The clinicopathological and prognostic significance of membrane type 1 matrix metalloproteinase (MT1-MMP) and MMP-9 according to their localization in invasive breast carcinoma

Aims: To investigate the clinicopathological and prognostic significance of membrane type 1 matrix metalloproteinase (MT1‐MMP) and MMP‐9 proteins expression in invasive breast carcinoma and their relationship to tumour proliferation and expression of c‐erbB2 and peroxisome proliferator‐activated receptor (PPAR) gamma. Methods: Immunohistochemistry was carried out on 175 paraffin‐embedded breast tissue specimens to detect MT1‐MMP, MMP‐9, oestrogen receptor (ER), progesterone receptor, c‐erbB‐2, Ki67, topoisomerase IIα (topo IIα) and PPARγ protein expression. Results: Both MT1‐MMP and MMP‐9 were expressed in the cytoplasm of the malignant cells and the peritumoral stroma. Cytoplasmic MT1‐MMP was more often observed in ER+ tumours (P = 0.022), of a lower nuclear grade (P = 0.020) and with reduced expression of Ki67 and topo IIα (P = 0.027 and P = 0.006, respectively). Moreover, cytoplasmic MT1‐MMP was positively associated with MMP‐9 (P = 0.010) and PPARγ (P