYP3A4*22 and CYP3A5*3, respectively) in patients (n = 59) with congenital low-flow vascular malformations treated with sirolimus. No association with treatment outcome was identified in this small cohort of patients.

Radboud University, 03 november 2023, Promotor : Schultze Kool, L.J. Co-promotores : Loo, D.M.W.M. te, Vleuten, C.J.M. van der, Verhoeven, B.H., Item does not contain fulltext

Contains fulltext : 300000.pdf (Publisher’s version ) (Open Access), A cross-sectional study was performed to evaluate health-related quality of life (HRQOL) in children with congenital vascular malformations (CVM) and to investigate factors associated with an impaired HRQOL. Children (2-17 years) with CVMs who visited the HECOVAN expertise center between 2016-2018 were included. The PedsQL 4.0 Generic Core Scales were used and a score ≥ 1.0 SD below the normative mean was defined as an impaired HRQOL. Factors associated with impairment were investigated using univariate and multivariate logistic regression analysis. The median overall HRQOL was 84.8/100 (n = 207; 41% boys, 59% girls; self-reported IQR 73.9-92.4 and parent-reported IQR 71.4-92.4). Patients aged 13-17 years reported significantly worse physical functioning than those aged 8-12 years (median 84.4, IQR 71.1-93.8 versus median 90.6, IQR 81.3-96.9; p = 0.02). Parents reported a significantly lower overall HRQOL than their children (median 80.4, IQR 70.7-90.8 versus median 85.9, IQR 76.1-92.4; p = 0.001). HRQOL was impaired in 25% of patients. Impairment occurred significantly more often in lower extremity CVMs (38%, p = 0.01) and multifocal CVMs (47%, p = 0.01) compared to CVMs in the head/neck region (13%). Other associated factors included invasive management (31% versus 14%; p = 0.01), age at first treatment ≤ 5 years (48% versus 25%; p = 0.02) and ongoing treatment (38% versus 18%; p = 0.004). After correction for other factors, significance remained for lower extremity CVMs and ongoing invasive treatment. CONCLUSIONS: Overall median HRQOL was reasonable and not significantly different from the norm sample. Parental ratings were significantly lower than their children's ratings. A quarter of the patients had an impaired HRQOL, which seemed to worsen with age. Independently associated factors included a lower extremity CVM and invasive management. WHAT IS KNOWN: • Congenital vascular malformations could affect health-related quality of life (HRQOL). • Studies on pediat, 01 november 2023

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Item does not contain fulltext, AIMS: Management of kaposiform haemangioendotheliomas (KHE) with Kasabach-Merritt phenomenon is challenging in young infants who are subjected to developmental pharmacokinetic changes. Sirolimus, sometimes combined with corticosteroids, can be used as an effective treatment of KHE. Simultaneously, toxicities such as interstitial pneumonitis related to the use of sirolimus may be fatal. As infants have a very low CYP3-enzyme expression at birth, which rises during ageing, we hypothesize that a reduced metabolization of sirolimus might lead to high sirolimus serum levels and low dose may be sufficient without the side effects. METHODS: A case series of 5 infants with kaposiform haemangioendothelioma with Kasabach-Merritt phenomenon was analysed retrospectively. All infants were treated with sirolimus 0.2 mg/m(2) every 24 or 48 hours according to their age. Prednisone was added to the therapy for additional effect in 4 patients. RESULTS: In all patients, low dose of sirolimus led to therapeutic sirolimus levels (4-6 ng/mL). All infants (aged 4 days-7 months) had a complete haematological response, without serious adverse events. In all patients, the Kasabach-Merritt phenomenon resolved, the coagulation profile normalized and tumour size reduction was seen. CONCLUSION: Low-dose sirolimus treatment is safe for infants with kaposiform haemangioendothelioma and Kasabach-Merritt phenomenon. It is essential to realize that during the first months of life, metabolism is still developing and enzymes necessary to metabolise drugs like sirolimus still have to mature. To avoid toxic levels, the sirolimus dosage should be based on age and the associated pharmacological developments.

