Matrix Metalloproteinases In Cancer Research Articles

Bibliometric Analysis Reveals the Progress of PM2.5 in Health Research, Especially in Cancer Research.

PM2.5 has an aerodynamic diameter of less than or equal to 2.5 microns due to its inherent physical and chemical properties so that it can enter the alveoli through the respiratory tract for blood gas exchange. Numerous studies have shown that PM2.5 is a serious air pollutant that poses a wide range of health risks, especially for cancer. Bibliometric methods were employed to have comprehensively analyzed the research of PM2.5 in cancer for about a decade in Web of Science to identify hotspots and trends using VOSviewer, CiteSpace, and R. The field has undergone overall growth in the past decade. As research on PM2.5 in health deepens, cancer related to it expanded beyond the respiratory system to the digestive system, urinary system, female gonadal axis, breast cancer and other cancers. Another observation is that research on PM2.5 in cancer has progressed in the mechanisms of deterioration, such as the role of matrix metalloproteinases in cancer. In addition, research on the risks of PM2.5 in combination with polycyclic aromatic hydrocarbons and heavy metals has also emerged. Results showed that there are relatively more studies on PM2.5 in high-latitude countries, which may be due to different national conditions, such as climate and coal combustion. Our research has combed through the progress of PM2.5 in cancer research and provided a supplement for developing pollution prevention ideas with different national conditions in this field.

Insights Into the Role of Matrix Metalloproteinases in Cancer and its Various Therapeutic Aspects: A Review.

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that regulate the turnover of extracellular matrix (ECM) components. Gross and La Piere discovered MMPs in 1962 during an experiment on tissue samples from a tadpole’s tail. Several subtypes of MMPs have been identified, depending on their substrate specificity and localization. MMPs are involved as essential molecules in multiple and diverse physiological processes, such as reproduction, embryonic development, bone remodeling, tissue repair, and regulation of inflammatory processes. Its activity is controlled at various levels such as at transcription level, pro-peptide activation level and by the activity of a family of tissue inhibitors of metalloproteinase, endogenous inhibitors of MMPs. Cancer metastasis, which is the spread of a tumor to a distant site, is a complex process that is responsible for the majority of cancer-related death It is considered to be an indicator of cancer metastasis. During metastasis, the tumor cells have to invade the blood vessel and degrade the ECM to make a path to new loci in distant places. The degradation of blood vessels and ECM is mediated through the activity of MMPs. Hence, the MMP activity is critical to determining the metastatic potential of a cancer cell. Evasion of apoptosis is one of the hallmarks of cancer that are found to be correlated with the expression of MMPs. As a result, given the importance of MMPs in cancer, we describe the role of these multifunctional enzymes MMPs in various aspects of cancer formation and their rising possibilities as a novel therapeutic target in this review. There is also a brief discussion of various types of therapeutic components and drugs that function against MMPs.

Micro-RNAs as critical regulators of matrix metalloproteinases in cancer.

Metastasis is known to be one of the important factors associated with cancer-related deaths worldwide. Several cellular and molecular targets are involved in the metastasis process. Among these targets, matrix metalloproteinases (MMPs) play central roles in promoting cancer metastasis. MMPs could contribute toward tumor growth, angiogenesis, migration, and invasion via degradation of the extracellular matrix and activation of pre-pro-growth factors. Therefore, identification of various cellular and molecular pathways that affect MMPs could contribute toward a better understanding of the metastatic pathways involved in various tumors. Micro-RNAsare important targets that could affect MMPs. Multiple lines of evidence have indicated that deregulation of various micro-RNAs, including miR-9, Let-7, miR-10b, and miR-15b, affects metastasis of tumor cells via targeting MMPs.

P1. Surgery for locally recurrent rectal cancer

P1. Surgery for locally recurrent rectal cancer

Pathological and prognostic significance of matrix metalloproteinase-2 expression in ovarian cancer: a meta-analysis.

