A novel matrix metalloproteinase inhibitor,FYK-1388 suppresses tumor growth,metastasis and angiogenesis by human fibrosarcoma cell line

The matrix metalloproteinases (MMPs) are likely to contribute to tumor cell invasion, metastasis and angiogenesis. Several MMP inhibitors have been developed, recently and their anti-tumor efficacy is being evaluated in clinical trials. FYK-1388 is a novel broad MMP inhibitor which blocks the activity of MMP-1, -2, -3, -7, -9, -13 and -14 (MT-MMP-1). It is especially effective against MMP-2 and -9 more so than other MMP inhibitors such as Marimastat, Ro 32-3555 and D-2163. Here, we investigated the anti-tumor efficacy of FYK-1388 using the human fibrosarcoma cell line HT-1080. These cells produced MMP-2 and -9, which FYK-1388 inhibited at a dose of 10(-8) M. FYK-1388 at 0.2 mg/mouse/day significantly suppressed tumor growth when given by s.c. injection for 22 days, experimental lung metastasis after 5 days s.c. injection and also suppressed tumor-induced angiogenesis in the dorsal air sac assay after 7 days s.c. injection. In the MTT assay, FYK-1388 had no effect on the in vitro growth of HT-1080 cells. These results suggest that FYK-1388 possesses anti-tumor efficacy as a result of inhibiting angiogenesis through the suppression of MMP-2 and -9 activity.     

Phase III study of matrix metalloproteinase inhibitor prinomastat in non-small-cell lung cancer.

PURPOSE: Matrix metalloproteinases (MMPs) degrade extracellular proteins and facilitate tumor growth, invasion, metastasis, and angiogenesis. This trial was undertaken to determine the effect of prinomastat, an inhibitor of selected MMPs, on the survival of patients with advanced non-small-cell lung cancer (NSCLC), when given in combination with gemcitabine-cisplatin chemotherapy. PATIENTS AND METHODS: Chemotherapy-naive patients were randomly assigned to receive prinomastat 15 mg or placebo twice daily orally continuously, in combination with gemcitabine 1,250 mg/m2 days 1 and 8 plus cisplatin 75 mg/m2 day 1, every 21 days for up to six cycles. The planned sample size was 420 patients. RESULTS: Study results at an interim analysis and lack of efficacy in another phase III trial prompted early closure of this study. There were 362 patients randomized (181 on prinomastat and 181 on placebo). One hundred thirty-four patients had stage IIIB disease with T4 primary tumor, 193 had stage IV disease, and 34 had recurrent disease (one enrolled patient was ineligible with stage IIIA disease). Overall response rates for the two treatment arms were similar (27% for prinomastat v 26% for placebo; P = .81). There was no difference in overall survival or time to progression; for prinomastat versus placebo patients, the median overall survival times were 11.5 versus 10.8 months (P = .82), 1-year survival rates were 43% v 38% (P = .45), and progression-free survival times were 6.1 v 5.5 months (P = .11), respectively. The toxicities of prinomastat were arthralgia, stiffness, and joint swelling. Treatment interruption was required in 38% of prinomastat patients and 12% of placebo patients. CONCLUSION: Prinomastat does not improve the outcome of chemotherapy in advanced NSCLC.     

金属蛋白酶类组织抑制剂及其基因多态性与肿瘤

金属蛋白酶类组织抑制剂（TIMP）是基质金属蛋白酶（MMP）的天然抑制物。目前的研究表明,它可以通过调节MMP活性或不依赖MMP的方式,来影响肿瘤的生长、侵袭、转移等过程;而且TIMP基因多态性可以调节肿瘤的遗传易感性。因此,对于TIMP在肿瘤发生发展中所发挥作用的深入研究,可以为肿瘤的预防及治疗提供帮助。     

Low plasma levels of matrix metalloproteinase 9 permit increased tumor angiogenesis.

