The results of MR analysis showed significant causal association between CXCL13 [OR (95%CI), 0.93 (0.88–0.99), p = 0.021] and breast cancer (ieu-a-1129), CCL2 [OR (95%CI), 1.04 (1.01–1.07), p = 0.021] and breast cancer (ieu-a-1130), and CCL1 [OR, (95%CI), 1.18 (1.02–1.38), p = 0.030], CCL18 [OR (95%CI), 0.95 (0.90–0.99), p = 0.031], CXCL5 [OR (95%CI), 0.95 (0.91–1.00), p = 0.030], CXCL12 [OR (95%CI), 0.87 (0.79–0.96), p = 0.004] and breast cancer (finn-b-C3_BREAST) (Figure 2). The gene discussed is CCL18; the disease is breast cancer.