Associated downstream targets of ERK1/2 included the chemokines CXCL1, CXCL3, CXCL5, and CXCL6 and interleukin receptor IL13RA2, which were all observed to be upregulated in DCIS fibroblasts relative to IDC fibroblasts. Here, CXCL1 is linked to ductal breast carcinoma in situ.