Angiogenesis is essential for tumor growth and blocking this process might be a valid tool for the control of cancer growth. We showed previously that tumor angiogenesis in integrin alpha1-null mice is reduced compared to that of wild type animals and that over-expression of matrix metalloproteinase 9 (MMP-9) in the alpha1-null and consequent generation of angiostatin (an inhibitor of endothelial cell growth) from circulating plasminogen was implicated in the mechanism of tumor inhibition. Our findings suggested that secretion of excess MMPs generates inhibitors of endothelial cell proliferation, including but not necessarily limited to angiostatin, resulting ultimately in auto-inhibition of angiogenesis. Thus MMP inhibitors used as anti-tumor drugs might in fact cause a paradoxical increase in tumor angiogenesis and tumor growth. In order to determine whether MMP-9 expression was directly involved in the regulation of tumor growth, we specifically inhibited or enhanced MMP-9 synthesis in vitro and in vivo, and subsequently analysed primary endothelial cell proliferation and angiostatin synthesis, as well as tumor vascularization and development. We provide evidence that reduction of plasma levels of MMP-9 in either normal or integrin alpha1-null mice leads to decreased synthesis of angiostatin and consequent increased tumor growth and vascularization. In contrast, specifically enhancing MMP-9 expression in vivo caused a reduction in tumor vascularization. These findings are the opposite to other studies suggesting a pro-tumorigenic role for MMP-9, and may account for some of the recently observed failures of anti MMP therapy in tumor treatment.     

基质金属蛋白酶与肿瘤血管形成关系的研究进展

基质金属蛋白酶(MMP)家族的主要作用是降解细胞外基质,促进肿瘤侵袭和转移.近来研究发现MMP除了降解基质外,还与肿瘤血管形成有密切关系,现对此研究现状作一综述.     

肺癌组织中MMP-9及TIMP-1的表达与转移、预后相关性研究

目的 探讨MMP—9及其抑制剂TIMP—1在人肺癌中的表达及其与肺癌转移、预后的相关性，分析肺癌发生、发展、侵袭和转移的机制。方法 应用免疫组化S—P法检测65例肺癌、35例其他肺部疾患病变支气管粘膜增生及不典型增生上皮和30例正常支气管粘膜上皮组织中MMP—9和TIMP—1的蛋白表达。结果 肺癌与正常、增生上皮相比，增生与正常上皮相比，MMP—9和TIMP—1阳性表达率的升高均具有显著性(P＜0．05)。不同组织学类型中MMP—9的阳性表达有显著性差异(P＜0．025)；MMP—9的阳性表达与肺癌细胞分化程度负相关(P＜0．05)，与TNM分期正相关(P＜0．025)。生存期小于2年者的MMP—9和TIMP—1阳性表达率显著高于生存期大于或等于2年者(P＜0．05)。MMP—9阳性表达上调与肺癌转移相关(P＜0．005)，TIMP—1与转移无关。结论 MMP—9阳性表达上调可出现在癌前病变及肺癌发病的早期阶段，MMP—9基因激活可能是肺癌癌变的重要因素；MMP—9、TIMP—1在肺肿瘤浸润转移中发挥重要作用，其过度表达可作为评估肺癌浸润转移和预后不良的参考指标。     

