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
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
Although clinical aspects of melanoma have been extensively studied, the literature largely concerns relatively healthy 20-70 years old patients. Special populations, such as the elderly, children,... Show moreAlthough clinical aspects of melanoma have been extensively studied, the literature largely concerns relatively healthy 20-70 years old patients. Special populations, such as the elderly, children, patients with multiple primary melanoma and those with familial melanoma, are frequently excluded from clinical studies. The studies presented in this thesis were aimed to assess prognostic factors and management of patients with clinically localized melanoma, in particular among the aforementioned special populations. Show less
A type I immune response is crucial for adequate tumor eradication by the immune system. However, tumors often gain evasion mechanisms that create barriers to the generation or effectiveness of a... Show moreA type I immune response is crucial for adequate tumor eradication by the immune system. However, tumors often gain evasion mechanisms that create barriers to the generation or effectiveness of a type I immune response. Among these barriers is the suppression of effective T cell priming and the inhibition of proper T cell infiltration and function in tumors. At present, the only therapies to target these barriers are focused on direct inhibition of T cell function by the tumor, through checkpoint molecules. These therapies are thus dependent on an existing type I response, and are generally not successful when tumors have insufficient T cells primed or infiltrated. This thesis has revealed ways to improve T cell priming and the infiltration of T cells in tumors. Show less
Melanoma is the most aggressive and lethal type of skin cancer since it has the ability to spread to other organs in the body making it harder to control the disease.In this thesis, we aim to... Show moreMelanoma is the most aggressive and lethal type of skin cancer since it has the ability to spread to other organs in the body making it harder to control the disease.In this thesis, we aim to explore the degree to which epigenetics play a role in melanoma, namely, inherited and acquired epigenetic alterations in melanoma susceptibility and development. Show less
In summary, this thesis focused on the understanding the underlying mechanisms driving TNBC metastatic progression. We established DUB activity profiling methods and identified UCHL1 as a candidate... Show moreIn summary, this thesis focused on the understanding the underlying mechanisms driving TNBC metastatic progression. We established DUB activity profiling methods and identified UCHL1 as a candidate oncoprotein that promotes TGFβ-induced breast cancer metastasis. Importantly, we found UCHL1 activity inhibitor as a potential drug for TNBC therapy and developed UCHL1 activity-based probe. For vemurafenib-resistance melanoma, we provided insights that targeting TGFβ signaling may help to overcome drug resistant phenotype. Show less
The aim of the research described in this thesis was to gain a better understanding of the role of the different immune cells and the different FcR on their cell surface, in antibody therapy and... Show moreThe aim of the research described in this thesis was to gain a better understanding of the role of the different immune cells and the different FcR on their cell surface, in antibody therapy and to investigate whether the effectiveness of the tumor-killing mechanisms, activated by the antibodies, can be improved. First, we investigated the role of FcR in various immune responses using a genetically modified mouse, in which all FcR were missing. After defining that role, we studied antibody therapy in a mouse model for melanoma in two different ways: on the one hand, after vaccination using a viral vector that expressed a melanoma antigen, on the other hand, by injecting a melanoma-specific antibody in combination with other substances that activate the immune system. Show less
The focus of this thesis is uveal melanoma (UM) which, once metastasized, is lethal due to lack of effective treatment options. To repress p53 activity approximately 65% of UM tumors express high... Show moreThe focus of this thesis is uveal melanoma (UM) which, once metastasized, is lethal due to lack of effective treatment options. To repress p53 activity approximately 65% of UM tumors express high levels of the p53 inhibitory proteins MDMX or MDM2. The aim of this thesis is to unravel the oncogenic function of MDMX and provide new treatment options for patients with metastasized UM. Chapter 2 describes the regulation of the transcriptome by MDMX in UM and proposes novel p53-independent effects of MDMX, i.e. FOXO inhibition. In chapter 3 the opportunities of a combined targeting of two common signaling pathways as therapeutic intervention for metastasized UM patients is investigated. Genetic interference with either MDMX or PKC δ expression or activity showed that beneficial effects can already be achieved by a more specific targeting, which is presumable less toxic to the patient. In chapter 4 it is described, opposed to what has been reported before, that enhancer of zeste homolog 2 (EZH2) inhibition poses a valuable novel therapeutic invention for UM. In chapter 5 it is shown that combining two clinically approved drugs, Quisinostat and Flavopiridol, could serve as an effective therapeutic intervention for UM patients. Show less
This thesis focused on different aspects of melanoma treatment with immunotherapy and targeted therapy. In chapter 2 we search for biomarkers that could be associated with overall survival in... Show moreThis thesis focused on different aspects of melanoma treatment with immunotherapy and targeted therapy. In chapter 2 we search for biomarkers that could be associated with overall survival in patients treated with ipilimumab. In chapter 3 we describe diarrea, a commonly seen side effect of immunotherapy. Here we show that there is no significant correlation between grade of diarrhea and severity of colitis as seen during endoscopy. Chapters 4 and 5 describe patients with brain metastases and/or leptomeningeal metastases. In chapter 4 we show the difference in overall survival in patients treated with vemurafenib, dabrafenib or the combination of dabrafenib + trametinib. Chapter 5 focusses on the treatment of leptomeningeal metastases. Here a significant difference in overall survival was noted between treated and untreated patients. Furthermore LDH was a predictive biomarker for overall survival. In chapter 6 we show that treating patients with vemurafenib beyond progression of disease has a significant impact on overall survival. Lastly in chapter 7 we review the past, present and future of treating patients with different kinds of cancer with tumor-infiltrating lymphocytes. Show less
