llumina 450k array was used to identify DNA methylation data from formalin-fixed paraffine-embedded (FFPE) human uveal melanoma correlated to gene expression, metastasis and poor prognosis

Uveal melanoma (UM) is an aggressive malignancy, in which nearly 50% of the patients die from metastatic disease. Formalin-fixed paraffin-embedded (FFPE) samples represent a valuable source of tumor tissue. Our aim was to investigate differential DNA methylation in relation to histopathological classification and survival data. In addition, we sought to identify aberrant DNA methylation of genes that could be linked to metastatic disease and poor survival. 23 formalin-fixed paraffin-embedded human uveal melanoma tumours divided into 3 subgroups based on metastasis and survival; (1) 2-4 years “Early metastasis” (n=8), (2) 9-21 years “Late metastasis” (n=7), and (3) Alive or death of other cause ≥18 years “No metastasis” (n=8). UM tumours were also divided into 3 groups based on tumour cell morphology; (1) Spindle (n=11), (2) Epitheloid (n=6), and (3) Mixed-both spindle and epitheloid (n=6). Methylation data of 23 FFPE human uveal melanoma samples were linked to histopathological classification, metastasis and survival data. Subset early metastasis (n=4) and Subset no metastasis (n=4) were used to investigate differential DNA methylation correlated to gene expression in relation to survival data of human uveal melanoma. We sought to identify aberrant DNA methylation of genes that could be linked to metastatic disease and poor survival.