Functional analysis of the regulatory interconnection among the genes modulated in both steps of DCIS progression revealed that 50% of the genes (13 out of 26) were related to cell-to-cell signaling and interaction, and the resulting network included highly interconnected genes such as EDN1 and MAPK8. Both genes are associated with players in important cancer-related pathways, including p38 MAPK [30], PI3K [31], ERK1/2 [32], JNK [32] and TGF-beta [33]. Here, EDN1 is linked to ductal breast carcinoma in situ.