Ate G J van der Zee

University of Groningen, Groningen, Groningen, Netherlands

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Publications (142)791.68 Total impact

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    ABSTRACT: DNA hypermethylation is extensively explored as therapeutic target for gene expression modulation in cancer. Here we re-activated hypermethylated candidate tumor suppressor genes (TSGs) (C13ORF18, CCNA1, TFPI2, Maspin) by TET2-induced demethylation in cervical cancer cell lines. To redirect TET2 to hypermethylated TSGs, we engineered zinc finger proteins (ZFPs), which were first fused to the transcriptional activator VP64 to validate effective gene re-expression and confirm TSG function. ChIP-Seq revealed enriched binding of ZFPs to their intended sequence, but also considerable off-target binding, especially at promoter regions. Nevertheless, results obtained by targeted re-expression using ZFP-VP64 constructs were in line with cDNA overexpression; both revealed strong growth inhibition for C13ORF18 and TFPI2, but not for CCNA1 and Maspin. To explore effectivity of locus-targeted demethylation, ZFP-TET2 fusions were constructed which efficiently demethylated genes with subsequent gene re-activation. Moreover, targeting TET2 to TFPI2 and C13ORF18, but not CCNA1, significantly decreased cell growth, viability and colony formation in cervical cancer cells compared to a catalytically inactive mutant of TET2. These data underline that effective re-activation of hypermethylated genes can be achieved through targeted DNA demethylation by TET2, which can assist in realizing sustained re-expression of genes of interest.Molecular Therapy (2015); doi:10.1038/mt.2015.226.
    No preview · Article · Dec 2015 · Molecular Therapy
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    ABSTRACT: Using patient-derived xenografts (PDXs) for preclinical cancer research demands proper storage of tumour material to facilitate logistics and to reduce the number of animals needed. We successfully established 45 subcutaneous ovarian cancer PDXs, reflecting all histological subtypes, with an overall take rate of 68%. Corresponding cells from mouse replaced human tumour stromal and endothelial cells in second generation PDXs as demonstrated with mouse-specific vimentin and CD31 immunohistochemical staining. For biobanking purposes two cryopreservation methods, a fetal calf serum (FCS)-based (95%v/v) " FCS/DMSO " protocol and a low serum-based (10%v/v) " vitrification " protocol were tested. After primary cryopreservation, tumour take rates were 38% and 67% using either the vitrification or FCS/DMSO-based cryopreservation protocol, respectively. Cryopreserved tumour tissue of established PDXs achieved take rates of 67% and 94%, respectively compared to 91% using fresh PDX tumour tissue. Genotyping analysis showed that no changes in copy number alterations were introduced by any of the biobanking methods. Our results indicate that both protocols can be used for biobanking of ovarian tumour and PDX tissues. However, FCS/DMSO-based cryopreservation is more successful. Moreover, primary engraftment of fresh patient-derived tumours in mice followed by freezing tissue of successfully established PDXs is the preferred way of efficient ovarian cancer PDX biobanking.
    Full-text · Article · Nov 2015 · Scientific Reports
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    ABSTRACT: High-grade serous ovarian cancer (HGSOC) has the highest mortality rate among all gynecological cancers. Patients are generally diagnosed in an advanced stage with the majority of cases displaying platinum resistant relapses. Recent genomic interrogation of large numbers of HGSOC patient samples indicated high complexity in terms of genetic aberrations, intra- and intertumor heterogeneity and underscored their lack of targetable oncogenic mutations. Sub-classifications of HGSOC based on expression profiles, termed 'differentiated', 'immunoreactive', 'mesenchymal' and 'proliferative', were shown to have prognostic value. In addition, in almost half of all HGSOC patients, a deficiency in homologous recombination (HR) was found that potentially can be targeted using PARP inhibitors. Developing precision medicine requires advanced experimental models. In the current review, we discuss experimental HGSOC models in which resistance to platinum therapy and the use of novel therapeutics can be carefully studied. Panels of better-defined primary cell lines need to be established to capture the full spectrum of HGSOC subtypes. Further refinement of cell lines is obtained with a 3-dimensional culture model mimicking the tumor microenvironment. Alternatively, ex vivo ovarian tumor tissue slices are used. For in vivo studies, larger panels of ovarian cancer patient-derived xenografts (PDXs) are being established, encompassing all expression subtypes. Ovarian cancer PDXs grossly retain tumor heterogeneity and clinical response to platinum therapy is preserved. PDXs are currently used in drug screens and as avatars for patient response. The role of the immune system in tumor responses can be assessed using humanized PDXs and immunocompetent genetically engineered mouse models. Dynamic tracking of genetic alterations in PDXs as well as patients during treatment and after relapse is feasible by sequencing circulating cell-free tumor DNA and analyzing circulating tumor cells. We discuss how various models and methods can be combined to delineate the molecular mechanisms underlying platinum resistance and to select HGSOC patients other than BRCA1/2-mutation carriers that could potentially benefit from the synthetic lethality of PARP inhibitors. This integrated approach is a first step to improve therapy outcomes in specific subgroups of HGSOC patients.