Matrix metalloproteinase-2 (MMP-2) has been linked with tumor invasion and metastasis. However, the role of MMP-2 expression in ovarian cancer remains controversial. By searching the PubMed, Embase, Wanfang, and China National Knowledge Infrastructure databases, we conducted a meta-analysis to evaluate the pathological and prognostic significance of MMP-2 in ovarian cancer. Studies were pooled, and the odds ratio (OR) and its corresponding 95% confidence interval (CI) were calculated. Version 11.0 STATA software was used for statistical analysis. Twenty-seven relevant articles were included for this meta-analysis study. The expression of MMP-2 in cancer tissue was significantly higher than that in benign or normal ovarian tissue [cancer vs. benign, OR 10.09 (95% CI 6.95-14.64); P<0.001; cancer vs. normal, OR 30.48 (95% CI 17.19-54.05); P<0.001; benign vs. normal, OR 1.88 (95% CI 1.08-3.29); P=0.025]. The expression of MMP-2 in stage III-IV or lymph node metastasis was significantly higher than that in stage I-II or that without metastasis, respectively [OR 5.83 (95% CI 4.32-7.85); P<0.001; OR 7.20 (95% CI 4.75-10.91); P<0.001]. MMP-2 was associated with histological types and grade of ovarian cancer [serous vs. mucinous, OR 1.67 (95% CI 1.17-2.39); P=0.004; grade 3 vs. 1, 2, OR 3.23 (95% CI 2.29-4.55); P<0.001]. However, the age of patients was not associated with MMP-2 expression [OR 1.25 (95% CI 0.61-2.58); P=0.546]. In conclusion, MMP-2 is related to the malignant degree, FIGO stage, histological types and grade, and lymph node metastasis of ovarian cancer. It may play a significant role in clinical guidelines for the treatment and prognostic evaluation.

Matrix metalloproteinases and gastrointestinal cancers: Impacts of dietary antioxidants.

The process of carcinogenesis is tightly regulated by antioxidant enzymes and matrix degrading enzymes, namely, matrix metalloproteinases (MMPs). Degradation of extracellular matrix (ECM) proteins like collagen, proteoglycan, laminin, elastin and fibronectin is considered to be the prerequisite for tumor invasion and metastasis. MMPs can degrade essentially all of the ECM components and, most MMPs also substantially contribute to angiogenesis, differentiation, proliferation and apoptosis. Hence, MMPs are important regulators of tumor growth both at the primary site and in distant metastases; thus the enzymes are considered as important targets for cancer therapy. The implications of MMPs in cancers are no longer mysterious; however, the mechanism of action is yet to be explained. Herein, our major interest is to clarify how MMPs are tied up with gastrointestinal cancers. Gastrointestinal cancer is a variety of cancer types, including the cancers of gastrointestinal tract and organs, i.e., esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum and anus. The activity of MMPs is regulated by its endogenous inhibitor tissue inhibitor of metalloproteinase (TIMP) which bind MMPs with a 1:1 stoichiometry. In addition, RECK (reversion including cysteine-rich protein with kazal motifs) is a membrane bound glycoprotein that inhibits MMP-2, -9 and -14. Moreover, α2-macroglobulin mediates the uptake of several MMPs thereby inhibit their activity. Cancerous conditions increase intrinsic reactive oxygen species (ROS) through mitochondrial dysfunction leading to altered protease/anti-protease balance. ROS, an index of oxidative stress is also involved in tumorigenesis by activation of different MAP kinase pathways including MMP induction. Oxidative stress is involved in cancer by changing the activity and expression of regulatory proteins especially MMPs. Epidemiological studies have shown that high intake of fruits that rich in antioxidants is associated with a lower cancer incidence. Evidence indicates that some antioxidants inhibit the growth of malignant cells by inducing apoptosis and inhibiting the activity of MMPs. This review is discussed in six subchapters, as follows.

