Our results showed that reduced E-cadherin expression in BC was associated with poor overall survival (hazard ratio [HR] = 2.73, 95% CI: 1.74–4.27, p < 0.001), poor progression-free survival (HR = 6.39, 95% CI: 3.48–11.73, p < 0.001), and poor recurrence-free survival (HR = 2.48, 95% CI: 1.68–3.64, p < 0.001). The gene discussed is CDH1; the disease is breast cancer.