    No preview · Article · Nov 2015
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    ABSTRACT: Every year, cervical cancer affects ∼500,000 women worldwide, and ∼275,000 patients die of this disease. The addition of platin-based chemotherapy to primary radiotherapy has increased 5-year survival of advanced-stage cervical cancer patients, which is, however, still only 66%. One of the factors thought to contribute to treatment failure is the ability of tumor cells to repair chemoradiotherapy-induced DNA damage. Therefore, sensitization of tumor cells for chemoradiotherapy via inhibition of the DNA damage response (DDR) as a novel strategy to improve therapy effect, is currently studied pre-clinically as well as in the clinic. Almost invariably, cervical carcinogenesis involves infection with the human papillomavirus (HPV), which inactivates part of the DNA damage response. This HPV-mediated partial inactivation of the DDR presents therapeutic targeting of the residual DDR as an interesting approach to achieve chemoradio-sensitization for cervical cancer. How the DDR can be most efficiently targeted, however, remains unclear. The fact that cisplatin and radiotherapy activate multiple signaling axes within the DDR further complicates a rational choice of therapeutic targets within the DDR. In this review, we provide an overview of the current preclinical and clinical knowledge about targeting the DDR in cervical cancer.
    No preview · Article · Nov 2015 · Cancer Treatment Reviews
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    ABSTRACT: Background: Understanding carboplatin resistance in ovarian cancer is critical for the improvement of patients' lives. Multipotent mesenchymal stem cells or an aggravated epithelial to mesenchymal transition phenotype of a cancer are integrally involved in pathways conferring chemo-resistance. Long non-coding RNA HOTAIR (HOX transcript antisense intergenic RNA) is involved in mesenchymal stem cell fate and cancer biology. Methods: We analyzed HOTAIR expression and associated surrogate DNA methylation (DNAme) in 134 primary ovarian cancer cases (63 received carboplatin, 55 received cisplatin and 16 no chemotherapy). We validated our findings by HOTAIR expression and DNAme analysis in a multicentre setting of five additional sets, encompassing 946 ovarian cancers. Chemo-sensitivity has been assessed in cell culture experiments. Results: HOTAIR expression was significantly associated with poor survival in carboplatin-treated patients with adjusted hazard ratios for death of 3.64 (95 % confidence interval [CI] 1.78-7.42; P < 0.001) in the discovery and 1.63 (95 % CI 1.04-2.56; P = 0.032) in the validation set. This effect was not seen in patients who did not receive carboplatin (0.97 [95 % CI 0.52-1.80; P = 0.932]). HOTAIR expression or its surrogate DNAme signature predicted poor outcome in all additional sets of carboplatin-treated ovarian cancer patients while HOTAIR expressors responded preferentially to cisplatin (multivariate interaction P = 0.008). Conclusions: Non-coding RNA HOTAIR or its more stable DNAme surrogate may indicate the presence of a subset of cells which confer resistance to carboplatin and can serve as (1) a marker to personalise treatment and (2) a novel target to overcome carboplatin resistance.
    Full-text · Article · Oct 2015 · Genome Medicine
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    Full-text · Dataset · Oct 2015
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    ABSTRACT: Aims: Tumor-specific targeted imaging is rapidly evolving in cancer diagnosis. The folate receptor alpha (FR-α) has already been identified as a suitable target for cancer therapy and imaging. FR-α is present on ~40% of human cancers. FR-β is known to be expressed on several hematologic malignancies and on activated macrophages, but little is known about FR-β expression in solid tumors. Additional or simultaneous expression of FR-β could help extend the indications for folate-based drugs and imaging agents. In this study, the expression pattern of FR-β is evaluated in ovarian, breast and colorectal cancer. Methods: FR-β expression was analyzed by semi-quantitative scoring of immunohistochemical staining on tissue microarrays (TMAs) of 339 ovarian cancer patients, 418 breast cancer patients, on 20 slides of colorectal cancer samples and on 25 samples of diverticulitis. Results: FR-β expression was seen in 21% of ovarian cancer samples, 9% of breast cancer samples, and 55% of colorectal cancer samples. Expression was weak or moderate. Of the diverticulitis samples, 80% were positive for FR-β expression in macrophages. FR-β status neither correlated to known disease-related variables, nor showed association with overall survival and progression free survival in ovarian and breast cancer. In breast cancer, negative axillary status was significantly correlated to FR-β expression (p=0.022). Conclusions: FR-β expression was low or absent in the majority of ovarian, breast and colorectal tumor samples. From the present study we conclude that the low FR-β expression in ovarian and breast tumor tissue indicates limited practical use of this receptor in diagnostic imaging and therapeutic purposes. Due to weak expression, FR-β is not regarded as a suitable target in colorectal cancer.
    Full-text · Article · Aug 2015 · PLoS ONE