Matrix metalloproteinases in cancer: their value as diagnostic and prognostic markers and therapeutic targets

Biomarkers are used as tools in cancer diagnostics and in treatment stratification. In most cancers, there are increased levels of one or several members of the matrix metalloproteinases (MMPs). This is a family of proteolytic enzymes that are involved in many phases of cancer progression, including angiogenesis, invasiveness, and metastasis. It has therefore been expected that MMPs could serve as both diagnostic and prognostic markers in cancer patients, but despite a huge number of studies, it has been difficult to establish MMPs as cancer biomarkers. In the present paper, we assess some of the challenges associated with MMP research as well as putative reasons for the conflicting data on the value of these enzymes as diagnostic and prognostic markers in cancer patients. We also review the prognostic value of a number of MMPs in patients with lung, colorectal, breast, and prostate cancers. The review also discusses MMPs as potential target molecules for therapeutic agents and new strategies for development of such drugs.

Insights into Ectodomain Shedding and Processing of Protein-tyrosine Pseudokinase 7 (PTK7)

The membrane PTK7 pseudokinase, a component of both the canonical and noncanonical/planar cell polarity Wnt pathways, modulates cell polarity and motility in biological processes as diverse as embryo development and cancer cell invasion. To determine the individual proteolytic events and biological significance of the ectodomain shedding in the PTK7 function, we used highly invasive fibrosarcoma HT1080 cells as a model system. Current evidence suggested a likely link between PTK7 shedding and cell invasion in our HT1080 cell model system. We also demonstrated that in HT1080 cells the cleavage of the PTK7 ectodomain by an ADAM proteinase was coupled with the membrane type-1 matrix metalloproteinase (MT1-MMP) cleavage of the PKP(621)↓LI site in the seventh Ig-like domain of PTK7. Proteolytic cleavages led to the generation of two soluble, N-terminal and two matching C-terminal, cell-associated fragments of PTK7. This proteolysis was a prerequisite for the intramembrane cleavage of the C-terminal fragments of PTK7 by γ-secretase. γ-Secretase cleavage was predominantly followed by the efficient decay of the resulting C-terminal PTK7 fragment via the proteasome. In contrast, in HT1080 cells, which overexpressed the C-terminal PTK7 fragment, the latter readily entered the nucleus. Our data imply that therapeutic inhibition of PTK7 shedding may be used to slow cancer progression.

Matrix Metalloproteinase-13 (MMP-13) Directly and Indirectly Promotes Tumor Angiogenesis

Matrix metalloproteinases (MMPs) are extracellular zinc-dependent endopeptidases involved in the degradation and remodeling of extracellular matrix in physiological and pathological processes. MMPs also have a role in cell proliferation, migration, differentiation, angiogenesis, and apoptosis. We previously identified cancer invasion-related factors by comparing the gene expression profiles between parent and the highly invasive clone of cancer cells. Matrix metalloproteinase-13 (MMP-13) was identified as a common up-regulated gene by cancer invasion-related factors. Although MMP-13 slightly promoted tumor invasion, we found that MMP-13 was involved in tumor angiogenesis. Conditioned medium from MMP-13-overexpressing cells promoted capillary formation of immortalized human umbilical vein endothelial cells. Furthermore, treatment with recombinant MMP-13 protein enhanced capillary tube formation both in vitro and in vivo. MMP-13-promoted capillary tube formation was mediated by activation of focal adhesion kinase and ERK. Interestingly, MMP-13 promoted the secretion of VEGF-A from fibroblasts and endothelial cells. By immunohistochemical analysis, we found a possible correlation between MMP-13 expression and the number of blood vessels in human cancer cases. In summary, these findings suggest that MMP-13 may directly and indirectly promote tumor angiogenesis.

