The putative CCND1 enhancer we identified in breast tumors (Fig. 6c) was shown to directly regulate the CCND1 gene in response to estradiol in breast cancer cells [56] and a putative MYC enhancer we identified in colon tumors (Additional file 14) was shown to be directly responsible for MYC expression in colon cancer cells [57], and in vivo in a mouse model of colorectal cancer [58]. Here, MYC is linked to breast cancer.