Lung cancer is the leading cause of cancer death in the Netherlands. For years chemotherapy was the only (palliative) treatment, with a short survival of only months. Since the introduction of... Show moreLung cancer is the leading cause of cancer death in the Netherlands. For years chemotherapy was the only (palliative) treatment, with a short survival of only months. Since the introduction of immunotherapy in 2015, this survival has increased significantly, with the first results showing a survival of even a few years. However, the response rate is relatively low, the treatment is expensive and the (low percentage of) side effects are severe. Therefore a biomarker is needed to predict which patients would benefit of immunotherapy.This thesis is about the search for a new biomarker. With the use of the RNA of platelets, proteins, tumor markers in blood and a an electronic nose for exhaled breath, we tried to find a non-invasive biomarker for the prediction of response on immunotherapy and for the (future) use in clinical practice, some of which are promising. Show less
Radiotherapy is intriguing as it not only eliminates tumor cells but also triggers a response from cytotoxic T cells, which attack the tumor. Thus, radiotherapy and immunotherapy are being combined... Show moreRadiotherapy is intriguing as it not only eliminates tumor cells but also triggers a response from cytotoxic T cells, which attack the tumor. Thus, radiotherapy and immunotherapy are being combined in clinical studies, although their success has been limited. We used mouse tumor models to understand how radiotherapy induces T cell priming and subsequent anti-tumor immunity. In a model resembling lymphocyte-depleted cancer, we identified obstacles to systemic radiotherapy-induced T cell responses and proposed interventions to overcome them. Additionally, we explored strategies to counter local T cell suppression in the tumor microenvironment. In poorly immunogenic tumors, radiotherapy can provoke a T cell response, but this is counteracted by the generation of immunosuppressive Tregs. Combining radiotherapy with checkpoint immunotherapy, despite its success in humans, unexpectedly amplified the Treg response, further hindering cytotoxic T-cell activity. Our findings suggest this immunotherapy may not benefit these cancers. We discovered that molecules like CD80 and CD86, capable of stimulating T cells via the CD28 receptor, have distinct roles in promoting cytotoxic and Treg cells. Blocking CD86 enhanced cytotoxic T cell responses post-radiotherapy, leading to tumor rejection. Our study elucidates how tumor characteristics shape T-cell responses, how radiotherapy can evoke both favorable and unfavorable responses, and how targeted antibody immunotherapy can influence this interplay. Show less
Mucosal melanomas (MM) are malignant tumours arising from melanocytes located at the mucosal lining of the head and neck region or the respiratory, gastrointestinal, anorectal, or genital tract.... Show moreMucosal melanomas (MM) are malignant tumours arising from melanocytes located at the mucosal lining of the head and neck region or the respiratory, gastrointestinal, anorectal, or genital tract. Due to the low incidence the disease is still poorly understood and management is mostly based on guidelines of cutaneous melanoma (CM). Survival of patients with MM is poor and regardless of stage is worse than that of CM. This is explained by the advanced stage at diagnosis and high recurrence rates of MM. Moreover, whilst immunotherapeutic agents have revolutionized the therapeutic landscape in CM, in MM, the efficacy is low and survival has not improved since the introduction of these therapies.The MM located at the vulva (VMM) account for 60% of the female genital tract MM and together with the head and neck region are the most common locations of MM. In line with the MM located at all other locations, prognosis is poor. Whilst the majority of the patients is diagnosed with local disease, the aggressive course of disease is demonstrated by the high recurrence rates with short time to recurrence with a median overall survival of 33 months. To improve outcomes in MM, there is a critical need for clinical trials specifically designed for this disease and international collaboration. Show less
