SPAG5 and breast cancer: SPAG5 upregulation in tumor tissues indicated poor disease-free survival (DFS, HR = 2.470, 95%CI 1.203–5.073, p = 0.016) and overall survival (OS, HR = 3.327, 95%CI 1.204–9.196, p = 0.029, Additional file 2: Fig. S1c) and it was also an independent prognostic factor for breast cancer patients (Additional file 4: Table S3).