基质金属蛋白酶在肺癌转移中作用的研究

目的:观察基质金属蛋白酶MMP2和MMP9在肺癌组织中的表达,探讨其与肺癌浸润及转移的关系。方法:采用免疫组织化学及逆转录聚合酶链反应(RTPCR)的方法分别检测30例非癌肺组织及有随访资料的87例肺癌组织中MMP2和MMP9及其mRNA的表达。结果:MMP2和MMP9在肺癌与非癌肺组织均存在阳性表达,但在肺癌组织表达率高于非癌肺组织(P<0.05),小细胞肺癌、鳞癌、腺癌和非癌肺组织MMP2阳性率分别为85.7%、44.7%、47.6%和23.3%;MMP9阳性率分别为78.6%、47.4%、38.1%和20.0%,其中小细胞肺癌组织中表达率最高(P<0.05)。MMP2和MMP9mRNA在低分化程度肺癌组织中表达较高,Ⅰ级最高,Ⅱ级次之,Ⅲ级最低;在不同肿瘤类型之间MMP2和MMP9mRNA表达有显著差异,小细胞肺癌的MMP2及MMP9mRNA表达量明显高于腺癌和鳞癌;肺癌伴淋巴结转移患者癌组织MMP2及MMP9mRNA表达量明显高于未转移者。结论:MMP2和MMP9的表达与肺癌的病理类型、分化程度及是否有淋巴结转移等因素有关,MMP2和MMP9可能在肺癌侵袭转移中起重要作用。     

A third-generation matrix metalloproteinase (MMP) inhibitor (ONO-4817) combined with docetaxel suppresses progression of lung micrometastasis of MMP-expressing tumor cells in nude mice

The lung is the common target organ of hematogenous metastasis that restricts the prognosis of cancer patients. MMPs play a pivotal role in metastasis by promoting tumor invasion and angiogenesis; therefore, a large number of MMPIs have been developed. Our purpose was to determine the therapeutic efficacy of a selective-spectrum MMPI, ONO-4817 (inhibits MMP-2 and MMP-9 but not MMP-1), against established lung micrometastasis in combination with a cytotoxic anticancer drug, DOC, in a nude mouse model. Human non-small cell lung cancer PC14PE6 (adenocarcinoma) or H226 (squamous cell carcinoma) cells, expressing MMP-2, MMP-9 and/or MMP-1, were injected i.v. into nude mice on day 0. Mice received a single injection of DOC on day 7 (after establishment of micrometastasis) and/or ONO-4817 mixed with food from day 7 to the end of experiments. Monotherapy with ONO-4817 or DOC inhibited formation of lung metastasis by PC14PE6 and H226 cells. In addition, combined use of ONO-4817 with DOC significantly suppressed the tumor burden of H226 and PC14PE6 cells in the lung and prolonged the survival of PC14PE6-bearing mice compared to ONO-4817 or DOC alone. These therapies did not affect the body weight or food intake of tumor-bearing mice. FIZ revealed that lung lesions, but not nontumor parenchyma of the lung, expressed gelatinolytic activity and that treatment with ONO-4817 abrogated the gelatinolytic activity in lung lesions. These results suggest that the combined use of MMPIs with cytotoxic anticancer drugs may be helpful in the control of established lung micrometastasis by tumor cells expressing MMPs.     

Decorin suppresses tumor cell-mediated angiogenesis

The progressive growth of most neoplasms is dependent upon the establishment of new blood vessels, a process regulated by tumor-secreted factors and matrix proteins. We examined the in vitro and in vivo angiogenic ability of conditioned media obtained from fibrosarcoma, carcinoma, and osteosarcoma cells and their decorin-transfected counterparts. Human endothelial cells were investigated in vitro by evaluating three essential steps of angiogenesis: migration, attachment, and differentiation. On the whole, wild-type tumor cell-secretions enhanced endothelial cell attachment, migration, and differentiation, whereas their decorin-expressing forms inhibited these processes. Similarly, decorin-containing media suppressed endothelial cell sprouting in an ex vivo aortic ring assay. Since angiogenesis is an important component of tumor expansion, the growth rate of these cells as tumor xenografts was examined by implantation in nude mice. In vivo, the decorin-expressing tumor xenografts grew at markedly lower rates and showed a significant suppression of neovascularization. Immunohistochemical, Northern and Western blot analyses indicated that the decorin-expressing cells produced vascular endothelial growth factor (VEGF) at markedly reduced rates vis-á-vis their wild-type counterparts. Specificity of this process was confirmed by experiments where addition of recombinant decorin to the wild-type tumor cells caused 80-95% suppression of VEGF mRNA and protein. These results provide a novel mechanism of action for decorin, and indicate that decorin could adversely affect in vivo tumor growth by suppressing the endogenous tumor cell production of a powerful angiogenic stimulus.     