This thesis focuses on the outcome to immunotherapy in locoregional and metastatic urothelial cancer and biomarkers in the tumor-immune microenvironment that may inform outcome, ultimately... Show moreThis thesis focuses on the outcome to immunotherapy in locoregional and metastatic urothelial cancer and biomarkers in the tumor-immune microenvironment that may inform outcome, ultimately enhancing cancer immunotherapy. Firstly, we discuss the outcome of urothelial cancer patients treated with checkpoint immunotherapy in the metastatic (Part I) and preoperative setting (Part II). Next, we focus on the UC tumor immune microenvironment (Part III), as this may facilitate the discovery and development of novel cancer immunotherapy as well as predictive biomarkers for immunotherapy response in UC. A comprehensive framework based on tumor- and host-specific parameters to better understand immunotherapy response in UC is also provided (Part III). Show less
The aim of this thesis was to investigate if a text-mining tool is suitable for collecting real-world data from electronic health records to evaluate cancer treatments in clinical practice. By... Show moreThe aim of this thesis was to investigate if a text-mining tool is suitable for collecting real-world data from electronic health records to evaluate cancer treatments in clinical practice. By investigating a range of use cases including treatments of patients with renal cell carcinoma, hepatocellular carcinoma, melanoma, breast cancer, and COVID-19, it showed that the text-mining tool is a suitable method of data needed for the evaluation of treatment patterns, effectiveness, safety, prognostic factors, and guideline adherence. The discussion showed that enhancing the data quality and actively using real-world data for treatment evaluation regarding treatment policies are some of the next steps. Show less
This thesis focuses on treatment outcomes of high risk endometrial cancer and corresponding patients’ and clinicians’ preferences regarding adjuvant treatment decisions; molecular studies on the... Show moreThis thesis focuses on treatment outcomes of high risk endometrial cancer and corresponding patients’ and clinicians’ preferences regarding adjuvant treatment decisions; molecular studies on the etiology of mismatch repair deficiency (MMRd) in intermediate and high risk endometrial cancer; and the combination of immunotherapy and PARP inhibition for the treatment of recurrent or metastatic endometrial cancer.The overall aims of this thesis were:• To evaluate health-related quality of life up to 5 years after chemoradiotherapy compared with pelvic radiotherapy alone in the adjuvant treatment of high risk endometrial cancer in the PORTEC-3 trial;• To investigate the preferences of patients and clinicians regarding the benefit-risk trade-off of the addition of chemotherapy to adjuvant pelvic radiotherapy;• To investigate the prevalence and prognosis of Lynch syndrome-associated endometrial cancer among MMRd endometrial cancers;• To evaluate the role of combined checkpoint inhibition and PARP inhibition in women with metastatic or recurrent endometrial cancer in terms of progression-free survival and toxicity in the DOMEC trial. Show less
This thesis aims to improve the treatment of patients with stage III melanoma. The first part describes different aspects of treatment with Talimogene Laherparepvec (T-VEC), a genetically modified... Show moreThis thesis aims to improve the treatment of patients with stage III melanoma. The first part describes different aspects of treatment with Talimogene Laherparepvec (T-VEC), a genetically modified herpes virus, which is used as oncolytic immunotherapy for skin and lymph node metastases in melanoma patients. We show that patients with a low tumor burden have the best outcomes, suggesting T-VEC should be used earlier on in the course of the disease. We present a prediction model, allowing a more accurate selection of patients for T-VEC monotherapy. Two studies focused on the use of T-VEC in clinical practice and the results allowed us to make recommendations on the use of PET/CT and dermoscopy during T-VEC treatment. Part two focuses on the value of surveillance and screening imaging in high-risk melanoma patients. We show that FDG-PET/CT is a valuable imaging tool to detect recurrence after complete resection of stage III disease, even shortly after surgery (before starting adjuvant therapy). Finally, we conclude that nodal staging with US as adjunct to SLNB is useful in the work- up of stage IIB/C melanoma, as it can lead to alterations in treatment and prevent unnecessary surgery. Show less
