Expression of urokinase-type plasminogen activator, urokinase-type plasminogen activator receptor, and plasminogen activator inhibitor-1 and -2 in hepatocellular carcinoma

It has become more and more clear in recent decades that the plasminogen activation system, which includes urokinase-type plasminogen activator (uPA), urokinase-type plasminogen activator receptor (uPAR), plasminogen activator inhibitor (PAI)-1 and PAI-2, plays a very important role in the aggressiveness of cancer. Using immunohistochemistry and enzyme-linked immunosorbent assay (ELISA), the expression of these four components of the uPA system was analyzed in 19 cases of hepatocellular carcinoma (HCC) and 18 cases of the adjacent non-cancer tissues which all had chronic active hepatitis with liver fibrosis or liver cirrhosis. Four cases of normal liver tissues, as controls for immunohistochemical stains, were obtained from the hepatectomized liver of patients with metastatic cancer in the liver. The positive rates of uPA, uPAR, PAI-1 and PAI-2 for immunohistochemical stains in cancer tissues were 78.9, 68.4, 57.9 and 31.6%, respectively. Positive signals were mainly distributed in the cytoplasm of the cancer and in stromal cells. Moreover, the strong stains were chiefly located in the invasive front of the cancer cells. No specific stain was detected in four cases of normal liver tissues. In ELISA, there were significant differences between cancer and non-cancer tissues in concentration of uPA, uPAR and PAI-1 (P < 0.0003, 0.0024 and 0.01, respectively), but there was no significant difference in that of PAI-2 (P = 0.37). These results suggest that uPA, uPAR and PAI-1 are related to invasion of HCC.     

miRNA-221 promotes proliferation,migration and invasion by targeting TIMP2 in renal cell carcinoma

Introduction: MicroRNAs (miRNAs) play important roles in tumorigenesis. In this study, we investigated the role of miR-221 in the development and progression of clear cell renal cell carcinoma (ccRCC). Methods: Quantitative real-time PCR (qRT-PCR) was used to measure the expression level of miR-221 in ccRCC tissues and cell lines. Then, we investigated the role of miR-221 to determine its potential roles on renal cancer cell proliferation, migration and invasion in vitro. A luciferase reporter assay was conducted to confirm the target gene of miR-221 and the results were validated in renal cancer cells. Results: In the present study, we found that miR-221 was significantly increased in ccRCC tissues and cell lines. Knocked-down expression of miR-221 remarkably inhibited cell proliferation, migration and invasion of renal cancer cells. Moreover, at the molecular level, our results suggested that TIMP2 as a direct target of miR-221 through which miR-221 promoted tumor cell proliferation, migration and invasion. Conclusions: These findings suggested that miR-221 play an oncogenic role in the renal cancer cell proliferation, migration and invasion by directly inhibiting the tumor suppressor TIMP2, indicating miR-221 act as a potential new therapeutic target for the treatment of ccRCC.     

miR-27a promotes cell proliferation and metastasis in renal cell carcinoma

miR-27a has been reported to exhibit abnormal expression in renal cell carcinoma (RCC), but the role of miR-27a in RCC remains unknown. In our study, up-regulation of miR-27a was validated by Real-time PCR analysis in 133 RCC samples. Overexpression of miR-27a promoted cell migration, invasion and proliferation in vitro, while its low expression exerted opposite effects. Kaplan-Meier analysis demonstrated that the patients with high expression of miR-27a had a worse overall and relapse-free survivals compared with those with low expression of miR-27a. Cox proportional hazards analyses showed that miR-27a expression was an independent prognostic factor for RCC patients. Collectively, our findings illustrate the promoting-cancer effect of miR-27a in RCC, suggesting that miR-27a could be a potential therapeutic target for RCC. Additionally, Kaplan-Meier analyses and Cox proportional regression analysis suggest that miR-27a may be a potential biomarker for predicting the survival of RCC patients.     