Correlation between cyclooxygenase-2 and tumor angiogenesis in non-small cell lung cancer

The role of COX-2 expression and angiogenesis of lung cancer is yet to be delineated. Eighty four non-small cell lung cancer (NSCLC) specimens were evaluated for COX-2 expression, microvessel density (MVD), and vascular endothelial growth factor (VEGF) expression by immunohistochemical methods. The relationships between COX-2 expression and MVD, VEGF expression, and survival time were analyzed. COX-2 expression was observed in the cytoplasm and membrane of the carcinoma cells, and premalignant cells. COX-2 was positive in 67 cases (79.8%). There was a statistically significant correlation between COX-2 expression and tumor size, TNM stage, tumor type, VEGF expression, and vascular pattern with survival in univariate analysis. No significant correlation was seen between COX-2, VEGF expression and MVD. A lack of expression of either COX-2 or VEGF expression or both, however, was associated with lower MVD than the group with both expressed. The difference was statistically significant (P=0.005). Statistically significant differences were also observed according to TNM stage, vascular pattern, COX-2 expression, and VEGF expression. With multivariate analysis, only TNM stage and COX-2 expression retained their significance as independent predictors of survival. COX-2 expression takes part in tumor angiogenesis and is a significant poor prognostic factor in the surgically resected NSCLC. COX-2 inhibitor, either in combination therapy with other agents, or for chemoprevention, may be effective via suppression of angiogenesis in this fatal disease.     

Controlling tumor angiogenesis and metastasis of C26 murine colon adenocarcinoma by a new matrix metalloproteinase inhibitor, KB-R7785, in two tumor models

Experimental evidence has directly implicated matrix metalloproteinases (MMPs) in the remodeling of the stromal tissue surrounding tumors. Thus, MMP inhibitors could limit the expansion of both neoplastic cell compartment and endothelial cell compartment of a tumor. Much of the work on the role of MMP inhibitors has concentrated on their inhibitory effects on tumor cell invasion. We have examined the effects of a new MMP inhibitor, KB-R7785 (acting on MMP-1, MMP-3, and MMP-9), on tumor angiogenesis and metastasis of murine colon adenocarcinoma (C-26) in two tumor models in BALB/c mice (transparent chamber model and lung colonization model). KB-R7785 has not shown inhibitory effects on in vitro growth of either C-26 or KOP2.16 murine endothelial cells. In vivo, KB-R7785 administrated twice daily for 15 days (100 mg/kg, i.p.), starting the day of tumor inoculation (5 x 10(5) C26 cells) in transparent chamber, has resulted in 88.2% suppression of tumor growth, compared with that in vehicle-administered mice (controls). Tumors grown in controls have doubled their area in 3.3 days, whereas those treated by KB-R7785 progressed almost four times slower (tumor area doubling time, 12 days). KB-R7785 rendered centrally avascular tumors with only a rim of peripheral neovasculature, which had significant lower functional vascular density and vascular area than the corresponding parameters in control tumors 10 days after inoculation [79.9+/-6.7 cm/cm2 versus 164.1+/-10.1 cm/cm2 (P < 0.01) and 19.8+/-1.5% versus 42.6+/-2.7% (P < 0.01), respectively]. In the lung colonization model (tail vein inoculation of 5 x 10(5) C-26 cells), administration of KB-R7785 (100 mg/kg, i.p.) twice daily for 20 days has reduced the number of surface metastasis by 85.8% and abolished the tumor burden, as compared with controls. The few metastatic colonies found in the lungs of KB-R7785 treated mice appeared to be dormant (i.e., staining with von Willebrand factor antibody revealed few, if any, positive cells within the metastatic foci from MMP inhibitor-treated lungs, whereas terminal deoxynucleotidyl transferase-mediated nick end labeling showed a 4-fold increase in the rate of tumor cell apoptosis compared with controls. The fact that KB-R7785 interferes with early steps of angiogenesis and cancer spread suggests that MMP inhibitors may control both primary and secondary tumor growths by limiting the expansion of endothelial cells, as well as cancer cells, composing the tumors.     

