An epigenetic signature of advanced colorectal cancer metastasis.

Colorectal cancer (CRC) is a leading cause of morbidity and mortality worldwide. The majority of CRC deaths are caused by tumor metastasis, even following treatment. There is strong evidence for epigenetic changes, such as DNA methylation, accompanying CRC metastasis and poorer patient survival. Earlier detection and a better understanding of molecular drivers for CRC metastasis are of critical clinical importance. Here, we identify a signature of advanced CRC metastasis by performing whole genome-scale DNA methylation and full transcriptome analyses of paired primary cancers and liver metastases from CRC patients. We observed striking methylation differences between primary and metastatic pairs. A subset of loci showed coordinated methylation-expression changes, suggesting these are potentially epigenetic drivers that control the expression of critical genes in the metastatic cascade. The identification of CRC epigenomic markers of metastasis has the potential to enable better outcome prediction and lead to the discovery of new therapeutic targets.