Contains fulltext : 283062.pdf (Publisher’s version ) (Open Access)

Contains fulltext : 285445.pdf (Publisher’s version ) (Open Access)

Contains fulltext : 251722.pdf (Publisher’s version ) (Open Access)

Radboud University, 06 september 2022, Promotor : Brunner, H.G. Co-promotores : Coenen, M.J.H., Loo, D.M.W.M. te, Contains fulltext : 252878.pdf (Publisher’s version ) (Open Access)

Item does not contain fulltext, BACKGROUND AND PURPOSE: Sturge-Weber syndrome (SWS) is a neurocutaneous disorder characterized by clinical manifestations involving the brain, eye and skin. SWS is commonly caused by somatic mutations in G protein subunit Alpha Q (GNAQ). Five cases of subunit Alpha 11 (GNA11) mutations have been reported. We studied phenotypic features of GNA11-SWS and compared them with those of classic SWS. METHODS: Within two European multidisciplinary centers we looked for patients with clinical characteristics of SWS and a GNA11 mutation. Clinical and radiological data were collected retrospectively and prospectively. RESULTS: We identified three patients with SWS associated with a somatic GNA11 mutation. All had disseminated capillary malformation (CM) and hyper- or hypotrophy of an extremity. At birth, the CMs of the face, trunk and limbs were pink and patchy, and slowly darkened with age, evolving to a purple color. Two of the patients had glaucoma. All had neurological symptoms and moderate brain atrophy with a lower degree of severity than that classically associated with SWS. Susceptibility-weighted imaging (SWI) and contrast-enhanced fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging demonstrated the best sensitivity to reveal the pial angiomas. CONCLUSIONS: We have differentiated two distinct clinical/radiological phenotypes of SWS; GNAQ- and GNA11-SWS. The classic GNAQ-SWS is characterized by a homogeneous dark-red CM, commonly associated with underlying soft tissue hypertrophy. The CM in GNA11-SWS is more reticulate and darkens with time, and the neurological picture is milder. SWI and post-contrast FLAIR sequences appear to be necessary to demonstrate leptomeningeal angiomatosis. Anti-epileptic medication or future targeted therapies may be useful, as in classic SWS.

Item does not contain fulltext, AIMS: Studies implicated a role for a genetic variant in CEP72 in vincristine-induced peripheral neuropathy. This study aims to evaluate this association in a cohort of brain tumour patients, to perform a cross-disease meta-analysis and explore the protein-coding region of CEP72. METHODS: In total, 104 vincristine-treated brain tumour patients were genotyped for CEP72 rs924607, and sequenced for the protein-coding region. Data regarding patient and treatment characteristics, and peripheral neuropathy, were collected. Logistic regression and meta-analysis were performed for rs924607 replication. A weighted burden analysis was applied to evaluate impact of overall genetic variation in CEP72. RESULTS: Analysis of 24 cases and 80 controls did not show a significant association between CEP72 rs924607 and neuropathy (odds ratio, OR [95% confidence interval, CI] 2.076 [0.359-11.989], P = .414). When combined with 8 cohorts (1095 cancer patients), a significant increase in risk for neuropathy was found for patients with a TT genotype (OR [95% CI] 2.15 [1.35-3.43], P = .001). Additionally, a missense variant (rs12522955) was significantly associated (OR [95% CI] 2.3 [1.2-4.4], P = .041) and patients with severe neuropathy carried more impactful variants in CEP72 coding regions (P = .039). CONCLUSION: The association of CEP72 rs924607 in vincristine-induced neuropathy was not confirmed in a cohort of brain tumour patients, but did contribute to its suggested effect when combined in a cross-disease meta-analysis. The importance of other genetic variations in CEP72 on vincristine-induced neuropathy was demonstrated. This study contributes to evidence of the importance of genetic variants in CEP72 in development of vincristine-induced toxicity, and provides guidance for future prospective studies.

Radboud University, 16 december 2022, Promotores : Noordam, C., Guchelaar (LUMC), H.J. Co-promotores : Coenen, M.J.H., Loo, D.M.W.M. te, Contains fulltext : 284845.pdf (Publisher’s version ) (Open Access), Brain tumors are the most common type of solid tumors in childhood. Some type of brain tumors need to be treated with chemotherapy, which can lead to severe side effects. It is known that one child is more sensitive to develop chemotherapy side effects than the other child, but it is unknown what causes this difference. This thesis describes studies in which the impact of differences in DNA between these patients as a cause of the differences in chemotherapy side effects. These studies, two new genes came to light in relation to hearing loss and kidney damage caused by chemotherapy (TSPAN5 and RBMS3). Also, an already discovered gene (CEP72) is studied in more detail in relation to the side effect nerve damage. By doing so, this thesis has contributed to a better understanding of the role of differences in DNA in the development of chemotherapy side effects, and a step towards prediction and prevention of these side effects.

