CXCL6 and ductal breast carcinoma in situ: 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.