MMP1 and breast cancer: According to the well-established role of MMP-1 in BC promotion and outcome [21,35], the authors claim that the independent prognostic value of MMP-1 is mainly based on the positive correlations with tumor grade and p53 positivity in tumor and stromal cells; the peculiar expression of MMP-1 in stromal cells also showed a significant association of BC with HER-2 over-expression and triple negative BC.