Synthesis of PEG hydrogel with dityrosine for multi-functionality and pH-dependent fluorescence

A poly(ethylene glycol) (PEG)-based hydrogel was synthesized by the copolymerization of PEG diacrylate (PEGDA) and PEG methacrylate (PEGMA) linked with N,N′-di(tert-butoxycarbonyl)-dityrosine (DBDY). Owing to the presence of the dityrosine derivative DBDY, the resulting hydrogel exhibited pH-dependent fluorescence and contained multi-functional groups (1 carboxylic acid group and 2 amine groups protected by tert-butoxycarbonyl groups). A high molecular mass chemical can be bound to DBDY in the hydrogel through one of these functional groups (i.e. the formation of amide bonding). Then the porosity of the resulting hydrogel is increased by the action of an enzyme such as proteinase. Also, if a drug is bound directly to DBDY, the enzyme can control its detachment. Hence, the PEGMA–DBDY hydrogel could be useful for drug release near the site of the disease where the expression level of a certain enzyme is especially high (e.g. matrix metalloproteinases in cancers). Binding of a UV-absorbing compound to DBDY was monitored by measuring the change in fluorescence intensity, which is known as the phenomenon of fluorescence resonance energy transfer (FRET).

The CCL21/CCR7 pathway plays a key role in human colon cancer metastasis through regulation of matrix metalloproteinase-9

Purpose CC chemokine receptor 7 (CCR7) and matrix metalloproteinase-9 (MMP-9) have been associated with lymph node metastasis in human colon cancer. Studies have suggested a potential link between CCR7 and MMP-9 in cancer; however, the molecular mechanism by which C–C ligand 21/CCR7 promotes tumour dissemination in human colon cancer is not well understood. Thus, we aimed to determine whether MMP-9 is regulated by the C–C ligand 21/CCR7 in human colon cancer. Method RNA interference technology was employed to detect effect of CCR7 deficiency on the expression of MMP-9 in SW480 human colon cancer cells. We also evaluated the ability of CCR7 short hairpin RNA to inhibit MMP-9 production and tumour invasion in a xenografted mouse model by using whole-body fluorescence imaging and gelatin zymography. Result We found that CCR7 short hairpin RNA significantly inhibited C–C ligand 21/CCR7-induced up-regulation of MMP-9 in SW480 cells. Furthermore, knockdown of CCR7 significantly limited the production of MMP-9 and colon cancer metastasis in a xenografted mouse model. Mice that received SW480/control cells had progressively enlarging tumours and more lymphatic metastases, and these animals did not survive as long as mice that received SW480/CCR7 − cells. Conclusion MMP-9 and CCR7 may be useful targets for the treatment of lymphatic metastasis in colon cancer.

Inducible Nitric Oxide Synthase Deficiency Impairs Matrix Metalloproteinase-9 Activity and Disrupts Leukocyte Migration in Hepatic Ischemia/Reperfusion Injury

Matrix metalloproteinase 9 (MMP-9) is a critical mediator of leukocyte migration in hepatic ischemia/reperfusion (I/R) injury. To test the relevance of inducible nitric oxide synthase (iNOS) expression on the regulation of MMP-9 activity in liver I/R injury, our experiments included both iNOS-deficient mice and mice treated with ONO-1714, a specific iNOS inhibitor. The inability of iNOS-deficient mice to generate iNOS-derived nitric oxide (NO) profoundly inhibited MMP-9 activity and depressed leukocyte migration in livers after I/R injury. While macrophages expressed both iNOS and MMP-9 in damaged wild-type livers, neutrophils expressed MMP-9 and were virtually negative for iNOS; however, exposure of isolated murine neutrophils and macrophages to exogenous NO increased MMP-9 activity in both cell types, suggesting that NO may activate MMP-9 in leukocytes by either autocrine or paracrine mechanisms. Furthermore, macrophage NO production through the induction of iNOS was capable of promoting neutrophil transmigration across fibronectin in a MMP-9-dependent manner. iNOS expression in liver I/R injury was also linked to liver apoptosis, which was reduced in the absence of MMP-9. These results suggest that MMP-9 activity induced by iNOS-derived NO may also lead to detachment of hepatocytes from the extracellular matrix and cell death, in addition to regulating leukocyte migration across extracellular matrix barriers. These data provide evidence for a novel mechanism by which MMP-9 can mediate iNOS-induced liver I/R injury.

