Strong expression of many matrix metalloproteinases (MMPs) has been related to poor survival of colorectal cancer (CRC) patients. The expression of tissue inhibitors of metalloproteinases (TIMPs) has been associated with both a beneficial and a poor outcome and there is thus a need to further clarify the significance of MMPs and TIMPs in CRC. The prognostic significance of 4 MMPs and TIMPs in CRC was evaluated. Formalinfixed, paraffin-embedded tissue arrayed samples of 351 patients with primary colon or rectal cancer of Dukes' stages A-D were selected for immunohistochemical staining of MMP-1, -2, -7 and -13, and TIMP-1, -2, -3 and -4. High expression of MMP-2 in the malignant epithelium as well as in the surrounding stroma was associated with reduced survival of colon cancer patients. Strong epithelial and stromal cytoplasmic staining of TIMP-3 was associated with a longer survival in rectal cancer patients, and here the interobserver variation for evaluating the degree of staining was lower than for epithelial staining. Strong stromal cytoplasmic staining of TIMP-4 predicted longer survival of rectal cancer patients. Multivariate analysis showed that stromal cytoplasmic TIMP-3 staining was the only marker of independent prognostic value. MMP-2 might be a useful prognostic marker in colon cancer, and TIMP-3 and TIMP-4 in rectal cancer, but the findings associated with stromal staining should be interpreted with some caution. Different biologic behavior or different genetic development may explain the differences between colon and rectal cancers regarding the expression of MMP-2, TIMP-3 and TIMP-4. ' 2007 Wiley-Liss, Inc.Key words: colorectal cancer; matrix metalloproteinases; tissue inhibitors of metalloproteinases; prognosis; survival Matrix metalloproteinases (MMPs) are a large family of zincdependent neutral endopeptidases that play an important role in the degradation of all matrix components crucial for malignant tumor growth, invasion and metastasis. 1,2 Metalloproteinases are inhibited by tissue inhibitors (TIMPs) which are secreted proteins. These bioactive substances are specific inhibitors of MMPs that bind to enzymatically active MMPs at a 1:1 molar stoichiometry thus inhibiting proteolysis. 3 The role of TIMPs for the homeostasis of the extracellular matrix is critical and may inhibit or stimulate tumorigenesis. 4 Many studies have shown that the expression of several MMPs is enhanced in a number of malignancies, including colorectal cancer (CRC), but the relation between the expression of MMPs and overall patient survival is not clear. 5,6 Enhanced expression of MMP-1, -7 and -13 has been reported to be associated with metastasis and poor survival of patients with CRC. 7-9 Tissue concentrations of MMP-1, MMP-2 and TIMP-1 are increased in CRC compared to healthy colorectal tissue. This has been related to the role of these endogenous substances in cancer progression. 2 Healthy tissue may contain high levels of TIMP-2 10 and the levels of TIMP-3 mRNA are regionally increased in moderately and poorl...

Extracellular matrix degradation is required for invasion and metastasis formation in colorectal carcinoma (CRC), therefore, we have examined matrix metalloproteinases MMP-9 expression in tumors from patients with CRC. The study comprises of 360 patients who underwent bowel resection for stage II, III, IV tumors. Paraffin-embedded CRC tissue samples were used for immunohistochemical staining. Negative MMP-9 expression levels correlated with longer survival time as evaluated by disease-free survival and disease-specific survival (p =.023, p =.006). In multivariate survival (Cox) analysis, MMP9 was a significant independent predictor of DFS (p =.014), but not of DSS, which was independently predicted by disease recurrence, stage and localization. The detection of MMP-9 expression may be valuable in finding patients who are at high risk of developing disease recurrence.

Colon cancer and rectal cancer seem to have different biologic behavior, at least with respect to apoptosis, cytoplasmic p53 expression, and perhaps Ki-67 and carcinoembryonic antigen. Further studies are needed to clarify the significance of these factors.