The actions of most factors that regulate gene expression, including transcription factors, long non-coding RNAs, and others, are modulated by the underlying packaging of each eukaryotic gene into chromatin. The relative "openness" of chromatin controls the access of each of these factors to DNA. Consequently, careful control of chromatin structure is necessary to establish and maintain cell type-specific gene expression patterns. The Fazzio lab studies how chromatin structure is controlled in stem cells, adult cells, and how chromatin structure is perturbed in cancer cells.