OR4P4 and breast cancer: A genome-wide association study of the cases and controls identified deletions overlapping three gene regions (DOCK5, 6.9-fold, P = 0.003; OR4C11, 2.6-fold, P = 0.02, and OR4P4, 2.4-fold, P = 0.03) that were associated with an increased risk of breast cancer after accounting for multiple testing (Additional file 4: Table S5).