  • No preview · Article · Aug 2015 · Cancer Research

  • No preview · Article · Aug 2015 · Cancer Research
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    ABSTRACT: The first version of ENGOT's Requirements for Trials Between Academic Groups and Industry Partners in Europe was published 2010. This first update integrates the experiences made by the ENGOT network and the cooperative group studies while performing, analyzing, and publishing -among others - three large phase III trials. Furthermore, progress in European legislation and its impact on clinical studies in Europe have been considered in this update process.
    No preview · Article · Jun 2015 · International Journal of Gynecological Cancer
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    ABSTRACT: Epigenetic silencing of tumor suppressor genes (TSGs) is considered a significant event in the progression of cancer. For example, EPB41L3, a potential biomarker in cervical cancer, is often silenced by cancer-specific promoter methylation. Artificial transcription factors (ATFs) are unique tools to re-express such silenced TSGs to functional levels; however, the induced effects are considered transient. Here, we aimed to improve the efficiency and sustainability of gene re-expression using engineered zinc fingers fused to VP64 (ZF-ATFs) or DNA methylation modifiers (ZF-Tet2 or ZF-TDG) and/or by co-treatment with epigenetic drugs [5-aza-dC2'-deoxycytidine or Trichostatin A (TSA)]. EPB41L3-ZF effectively bound its methylated endogenous locus, as also confirmed by ChIP-seq. ZF-ATFs reactivated the epigenetically silenced target gene EPB41L3 (˜10-fold) in breast, ovarian, and cervical cancer cell lines. Prolonged high levels of EPB41L3 (˜150-fold) induction could be achieved by short-term co-treatment with epigenetic drugs. Interestingly, for otherwise ineffective ZF-Tet2 or ZF-TDG treatments, TSA facilitated re-expression of EPB41L3 by up to twofold. ATF-mediated re-expression demonstrated a tumor suppressive role for EPB41L3 in cervical cancer cell lines. In conclusion, epigenetic reprogramming provides a novel way to improve sustainability of re-expression of epigenetically silenced promoters.
    No preview · Article · Apr 2015 · Epigenetics: official journal of the DNA Methylation Society
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    ABSTRACT: This study demonstrates that both the clinical sensitivity and specificity of the Cervista HPV HR test for high-risk human papillomavirus (HPV) detection are not inferior to those of the Hybrid Capture 2 (HC2) test. The intra- and interlaboratory reproducibilities of Cervista were 92.0% (kappa, 0.83) and 90.4% (kappa, 0.80), respectively. The Cervista HPV HR test fulfills all the international HPV test requirements for cervical primary screening purposes.
    Full-text · Article · Oct 2014 · Journal of Clinical Microbiology

