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
Pathogenic variants in PALB2 and CHEK2 are associated with an increased risk of breast cancer. By contrast, for missense variants of uncertain significance (VUS) in these genes, the associated... Show morePathogenic variants in PALB2 and CHEK2 are associated with an increased risk of breast cancer. By contrast, for missense variants of uncertain significance (VUS) in these genes, the associated breast cancer risk is often unclear. To aid in their clinical classification, functional assays that determine the impact of missense VUS on PALB2 and CHK2 protein function have been performed in this thesis. By means of these functional analyses, numerous missense VUS (in both PALB2 and CHEK2) have been identified that are, from a functional viewpoint, just as damaging as known pathogenic (i.e., truncating) variants. In agreement, we observe that the level of impaired protein function correlates with the degree of increased breast cancer risk. Overall, these findings suggest that damaging PALB2 and CHEK2 missense VUS are associated with a risk of breast cancer similar to that of protein-truncating variants in these genes. This indicates the urgency of expanding the functional characterization of missense VUS in both PALB2 and CHEK2 to further understand the associated cancer risk. Show less
Breast cancer has a high mortality in women worldwide. Tumor cells experience hypoxia, which is accompanied by alterations in cell metabolism and can drive metastasis by triggering an epithelial... Show moreBreast cancer has a high mortality in women worldwide. Tumor cells experience hypoxia, which is accompanied by alterations in cell metabolism and can drive metastasis by triggering an epithelial–mesenchymal transition (EMT) in the tumor cells. Yes-associated protein (YAP) and a transcriptional co-activator with PDZ-binding (TAZ) are two transcriptional co-activators involved in growth, metabolism, and metastasis in cancer. Breast cancer can be divided into different subtypes. One criterium underlying such subtypes is based on the levels of Human Epidermal growth factor Receptor 2 (HER-2), Estrogen Receptor (ER) and Progesterone Receptor (PR). The subtypes include luminal-like (luminal A and luminal B), HER-2 enriched and basal-like (often “triple negative”). Triple negative breast cancer (TNBC) has a lower survival rate due to the lack of therapeutic targets. Fundamental research exploring the molecular mechanisms at work in cancer cells and their response to a hypoxic environment may contribute to insights for future clinical treatment. This thesis focused on profiling breast cancer cells belonging to distinct subtypes under acute and chronic hypoxia, investigating the crosstalk between hypoxia regulated pathways and YAP/TAZ signaling in luminal breast cancer versus TNBC cells, and identification of the potential targets of TAZ in breast cancer cells. 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