Novel MMP-9 Substrates in Cancer Cells Revealed by a Label-free Quantitative Proteomics Approach

Matrix metalloproteinase-9 (MMP-9) is implicated in tumor metastasis as well as a variety of inflammatory and pathological processes. Although many substrates for MMP-9, including components of the extracellular matrix, soluble mediators such as chemokines, and cell surface molecules have been identified, we undertook a more comprehensive proteomics-based approach to identify new substrates to further understand how MMP-9 might contribute to tumor metastasis. Previous proteomics approaches to identify protease substrates have depended upon differential labeling of each sample. Instead we used a label-free quantitative proteomics approach based on ultraperformance LC-ESI-high/low collision energy MS. Conditioned medium from a human metastatic prostate cancer cell line, PC-3ML, in which MMP-9 had been down-regulated by RNA interference was compared with that from the parental cells. From more than 200 proteins identified, 69 showed significant alteration in levels after depletion of the protease (>+/-2-fold), suggesting that they might be candidate substrates. Levels of six of these (amyloid-beta precursor protein, collagen VI, leukemia inhibitory factor, neuropilin-1, prostate cancer cell-derived growth factor (PCDGF), and protease nexin-1 (PN-1)) were tested in the conditioned media by immunoblotting. There was a strong correlation between results by ultraperformance LC-ESI-high/low collision energy MS and by immunoblotting giving credence to the label-free approach. Further information about MMP-9 cleavage was obtained by comparison of the peptide coverage of collagen VI in the presence and absence of MMP-9 showing increased sensitivity of the C- and N-terminal globular regions over the helical regions. Susceptibility of PN-1 and leukemia inhibitory factor to MMP-9 degradation was confirmed by in vitro incubation of the recombinant proteins with recombinant MMP-9. The MMP-9 cleavage sites in PN-1 were sequenced. This study provides a new label-free method for degradomics cell-based screening leading to the identification of a series of proteins whose levels are affected by MMP-9, some of which are clearly direct substrates for MMP-9 and become candidates for involvement in metastasis.

Imaging matrix metalloproteinases in cancer

Early detection of both primary tumors and metastatic disease remains a major challenge in the diagnosis and staging of cancer. The recognition of the role of MMPs in both the growth and metastasis of tumors has guided the development not only of therapeutic strategies utilizing synthetic, small-molecule MMP inhibitors (MMPIs), but has also catalyzed methods to detect and image tumors in vivo by means of tumor-associated proteolytic activity. These imaging approaches target MMPs involved in cancer progression via contrast agents linked to MMPIs or to MMP selective and specific substrates with sensitivity enhanced by amplification during enzymatic processing. This review draws attention to a variety of strategies utilized to image MMP activity in vivo.

Clinical significance of matrix metalloproteinase-2 in cancer of uterine cervix: A semiquantitative study of immunoreactivities using tissue array

Objectives. To study the expression of matrix metalloproteinase-2 (MMP-2) in cancer of uterine cervix and correlate its expression with clinicopathological parameters, recurrence and survival of patients. Methods. Twenty cervical cancer and 20 normal tissues from the same patients were collected to detect MMP-2 mRNA expression. From them, 16 cancer and 16 normal tissues were collected and added with another 64 cancer tissues to construct a 96-tissue core microarray for immunohistochemical study. We evaluated the relationships among MMP-2 immunoreactivity using semiquantitative H scores, obtained by multiplying proportion score of stained cells and their mean digital density, and clinicopathological variables, recurrence and survival in cervical cancer patients. We used univariate and multivariate analyses of all parameters for recurrence and survival, further including time interval for evaluation. Results. MMP-2 mRNA expression was higher in most of cervical cancerous tissues than normal counterparts. H score of MMP-2 was significantly higher in cancerous tissue cores than normal counterparts (median H scores: 1.5 vs. 0.3, P < 0.001). MMP-2 expression was significantly associated with parametrium invasion ( P = 0.004) and lymph node metastasis ( P = 0.015), but not with cancer recurrence, recurrence-free and overall survival rates of these patients. However, poor tumor cell differentiation and positive parametrium invasion significantly increased the recurrence and poor cell differentiation increased the risk of death. Conclusions. MMP-2 is highly expressed in cervical cancer tissues at mRNA and protein levels and associated with lymph node metastasis and parametrium invasion but not predictive of recurrence and survival in cervical cancer patients.

