Effects of phenobarbital and secondary bile acids on liver, gallbladder, and pancreas carcinogenesis initiated by N-nitrosobis (2-hydroxypropyl)amine in hamsters.

The effects of dietary administration of phenobarbital [(PB) CAS: 50-06-6] or the secondary bile acids, deoxycholic acid [(DCA) CAS: 83-44-3] and lithocholic acid [(LCA) CAS: 434-13-9], on tumorigenesis in the liver, gallbladder, and pancreas were investigated in male Syrian golden hamsters after carcinogenic initiation by N-nitrosobis(2-hydroxypropyl)amine [(BHP) CAS: 53609-64-6]. BHP [500 mg/kg (body wt)] was injected sc once weekly for 5 weeks. The animals were then maintained on a basal diet or a diet containing either 0.05% PB, 0.1% DCA, 0.5% DCA, or 0.5% LCA for 30 weeks. DCA enhanced the development of cholangiocarcinomas without influencing that of hepatocellular lesions. PB promoted the induction of hepatocellular carcinomas but not that of cholangiocarcinomas. LCA was without effect on the induction of either hepatocellular carcinomas or cholangiocarcinomas. DCA at a dose of 0.5% enhanced the induction of polyps in the gallbladder. Both DCA, at a dose of 0.1%, and LCA significantly enhanced the induction of pancreas carcinomas. PB had no effect on the induction of polyps in the gallbladder or of pancreas carcinomas. These data document that different tumors may be differentially promoted following initiation with a common carcinogen.

Invasive and metastatic potential of a v-Ha-ras-transformed human bronchial epithelial cell line.

The in vivo growth behavior and invasive potential of normal and "immortalized" human bronchial epithelial cells were studied by xenotransplantation procedures, an in vitro assay of invasiveness, and determinations of type IV collagenase activity and mRNA expression. BEAS-2B cells, immortalized after hybrid virus infection (adenovirus 12-simian virus 40), reconstituted a columnar epithelium when xenotransplanted into de-epithelialized rat tracheas transplanted sc into athymic BALB/c mice. A few adenomatous growths could be seen 16 weeks after transplantation. BZR cells, obtained by transfer of the v-Ha-ras oncogene into BEAS-2B cells, were tumorigenic in this xenotransplantation model. BZR-T33 cells, obtained from a tumor produced after injection of BZR cells, were also tumorigenic; however, they exhibited a shorter latent period. When these same cell lines were injected sc and iv into athymic BALB/c mice, BEAS-2B cells were not tumorigenic, and the BZR-T33 cells were more tumorigenic than the BZR cells. The incidence of spontaneous metastases after sc inoculation was zero for BEAS-2B cells, 33% for BZR cells, and 100% for BZR-T33 cells. Similar increasing values that correlated well with the data on in vivo growth were noted in the in vitro invasion assay, the collagenolytic ability, and the mRNA expression of type IV collagenase. Normal human bronchial epithelial cells showed the lowest values in all the assays. These progressive changes occurring in cells derived from the same parental line indicate that the presence of the v-Ha-ras oncogene in immortalized bronchial cells is associated with a full-fledged malignant phenotype, which is further enhanced by in vivo passaging.

Effects of transforming growth factor-beta released from gastric carcinoma cells on the contraction of collagen-matrix gels containing fibroblasts.

To investigate the mechanisms underlying contraction of the stomach wall in cases of gastric scirrhous carcinoma, we have developed an in vitro model for gastric cancer, in which both fibroblasts and gastric carcinoma cells are embedded within a collagen matrix. Gastric carcinoma cells of the scirrhous type (KATO-III) but not the nonscirrhous type (MKN-28) markedly enhanced the ability of human intestine, human lip, and mouse kidney fibroblasts to contract collagen gels. KATO-III cells released transforming growth factor-beta (TGF-beta) into culture media in an activated form, whereas the MKN-28 cells produced a latent form. The role of TGF-beta produced by gastric cancer cells from the scirrhous type was clarified by adding TGF-beta (receptor grade) into collagen gels embedded with fibroblasts, contraction being enhanced. Other growth factors tested, including transforming growth factor-alpha and epidermal growth factor, did not enhance the contraction of collagen gels containing embedded human and rodent fibroblasts. These results suggest that the activated form of TGF-beta released from gastric scirrhous carcinoma cells stimulates fibroblasts to contract the collagenous stroma of the stomach wall, which leads to the so-called "linitis plastica" stomach condition.

Combined effects of cholecystectomy and lithocholic acid on pancreatic carcinogenesis of N-nitrosobis(2-hydroxypropyl)amine in Syrian golden hamsters.

The effects of cholecystectomy and/or lithocholic acid (LCA) on the composition of biliary bile acid and on pancreatic carcinogenesis by N-nitrosobis(2-hydroxypropyl)amine (BHP) were examined in male Syrian golden hamsters. Cholecystectomy was performed 1 wk before BHP initiation. BHP (250 mg/kg of body weight) was injected s.c. once a wk for 5 wk. A diet containing 0.5% LCA was begun 1 wk after the final BHP injection. All hamsters were sacrificed 36 wk after cholecystectomy, and the pancreas was examined histologically. Only the LCA treatment but no other treatment influenced the bile acid composition, i.e., the increase in LCA and decrease in cholic acid. The incidence of pancreatic carcinoma was 23 of 30 (76.7%) in hamsters receiving cholecystectomy plus BHP followed by LCA diet. The tumor incidence was five of 18 (27.8%) with BHP followed by basal diet, ten of 18 (55.6%) with cholecystectomy plus BHP followed by basal diet, and six of 18 (33.3%) with BHP followed by LCA diet, respectively. The total number of pancreatic carcinomas in hamsters receiving cholecystectomy and BHP followed by LCA diet also increased significantly. These results indicate that combined treatments of cholecystectomy and dietary LCA enhanced BHP-inducing pancreatic carcinogenesis in hamsters.