Anin vitro invasion model for human renal cell carcinoma cell lines mimicking their metastatic abilities

We developed a modifiedin vitro invasion assay system using monolayers of vascular endothelial cells. A type I collagen gel was formed in plastic dishes, and overlaid with type IV collagen. Calf pulmonary arterial endothelial (CPAE) cells were seeded onto these plates, and incubated until they reached confluence. Five human renal cell carcinoma cell lines with various metastatic potentialsin vivo were then seeded on the monolayer CPAE cells, and their colony formation and invasion activities were examined for 9 days. At day 4, the highly metastatic cell lines increased the number of colony foci on monolayer CPAE cells several fold higher than their poorly metastatic counterpart. The horizontal spreading patterns were also different between poorly and highly metastatic cell lines. On day 9, the number of carcinoma foci that penetrated the monolayer of CPAE cells and type IV collagen sheets into type I collagen gels in highly metastatic cell lines greatly increased as compared with that of poorly metastatic cell lines. Ourin vitro invasion assay using monolayer CPAE cells would be useful to evaluate protease activities and colony formation during invasion.     

牛磺酸联合SN50协同抑制人肝癌细胞系HepG2的增殖

目的探讨牛磺酸联合NF-κB信号通路抑制剂SN50对肝癌细胞系HepG2增殖的影响及其机制。方法将HepG2细胞分为对照组、牛磺酸组(给予150 mmol/L牛磺酸处理24 h)、抑制剂组(给予36μmol/L SN50处理24 h)和牛磺酸+抑制剂组;用MTT法、克隆形成实验和流式细胞仪分别检测细胞的增殖和凋亡;Western blot和RT-qPCR检测细胞中cyclin D1、Bcl-2蛋白和mRNA的表达情况。结果与对照组相比,经150 mmol/L牛磺酸或36μmol/L SN50处理24 h后,HepG2细胞的生存率和集落形成率均明显降低,凋亡率明显升高,细胞中cyclin D1和Bcl-2蛋白和mRNA表达均明显受到抑制(P<0. 05)。同时,SN50增强了牛磺酸对HepG2细胞的增殖和cyclin D1、Bcl-2表达的抑制作用以及对细胞凋亡的促进作用。结论牛磺酸联合NF-κB信号通路抑制剂协同抑制肝癌细胞系HepG2的增殖。     

Cellular localization of urokinase-type plasminogen activator,its inhibitors,and their mRNAs in breast cancer tissues

The plasminogen activation (PA) system may participate in cancer invasion and metastasis. A series of breast cancer tissue specimens was analysed using in situ hybridization and immunohistochemistry. Urokinase-type plasminogen activator (u-PA) mRNA was detected in cancer cells and fibroblasts adjacent to them and its expression was found to be more intense in invasive than in intraductal regions. In invasive but not in intraductal regions, especially those with abundant stroma, plasminogen activator inhibitor-1 (PAI-1) mRNA was observed in cancer cells, fibroblasts, macrophages, and endothelial cells, and PAI-2 mRNA was present in cancer cells, and fibroblasts, macrophages, and lymphocytes around them. These PAI-1- and PAI-2-positive cancer cells were localized at the periphery of the invasive front. Immunohistochemistry yielded basically similar results. A retrospective study of surgically resected breast cancers from 73 patients revealed significant clinical differences associated with u-PA and PAI-2 expression in cancer cells, associated with a poor and a good prognosis, respectively. These findings indicate that breast cancer cells and fibroblasts express u-PA initially and then its inhibitors, and that this process is related to invasion. Expression of u-PA and PAI-2 in cancer cells themselves may serve to up-regulate and limit PA-mediated invasion and metastasis, respectively. © 1997 John Wiley & Sons, Ltd.     

Organ-site dependence for the production of urokinase-type plasminogen activator and metastasis by human renal cell carcinoma cells.