Contains fulltext : 235319.pdf (Publisher’s version ) (Open Access), INTRODUCTION: Patients with congenital vascular malformations often suffer from an impaired quality of life (QoL) because of pain and functional disabilities. Previous studies have shown that the mTOR inhibitor sirolimus can reduce complaints and improve QoL in some patients. High target levels of sirolimus of 10-15 ng/ml were well tolerated; however, in a relative high percentage of patients sirolimus caused serious adverse events (AEs). METHODS: A case series of 12 patients with therapy-resistant low-flow vascular malformations was treated with sirolimus, using low target levels of 4-10 ng/ml. Efficacy of sirolimus was evaluated in regard to pain symptoms using the visual analogue scale/numeric rating scale and patients reported QoL. To rule out a placebo effect of sirolimus, sirolimus was stopped after a certain time point and reintroduced as soon as complaints returned. Adverse events were closely monitored and graded using the Common Terminology Criteria for Adverse Events (CTCAE) grading. RESULTS: An improvement in symptoms was seen in 92% (n = 11/12) of patients. In nine patients pain complaints returned. Seven out of nine of them (78%) again experienced a reduction of symptoms after restarting sirolimus treatment. Despite low target levels, these response rates are comparable to those found in the literature using higher target levels of sirolimus. However, significantly less serious AEs were observed with low dose sirolimus, suggesting low dose sirolimus might be safer. Unfortunately, young adolescent female patients developed serious menstrual disturbances during treatment with low dose sirolimus. We describe this adverse event for the first time in patients with congenital vascular malformations and this might be specifically related to low dose sirolimus. CONCLUSIONS: Low dose sirolimus showed a high efficacy in patients with therapy-resistant and low-flow malformation, with a lower incidence of serious adverse events. At the same time a new adverse even

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Contains fulltext : 218271.pdf (Publisher’s version ) (Closed access), 6-mercaptopurine (6-MP) is the mainstay in pediatric acute lymphoblastic leukemia (ALL) maintenance treatment. Variants in genes coding for thiopurine S-methyl transferase (TPMT) and inosine triphosphate pyrophosphatase (ITPA) are known to influence 6-MP metabolism. We determined TPMT and ITPA genotype and enzyme activity and the mean 6-MP doses during maintenance treatment in 40 children treated for ALL according to the Dutch Childhood Oncology Group (DCOG)-ALL11 protocol in the Radboudumc Amalia Children's Hospital, Nijmegen, The Netherlands. Patients with genetic variants in TPMT (N=3) had significantly lower TPMT enzyme activity (mean 0.46 vs. 0.72 micromol/mmol hemoglobin/h, P=0.005). Although the difference was not statistically significant, they were treated with lower mean 6-MP doses (28.1 mg/m [SD 25.5 mg/m] vs. 41.3 mg/m [SD 17.2 mg/m], P=0.375). In patients with genetic ITPA variants (N=21), ITPA enzyme activity was significantly lowered (mean 3.67 vs. 6.84 mmol/mmol hemoglobin/h, P<0.0005). The mean 6-MP doses did not differ between patients with and without variants in ITPA (40.0 mg/m [SD 20.3 mg/m] vs. 40.6 mg/m [SD 14.9 mg/m], P=0.663). The TPMT genotype, but not the ITPA genotype, should be considered as part of standard evaluation before starting ALL maintenance treatment.

Contains fulltext : 222069.pdf (publisher's version ) (Open Access)

1 januari 2020, Contains fulltext : 219893.pdf (Publisher’s version ) (Closed access), BACKGROUND: Treatment of venous thromboembolism in children is based on data obtained in adults with little direct documentation of its efficacy and safety in children. The aim of our study was to compare the efficacy and safety of rivaroxaban versus standard anticoagulants in children with venous thromboembolism. METHODS: In a multicentre, parallel-group, open-label, randomised study, children (aged 0-17 years) attending 107 paediatric hospitals in 28 countries with documented acute venous thromboembolism who had started heparinisation were assigned (2:1) to bodyweight-adjusted rivaroxaban (tablets or suspension) in a 20-mg equivalent dose or standard anticoagulants (heparin or switched to vitamin K antagonist). Randomisation was stratified by age and venous thromboembolism site. The main treatment period was 3 months (1 month in children <2 years of age with catheter-related venous thromboembolism). The primary efficacy outcome, symptomatic recurrent venous thromboembolism (assessed by intention-to-treat), and the principal safety outcome, major or clinically relevant non-major bleeding (assessed in participants who received >/=1 dose), were centrally assessed by investigators who were unaware of treatment assignment. Repeat imaging was obtained at the end of the main treatment period and compared with baseline imaging tests. This trial is registered with ClinicalTrials.gov, number NCT02234843 and has been completed. FINDINGS: From Nov 14, 2014, to Sept 28, 2018, 500 (96%) of the 520 children screened for eligibility were enrolled. After a median follow-up of 91 days (IQR 87-95) in children who had a study treatment period of 3 months (n=463) and 31 days (IQR 29-35) in children who had a study treatment period of 1 month (n=37), symptomatic recurrent venous thromboembolism occurred in four (1%) of 335 children receiving rivaroxaban and five (3%) of 165 receiving standard anticoagulants (hazard ratio [HR] 0.40, 95% CI 0.11-1.41). Repeat imaging showed an improved e