Monique Krystyna van der Kooij shows that a combination of treatments enhancing the immune system can conquer metastasized melanoma in heavily pre-treated patients. Immunotherapy is not a new... Show moreMonique Krystyna van der Kooij shows that a combination of treatments enhancing the immune system can conquer metastasized melanoma in heavily pre-treated patients. Immunotherapy is not a new concept. However, in Leiden a milder, and therefore better tolerated preconditioning regimen is used before the immune cells are administered. This milder preconditioning, in combination with the patient’s own immune cells and an immune checkpoint inhibitor is unique. This thesis shows that this combination is safe and preliminary data also show that some patients have (lasting) clinical responses. A second important finding described in this thesis is that treatment with immune checkpoint inhibitors can safely be prescribed to patients with common autoimmune diseases. Approximately 1 in 10 metastatic melanoma patients suffer from such an autoimmune disease. Until now clinicians were hesitant to prescribe these immune checkpoint inhibitors out of fear of unleashing the autoimmune disease. Showing that this is not the case made it possible for this large group of patients to gain access to this often-successful treatment. However, immune checkpoint inhibitor monotherapy is not indicated for all patients with metastatic melanoma. Patients with uveal melanoma do not benefit from this type of treatment, and do suffer from the adverse events. Show less
In this thesis, we start with a general introduction in Chapter 1 to briefly present the state of PDT, immune therapies, and nanotechnology in the field of cancer. PDT is a well-established... Show moreIn this thesis, we start with a general introduction in Chapter 1 to briefly present the state of PDT, immune therapies, and nanotechnology in the field of cancer. PDT is a well-established approach in superficial cancer treatment. The aim of my Ph.D. research work has been to improve therapeutic responses in solid tumors by novel combinatorial strategies based on PDT and the utilization of nanotechnology. Insights and concepts in these works are expected to help to design personalized therapeutic interventions in cancer progression. In Chapter 2, we focused on the combination of PDT with a stimulator of interferon genes (STING) agonist: ADU-S100. We investigated the anti-tumor efficiency and survival time after this combined treatment in colon tumor mice models. We found that ADU-S100 post-PDT treatment could enhance PDT-induced inflammation and immune responses, which lead to abscopal effects in a distal untreated tumor. The combination also protected cured mice from tumor recurrence through memory T cell anti-tumor immune responses with high probability. In Chapter 3, we found that PDT in combination with viral core particles could prime systematic immune responses and serum antibody intensity to against colon cancer process in MC38 tumor-bearing mice. In Chapter 4, we reviewed the current challenges facing the combination of PDT and multiple cancer treatment options based on current published literature. We highlighted the opportunities of nanoparticle-based PDT in cancer therapies. In Chapter 5, we investigated how hydrogel-supported near-infrared (NIR) -PDT with improved therapy potential in tumor-bearing mice by combining it with immune checkpoint inhibitors. In addition to the improved tumor growth inhibitory effects and prolonged survival time, immune mechanisms were also studied. We found that hydrogel-supported NIR-PDT by multi-stimulation could induce a higher level of lymphocytes in the circulating blood and increased lymphocytes infiltration into tumor site. A general discussion of overall data observed in this work, and clinical and research prospects related to this thesis are provided in Chapter 6. Show less
The immune system plays a dual role in cancer development. Besides the potential to eliminate cancer cells, immunoregulatory mechanisms exist that counteract anti-tumor immunity.Research in this... Show moreThe immune system plays a dual role in cancer development. Besides the potential to eliminate cancer cells, immunoregulatory mechanisms exist that counteract anti-tumor immunity.Research in this thesis focusses on the role of regulatory T cells (Tregs), a type of adaptive immune cell that plays a major role in tumor-associated immunosuppression. Specifically, the role of Tregs was investigated during the development of primary- and metastatic breast cancer, and in the context of novel immunotherapeutics. This was done by using advanced genetically engineered mouse models that recapitulate human breast cancer.The results in this thesis describe that breast tumors are, already early in their development, able to mobilise Tregs in the tumor-draining lymph nodes, thereby creating a local immunosuppressive niche leading to increased lymph node metastasis. In addition, it was found that the immunotherapeutic treatments anti-PD1 and anti-CTLA4 inadvertently activate Tregs, resulting in a diminished efficacy of this treatment in mice bearing breast tumors. Finally, we describe a mechanism by which intratumoral macrophages are critical promote the intratumoral accumulation of Tregs in breast tumors.Insights from this thesis may eventually contribute to the development of therapeutic applications that are aimed at overcoming immunoregulatory mechanisms in breast cancer. Show less