We examined the role of urokinase-type plasminogen activator (u-PA) in the metastasis of the human renal cell carcinoma (HRCC) implanted in athymic nude mice. Cells from a HRCC KG-2 line were implanted in orthotopic (kidney) and ectopic (subcutaneous) organs. The KG-2 cells implanted in the kidney produced local tumors and lung metastases, whereas those implanted subcutaneously produced only local tumors. The production of u-PA was determined by immunohistochemistry and an enzyme-linked immunosorbent assay (ELISA). High levels of u-PA were produced by the metastatic kidney tumors and lung metastases, whereas the subcutaneous tumors produced low levels. KG-2 cells co-cultured with mouse kidney or lung fibroblasts produced higher levels of u-PA than KG-2 cells co-cultured with mouse skin fibroblasts. Furthermore, KG-2 cells cultured with the conditioned medium from mouse kidney or lung fibroblasts produced higher levels of u-PA than KG-2 cells cultured with the conditioned medium from mouse skin fibroblasts. The results indicate that the expression of u-PA by KG-2 cells is one of the important factors that determine their metastatic potential and that the production of u-PA is influenced by the organ microenvironment, including soluble factors produced by surrounding fibroblasts.     

Cyclooxygenase-2 expression and relationship to tumour progression in human renal cell carcinoma

AIMS: Cyclooxygenase (COX), which catalyses the synthesis of prostaglandins from arachidonic acid, has two isoforms; COX-1 and COX-2. There is ample evidence to suggest an important role for COX-2 in cancer. The aim of this study was to evaluate the clinical significance of COX-2 expression and its localization in the development and progression of human renal cell carcinoma (RCC). METHODS AND RESULTS: The expression and localization of COX-2 were evaluated in human RCC tissues from 75 patients by immunohistochemistry. Immunoreactive COX-2 protein was observed in all cases of RCC, and the levels of COX-2 expression were correlated with tumour grade and pathological stage. Expression of COX-2 was higher in the granular cell subtype than in the clear cell subtype of RCC. Immunoelectron microscopy revealed that COX-2 was expressed in the nuclear membrane, rough endoplasmic reticulum, Golgi complex and mitochondrial membrane of RCC cells. CONCLUSION: COX-2 overexpression within these intracellular organelles in RCC may be associated with renal cell carcinogenesis and COX-2 may be a useful biomarker in RCC.     

蛋白激酶B抑制剂哌立福辛对卵巢透明细胞癌ES2细胞系的杀伤作用

目的探讨蛋白激酶B抑制剂哌立福辛对卵巢透明细胞癌ES2细胞系的杀伤作用。方法体外培养人卵巢透明细胞癌ES2细胞,以不同药物浓度(0、7、9、11、13和15μmol/L)哌立福辛处理细胞24 h,用细胞计数试剂盒CCK-8检测细胞的存活率;DAPI染色观察细胞核的形态;用annexin V-FITC/PI凋亡检测试剂盒及流式细胞术检测细胞的凋亡;实时荧光定量PCR法检测Ki-67和MCM2 mRNA表达。结果哌立福辛能够降低细胞存活率(P0.05),在一定程度上呈浓度依懒性;哌立福辛作用于细胞后,荧光显微镜下可见大量的核碎裂及凋亡小体;随着哌立福辛浓度的增加,细胞的凋亡率增加(P0.01);药物作用48 h后,Ki-67和MCM2 mRNA表达水平明显降低(P0.01)。结论哌立福辛对人卵巢透明细胞癌ES2细胞有明显的杀伤作用,并且可以负性调节Ki-67和MCM2mRNA的表达。     

