PTGER3 and ductal breast carcinoma in situ: Consistent with the previous study by our team (in which patients with DCIS were not excluded) [24], OS and DFS were superior in invasive BC patients with high expression of EP3 compared to patients with low EP3 expression (OS: p = 0.000019, HR = 0.407, 95% CI 0.266–0.623), Fig. 3d and DFS: p = 0.000086, HR = 0.426, 95% CI 0.274–0.660, Fig. 3e).