Study of matrix metalloproteinases and their inhibitors in breast cancer

Abstract

An immunohistochemical study was performed using tissue microarrays and specific antibodies against matrix metalloproteinases (MMPs) 1, 2, 7, 9, 11, 13, 14, and their tisullar inhibitors (TIMPs) 1, 2, and 3. More than 2600 determinations on cancer specimens from 131 patients with primary ductal invasive tumours of the breast (65 with and 66 without distant metastasis) and controls were performed. Staining results were categorised using a score based on the intensity of the staining and a specific software program calculated the percentage of immunostained cells automatically. We observed a broad variation of the total immunostaining scores and the cell type expressing each protein. There were multiple and significant associations between the expression of the different MMPs and TIMPs evaluated and some parameters indicative of tumour aggressiveness, such as large tumour size, advanced tumour grade, high Nottinham prognostic index, negative oestrogen receptor status, peritumoural inflammation, desmoplastic reaction, and infiltrating tumoural edge. Likewise, the detection of elevated immunohistochemical scores for MMP-9, 11, TIMP-1, and TIMP-2, was significantly associated with a higher rate of distant metastases. The expression of MMP-9 or TIMP-2 by tumour cells, MMP-1, 7, 9, 11, 13, or TIMP-3 by fibroblastic cells, and MMP-7, 9, 11, 13, 14, TIMP-1, or TIMP-2 by mononuclear inflammatory cells, was also significantly associated with a higher rate of distant metastases.

Figure 1

Left: examples of TMAs with immunostaining for each protein. 200 × Right: (A) immunohistochemical staining of MMP2 in epithelial cells, (B) TIMP3 in epithelial cells and fibroblastic cells, (C) TIMP3 in inflammatory mononuclear cells, and (D) TIMP2 in epithelial cells, fibroblast and inflammatory mononuclear cells. 400 × .

Figure 2

Kaplan–Meier survival curves as function a of the immunostaining score values of MMP-9 (A), MMP-11 (B), TIMP-1 (C), and TIMP-2 (D); expression by tumoral cells of MMP-9 (E) and TIMP-2 (F); expression by fibroblast cells of MMP-1 (G), MMP-7 (H), MMP-9 (I), MMP-11 (J), MMP-13 (K), TIMP-2 (L), and TIMP-3 (M); expression by mononuclear inflammatory cells of MMP-7 (N), MMP-9 (O), MMP-11 (P), MMP-13 (Q), MMP-14 (R), TIMP-1 (S), and TIMP-2 (T).

Figure 3

Graphical representation of two-dimensional unsupervised hierarchical clustering results on immunohistochemistry expression profiles of 10 proteins in 131 breast cancer samples. Rows: samples; columns, proteins. Protein expression scores are depicted according to a colour scale: red, positive staining; green, neative staining; grey, missing data. Dendogram of samples (to the left of matrix) and proteins (above matrix) represent overall similarities in expression profiles. Status column: 1=with recurrence; 0, without recurrence, at the census point.