Genetically raised MCP1 was associated with increased overall BC risk (OR: 1.08; 95% CIs: 1.03–1.12; P value: 3.55 × 10−4), and ER-positive BC cases (OR: 1.08; 95% CIs: 1.03–1.13; P value: 2.70 × 10−3). This evidence concerns the gene CCL2 and breast cancer.