Interleukin-18 suppresses angiogenesis and lymphangiogenesis in implanted Lewis lung cancer

Objective  

To investigate the effects of interleukin-18 (IL-18) on implanted Lewis lung cancer in suppressing angiogenesis and lymphangiogenesis.     

Overexpression of matrix metalloproteinase 2 predicts unfavorable outcome in early-stage non-small cell lung cancer.

This prospective study was performed to assess the impact of matrix metalloproteinase (MMP) 2 expression on the clinical course of patients with operable non-small cell lung cancer (NSCLC). Specimens of 193 consecutive patients with completely resected NSCLC were examined for MMP-2 expression by immunohistochemical staining with a polyclonal antibody. Homogeneous immunostaining of cancer cells was considered positive and heterogeneous, or no staining was considered negative concerning overexpression of MMP-2. Four specimens were excluded from further analyses because of unspecific staining. The median follow-up period was 71.5 months (range, 12-120 months). Overexpression of MMP-2 was observed in 64 (33.9%) of 189 patients and did not correlate with clinicopathoiogical parameters. In patients without lymph node involvement (pN0 stage) MMP-2 overexpression was an independent prognostic parameter for unfavorable outcome: Log-rank analysis showed a significant association of MMP-2 overexpression with shortened cancer-related survival (P = 0.04) and disease-free survival (P = 0.03). Multivariate regression analysis confirmed MMP-2 overexpression as predictor of shortened cancer-related survival in NSCLC without lymph node involvement (P = 0.005, relative risk, 2.6). The present study revealed that MMP-2 overexpression predicts a poor prognosis in early-stage NSCLC. Therefore, it might be worth investigating the role of MMP inhibitors as adjuvant therapeutic agents in NSCLC.     

Role of pericellular proteolysis by membrane-type 1 matrix metalloproteinase in cancer invasion and angiogenesis

Membrane-type 1 matrix metalloproteinase (MT1-MMP) is an integral membrane proteinase that is frequently expressed in malignant cancer cells and has potent invasion-promoting activity. When expressed on the cell surface, MT1-MMP degrades the extracellular matrix (ECM) barrier adjacent to the cells to maintain the migration route to traverse the tissue. But MT1-MMP is not just an enzyme that degrades ECM. MT1-MMP also introduces limited cleavage into proteins at the cell-ECM interspaces and converts their functions. The target molecules are ECM components, cell adhesion molecules, and latent forms of MMPs. Through these processing events MT1-MMP modulates the migratory and invasive behavior of the cells.     

Extracellular matrix metalloproteinase inducer stimulates tumor angiogenesis by elevating vascular endothelial cell growth factor and matrix metalloproteinases

Matrix metalloproteinases (MMPs) are endopeptidases that play pivotal roles in promoting tumor disease progression, including tumor angiogenesis. In many solid tumors, MMP expression could be attributed to tumor stromal cells and is partially regulated by tumor-stroma interactions via tumor cell-associated extracellular matrix metalloproteinase inducer (EMMPRIN). The role of EMMPRIN during tumor angiogenesis and growth was explored by modulating EMMPRIN expression and activity using recombinant DNA engineering and neutralizing antibodies. In human breast cancer cells, changes in EMMPRIN expression influenced vascular endothelial growth factor (VEGF) production at both RNA and protein levels. In coculture of tumor cells and fibroblasts mimicking tumor-stroma interactions, VEGF expression was induced in an EMMPRIN- and MMP-dependent fashion, and was further enhanced by overexpressing EMMPRIN. Conversely, VEGF expression was inhibited by suppressing EMMPRIN expression in tumor cells, by neutralizing EMMPRIN activity, or by inhibiting MMPs. In vivo, EMMPRIN overexpression stimulated tumor angiogenesis and growth; both were significantly inhibited by antisense suppression of EMMPRIN. Expression of both human and mouse VEGF and MMP, derived from tumor and host cells, respectively, was regulated by EMMPRIN. These results suggest a novel tumor angiogenesis mechanism in which tumor-associated EMMPRIN functionally mediates tumor-stroma interactions and directly contributes to tumor angiogenesis and growth by stimulating VEGF and MMP expression.     