Gemcitabine was examined as switch maintenance therapy after standard first line chemotherapy in the NVALT19 trial, which provided the first conformation of gemcitabine activity in malignant... Show moreGemcitabine was examined as switch maintenance therapy after standard first line chemotherapy in the NVALT19 trial, which provided the first conformation of gemcitabine activity in malignant mesothelioma (MM). We describe additional analyses to confirm the prognostic value of CYFRA 21-1 and examine the prognostic value of CYFRA 21-1 in MM patients treated with gemcitabine. We also searched how gemcitabine could improve antitumor immune responses by positively modulating the immune system.In this thesis we describe a cohort of 107 malignant mesothelioma patients treated with nivolumab in the Netherlands. The real- world data of single agent PD-1 blocking were disappointing compared to previous reported single arm phase II trials. To examine clinical and peripheral blood biomarkers univariable and multivariable analyses were performed.As malignant peritoneal mesothelioma is even rarer then pleural mesothelioma, we hypothesized that centralization of care for peritoneal mesothelioma could benefit patients as they would likely receive treatment more often.Prognosis has a significant influence on the treatment preferences of patients, but prognosis of individual MM patients is variable and is hard to predict. We presented the MESOPRO score for patient with MM which are about the start with any systemic treatment. Show less
Antibodies, the cardinal effector molecules of the immune system, are being leveraged to enormous success as biotherapeutic drugs. Adaptive immune responses consist of epitope-diverse polyclonal... Show moreAntibodies, the cardinal effector molecules of the immune system, are being leveraged to enormous success as biotherapeutic drugs. Adaptive immune responses consist of epitope-diverse polyclonal antibody mixtures that are capable of neutralizing their targets via binding interference and by mediating humoral and cellular effector functions. A mechanistic theme fundamental to virtually all aspects of antibody biology, including antibody-antigen binding, clonal selection and effector functions, is the utilization of avidity to drive and tune functional responses. Manipulating antibody avidity has since emerged as an important design principle for enhancing or engineering novel properties in antibody biotherapeutics. In the context of ‘classical’ effector functions, complement-dependent cytotoxicity (CDC) can be improved by single point mutations in the IgG Fc domain that increase intermolecular Fc-Fc interactions upon binding to membrane-bound targets, thereby facilitating enhanced IgG hexamer formation and C1q binding. Such engineering approaches illustrate the relevance of promoting avidity interactions such as antibody clustering to enhance effector functions. The aim of this thesis was to explore the role of antibody avidity interactions, and more specifically the importance of ‘ordered clustering’, in antibody mechanisms of action and to apply the knowledge obtained in designing novel and improved antibody-based therapeutics Show less
The TME has increasingly been recognized as an important player in tumor progression and metastasis and a possible target for therapy. The TME consists of multiple cell types secreting growth... Show moreThe TME has increasingly been recognized as an important player in tumor progression and metastasis and a possible target for therapy. The TME consists of multiple cell types secreting growth factors and cytokines that exert either pro- or anti-tumor effects. This thesis mainly focuses on studies of the TME, especially the effects of Endoglin, on several cell types within the TME, including endothelial cells, fibroblasts, and immune cells.The TME has increasingly been recognized as an important player in tumor progression and metastasis and a possible target for therapy. The TME consists of multiple cell types secreting growth factors and cytokines that exert either pro- or anti-tumor effects. This thesis mainly focusses on studies of the TME, especially the effects of Endoglin, on several cell types within the TME, including endothelial cells, fibroblasts, and immune cells. This thesis aims to unravel the role of Endoglin as a possible target on various cell types within the TME of solid tumors. Endoglin is known for its role during angiogenesis, however, an increasing number of studies have shown the importance of Endoglin expression on several other cell types (e.g., immune cells, CAFs, tumor cells). Show less
