Project description:Primary uveal melanomas show multiple chromosomal aberrations. To identify genome variation in six human primary uveal melanomas, genome wide copy number variation (CNV) analyses were carried out in human primary uveal melanoma samples using array comparative genome hybridization.
Project description:Analysis of DNA from fixed tissues specimens of 58 primary uveal melanomas, with known clinical outcome, to determine gene copy number variations that were associated with survival. Abstract: Uveal melanomas can be stratified into subgroups with high or low risk of metastatic death, according to the presence of gross chromosomal abnormalities. Where a monosomy 3 uveal melanoma is detected, patient survival at three years is reduced to 50%. However, approximately 5% of patients with a disomy 3 tumour ultimately develop metastasis, and a further 5% of monosomy 3 uveal melanoma patients’ exhibit disease-free survival for more than five years. Despite extensive knowledge of the chromosomal abnormalities occurring in uveal melanoma, the genes driving metastasis are not well defined. Gene copy number variations occurring in a well-characterised cohort of 58 formalin-fixed, paraffin-embedded uveal melanoma samples were identified using the Affymetrix SNP 6.0 whole genome microarray. Four genetic sub-groups of primary uveal melanoma were represented in the patient cohort: 1) disomy 3 with long-term survival; 2) metastasizing disomy 3; 3) metastasizing monosomy 3; and 4) monosomy 3 with long-term survival. Cox regression and Kaplan-Meier survival analysis identified three genes that were associated with differences in patient survival. Patients with an amplification of CNKSR3 (6q) or RIPK1 (6p) demonstrated longer survival than those with gene deletions or no copy number change (log rank, p=0.022 and p<0.001, respectively). Conversely, those patients with an amplification of PENK (8q) showed reduced survival (log rank p<0.001). CNKSR3, RIPK1 and PENK are novel candidate metastasis regulatory genes in uveal melanoma. This is the first report of amplification of a specific gene on 6p that is associated with improved uveal melanoma patient survival and suggests that the development of uveal melanomas with a propensity to metastasise may be limited by genes on 6p. 58 samples in total. Ten disomy 3 with long-term survival. Fifteen disomy 3 with metastasising. Seventeen monosomy 3 with long-term survival. Sixteen monosomy 3 metastasising.
Project description:Uveal melanoma is an aggressive cancer that metastasizes to the liver in about half of patients, being at that time almost always fatal. Identification of patients at high risk of metastases may provide indication for a frequent follow-up for early detection of metastases and treatment. The analysis of the gene expression profiling of primary human uveal melanomas showed high expression of SDCBP (encoding for syndecan-binding protein-1 or syntenin-1), which appeared higher in patients with recurrence, whereas expression of syndecans was lower and unrelated to progression. Moreover, we found that high expression of SDCBP gene was related to metastatic progression in two additional independent dataset of uveal melanoma patients. More importantly, immunohistochemistry showed that high expression of syntenin-1 protein in primary tumours was significantly related to metastatic recurrence in our cohort of patients. Syntenin-1 expression was confirmed by RT-PCR, immunofluorescence and immunohistochemistry in cultured uveal melanoma cells or primary tumours. A pseudo-metastatic model of uveal melanoma to the liver was developed in NOD/SCID/IL2R null mice and the study of syntenin-1 expression in primary and metastatic lesions revealed higher syntenin-1 expression in metastases. The inhibition of SDCBP expression by siRNA impaired the ability of uveal melanoma cells to migrate in a woundâhealing assay. These results suggest that SDCBP is involved in uveal melanoma progression and that it represents a candidate molecular marker of metastases and a potential therapeutic target. Gene expression profiles of 29 unique samples from uveal melanoma patients were measured.
Project description:Uveal melanoma (UM) is a rare form of melanoma with a genetics and immunology that is different from skin melanoma. Previous studies have identified genetic driver events of early stage disease when the tumor is confined to the eye. In this study, we have characterized genomic events in UM metastases using whole-genome and RNA sequencing from thirty-two and twenty-eight patients, respectively, and profiled individual tumor infiltrating lymphocytes in a number of the metastases. We find that 91% of the patients have metastases carrying inactivating events in the tumor suppressor BAP1 and this coincided with somatic alterations in GNAQ, GNA11, CYSLTR2, PLCB4, SF3B1 and/or CDKN2A. Mutational signature analysis revealed a rare subset of tumors with prominent signs of UV damage, associated with outlier mutational burden. We study copy number variations (CNV) and find overrepresented events, some of which were not altered in matched primary eye tumors. A focused siRNA screen identified functionally significant genes of some of the segments recurrently gained. We reintroduced a functional copy of BAP1 into a patient-derived BAP1 deficient tumor cell line and found broad transcriptomic changes of genes associated with subtype distinction and prognosis in primary UM. Lastly, our analysis of the immune microenvironments of metastases revealed a presence of tumor-reactive T cells. However, a large fraction expressed the immune checkpoint receptors such as TIM-3, TIGIT and LAG3. These results provide an updated view of genomic events represented in metastatic UM and immune interactions in advanced lesions.