Contains fulltext : 229840.pdf (Publisher’s version ) (Open Access), AIMS: The risk to develop adverse drug reactions (ADRs) is high for paediatric patients. This is, amongst other reasons, due to the inevitable use of off-label and unlicensed medicines. Moreover, there is limited knowledge on ADRs in children. Thus, adequate recognition may be challenging. The lack of dedicated studies and the voluntary nature of pharmacovigilance systems used to gain insight into the characteristics of ADRs contribute to this problem. The goal of this study is to identify whether ADRs in paediatric patients are adequately documented by the medical team and whether they are subsequently reported to the national pharmacovigilance system. METHODS: All patients admitted to the paediatric medium care of the Radboudumc Amalia Children's hospital during 1 month, and using one or more drugs, were included. Two researchers analysed retrospectively and independently the number of possible ADRs in the medical records. The ADRs were listed per paediatric subspecialty, to evaluate any differences in documentation and reporting of the ADRs. Subsequently, the causality, severity, and seriousness of the ADRs were assessed. The ADRs were categorised by system organ class and drug class. The national pharmacovigilance centre was consulted to check if there were any reports coming from our hospital and to collect the total number of reports. RESULTS: The medical records of 301 patients were analysed, 81 patients were suffering from one or more ADRs. In total 132 suspected ADRs were found, divided among 19 different paediatric subspecialties. Numbers were too small to investigate the differences in ADR documentation. Of these found ADRs, 55% were not explicitly noted as such in the medical records by the treating physician. None of the ADRs were reported to the national pharmacovigilance centre. Most ADRs scored 'possible' in the causality assessment, were mild or moderate, and a small number were serious. The ADRs occurred in 25 different organ systems. In total 25 d

Contains fulltext : 174077.pdf (publisher's version ) (Open Access), BACKGROUND: Venous thromboembolism (VTE) is a common and severe complication during treatment of acute lymphoblastic leukemia (ALL). An important cause is the intensive use of asparaginase. Prospective cohort studies in which prophylactic low-molecular-weight heparin (LMWH) was used to prevent VTE showed lower VTE risk than in historic control cohorts, with a negligible bleeding risk. However, the efficacy of thromboprophylaxis with LMWH during ALL treatment has never been investigated in a randomized design. Here, we present the protocol of a randomized controlled trial in which the efficacy and safety of thromboprophylaxis with high prophylactic dose LMWH versus no thromboprophylaxis will be assessed in children treated for primary ALL with asparaginase. METHODS/DESIGN: Thromboprophylaxis in Children treated for Acute Lymphoblastic Leukemia with Low-molecular-weight heparin (TropicALL) is a multicenter, randomized controlled open-label trial conducted in the Netherlands. Patients between 1 and 19 years of age with primary ALL, who are treated within the Dutch Childhood Oncology Group (DCOG) ALL-11 or 12 study will be randomized to thromboprophylaxis with LMWH once daily, (dose of 85 IU/kg (intervention arm A)), or to no thromboprophylaxis (arm B, standard of care) during asparaginase courses of ALL treatment. Primary efficacy endpoint is symptomatic objectified VTE during ALL treatment; secondary efficacy endpoints are overall survival and the composite of symptomatic and asymptomatic objectified VTE. Primary safety endpoints are major bleeding, clinically relevant non-major bleeding and minor bleeding. A total of 324 patients will be included to obtain a relative risk reduction of 75% with a power of 80%, using a two-sided test with significance level alpha = 0.05. DISCUSSION: This trial will be the first to assess efficacy and safety of thromboprophylaxis with LMWH during asparaginase treatment for ALL in children in a randomized design. TRAIL REGISTRATION: Nede

Contains fulltext : 170603pub.pdf (publisher's version ) (Closed access) Contains fulltext : 170603post.pdf (postprint version ) (Open Access), AIM: This systematic review provides an overview of publications concerning pharmacogenetic research in pediatric patients with medulloblastoma and low-grade glioma. MATERIALS & METHODS: Three electronic databases searches including a manual search were performed to identify studies investigating potential interactions between germline variants and chemotherapy efficacy and toxicity. RESULTS: Out of 3570 citations, 21 studies were included. Outcomes include overall survival, progression-free survival and treatment-related adverse events (n = 5), cisplatin-induced ototoxicity (n = 13) and vincristine-induced neurotoxicity (n = 3). CONCLUSION: This review shows that the number of pharmacogenetic studies in well-defined pediatric brain tumor cohorts is poor and studies often report conflicting results. Large-scale international collaborations allowing analysis of sufficiently sized cohorts are therefore very important for the future of personalized medicine in brain tumors.

