In dit proefschrift is gekeken naar de afweercellen die een rol spelen bij het ontstaan van alvleesklierkanker of als reactie teweeg worden gebracht door de tumor. daarnaast hebben we oude... Show moreIn dit proefschrift is gekeken naar de afweercellen die een rol spelen bij het ontstaan van alvleesklierkanker of als reactie teweeg worden gebracht door de tumor. daarnaast hebben we oude chemotherapeutica onderzocht op alvleesklierkanker cellen in vitro. Show less
To communicate with one another, cells in the body release signaling molecules called cytokines. The effects of these cytokines have been demonstrated to be extremely important for a successful... Show moreTo communicate with one another, cells in the body release signaling molecules called cytokines. The effects of these cytokines have been demonstrated to be extremely important for a successful immune response, but surprisingly little is known about how cytokines act in space and time. In this thesis, I describe the development of a set of new techniques that allow the efficient identification of cells that have encountered cytokine signals. Subsequently, I investigate the spreading of cytokines such as IFNγ and TNFα in in vivo cancer models and describe how activated cytotoxic T cells, which form a key compartment of our immune system, can profoundly modify the tumor microenvironment by the generation of widespread cytokine gradients. Show less
Mesothelioma is an aggressive tumor originating from the mesothelial cells of the pleural or peritoneal cavity. This thesis focuses on the treatment of pleural mesothelioma. For long, chemotherapy... Show moreMesothelioma is an aggressive tumor originating from the mesothelial cells of the pleural or peritoneal cavity. This thesis focuses on the treatment of pleural mesothelioma. For long, chemotherapy has been the standard of care, leading to an overall survival of about 15 months. In this thesis, a phase 2 trial is performed using two checkpoint inhibitors, nivolumab (anti-PD-1) plus ipilimumab (anti-CTLA-4), to treat recurrent mesothelioma after at least one line of chemotherapy. Of the 34 patients evaluable for response 29% had a partial response and 38% patients had stable disease, so 68% of patients achieved disease control, the primary endpoint. These results exceeded expectations and rejected the alternative hypothesis. In part III translational research was performed on blood samples, pleural biopsies and breath analyses at baseline and after 6 weeks of treatment. In order to find markers of response and try to explain how immunotherapy affects the tumor microenvironment and immune cell subsets of the peripheral blood. 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
There is a pending need for prognostic and predictive biomarkers in the treatment of patients with colorectal cancer.This thesis describes the prognostic and predictive application of the tumor... Show moreThere is a pending need for prognostic and predictive biomarkers in the treatment of patients with colorectal cancer.This thesis describes the prognostic and predictive application of the tumor-stroma ratio (TSR) in colorectal cancer, focusing on expanding current clinical-pathological standards and combining TSR with other diagnostic parameters. The TSR is a microscopy scoring method performed on hematoxylin-eosin stained tissue slides used for routine pathology assessment, and has proven to be a robust prognostic maker. Here, we investigate whether the TSR also exhibits predictive value with regard to adjuvant targeted therapy in stage II and III colon cancer. Moreover, exploring the value of collagen fiber organization in the intratumoral stroma, as well as combining this parameter with the TSR. Finally, expanding the application of the TSR with radiological diagnostics in rectal cancer. Assessing is there is a correlation between TSR and apparent diffusion coefficient values obtained from diagnostically performed MRI-DWI scans, in order to determine if there is potential with regards to neoadjuvant treatment choices or patient follow-up. 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
This thesis describes the detailed method of scoring the tumor-stroma ratio and the different possibilities to use it in routine clinical diagnostics, for different types of cancer. It can be used... Show moreThis thesis describes the detailed method of scoring the tumor-stroma ratio and the different possibilities to use it in routine clinical diagnostics, for different types of cancer. It can be used not only for prognostic purposes, but it might also be useful for predicting the response on neo-adjuvant therapy. As it is an easy and cheap method, based on routine hematoxylin-eosin stained tissue slides used for daily pathology routine, it can be implemented in clinical diagnostics with little effort. Show less
The generally poor prognosis of patients with epithelial ovarian cancer patients treated with curative intent, calls for additional treatment modalities and possible success might lie in a... Show moreThe generally poor prognosis of patients with epithelial ovarian cancer patients treated with curative intent, calls for additional treatment modalities and possible success might lie in a combination of chemotherapy and immunotherapy. This thesis focuses on the interaction of chemotherapy with the immune system and describes new combined chemo-immunotherapy treatment strategies. This thesis has explored new strategies, immune-modulation of the IL-6 pathway and a vaccine against p53, to enhance immune surveillance and to disable tumour immune evasion in ovarian cancer patients. The future challenge for immunotherapy against ovarian cancer is a tailored combinatorial approach to test the rationale of potentially synergistic therapies that can induce efficient antitumour immunity and prolong patients’ survival. Show less
In dit proefschrift worden studies besproken naar de rol van de TGF-β signaleringsroute in de tumor micro-omgeving in colorectaal kanker. Deze studies hebben zich voornamelijk gefocust op de rol... Show moreIn dit proefschrift worden studies besproken naar de rol van de TGF-β signaleringsroute in de tumor micro-omgeving in colorectaal kanker. Deze studies hebben zich voornamelijk gefocust op de rol van kanker-geassocieerde fibroblasten (CAFs) in kanker. Wij hebben aangetoond dat een co-receptor voor TGF-β, endoglin, een grote rol speelt in het CAF-gemedieerd uitzaaien van darmkanker en dat de expressie van endoglin op CAFs een prognostische marker is voor metastase-vrije overleving in vroeg stadium darmkankerpatienten. Daarnaast werd een nieuwe muizenstam ontwikkeld om specifiek op fibroblasten endoglin uit te schakelen, zodat de rol hiervan in het ontstaan van darmkanker bestudeerd kon worden in een chemisch geinduceerd model voor darmkanker. Samengevat laten de studies in dit proefschrift zien dat endoglin expressie op CAFs een belangrijke rol speelt in het metastaseren van colorectaalkanker en opent het deuren naar therapeutische toepassingen. Show less
Ewing sarcoma is an aggressive primary malignant bone tumor with high degree of tumor vascularization and is the second most common sarcoma of bone in children and young adults. Patients... Show more Ewing sarcoma is an aggressive primary malignant bone tumor with high degree of tumor vascularization and is the second most common sarcoma of bone in children and young adults. Patients with disseminated disease at diagnosis or early relapse have a poor prognosis. To identify novel therapies and biomarkers for these patients we focused on the chemokines and chemokine receptors in Ewing sarcoma cells and their role its tumor microenvironment. CCL21 CXCL14, CXCR7 and the ratio between CXCR4-1 and CXCR4-2 have been identified as candidate prognostic markers, CCL21 immunotherapy as potential therapy and CXCR4 as potential therapeutic target in EWS. In addition, the presented peptide-based life cell imaging methods improve the ability to study CXCR4 cell membrane expression and dynamics qualitatively and quantitatively. This approach might be helpful for the measurement of anti-CXCR4 therapy efficacy. This work identified specific the chemokine signaling pathways that can be used to target Ewing sarcoma and its tumor microenvironment. Show less