Novel approach to analysis of in vitro tumor angiogenesis with a variable-pressure scanning electron microscope: suppression by matrix metalloproteinase inhibitor SI-27

Degradation of basement membrane by metallo-proteinases (MMP) is a critical step in tumor angiogenesis. To evaluate in vitro angiogenesis, several models have been employed, including bovine cornea, fenestrated rat brain, Matrigel, and others. These models did not provide quantitative analysis of capillary formation. The current study aimed for a novel approach to in vitro assay of angiogenesis with a “wet scanning electron microscope (SEM)” to investigate suppression of tumor angiogenesis by the MMP inhibitor, SI-27. The effects of noncytotoxic concentrations of SI-27 (1–100μM) were determined on nonmitogenic vascular endothelial growth factor (VEGF) (10ng/ml)-mediated cell motility and in vitro angiogenesis of human umbilical vein endothelial cells (HUVECs). Activities of MMP and tissue inhibitor of metalloproteinase (TIMP) were determined by enzyme-linked immunosorbent assay (ELISA). Subsequently, the inhibitory effect of SI-27 was examined on in vitro angiogenesis stimulated by supernatants of human glioma cell lines (U87MG, U251MG, or U373MG). In vitro angiogenesis was quantitatively analyzed with a variable-pressure SEM. Cell motility and in vitro angiogenesis by HUVECs were significantly increased by VEGF along with elevated MMP-1 and-2 activity, whereas SI-27 significantly suppressed VEGF-mediated in vitro angiogenesis and inactivated both MMP-1 and MMP-2, but not inhibited cell motility. The angiogenesis promoted by glioma supernatants showed a significant reduction in the presence of SI-27. SI-27, a novel MMP inhibitor, inhibited tumor angiogenesis in vitro. It can be anticipated to prevent tumor growth through its angiosuppressive effect. Quantitative analysis with a variable-pressure SEM is a novel approach to in vitro angiogenesis assay.     

Semaphorin-3F is an inhibitor of tumor angiogenesis

The neuropilin-1 (np1) and neuropilin-2 (np2) receptors form complexes with type-A plexins. These complexes serve as signaling receptors for specific class-3 semaphorins. Np1 and np2 function in addition as receptors for heparin-binding forms of vascular endothelial growth factor (VEGF), such as VEGF(165). Human umbilical vein endothelial cells (HUVEC) express tyrosine-kinase receptors for VEGF and basic fibroblast growth factor (bFGF), as well as np1, np2, and several type-A plexins. We have found that semaphorin-3F (s3f), a semaphorin which signals through the np2 receptor, was able to inhibit VEGF(165), as well as bFGF-induced proliferation of HUVECs. Furthermore, s3f inhibited VEGF as well as bFGF-induced phosphorylation of extracellular signal-regulated kinase-1/2. Our experiments indicate that bFGF does not bind to neuropilins, nor does s3f inhibit the binding of bFGF to FGF receptors. It is therefore possible that s3f inhibits the activity of bFGF by a mechanism that requires active s3f signal transduction rather than by inhibition of bFGF binding to FGF receptors. s3f also inhibited VEGF(165), as well as bFGF-induced in vivo angiogenesis as determined by the alginate micro-encapsulation and Matrigel plug assays. Overexpression of s3f in tumorigenic human HEK293 cells inhibited their tumor-forming ability but not their proliferation in cell culture. The tumors that did develop from s3f-expressing HEK293 cells developed at a much slower rate and had a significantly lower concentration of tumor-associated blood vessels, indicating that s3f is an inhibitor of tumor angiogenesis.     

