In addition, MMP9 overexpression was correlated with unfavorable OS in patients with IDC (HR = 1.37, 95% CI 1.11–1.68, P = 0.003) and triple-negative breast cancer (TNBC) (HR = 1.88, 95% CI 1.39–2.55, P < 0.001). Here, MMP9 is linked to triple-negative breast carcinoma.