Radboud University, 23 december 2016, Promotores : Noordam, C., Guchelaar (LUMC), H.J. Co-promotores : Loo, D.M.W.M. te, Coenen, M.J.H., Contains fulltext : 161367.pdf (publisher's version ) (Open Access)

Item does not contain fulltext, In osteosarcoma, large variation is observed in the efficacy and toxicity of chemotherapeutic drugs among similarly treated patients. Treatment optimization using predictive factors or algorithms is of importance, because there has been a lack of improvement of treatment outcome and survival for decades. The outcome of cancer treatment is influenced by the genome, thus studying genetic variants involved in the efficacy and toxicity of the chemotherapeutic drugs used in the treatment of osteosarcoma could be an opportunity to optimize current treatments and improve our understanding of the individual's drug response in osteosarcoma patients. This review discusses the current insights in the pharmacogenetics of the treatment response of osteosarcoma patients regarding efficacy and toxicity, and implications for future research and treatment.

Contains fulltext : 167307.pdf (publisher's version ) (Closed access)

Contains fulltext : 154635.pdf (publisher's version ) (Closed access), PURPOSE: Overall survival in patients with osteosarcoma is only 60%. Poor response to chemotherapy is the dominant risk factor for poor survival. Pharmacogenetic research can offer possibilities to optimize treatment and improve outcome. We applied a pathway-based approach to evaluate the cumulative effect of genes involved in the metabolism of cisplatin and doxorubicin in relationship to clinical outcome. EXPERIMENTAL DESIGN: We included 126 patients with osteosarcoma. To comprehensively assess common genetic variation in the 54 genes selected, linkage disequilibrium (LD; r(2) = 0.8)-based tag-single nucleotide polymorphisms (SNP) strategy was used. A final set of 384 SNPs was typed using Illumina Beadarray platform. SNPs significantly associated with 5-year progression-free survival (PFS) were replicated in another 64 patients with osteosarcoma. RESULTS: We identified five variants in FasL, MSH2, ABCC5, CASP3, and CYP3A4 that were associated with 5-year PFS. Risk stratification based on the combined effects of the risk alleles showed a significant improvement of 5-year PFS. Patients that carried no or only one risk allele had a 5-year PFS of 100% compared with a 5-year PFS of 84.4% for carriers of two or three risk alleles, 66.7% PFS if a patient carried four to five alleles, and a 5-year PFS of 41.8% for patients with >5 risk alleles (P < 0.001). CONCLUSIONS: We identified several genes that showed association with PFS in patients with osteosarcoma. These pharmacogenetic risk factors might be useful to predict treatment outcome and to stratify patients immediately after diagnosis and offer the possibility to improve treatment and outcome. Clin Cancer Res; 21(15); 3436-41. (c)2015 AACR.

Item does not contain fulltext, The Affymetrix Drug Metabolizing Enzymes and Transporters (DMET) Plus array covers 1936 markers in 231 genes involved in drug metabolism and transport. Blood- and saliva-derived DNA works well on the DMET array, but the utility of DNA from FFPE tissue has not been reported for this array. As the ability to use DNA from FFPE tissue on the array could open the potential for large retrospective sample collections, we examined the performance and reliability of FFPE-derived DNA on the DMET Plus array. Germline DNA isolated from archived normal FFPE tissue blocks stored for 3 to 19 years and matched blood or saliva from 16 patients with osteosarcoma were genotyped on the DMET Plus array. Concordance was assessed by calculating agreement and the kappa-statistic. We observed high call rates for both the blood- or saliva-derived DNA samples (99.4%) and the FFPE-derived DNA samples (98.9%). Moreover, the concordance among the 16 blood- or saliva-derived DNA and FFPE DNA pairs was high (97.4%, kappa = 0.915). This is the first study showing that DNA from normal FFPE tissue provides accurate and reliable genotypes on the DMET Plus array compared with blood- or saliva-derived DNA. This finding provides an opportunity for pharmacogenetic studies in diseases with high mortality rates and prevents a bias in studies where otherwise only alive patients can be included.