  • No preview · Article · Oct 2014 · Cancer Research

  • No preview · Article · Oct 2014 · Cancer Research
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    ABSTRACT: The diagnostic performance of the widely-used Cervista HPV HR test was compared to the Hybrid Capture 2 (HC2) test in a Dutch population-based cervical cancer screening program. In 900 scrapings of women with normal cytomorphology, specificity was 90% (95%CI: 87.84-91.87) for the Cervista HPV HR test and 96% (95%CI: 94.76-97.37) for the HC2 test with 93% agreement between both tests (κ = 0.5, p<0.001). The sensitivity for CIN2+ using 65 scrapings of women with histological-confirmed CIN2+ was 91% (95%CI: 80.97-96.51) for the Cervista HPV HR test and 92% (95%CI: 82.94-97.43) for the HC2 test with 95% agreement between both tests (κ = 0.7, p<0.001). Fifty-seven of 60 HC2 negative/Cervista positive cases tested HPV-negative with PCR-based HPV assays; of these cases 56% were defined as Cervista triple-positive with FOZ values in all 3 mixes higher than the second cut-off of 1.93 (as set by manufacturer). By setting this cut-off at 5.0, specificity improved significantly without affecting sensitivity. External validation of this new cut-off at 5.0 in triple-positive scrapings of women selected from the SHENCCASTII database revealed that 22/24 histological normal cases now tested HPV-negative in the Cervista HPV HR test, while CIN2+ lesions remained HPV-positive. The intra-laboratory reproducibility of the Cervista HPV HR test (n = 510) showed a concordance of 92% and 93% for cut-off 1.93 and 5.0 (κ = 0.83 and κ = 0.84, p<0.001) and inter-laboratory agreement of the Cervista HPV HR test was 90% and 93% for cut-off 1.93 and 5.0 (κ = 0.80 and κ = 0.85, p<0.001). In conclusion, the specificity of the Cervista HPV HR test could be improved significantly by increasing the second cut-off from 1.93 to 5.0, without affecting the sensitivity of the test in a population-based screening setting.
    Full-text · Article · Jul 2014 · PLoS ONE
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    ABSTRACT: Objective: The aim of this study was to determine possible impact of routinely scheduled biopsies and more radical surgery for residual central disease in locally advanced cervical cancer after (chemo)radiation. Methods/materials: Data were analyzed of a consecutive series of cervical cancer patients (The International Federation of Gynecology and Obstetrics stages IB1-IVA) treated with (chemo) radiation between 1994 and 2011. Patients underwent gynecologic examination with biopsies 8 to 10 weeks after treatment. Since 2001, larger biopsies by electric loop excision were taken, and more radical surgery (type III hysterectomy or exenteration) was performed for central residual disease. Primary outcome was locoregional recurrence. Secondary outcomes were treatment-associated morbidity and disease-specific survival. Results: Primary (chemo)radiation was given to 491 cervical cancer patients; 345 patients had a posttreatment biopsy. Viable tumor cells were identified in 84 patients, and 61 patients were eligible for salvage surgery. Residual disease after (chemo)radiation was an independent poor prognostic factor (hazard ratio, 3.59; 95% confidence interval, 2.18-5.93; P < 0.001). After 2001, larger biopsies were more frequently taken (29% vs 76%, P < 0.001), and in patients without viable tumor cells, locoregional recurrence after 2001 decreased from 21% to 10% (P = 0.01). After 2001, more patients underwent more radical surgery (46% vs 90%) (P < 0.001). Locoregional recurrence after surgery before 2001 occurred in 6 (46%) of the 13 patients, comparable with 19 (40%) of the 48 (P = 0.67) after 2001. More radical surgery was not associated with improved disease-specific survival (HR, 0.84; 95% CI, 0.20-3.46; P = 0.81) but did result in significantly more severe morbidity. Conclusion: More radical surgery in patients with (minimal) central residual disease identified by routine biopsy 8 to 10 weeks after (chemo)radiation does not improve survival and should not be recommended.
    No preview · Article · Jul 2014 · International Journal of Gynecological Cancer