二甲双胍对人肝癌细胞Bel-7402增殖与凋亡的影响

目的:研究二甲双胍抑制人肝癌细胞Bel-7402增殖及调亡的影响,并初步探讨其机制。方法:体外培养人肝癌细胞株Bel-7402,以不同浓度的二甲双胍(10mM、20mM、40mM)干预细胞48h。采用MTT法检测药物对细胞增殖的影响;采用Hoechst 33258荧光染色法和流式细胞术检测细胞凋亡;Real-time PCR检测caspase-3、bax和bcl-2的mRNA水平表达。结果:与对照组相比,不同浓度的二甲双胍作用于Bel-7402细胞48h后,MTT结果显示对细胞增殖有明显抑制作用(P0.05);Hoechst 33258荧光染色法显示凋亡细胞明显增多;流式细胞术分析显示二甲双胍可明显诱导Bel-7402细胞凋亡,晚期凋亡率分别为3.76%,8.96%和18.67%;caspase-3、bax和bcl-2的mRNA表达水平均上调(P0.05);以上结果均具有浓度依赖性。结论:二甲双胍能抑制Bel-7402细胞增殖并诱导其凋亡,其机制可能与caspase-3、bax和bcl-2的mRNA表达水平改变有关。     

Characterization of HLA-G expression in renal cell carcinoma

Previous studies showed that human leukocyte antigen (HLA)-G is specifically upregulated in renal cell carcinoma (RCC). However, a larger cohort of RCC patients are necessary to obtain more information. In this study, 109 RCC primary lesions (clear cell, n  = 95; chromophobe, n  = 4; papillary, n  = 4; collecting duct, n  = 6) and corresponding adjacent tumor-negative renal tissues ( n  = 34) were analyzed for the HLA-G expression by immunohistochemistry (IHC). Meanwhile, plasma soluble HLA-G (sHLA-G) from 16 RCC patients and 144 sex- and age-matched normal individuals was detected by enzyme-linked immunosorbent assay. Correlations between lesion HLA-G expression and various clinical parameters were evaluated. Receiver-operating characteristic (ROC) curve analysis was used to determine the feasibility of HLA-G protein staining and sHLA-G as a diagnosis marker for RCC. IHC data showed that HLA-G was observed in 49.5% of clear cell, 50% of either chromophobe or collecting duct RCC lesions but undetectable in papillary RCC and tumor-negative renal tissues. This finding was consistent with the western blot results. sHLA-G was pronouncedly increased in RCC patients when compared with normal controls (median: 39.5 vs 19.2 U/ml, P  = 0.002). However, no correlation was observed between HLA-G expression and various clinical parameters. We found that the area under ROC curve for HLA-G expression and sHLA-G was 0.739 [95% confidence interval (95% CI): 0.659–0.816, P  = 0.000] and 0.733 (95% CI: 0.619–0.847, P  = 0.002), respectively. Our findings indicated that, except the papillary RCC, other types of RCC could express HLA-G. Furthermore, both lesion HLA-G expression and plasma sHLA-G level might be a useful preoperative biomarker for diagnosis.     

Epigenetic inactivation of HOXA5 and MSH2 gene in clear cell renal cell carcinoma

The high‐throughput method using microarray is an easy and fast way to analyze the methylation status of hundreds of preselected genes and to screen them for signatures in methylation. The aim of our study is to detect hypermethylated genes and to analyze the association between methylation status and clinicopathological parameters of clear cell renal cell carcinoma. The genetic substrate included 62 cancer tissues and 62 matched adjacent normal kidney tissues. We adapted the GoldenGate genotyping assay to determine the methylation state of 1505 specific CpG sites in 807 genes. We identified two genes (HOXA5 and MSH2) with β‐value differences of more than 0.3 between cancer and normal tissues. The high methylation group in HOXA5 had high Fuhrman's nuclear grade (P= 0.041). Other data in HOXA5 and MSH2 were not significant with methylation status (P > 0.05). Survival curve of the high methylation group in HOXA5 was slightly lower than that of the low methylation group. However, the statistical significances of overall survival in HOXA5 and MSH2 were low (P > 0.05). We report the hypermethylation of two genes in clear cell renal cell carcinoma. The data we obtained could provide the basis for a diagnostic test pathological assessment, or prognosis in clear cell renal cell carcinoma.     