Radboud Universiteit Nijmegen, 17 maart 2015, Promotores : Hoogerbrugge, P.M., Guchelaar (LUMC), H.J. Co-promotores : Loo, D.M.W.M. te, Coenen, M.J.H., Contains fulltext : 139140.pdf (publisher's version ) (Open Access)

Contains fulltext : 136201.pdf (publisher's version ) (Closed access)

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Item does not contain fulltext, New targets for Ewing sarcoma (ES) patients are urgently needed. Therefore, we investigated the expression and genetic aberrations of the oncogenic receptor tyrosine kinase (RTK) AXL in ES and determined the efficacy of AXL targeting on cell viability and migration. First, AXL and Gas6 (ligand) mRNA expression was determined by RT-PCR on 29 ES samples. Low, medium and high AXL mRNA expression was observed in 31% (n = 9), 48% (n = 14) and 21% (n = 6) of samples. Gas6 was abundantly present in all specimens. We next tested AXL protein expression immunohistochemically in 36 tumors (primary, post-chemotherapy, metastasized and relapsed samples) from 25 ES patients. Low, medium and high AXL protein expression was observed in 17% (n = 6), 19% (n = 7) and 36% (n = 13) of samples. In primary tumors (n = 15), high AXL expression correlated significantly with a worse overall survival compared to patients with lower expression (61 vs. 194 months, p = 0.026). No genetic aberrations were detected in the AXL RTK domain (n = 29). The AXL-inhibitor BGB324 affected viability (IC50 0.79-2.13 mumol/L) and migratory potential of all tested ES cell lines in vitro (n = 5-6). BGB324 chemosensitized chemotherapy-resistant ES-4 cells to vincristine and doxorubicin. These data suggest that AXL is a potential novel, druggable therapeutic target in ES.

Item does not contain fulltext, Methotrexate (MTX), one of the important pillars in the treatment of different forms of cancer, is associated with the development of hepatotoxicity. The 677C>T variant (rs1801133) in the methylenetetrahydrofolate reductase (MTHFR) gene might affect the development of hepatotoxicity. Results in literature are, however, contradictive. The aim of this study was to evaluate the role of the MTHFR 677C>T polymorphism in MTX-induced hepatotoxicity by analyzing a Dutch cohort of pediatric patients treated with high doses of MTX and subsequently performing a meta-analysis. Ninety-eight patients receiving 542 courses of high-dose MTX were genotyped for the MTHFR 677C>T variant. Hepatotoxicity was evaluated retrospectively according to common terminology criteria for adverse events-National Cancer Institute criteria. The influence of MTHFR 677C>T on hepatotoxicity was examined using a generalized estimating equation (GEE) analysis. A fixed-effect meta-analysis based on this and previous studies investigating the association between the MTHFR 677C>T polymorphism and uniformly coded hepatotoxicity was performed. The GEE analysis showed an increased risk of developing hepatotoxicity for T versus C allele (odds ratio (OR) 1.8; 95% confidence interval (CI) 1.0-3.2, P=0.04). This finding was not supported by the meta-analysis including seven studies and 1044 patients; the OR for the 677T versus C allele was 1.1 (95% CI 0.84-1.5, P=0.25). Heterogeneity between studies was observed, possibly related to differences in MTX dose and leucovorin rescue. In conclusion, in patients with cancer, the MTHFR 677T allele has only a minor role in the development of MTX-induced hepatotoxicity. Observed heterogeneity between studies warrants further study into (tailored) leucovorin rescue.

1 maart 2011, Contains fulltext : 97293.pdf (publisher's version ) (Closed access), In this case report, we describe a 5-month-old girl with a rapid-growing mass of the lower lip extending to the buccal cheek. After surgical interference, the diagnosis lipoblastoma was made. Dealing with a fast-growing tumor in an infant, lipoblastic tumors belong in the differential diagnosis, however, a malignant process cannot be excluded. Rapid-growing lipoblastoma of infancy is a very rare benign tumor of embryonic white fatty cells. Magnetic resonance imaging might help with the diagnosis and often shows a lesion composed mostly, but not entirely, of fat. In this case report, we want to draw attention to the problems with diagnosis and therapeutic management of children with lipoblastoma.