Characterisation of a novel matrix metalloproteinase inhibitor on pancreatic adenocarcinoma cells in vitro and in an orthotopic pancreatic cancer model in vivo

Matrix metalloproteinases (MMPs) play a central role in tissue maintenance, inflammation and during tumour invasion and metastasis. The impact of MMPs in cancer has encouraged the development of novel MMP-inhibitors without adverse effects on the cell viability. We describe here the synthesis and characterisation of a triazine-derivative as a highly potent MMP-inhibitor. The new compound Triazin 17-2 was developed on the basis of a triazine backbone as a well known and well tolerated chemical scaffold. It was de novo synthesized and tested for MMP inhibition in a cell free assay. In vitro characterisation included tests for cell viability, protein expression and MMP activity in PancTu-1 cells. Effectivity of MMP inhibition was analysed in vitro by invasion assay. Triazin 17-2 was investigated in vivo using an orthotopic pancreatic ductal adenocarcinoma (PDAC) xenograft model in SCID/bg mice. Triazin 17-2 proved to have no adverse effects on cell viability in vitro at concentrations effectively inhibiting MMPs in an invasion assay. Application of Triazin 17-2 in vivo in the orthotopic PDAC model in SCID/bg mice showed a significant reduction of primary tumour weight using conservative therapy and inhibition of metastasis in adjuvant therapy. The MMP-inhibitor Triazin 17-2 was developed and characterised in vitro and in vivo. The new compound has no intrinsic activity to kill cells but is very effective in inhibition of MMPs. In vivo testing revealed that MMP-inhibitors are useful tools in anticancer therapy reducing tumour size and invasion even without direct effects on cell survival.

Gelatinase concentrations and zymographic profiles in human breast cancer: Matrix metalloproteinases circulating in plasma are better markers for the subclassification and early prediction of cancer: The coagulation/fibrinolysis pathways alter the release, activation and recovery of different gelatinases in serum

Gelatinase concentrations and zymographic profiles in human breast cancer: Matrix metalloproteinases circulating in plasma are better markers for the subclassification and early prediction of cancer: The coagulation/fibrinolysis pathways alter the release, activation and recovery of different gelatinases in serum

Molecular Imaging of Matrix Metalloproteinases In Vivo Using Small Molecule Inhibitors for SPECT and PET

Matrix metalloproteinases (MMPs) are a family of zinc- and calcium-dependent secreted or membrane anchored endopeptidases. MMPs are involved in many physiological processes but also take part in the pathophysiological mechanisms responsible for a wide range of diseases. Pathological expression and activation of MMPs are associated with cancer, atherosclerosis, stroke, arthritis, periodontal disease, multiple sclerosis and liver fibrosis. Thus, noninvasive visualisation and quantification of MMP activity in vivo are of great interest in basic research and clinical application. This can be achieved by scintigraphic molecular imaging techniques such as single photon emission computed tomography (SPECT) and positron emission tomography (PET) provided suitable radiolabelled tracers exist, e.g. radioactive inhibitors of matrix metalloproteinases (MMPIs). The approach to monitor MMP activity in vivo using radiolabelled small molecule inhibitors suitable for SPECT and PET is summarised in this review. Briefly, latest advances in scintigraphic imaging are introduced and followed by a report about the enzyme class of MMPs. The involvement of MMPs in cancer and atherosclerosis is exemplified and small molecule MMPIs are classified. Subsequently, the development of radiolabelled small molecule MMPIs, their synthesis and in vitro and in vivo evaluation is reviewed. Finally, an outlook on the clinical potential of labelled MMPIs in diagnostic algorithms is given.