Ocular melanoma is a rare disease that originates from melanocytes in the eye. It is the most prevalent primary ocular malignancy in adults, and has a high metastatic rate. Two important questions... Show moreOcular melanoma is a rare disease that originates from melanocytes in the eye. It is the most prevalent primary ocular malignancy in adults, and has a high metastatic rate. Two important questions for good patient care are: 1) How to differentiate between (benign) nevi, and (malignant) melanoma?, and 2) How to treat this tumor best, particularly in cases with metastases?This thesis addresses two types of ocular melanoma: melanoma of the internal parts of the eye (uveal melanoma) and melanoma of the mucous membrane covering the eye (conjunctival melanoma). This thesis combines patient-related projects with projects from the lab.With new imaging techniques we demonstrate that oxygen values differ in eyes with melanoma compared to other eyes including those with a nevus. We use OCT-angiography to depict tumour vessels non-invasively in conjunctival and iris lesions. These two techniques may be used in the future to differentiate lesions, and to monitor patients after treatment.With studies in the lab we show that new drugs (immunotherapy) that are recently used in cutaneous melanoma, can also be used to treat conjunctival melanoma. We show that vascular growth in uveal melanoma is related to other (genetic and immunologic) characteristics, providing new clues for therapy. Show less
Cancer vaccines are aimed at raising an immune responses aganist defined tumor antigens. The formulation of a vaccine has a direct impact on the potency of the immune response generated. Cancer... Show moreCancer vaccines are aimed at raising an immune responses aganist defined tumor antigens. The formulation of a vaccine has a direct impact on the potency of the immune response generated. Cancer vaccines require particular effort in their formulation, as the immune system has to overcome immune suppression exerted by the tumor. In this thesis, different formulations to enhance cancer vaccine efficacy were explored. In the first part it is shown how chemical conjugation of antigen and adjuvant in form synthetic Toll-like receptor ligands represent a strategy to enahnce vaccine potency. Next, it is presented how the loading of peptide antigens onto dextran nanogel contributes to increase the breadth of the immune response induced. Lastly, a new DNA vaccine containing multiple tumor neoantigens was explored as a platform for personalized cancer vaccines. Together, these studies display how the formulation of cancer vaccines can be modified and optimized to achieve stronger therapeutic efficacy in the clinic. Show less
Type 1 Diabetes (T1D) is an auto-immune disease in which beta cells in the pancreas are killed by auto-reactive T-cells. Auto-reactive T-cells are activated by dendritic cells that present antigens... Show moreType 1 Diabetes (T1D) is an auto-immune disease in which beta cells in the pancreas are killed by auto-reactive T-cells. Auto-reactive T-cells are activated by dendritic cells that present antigens. Immunotherapy could reverse T1D, however. A case report of a T1D patient showed that after intravenous immunoglobulin treatment her insulin needs dropped completely. Similarly, the majority of T1D patients were insulin independent after autologous hematopoietic stem cell transplantation. As these therapies only showed incidental success or are a drastic reset of the immune system, respectively, other milder therapies were studied as well. Autologous tolerogenic dendritic cell therapy, for instance, is a reproducible, stable therapy and does not differ between T1D patients and healthy subjects. In addition, the author described that when mesenchymal stromal cells were activated, they were able to suppress an antigen-specific immune response, thereby potentiating them as an antigen-specific therapy besides their natural immunosuppressive nature. Activated mesenchymal stromal cells could also improve the islet of Langerhans’ microenvironment, as they secreted immunosuppressive and angiogenic factors. To conclude, the future of T1D therapies lies in finding a balance between suppressing the immune system and antigen-specific therapies combined with therapies that increase the vitality of beta cells. Show less
