ERBB2 and breast cancer: High MMP1 mRNA expression was correlated to worse OS in HER2-negative BC patients (HR = 3.17; 95% CI: 1.06 - 9.48, p = 0.029), but not related with OS of HER2-positive patients (HR = 1.25; 95% CI: 0.62 - 2.5, p = 0.53).