Metastatic risk stratification of clear cell renal cell carcinoma patients based on genomic aberrations

Prognostic markers for the definition of the individual metastatic risk in renal cell carcinoma are still missing. The aim of our study was to establish a total number of specific aberrations (TNSA) genetic score as a new prognostic test for metastatic risk evaluation. Fluorescence in situ hybridization (FISH) was performed on isolated cell nuclei of 100 ccRCCs (50 M1/50 M0) and 100 FFPE sections (second cohort, 32 M1/68 M0). For each chromosomal region (1q21.3, 7q36.3, 9p21.3p24.1, 20q11.21q13.32) cut‐off values were determined by receiver‐operator curve (ROC)‐curve analysis. TNSA was calculated based on the dichotomized specific CNVs. The prognostic significance of CNVs was proven by Cox and logistic regression. TNSA was the best predictor of metastasis and recurrence free survival in both cohorts. We derived an algorithm for risk stratification by combining TNSA and T‐category, which increased the prognostic accuracy to 87% (specificity = 86%, sensitivity = 88%). This model divides patients into two risk groups with significantly different RFS, CSS, and OS (P = 3.8×10^?5, P = 5×10^?6 and P = 3.57×10^?8 respectively). The genetic risk model was superior to Leibovich score and was able to identify patients with metachronous metastatic spread which were incorrectly classified as “low” or “intermediate risk.” We present a new tool for individual risk stratification by combining genetic alterations with clinico‐pathologic parameters. Interphase FISH proves to be a dependable method for prognostic evaluation in primary tumor tissue on isolated cell nuclei as well as on FFPE sections. Especially in organ‐confined tumors the genetic score seems to be an important tool to identify patients at high risk for metastatic disease.     

Analysis of the expression of HLA class I, proinflammatory cytokines and chemokines in primary tumors from patients with localized and metastatic renal cell carcinoma

Changes in the human leukocyte antigen (HLA) class I expression and cytokine and chemokine production both by cancer cells and by normal surrounding tissue are believed to be responsible for immune escape and tumor progression. In this study, we compared the tumor expression levels of HLA heavy chain (HLAhc), beta-2-microglobulin (beta2m), chemokines (Interferon-gamma-inducible Protein-10 (IP-10), Interferon-inducible T-cell Alpha-Chemoattractant (I-TAC), Stromal cell-Derived Factor-1 (SDF-1), Macrophage Inflammatory Protein-1-alpha (MIP-1-alpha) and Regulated upon Activation, Normally T-Expressed, and presumably Secreted (RANTES)) and cytokines (Vascular Endothelial Growth Factor (VEGF), Interferon-gamma (IFN-gamma), Interleukin-10 (IL-10), Tumor Growth Factor-beta (TGB-beta)) in primary tumors and adjacent normal tissues from patients with localized and metastatic renal cell carcinoma (RCC) using a quantitative real-time polymerase chain reaction technique. We report that the expression of HLAhc, beta2m and the studied cytokines and chemokines (except for SDF-1) was significantly higher in the tumor (29 samples) than in the normal tissue (14 samples). When we compared the tumor expression levels between patients with localized RCC and patients with advanced metastatic stage, we found that the messenger RNA expression levels of HLAhc and beta2m were much lower in patients with metastatic RCC (6 cases) than in patients with localized cancer (23 cases), with levels similar to those in normal tissue. This was also confirmed on a protein level by immunohistological labeling of tumor tissues. Thirty-nine percent of the analyzed RCC tumors showed partial loss of HLA class I molecules, while 6% of the tumors showed HLA class I total loss. The expression of IP-10, SDF-1 and VEGF-c was also significantly lower in patients with advanced tumor, while the IFN-gamma expression in metastatic RCC was not detectable. Our findings show that primary RCC tumors are characterized by a high expression of HLAhc and a presence of proinflammatory mediators and chemokines. We also observed that disease progression and development of metastasis in RCC are associated with decreased expression of HLAhc, beta2m, IP-10, SDF-1 and IFN-gamma. This microenvironment may suppress the cytotoxic response, creating conditions that favor tumor escape and cancer progression.     