Epidermal Growth Factor Receptor Is a Critical Mediator of Ultraviolet B Irradiation-Induced Signal Transduction in Immortalized Human Keratinocyte HaCaT Cells

Epidermal growth factor receptor (EGFR) is a critical mediator of several types of epithelial cancers. Skin cancer arising from exposure to ultraviolet B irradiation (UVB) from the sun is a prominent form of human cancer. Recent data indicate that in addition to cognate ligands, EGFR is activated by UVB irradiation. We used pharmacological and genetic approaches to investigate the function of EGFR in mediating UVB-induced signal transduction in human skin keratinocyte HaCaT cells. Pharmacological inhibition of EGFR tyrosine kinase significantly inhibited UVB-mediated induction of ERK, p38, and JNK MAP kinases, and their effectors, transcription factors c-Fos and c-Jun. Inhibition of UVB activation of EGFR also suppressed activation of AKT-, PKC-, and PKA-dependent signal transduction pathways. B82 mouse L cells devoid of EGFR were used to further investigate EGFR dependence of UVB-induced signal transduction. UVB failed to induce ERK, and JNK activation was reduced 60% in B82 cells compared to B82K+ cells, which express EGFR. In addition, UVB induced both c-Fos and c-Jun proteins in B82K+ cells, whereas neither were induced in B82 cells. Taken together, these data demonstrate that EGFR is required for UVB-mediated induction of multiple signaling pathways that are known to mediate tumor formation in skin.

Cyclooxygenase-2 Expression Correlates With Membrane-Type-1 Matrix Metalloproteinase Expression in Colorectal Cancer Tissue

Elevated expression of cyclooxygenase-2 has been found in colorectal cancer. One of the mechanisms through which cyclooxygenase-2 affects tumorigenesis is through its overexpression, which leads to increased invasiveness of cancer cells. A crucial step in this pathway is thought to be the induction of membrane-type-1 matrix metalloproteinase, which activates matrix metalloproteinase-2. However, to date there have been few clinicopathologic studies concerning cyclooxygenase-2-mediated invasiveness in human colorectal cancer tissues. We performed immunohistochemical analysis of the respective antigens on colorectal cancer specimens obtained by surgical resections from 96 patients with colorectal cancer. Cyclooxygenase-2 and membrane-type-1 matrix metalloproteinase expression was positive exclusively in cancer cells in 88 cases (92 percent) and 23 cases (24 percent), respectively. All 23 cases expressing membrane-type-1 matrix metalloproteinase also expressed cyclooxygenase-2. Matrix metalloproteinase-2 expression was positive in cancer cells in 20 cases (21 percent) and stromal cells in 52 cases (54 percent). Expression of matrix metalloproteinase-2 in cancer cells correlated with lymphatic invasion and local recurrence. Statistically, a significant correlation was found between cyclooxygenase-2 and membrane-type-1 matrix metalloproteinase expression, and membrane-type-1 matrix metalloproteinase and matrix metalloproteinase-2 expression in cancer cells. There was no association between cyclooxygenase-2 expression and matrix metalloproteinase-2 expression. However, immunostaining of serial sections revealed that in the majority of cases examined, nearly 100 percent of cancer cells expressing matrix metalloproteinase-2 also coexpressed cyclooxygenase-2. This study indicates strong association between both cyclooxygenase-2 and membrane-type-1 matrix metalloproteinase expression, and membrane-type-1 matrix metalloproteinase and matrix metalloproteinase-2 in colorectal cancer. These results support our thesis of a direct correlation between cyclooxygenase-2 and membrane-type-1 matrix metalloproteinase expression--with consequent association between cyclooxygenase-2 and matrix metalloproteinase-2 activation, and tumor invasiveness andrecurrence in certain cases of colorectal cancer.