Contains fulltext : 89715.pdf (publisher's version ) (Closed access), Male subjects with iron deficiency from the general population were examined for polymorphisms or sporadic mutations in TMPRSS6 to identify genetic risk factors for iron deficiency anemia. Three uncommon non-synonymous polymorphisms were identified, G228D, R446W, and V795I (allele frequencies 0.0074, 0.023 and 0.0074 respectively), of which the R446W polymorphism appeared to be overrepresented in the anemic population. In addition, three children with iron refractory iron deficiency anemia, and one sibling with iron responsive iron deficiency anemia were also examined for polymorphisms or sporadic mutations in TMPRSS6. Two children (family 1) were compound heterozygotes for a L674F mutation and a previously described splicing defect predicted to cause skipping of exon 13 (IVS13+1 G>A). One child from the second family was homozygous for a deletion (497T) causing a frameshift (L166X+36) and premature termination. The sibling and mother from the second family were compound heterozygotes for the L166X mutation and the uncommon R446W polymorphism. Although in vitro expression studies demonstrated that the R446W isoform was biologically similar to wildtype Tmprss6, clinical data indicate that the R446W produces a milder disease when carried in trans with severe mutation in Tmprss6. The four children carrying mutations in TMPRSS6 all exhibited inappropriately high urinary hepcidin levels for the degree of iron deficiency.

Contains fulltext : 51416.pdf (publisher's version ) (Closed access), BACKGROUND: After gastrointestinal infection with Shiga-like toxin (Stx) producing Escherichia coli, the toxin is transported from the intestine to the renal microvascular endothelium. This is the main target for Stx in humans. Previous studies indicated that polymorphonuclear leucocytes (PMN) could serve as carriers for Stx in the systemic circulation. As at a later stage we could not confirm these data, we performed new studies. METHODS: The binding of Stx1 to PMN was determined in vitro (isolated human PMN and whole blood) and in vivo (injection in mice). The specificity of binding of an antibody against Stx2 to PMN from patients with haemolytic uraemic syndrome (HUS) was determined. This was compared with binding to PMN from healthy controls, and patients after haemodialysis (HD) or on peritoneal dialysis (PD). Furthermore, PMN were incubated with Stx to study possible activation. RESULTS: No specific binding of Stx1 to PMN could be detected. After intravenous injection of the toxin in mice, it was not associated with PMN. The binding of an antibody against Stx2 to PMN was detected in both patients with HUS and patients after HD, but not in patients on PD. Stx was not able to activate PMN. CONCLUSIONS: PMN are not acting as transporter for Stx in the pathogenesis of HUS. The interaction of a Stx antibody with PMN from HUS patients is not specific as it can also be observed in patients after HD (possibly due to activation of the PMN). Therefore, binding of Stx antibody to PMN is not reliable as a diagnostic tool for HUS.

Contains fulltext : 49313.pdf (publisher's version ) (Closed access)

Contains fulltext : 49302.pdf (publisher's version ) (Closed access), PURPOSE: To determine the significance of blasts in the CSF without pleiocytosis and a traumatic lumbar puncture in children with acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: We retrospectively studied a cohort of 526 patients treated in accordance with the virtually identical Dutch protocols ALL-7 and ALL-8. Patients were classified into five groups: CNS1, no blasts in the CSF cytospin; CNS2, blasts present in the cytospin, but leukocytes less than 5/microL; CNS3, blasts present and leukocytes more than 5/microL. Patients with a traumatic lumbar puncture (TLP; > 10 erythrocytes/mL) were classified as TLP+ (blasts present in the cytospin) or TLP- (no blasts). RESULTS: Median duration of follow-up was 13.2 years (range, 6.9 to 15.5 years). Event-free survival (EFS) was 72.6% (SE, 2.5%) for CNS1 patients (n = 304), 70.3% (SE, 4.7%) for CNS2 patients (n = 111), and 66.7% (SE, 19%) for CNS3 patients (n = 10; no significant difference in EFS between the groups). EFS was 58% (SE, 7.6%) for TLP+ patients (n = 62) and 82% (SE, 5.2%) for TLP- patients (n = 39; P < .01). Cox regression analysis identified TLP+ status as an independent prognostic factor (risk ratio, 3.5; 95% CI, 1.4 to 8.8; P = .007). Cumulative incidence of CNS relapses was 0.05 and 0.07 in CNS1 and CNS2 patients, respectively (not statistically significant). CONCLUSION: In our experience, the presence of a low number of blasts in the CSF without pleiocytosis has no prognostic significance. In contrast, a traumatic lumbar puncture with blasts in the CSF specimen is associated with an inferior outcome.