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    ABSTRACT: To elucidate the role of biological and clinical impact of aberrant promoter hypermethylation (PH) in ovarian cancer (OC). PH of PGP9.5, HIC1, AIM1, APC, PAK3, MGMT, KIF1A, CCNA1, ESR1, SSBP2, GSTP1, FKBP4 and VGF were assessed by quantitative methylation specific PCR (QMSP) in a training set. We selected two genes (VGF and PGP9.5) for further QMSP analysis in a larger independent validation (IV) set with available clinical data. Biologic relevance of VGF gene was also evaluated. PH frequency for PGP9.5 and VGF were 85% (316/372) and 43% (158/366) respectively in the IV set of samples while no PH was observed in controls. In 372 OC cases with available follow up, PGP9.5 and VGF PH were correlated with better patient survival [Hazard Ratios (HR) for overall survival (OS) were 0.59 (95% Confidence Intervals (CI) = 0.42-0.84, p = 0.004), and 0.73 (95%CI = 0.55-0.97, p = 0.028) respectively, and for disease specific survival (DSS) were 0.57 (95%CI 0.39-0.82, p = 0.003) and 0.72 (95%CI 0.54-0.96, p = 0.027). In multivariate analysis, VGF PH remained an independent prognostic factor for OS (HR 0.61, 95%CI 0.43-0.86, p<0.005) and DSS (HR 0.58, 95%CI 0.41-0.83, p<0.003). Furthermore, PGP9.5 PH was significantly correlated with lower grade, early stage tumors, and with absence of residual disease. Forced expression of VGF in OC cell lines inhibited cell growth. Our results indicate that VGF and PGP9.5 PH are potential biomarkers for ovarian carcinoma. Confirmatory cohorts with longitudinal follow-up are required in future studies to define the clinical impact of VGF and PGP9.5 PH before clinical application.
    Full-text · Article · Oct 2013 · PLoS ONE
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    ABSTRACT: Combined detection of CADM1 and MAL promoter methylation in cervical scrapes is a promising triage strategy for hrHPV-positive women. Here, CADM1 and MAL DNA methylation levels were analysed in cervical scrapes of hrHPV-positive women with no underlying high-grade disease, high-grade CIN and cervical cancer. CADM1 and MAL methylation levels in scrapes were firstly related to CIN-grade of the corresponding biopsy and secondly to CIN-grade stratified by the presence of 'normal' or 'abnormal' cytology as present in the accompanying scrape preceding the cervical biopsy. The scrapes included 167 women with ≤CIN1, 54 with CIN2/3 and 44 with carcinoma. In a separate series of hrHPV-positive scrapes of women with cervical intraepithelial neoplasia grade 2/3 (CIN2/3) (n=48), methylation levels were related to duration of preceding hrHPV infection (PHI; <5 and ≥5 years). Methylation levels were determined by quantitative methylation-specific PCR and normal cytology scrapes of hrHPV-positive women with histologically ≤CIN1 served as reference. CADM1 and MAL methylation levels increased proportional to severity of the underlying lesion, showing an increase of 5.3- and 6.2-fold in CIN2/3, respectively, and 143.5- and 454.9-fold in carcinomas, respectively, compared to the reference. Methylation levels were also elevated in CIN2/3 with a longer duration of PHI (i.e. 11.5- and 13.6-fold, respectively). Moreover, per histological category, methylation levels were higher in accompanying scrapes with abnormal cytology than in scrapes with normal cytology. Concluding, CADM1 and MAL promoter methylation levels in hrHPV-positive cervical scrapes are related to the degree and duration of underlying cervical disease and markedly increased in cervical cancer. © 2013 Wiley Periodicals, Inc.
    Full-text · Article · Sep 2013 · International Journal of Cancer
