Detection of epigenetic alterations using tiling arrays.

The epigenetic status of cancer cells is a consequence of the neoplastic transformation of their normal counterpart. Epigenetic changes directly influence gene expression and chromatin organization, which consequently leads to escape from the tumor-suppression mechanisms. Global mapping for specific epigenetic modifications (e.g., DNA methylation) of the entire genome is required to reveal epigenetic hotspots associated with a cancer type/stage. DNA tiling arrays may be applied for genome-wide analysis of different epigenetic marks. Tiling arrays are high-density DNA microarrays that can be custom-made to survey regions of interest (e.g., gene promoters) or permit whole-genome analysis. To identify the genomic alterations associated with testicular cancers we used tiling arrays to profile their methylome. We successfully identified numerous epigenetically modified loci that arose as a consequence of tumor progression.