Contains fulltext : 58600.pdf (publisher's version ) (Closed access), The pathogenesis of hemolytic uremic syndrome (D+ HUS) is characterized by endothelial damage of glomeruli and tubules within the kidney. In several other diseases in which glomerular endothelial damage occurs, elevated serum levels of vascular endothelial growth factor (VEGF) have been reported. VEGF is involved in angiogenesis, permeabilization of blood vessel endothelium, and wound repair. In this study we evaluated VEGF levels in the serum of 40 D+ HUS patients in the acute phase and during the course of the disease. VEGF levels were measured using a double-sandwich ELISA. Indirect immunohistochemistry was performed for the detection of VEGF in renal biopsy material of 3 HUS patients. Significantly elevated VEGF levels were found in HUS patients compared with controls in both serum ( P<0.001) and plasma ( P<0.05). A significant relationship was found between VEGF levels and severity of the disease according to the classification of Gianantonio ( P<0.05). Levels of VEGF in blood increased during the 2nd and 3rd week after HUS was diagnosed. Immunohistochemistry of renal biopsy material showed increased levels of the receptors for VEGF in the glomeruli. During the course of HUS, plasma VEGF levels increase and the increase is dependent on the severity of the disease. This is probably associated with the repair process.

Item does not contain fulltext, BACKGROUND: Plasma hemopexin has been shown to induce proteinuria after intrarenal infusion in rats, as well as glomerular alterations identical to those seen in corticosteroid-responsive nephrotic syndrome (CRNS). The question emerged whether also renal cells are potentially able to release hemopexin. METHODS: Normal human mesangial cells (HMC) were incubated overnight in serum-free medium with or without tumor necrosis factor-alpha (TNF-alpha) (10 ng/mL). Parallel cultures were supplemented with prednisolone (10-3 mol/L). Concentrated supernatants were analyzed by Western blotting, using antihemopexin immunoglobulin G (IgG). Antitransferrin IgG served as control antibody. In addition, cytospins were stained using polyclonal or monoclonal antihemopexin IgG. A part of the cells was used for RNA isolation and reverse transcription-polymerase chain reaction (RT-PCR), to study hemopexin mRNA. RESULTS: Eighty five kD bands were exclusively detected by antihemopexin IgG in the Western blots in supernatants from TNF-alpha-stimulated cultures and to a lesser extent in prednisolone-treated cultures. Cells from TNF-alpha-stimulated cultures stain positive for hemopexin in contrast to those from prednisolone-treated or nonstimulated cultures. RT-PCR data suggest that mRNA for hemopexin is up-regulated in TNF-alpha-treated versus prednisolone-treated HMC. CONCLUSION: Stimulated HMC are able to release hemopexin in vitro in a corticosteroid-dependent manner. As preliminary data indicate that mesangial hemopexin is able to affect glomerular anionic sites, it is conceivable that stimulated mesangium may contribute to enhanced glomerular permeability in CRNS through local hemopexin release.

Item does not contain fulltext, The typical form of hemolytic uremic syndrome (D+HUS) is a thrombotic microangiopathy that causes acute renal failure in children. The etiology of this disease is a toxin called Shiga-like toxin (Stx), present in certain strains of gram-negative bacteria. Vascular endothelial cell (EC) injury appears to be central in the pathogenesis of D+HUS. Thrombomodulin (TM) is a glycoprotein present in EC with anti-thrombogenic properties. The objective of this study was to investigate the effects of Stx on the surface expression of TM in EC using an in vitro culture of human glomerular microvascular endothelial cells. We also evaluated other inflammatory mediators [tumor necrosis factor-alpha (TNF-alpha) and lipopolysaccharide], which are known to increase Stx receptor expression and are potentially involved in the pathogenesis of D+HUS. Stx2 induced a significant decrease of TM expression in this cell type after pre-incubation with TNF-alpha. This decrease could not be attributed to the inhibition of protein synthesis only, as cycloheximide, another inhibitor of protein synthesis, did not affect TM surface expression. These results suggest that the Stx2-induced decrease of TM expression in glomerular EC might contribute to the local procoagulant state present in D+HUS.

Item does not contain fulltext, The diarrhea-associated form of the hemolytic uremic syndrome (D+ HUS) is characterized by a triad of symptoms, namely thrombocytopenia, hemolytic anemia, and acute renal failure. Histopathological studies of patients with D+ HUS show microthrombi in arterioles and glomeruli of the kidney. Recently, it was suggested that antiphospholipid antibodies might play a pathogenic role in D+ HUS. However, an epiphenomenon could not be excluded. In this study we investigated the relationship between antiphospholipid antibodies and clinical symptoms in 22 patients with the classical form of HUS (D+ HUS). The first sample was obtained on the day of admission. The next samples were taken on day 7 and 14. We measured anticardiolipin (aCL) antibodies (IgM, IgA, and IgG) in the samples using an ELISA. A significant increase in IgM (60%) and IgG (41%) aCL antibodies was seen in patients versus controls. No relationship between aCL antibody levels and severity of renal failure could be demonstrated. These data suggest that antiphospholipid antibodies are increased, but have not been shown to have a role in the pathogenesis of the microangiopathy seen in D+HUS.