Uveal melanoma (UM) is the most common malignancy of the eye in adults and it is the second most common form of melanoma after cutaneous melanoma (CM). The identification of patients who have a... Show moreUveal melanoma (UM) is the most common malignancy of the eye in adults and it is the second most common form of melanoma after cutaneous melanoma (CM). The identification of patients who have a high risk of developing metastases would allow the possibility of providing adjuvant therapies to prevent metastases. The application of FISH on transvitreal fine-needle aspiration biopsies is thought to be a reliable method for assaying genetic parameters such as chromosome 3 loss. However, this is based on the assumption that this chromosomal abnormality is distributed homogeneously throughout the tumor. We show that UM can be heterogeneous for the number of copies of chromosome 3 and investigated whether any evidence can be found for heterogeneity in the regulation of tumor-suppressor genes (TSG). Recently, a segregation study identified a potential locus harboring a TSG. One of the genes in this area, RASEF, was analyzed whether the RASEF gene was affected by mutations or gene silencing due to promoter methylation. The MAPK pathway is involved in the balance between melanocyte proliferation and differentiation. Whereas mutant B-RAF and N-RAS are responsible for the activation of the MAPK pathway in most CM, mutations in these genes are usually absent in UM. Nowadays, an assay with increased potential to identify mutations is available and we set out to reanalyze UM cell lines and primary UM for B-RAF mutations. We set out to explore the MAPK pathway by using MAPK profiling and tyrosine kinase arrays. Finally, conclusions drawn from above mentioned studies are summarized and put into perspective. Show less
Sotos syndrome is a childhood overgrowth disorder which is characterised by an increased statural height and/or head circumference, characteristic facial dysmorphism and a variable level of... Show moreSotos syndrome is a childhood overgrowth disorder which is characterised by an increased statural height and/or head circumference, characteristic facial dysmorphism and a variable level of learning disability. The aim of this study was to perform a comprehensive study of Sotos syndrome and it__s molecular background. Therefore, the following three yet unresolved topics were addressed: 1. The molecular basis and mechanisms of the microdeletions in Sotos syndrome. 2. The causative molecular alterations in patients with features of Sotos syndrome but without NSD1 abnormalities. 3. The signaling pathways and downstream effectors of NSD1. Show less
