Identification and characteristic analysis of enhancers across 13 major cancer types.

Enhancers are often mutated and dysregulated in various diseases such as cancer. By integrating the function annotation of the mammalian genome (FANTOM) enhancers expression profiles and RNA-seq data from The Cancer Genome Atlas (TCGA) of 13 cancers and their corresponding para-cancerous tissues, we systematically identified a total of 4702 significantly differentially expressed (DE) enhancers. Furthermore, a total of 1036 DE genes regulated by DE enhancers were identified. It was found that in these 13 cancers, most (61.13%) enhancers were ubiquitously expressed, whereas DE enhancers were more likely to be tissue-specific expressed, and the DE genes regulated by DE enhancers were significantly enriched in cancer-related pathways. Finally, it was manifested that 74 single nucleotide polymorphisms (SNPs) were located in 37 DE enhancers, and these SNPs affected the gain and loss of functional transcription factor binding sites of 758 transcription factors, which were shown to be highly correlated with tumorigenesis and development.