In this thesis, the effects of a new form of immunotherapy was investigated and studied how it can be used against different types of cancers. The investigated immunotherapy is based on injecting... Show moreIn this thesis, the effects of a new form of immunotherapy was investigated and studied how it can be used against different types of cancers. The investigated immunotherapy is based on injecting nanoparticles loaded with various immunologically active molecules (immunomodulatory nanoparticles) that can modulate the immune system to attack cancer cells more efficiently. The effectiveness of this immunomodulatory nanoparticles have been studied on different mouse cancer models and investigated as a single treatment or in combination with other known therapies, such as chemotherapy, therapeutic cancer vaccination, or photodynamic therapy. Show less
The first part of this thesis provides insight in prognostic markers in VSCC to refine clinicopathological risk assessment. One of the most frequently described risk factors for recurrent disease... Show moreThe first part of this thesis provides insight in prognostic markers in VSCC to refine clinicopathological risk assessment. One of the most frequently described risk factors for recurrent disease is the minimal peripheral surgical margin. In order to improve the quality of future studies and clinical recommendations, we provided a practical guideline on how to uniformly measure this margin in chapter 2. We also determined the clinical relevance of the molecular classification of VSCC based on immunohistochemical staining for p16 and p53. In chapter 3 we described the immunohistochemical characterization of these molecular subtypes to aid their detection in routine clinical practice. We utilized this approach to show the difference in clinical outcome between the three distinct molecular subtypes of VSCC in chapter 4.The second part of this thesis contains studies on the tumor microenvironment as a first step towards immunotherapy for VSCC. An overview of the literature concerning immunity in VSCC at the start of our studies is provided in chapter 5. Subsequently, we interrogated the TME of different VSCC subtypes in chapter 6, and showed that high infiltration of CD4+ T cells is important for clinical outcome, irrespective of the molecular subtype of VSCC. In chapter 7 we performed an in-depth analysis on the TME based on RNA profiles and showed that highly T cell infiltrated VSCC are potentially eligible candidates for immunotherapy. In chapter 8 we exploited the expression of CD39 by CD4+ and CD8+ T cells as a marker to identify tumor specific T cells. Finally, in chapter 9 the general aspects and relevance of the studies mentioned in this thesis are combined, discussed, and placed in a broader perspective with suggestions for future research. Show less
Tumors are complex ecosystems containing not just cancer cells, but a large variety of cell types, including immune cells. Moreover, tumors have a systemic influence: they can signal long distances... Show moreTumors are complex ecosystems containing not just cancer cells, but a large variety of cell types, including immune cells. Moreover, tumors have a systemic influence: they can signal long distances using soluble molecules and hijack non-neoplastic cells (such as immune cells) in distant organs for their own benefit, thus maximising their metastatic potential. The phenotype of immune cells in tumors and in systemic environments is therefore a key determinant of cancer progression and response to therapy.This thesis aims to understand what governs the tumor-immune ecosystem. We argue that cancer-intrinsic genetic aberrations have a dominant role in determining the tumor immune contexture, as well as systemic inflammatory activation. Understanding the intricate connection between the genetics of breast cancer and anti-tumor immune responses will help develop personalised immune intervention strategies for cancer, tailored to the genetic makeup of a patient’s tumor. Furthermore, we examine in detail the role of neutrophils in cancer-induced systemic inflammation, and how they influence the progression and spread of breast cancer. While tumors can be highly heterogeneous in nature, we show that neutrophils themselves also have a tremendous phenotypic diversity. Mapping this heterogeneity in neutrophil phenotypes may help to utilise these cells in cancer immunotherapy. Show less