Tumour-to-tumour metastasis: a rare cause of apparent intratumoural heterogeneity in conventional clear cell renal cell carcinoma

Tumour-to-tumour metastasis is a rare phenomenon and few case reports exist that describe tumor-to-tumor metastases to and from clear cell renal cell carcinoma.¹ In order for metastases to become established, tumour cells must be shed, survive in circulation, and implant, grow, and establish vascularity in a distant site - which in our case was within another primary tumour.² Tumours are, by definition, environments that promote growth of neoplastic cells. Clear cell renal cell carcinoma, in particular, provides a unique pro-tumour environment, in part due to its molecular characteristics, affording metastatic tumours the opportunity to survive and grow.³ We describe a case of metastatic breast carcinoma that was found within a conventional clear cell type renal cell carcinoma. Further, this case illustrates the potential for sampling errors with percutaneous biopsies of renal masses and highlights the need for pathologists to consider the rare possibility of tumour-to-tumour metastasis when confronted with tumours showing striking morphologic heterogeneity.     

ADAM metallopeptidase with thrombospondin type 1 motif 16 is a potential marker for prognosis in clear cell renal cell carcinoma

The mortality rate of clear cell renal cell carcinoma (ccRCC) remains high. Immunohistochemical staining, Western blotting and real-time quantitative polymerase chain reaction were employed to evaluate ADAM (a disintegrin and metalloproteinase) metallopeptidase with thrombospondin type 1 motif 16 (ADAMTS16) levels in ccRCC tissues and paired normal tissues, and all tissues were obtained from clinical samples of 46 cases of ccRCC patients. Moreover, we analyzed the role ADAMTS16 in the progression of ccRCC using Cell Counting Kit-8 assay and flow cytometry. ADAMTS16 levels in ccRCC tissues were markedly low, relative to normal tissues, and ADAMTS16 level closely correlated with tumor stage, lymph node metastasis as well as pathological grade. Patients with elevated ADAMTS16 expressions have a more favorable survival outcome, relative to patients with low expression of ADAMTS16. In vitro study showed ADAMTS16 expression markedly decreased in ccRCC cells and acted as a tumor suppressor compared with the normal cells. The expression of ADAMTS16 is down-regulated in ccRCC tissues, relative to normal tissues, and it may inhibit the malignancies of ccRCC. Such inhibitory effect may be ascribed to the involvement of AKT/mammalian target of rapamycin signaling. Hence, the present study of ADAMTS16 will provide new insight into the underlying biological mechanisms of ccRCC.     

miR-497与肾癌预后的关系及其对肾癌786-0细胞增殖、凋亡和侵袭的影响

目的:探讨微小RNA-497(miR-497)与肾癌预后的关系及其对肾癌786-0细胞增殖、凋亡和侵袭的影响。方法:收集2011年~2015年80例肾细胞癌患者手术切除的癌组织和癌旁组织并回顾性分析患者随访资料。采用实时定量PCR法检测癌组织及配对的癌旁组织中miR-497的表达。在肾癌细胞系786-0中转染miR-497模拟物,应用MTT法、台盼兰拒染法活细胞计数、流式细胞术和Transwell小室实验检测miR-497对786-0细胞增殖、凋亡和侵袭能力的影响。通过生物信息学预测miR-497在786-0细胞中作用的靶基因。Western blotting法检测miR-497对靶基因蛋白表达影响。结果:肾癌组织中miR-497的表达量明显低于癌旁组织(P0.05)。786-0中miR-497表达量明显低于正常肾上皮细胞中miR-497表达量(P0.05)。随访时间2~48个月,中位随访时间29个月,失访6例,随访率92.5%。76例患者3年无复发生存率(recurrence-free survival,RFS)为55.2%。高miR-497表达组和低miR-497表达组肾癌患者的RFS分别为71.2%和40.1%,差异有统计学显著性(P0.05)。过表达miR-497可显著抑制786-0细胞的增殖和侵袭能力,显著促进细胞凋亡(P0.05)。过表达miR-497可显著抑制786-0细胞中cyclin D1蛋白的表达(P0.05)。结论:miR-497与肾癌预后相关,miR-497能明显抑制肾癌786-0细胞的增殖和凋亡,其机制可能与其靶向抑制cyclin D1有关。     

