Aims Human epidermal growth factor receptor 2 (HER2) amplification in endometrial cancer (EC) is almost completely confined to the p53-abnormal (p53abn) molecular subtype and independent of... Show moreAims Human epidermal growth factor receptor 2 (HER2) amplification in endometrial cancer (EC) is almost completely confined to the p53-abnormal (p53abn) molecular subtype and independent of histological subtype. HER2 testing should therefore be molecular subtype-directed. However, the most optimal approach for HER2 testing in EC has not been fully established. Therefore, we developed an EC-specific HER2 immunohistochemistry (IHC) scoring method and evaluated its reproducibility and performance to establish an optimal diagnostic HER2 testing algorithm for p53abn EC. Methods and results HER2 IHC slides of 78 p53abn EC were scored by six gynaecopathologists according to predefined EC-specific IHC scoring criteria. Interobserver agreement was calculated using Fleiss' kappa and the first-order agreement coefficient (AC1). The consensus IHC score was compared with HER2 dual in-situ hybridisation (DISH) results. Sensitivity and specificity were calculated. A substantial interobserver agreement was found using three- or two-tiered scoring [kappa = 0.675, 95% confidence interval (CI) = 0.633-0.717; AC1 = 0.723, 95% CI = 0.643-0.804 and kappa = 0.771, 95% CI = 0.714-0.828; AC1 = 0.774, 95% CI = 0.684-0.865, respectively]. Sensitivity and specificity for the identification of HER2-positive EC was 100 and 97%, respectively, using a HER2 testing algorithm that recommends DISH in all cases with moderate membranous staining in >10% of the tumour (IHC+). Performing DISH on all IHC-2+ and -3+ cases yields a sensitivity and specificity of 100%. Conclusions Our EC-specific HER2 IHC scoring method is reproducible. A screening strategy based on IHC scoring on all cases with subsequent DISH testing on IHC-2+/-3+ cases has perfect test accuracy for identifying HER2-positive EC. Show less
In this thesis, we aim to shed light on the diverse and often opposing roles of integrin α3β1 in cancer. Our work highlights that the role of α3β1 in cancer depends on time and place: the nature of... Show moreIn this thesis, we aim to shed light on the diverse and often opposing roles of integrin α3β1 in cancer. Our work highlights that the role of α3β1 in cancer depends on time and place: the nature of the cell environment (such as extracellular matrix composition), type of cancer and its driving mechanism, as well as the stage of the disease. We provide a new insight into the mechanisms behind the role of α3β1 in HER2-driven breast cancer and in DMBA/TPA-induced non-melanoma skin tumorigenesis. Show less
Antibody drug conjugates (ADCs) are emerging as powerful anti-cancer treatments. They are designed to combine the tumor specificity, pharmacokinetics and biodistribution properties of antibodies... Show moreAntibody drug conjugates (ADCs) are emerging as powerful anti-cancer treatments. They are designed to combine the tumor specificity, pharmacokinetics and biodistribution properties of antibodies with the potent cell-killing activity of small molecules. The approval of brentuximab vedotin (Adcetris) for the treatment of Hodgkin lymphoma and trastuzumab emtansine (Kadcyla) for the treatment of metastatic breast cancer has spurred clinical development of ADCs. As the field of ADCs is rapidly emerging, a better understanding of the requirements needed for optimal intracellular delivery of ADCs seems mandatory. The aim of this thesis was to better understand the antibody and antigen requirements that are needed for effective ADC treatment. Different tumor antigens and targeting antibodies were compared for their capacity to deliver a cytotoxic payload to tumor cells, uncovering general mechanisms. In the course of this work, TF was identified as an excellent ADC target because of its rapid internalization and lysosomal targeting characteristics. Furthermore we have explored a novel Ab platform that improves the intracellular delivery of cytotoxic payloads. These findings provide a better insight in the Ab and antigen requirements needed for optimal payload delivery and support the development of novel and further improved ADCs for the treatment of cancer. Show less
Rouwendal, G.J.A.; Lee, M.M. van der; Meyer, S.; Reiding, K.R.; Schouten, J.; Roo, G. de; ... ; Ubink, R. 2016