The matrix metalloproteinase inhibitor prinomastat enhances photodynamic therapy responsiveness in a mouse tumor model

Photodynamic therapy (PDT) clinical results are promising; however, tumor recurrences can occur and, therefore, methods for improving treatment efficacy are needed. PDT elicits direct tumor cell death and microvascular injury as well as expression of angiogenic, inflammatory, and prosurvival molecules. Preclinical studies combining antiangiogenic drugs or cyclooxygenase-2 inhibitors with PDT show improved treatment responsiveness (A. Ferrario et al., Cancer Res 2000;60:4066-9; A. Ferrario et al., Cancer Res 2002;62:3956-61). In the present study, we evaluated the role of Photofrin-mediated PDT in eliciting expression of matrix metalloproteinases (MMPs) and modulators of MMP activity. We also examined the efficacy of a synthetic MMP inhibitor, Prinomastat, to enhance tumoricidal activity after PDT, using a mouse mammary tumor model. Immunoblot analysis of extracts from PDT-treated tumors demonstrated strong expression of MMPs and extracellular MMP inducer along with a concomitant decrease in expression of tissue inhibitor of metalloproteinase-1. Gelatin zymography and enzyme activity assays performed on protein extracts from treated tumors confirmed the induction of both latent and enzymatically active forms of MMP-9. Immunohistochemical analysis indicated that infiltrating inflammatory cells and endothelial cells were primary sources of MMP-9 expression after PDT, whereas negligible expression was observed in tumor cells. Administration of Prinomastat significantly improved PDT-mediated tumor response (P = 0.02) without affecting normal skin photosensitization. Our results indicate that PDT induces MMPs and that the adjunctive use of an MMP inhibitor can improve PDT tumor responsiveness.     

Tissue inhibitor of metalloproteinase 2 (TIMP-2) expression in adenocarcinoma pleural effusions

Serous effusions are frequently a clinical manifestation of metastatic disease, with lung, breast and ovarian carcinoma and mesothelioma leading the list. The diagnosis of malignant effusion signifies disease progression and is associated with a worsening patient prognosis. The ability to grow in a dense exudative fluid suggests that the malignant cells are capable of acquiring nutrients, surviving and proliferating, despite the lack of a solid-phase scaffold. During proliferation, neoplastic cells release ligands and matrix metalloproteinases (MMPs) into their environment, which dissolve the extracellular matrix (ECM). Tissue inhibitors of metalloproteinase (TIMPs) are endogenous regulators of MMPs, the principal enzymes responsible for the degradation of ECM in metastasis, and reduce their proteolytic activity. TIMP-2 has demonstrated an association between high tumor tissue expression levels and poor prognosis. The purpose of this preliminary study is to investigate, by immunocytochemistry, TIMP-2 expression in non-neoplastic and metastatic adenocarcinoma pleural effusions. We selected 16 cases of reactive mesothelio, 7 of normal mesothelio, 14 of lung adenocarcinoma, 9 from the ovary, 4 from the gastrointestinal tract and 3 from the breast. In 23/30 cases (76%), we detected adenocarcinoma cells with strong TIMP-2 expression. Positive TIMP-2 expression was found in 2/7 cases (28%) of normal and 2/16 (12%) of reactive mesothelio. A statistical association was detected between TIMP-2 expression and metastatic adenocarcinoma cells compared to reactive and normal mesothelial cells (p<0.00003). The calculated sensitivities for TIMP-2 compared to CEA and Ber-EP4 were, respectively, 76.7, 80.0 and 93.3%, and the specificities 82.6, 95.7 and 87.0%. In conclusion, immunocytochemical detection of TIMP-2 could be considered an interesting marker in metastatic adenocarcinoma pleural effusions, and could possibly be used as a component of an antibody panel in diagnostic cytopathology.