ChIP data using c-Jun antibody exhibited that CM of 4T1 significantly enhanced binding of AP-1 on IL-6 promoter in RAW264.7 cells suggesting that breast cancer cell-derived CM can promote transcriptional activation of IL-6 in macrophages by inducing p38 mediated AP-1 binding on IL-6 promoter (Fig. 2E). Here, FOS is linked to breast carcinoma.