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    ABSTRACT: Objective: The purpose of this study was to assess the prevalence of underlying bleeding disorders in women with heavy menstrual bleeding (HMB) with and without gynecologic abnormalities. Study design: We performed a single-center prospective cohort study of 112 consecutive patients who were referred for heavy menstrual bleeding. Control subjects were 28 healthy volunteers who reported no HMB. Patients and control subjects had hemostatic testing in the first week after menstruation. Patients underwent gynecologic evaluation. Results: The median age was 42.5 years (range, 17-55 years) in patients and 40.0 years (range, 25-55 years) in control subjects. Forty-six percent of patients had anemia; the median pictorial bleeding assessment chart score was 271. Seven percent of the control subjects with a subjectively normal menstruation had anemia. Twenty-six percent of patients had gynecologic abnormalities, which was considered to explain HMB. Overall, we found an underlying bleeding disorder in 29% of the patients, which was comparable for unexplained and explained HMB (31% vs 27%; P = .75). We diagnosed 6 cases of Von Willebrand's disease, 4 cases of factor XI deficiency, and 1 case of factor VII deficiency. The only abnormalities that we found in control subjects were platelet aggregation defects (11% in control subjects vs 23% in patients). Patients had a significantly longer activated partial thromboplastin time compared with control subjects (26.5 vs 25.0 seconds; P = .001) that was caused by lower median levels of factor XI (100 vs 124 IU/dL; P < .001). Conclusion: Bleeding disorders play an equally important role in the cause of both unexplained and explained heavy menstrual bleeding. A novel finding is the occurrence of low, but not deficient, levels of factor XI.
    Full-text · Article · May 2013 · American journal of obstetrics and gynecology
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    ABSTRACT: C13ORF18 is frequently hypermethylated in cervical cancer but not in normal cervix and might serve as a biomarker for the early detection of cervical cancer in scrapings. As hypermethylation is often observed for silenced tumor suppressor genes (TSGs), hypermethylated biomarker genes might exhibit tumor suppressive activities upon re-expression. Epigenetic drugs are successfully exploited to reverse TSG silencing, but act genome-wide. Artificial Transcription Factors (ATFs) provide a gene-specific approach for re-expression of silenced genes. Here, we investigated the potential tumor suppressive role of C13ORF18 in cervical cancer by ATF-induced re-expression. Five zinc finger proteins were engineered to bind the C13ORF18 promoter and fused to a strong transcriptional activator. C13ORF18 expression could be induced in cervical cell lines: ranging from >40-fold in positive (C13ORF18-unmethylated) cells to >110-fold in negative (C13ORF18-methylated) cells. Re-activation of C13ORF18 resulted in significant cell growth inhibition and/or induction of apoptosis. Co-treatment of cell lines with ATFs and epigenetic drugs further enhanced the ATF-induced effects. Interestingly, re-activation of C13ORF18 led to partial demethylation of the C13ORF18 promoter and decreased repressive histone methylation. These data demonstrate the potency of ATFs to re-express and potentially demethylate hypermethylated silenced genes. Concluding, we show that C13ORF18 has a TSG function in cervical cancer and may serve as a therapeutic anti-cancer target. As the amount of epimutations in cancer exceeds the number of gene mutations, ATFs provide promising tools to validate hypermethylated marker genes as therapeutic targets.
    Full-text · Article · Mar 2013 · Molecular oncology

Publication Stats

6k Citations
791.68 Total Impact Points

Institutions

  • 1999-2015
    • University of Groningen
      • • Department of Obstetrics and Gynaecology
      • • Department of Gynecological Oncology
      • • Department of Gynecology
      • • Oncology Division
      Groningen, Groningen, Netherlands
  • 2002-2010
    • Universitair Medisch Centrum Groningen
      • • Department of Surgery
      • • Department of Internal Medicine
      Groningen, Province of Groningen, Netherlands
  • 2009
    • National Chung Cheng University
      Chia-i-hsien, Taiwan, Taiwan
    • Radboud University Medical Centre (Radboudumc)
      • Department of Human Genetics
      Nymegen, Gelderland, Netherlands
  • 2004
    • University of Texas MD Anderson Cancer Center
      Houston, Texas, United States