We compared CC chemokine expression across 20 types of cancers and normal tissues via the ONCOMINE database (Figure 1), which indicated that the mRNA expression of CCL2/3/4/5/7/8/11/17/19/20/22 was significantly up-regulated (Supplementary Figure S1), while CCL14/15/21/23/28 was significantly down-regulated in BC tissues compared with normal tissues (Supplementary Figure S2). Here, CCL2 is linked to cancer.