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
Cancer immunotherapy has experienced remarkable advances in the last decades. Striking clinical responses have been achieved for several solid cancers, particularly cancer types with a high... Show moreCancer immunotherapy has experienced remarkable advances in the last decades. Striking clinical responses have been achieved for several solid cancers, particularly cancer types with a high mutation burden, which placed tumour-mutated antigens (neoantigens) centre stage as targets of tumour immunity and cancer immunotherapy. Neoantigens can be presented in complex with HLA molecules on the tumour cell surface, where T cells with the correct specificity can recognize the neoantigen as ‘non-self’ which will trigger killing of the tumour cell by the T cell. In theory, cancers with a low/moderate mutation burden that present neoantigens in complex with HLA class molecules could still be eligible for T cell-mediated immunotherapy. This thesis, describes the finding that neoantigen-specific T cells are present in mismatch-repair proficient (MMR-p) colorectal cancer patients, a low mutation burden cancer type. Moreover, CD39 and CD103 were found as cell surface markers that pinpoint the T cell population that contains the neoantigen-specific T cells. In addition, subsequent metastasis of a melanoma patient cohort were studied and revealed that also at advanced, late-stage disease, neoantigen-directed T cell therapy is, in theory, still applicable. Taken together, the studies reveal potential for the development of neoantigen-directed cancer immunotherapy for a broader patient population. 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