LMP2, a novel immunohistochemical marker to distinguish renal oncocytoma from the eosinophilic variant of chromophobe renal cell carcinoma

LMP2 is a subunit of the immunoproteasome that is overexpressed in oncocytic lesions of the thyroid gland. This study was designed to assess the expression profile and diagnostic utility of LMP2 in two renal oncocytic tumors that share similar morphologic features but have different clinical outcomes: renal oncocytoma (RO) and the eosinophilic variant of chromophobe renal cell carcinoma (CHRCC-EO). A total of 56 RO, 38 classic CHRCC, and 7 CHRCC-EO cases, as well 84 normal kidney controls, were selected from the Johns Hopkins surgical pathology archive and stained for LMP2 using a standard immunohistochemical protocol. Sections were scored for cellular location (nuclear versus cytosolic), intensity (from 0 to 3), and percent of area involved (from 0 to 100%), and an H score was calculated multiplying the intensity by the extent of the staining signal. The cytoplasmic expression of LMP2 was similar among the renal lesions, being present in 44 of 56 (79%) ROs, 27 of 38 (71%) CHRCCs, and 7 of 7 (100%) CHRCC-EO cases. The nuclear expression of LMP2, however, was more informative. All CHRCC-EO cases (7 of 7, 100%) strongly showed nuclear LMP2 staining, as opposed to only 2 of 56 (4%, P < 0.0001) ROs and 9 of 38 (24%, P = 0.0001) classic CHRCCs. These results suggest that the nuclear LMP2 expression can be used in clinical scenarios where histological distinction between RO and CHRCC-EO remains challenging.     

Cellular distribution and clinical value of urokinase-type plasminogen activator, its receptor, and plasminogen activator inhibitor-2 in esophageal squamous cell carcinoma

To assess the participation of the plasminogen activation system in the invasiveness of esophageal squamous cell carcinoma, we performed immunohistochemistry and in situ hybridization to study the distribution of a urokinase-type plasminogen activator (u-PA), u-PA receptor (u-PAR), and plasminogen activator inhibitor-2 (PAI-2). u-PA and PAI-2 were expressed heterogeneously in cancer cells, and restricted expression was found in stromal cells, especially fibroblasts, that were located in the immediate proximity of the cancerous cells. u-PAR was found only in cancer cells located at the periphery of tumors. Compared with patients with u-PA-negative cancer cells, patients with u-PA-positive cancer cells more frequently showed a neoplastic invasion beyond the muscularis propria and lymph node metastases. They also showed a significantly shorter 5-year overall survival. Patients with PAI-2-positive fibroblasts showed significantly lower levels of local invasiveness, represented by a neoplastic invasion beyond the muscularis propria, than those who were PAI-2 negative. Our results suggest that the expression of u-PA in esophageal squamous cell carcinoma is predictive of poor survival, whereas the expression of PAI-2 in the fibroblasts surrounding them is protective. An analysis of u-PA and PAI-2 expression in cancer cells and their surrounding fibroblasts may be useful for predicting the prognosis of patients with esophageal squamous cell carcinoma.