Expression of type IV collagenase and procollagen genes and its correlation with the tumorigenic, invasive, and metastatic abilities of oncogene-transformed human bronchial epithelial cells.

In a series of immortalized human bronchial epithelial cell lines continuing various oncogenes, the transcriptional levels of the type IV collagenase and the type IV procollagen genes were compared with the properties of invasiveness in vitro and tumorigenicity and metastatic ability in athymic nude mice. v-Ha-ras greatly enhanced invasion and metastasis, whereas v-Ki-ras, c-myc, and c-raf had lesser effects on these malignant phenotypes. In addition, cell lines derived from tumors obtained by injecting the original immortalized human bronchial epithelial cell lines into nude mice exhibited enhanced invasive and metastatic abilities and increased level of type IV collagenase mRNA when compared with the original immortalized human bronchial epithelial cell lines. Invasiveness and metastatic capacity correlated positively with expression of the type IV collagenase gene and negatively with the expression of the type IV procollagen gene, suggesting that these phenotypes are associated both with decreased production and increased dissolution of extracellular matrix.

Multicentric development of pancreatic intraductal carcinoma through atypical papillary hyperplasia.

We report a case of multiple intraductal carcinomas of the pancreas associated with diffuse atypical papillary hyperplasia. A 67-year-old Japanese man with a complaint of epigastric pain was examined by endoscopic retrograde pancreatography, which demonstrated multiple dilated branches of the pancreatic duct in the body and tail of the pancreas. Histologic examination on the resected pancreas showed diffuse atypical papillary hyperplasia in multiple dilated ducts associated with multiple intraductal carcinomas. Histologic features are described and multicentric carcinogenesis through atypical papillary hyperplasia is discussed.

Temperature dependence of the enzyme-substrate recognition mechanism.

We determined the crystal structure of the liganded form of alpha-aminotransferase from a hyperthermophile, Pyrococcus horikoshii. This hyperthermophilic enzyme did not show domain movement upon binding of an acidic substrate, glutamate, except for a small movement of the alpha-helix from Glu16 to Ala25. The omega-carboxyl group of the acidic substrate was recognized by Tyr70* without its side-chain movement, but not by positively charged Arg or Lys. Compared with the homologous enzymes from Thermus thermophilus HB8 and Escherichia coli, it was suggested that the more thermophilic the enzyme is, the smaller the domain movement is. This rule seems to be applicable to many other enzymes already reported.

Substrate recognition mechanism of thermophilic dual-substrate enzyme.

Aspartate aminotransferase from an extremely thermophilic bacterium, Thermus thermophilus HB8 (ttAspAT), has been believed to be specific for an acidic substrate. However, stepwise introduction of mutations in the active-site residues finally changed its substrate specificity to that of a dual-substrate enzyme. The final mutant, [S15D, T17V, K109S, S292R] ttAspAT, is active toward both acidic and hydrophobic substrates. During the course of stepwise mutation, the activities toward acidic and hydrophobic substrates changed independently. The introduction of a mobile Arg292* residue into ttAspAT was the key step in the change to a "dual-substrate" enzyme. The substrate recognition mechanism of this thermostable "dual-substrate" enzyme was confirmed by X-ray crystallography. This work together with previous studies on various enzymes suggest that this unique "dual-substrate recognition" mechanism is a feature of not only aminotransferases but also other enzymes.

Papillary adenoma of the pancreas with excessive mucin secretion.

A 68-year-old woman with papillary adenoma of the pancreas with excessive mucin secretion is reported. The patient was initially diagnosed as having chronic pancreatitis because of a history of repeated attacks of pancreatitis and localized dilatation of the main pancreatic duct. Four years later, endoscopic retrograde pancreatography showed markedly diffuse dilatation of the entire main pancreatic duct with amorphous filling defects of mucin. Excretion of mucin was observed through the enlarged orifice of Vater's ampulla. The patient was treated with distal pancreatectomy, and papillary adenoma with abundant mucin in the cytoplasm was histologically demonstrated. We describe unique clinical features of "mucin-producing pancreatic tumor" and discuss an important role of endoscopic retrograde pancreatography in the diagnosis.

Pancreatic tumor antigen in transplantable adenocarcinomas induced by N-bis(2-hydroxypropyl)nitrosamine in hamsters.

An attempt was made to detect a pancreatic tumor antigen (PTA) in transplantable pancreatic adenocarcinomas induced by N-bis(2-hydroxypropyl)nitrosamine (DHPN) in hamsters. Antibody against antigenic protein was raised by immunizing rabbits with whole homogenate of the tumors transplanted into the back of hamsters. PTA was purified by affinity chromatography and shown to have the physicochemical properties of a glycoprotein with a molecular weight of 800,000, migrating in the beta regions upon agarose gel electrophoresis. Loss of immunological properties was observed after heating at 65 degrees C for 30 min. Enzyme immunoassay revealed that the levels of PTA in the serum and tissue showed a positive correlation with the induction of the presence of tumor, and size of the tumor. It is tentatively suggested that PTA values above 150 ng/ml serum are indicators of tumors, because in normal hamsters the PTA range is from 25 to 130 ng/ml serum. Immunohistochemically, PTA was demonstrated to be localized within the cytoplasm of epithelial tumor cells of well-differentiated tubular adenocarcinomas.

A new peritoneal dissemination model established from the human pancreatic cancer cell line.

We established a new cell line, HPC-3P4a, with high peritoneal disseminated potential in nude mice. HPC-3P4a was derived from a human pancreatic carcinoma cell line (HPC-3) that had low capacity for peritoneal dissemination. HPC-3P4a developed peritoneal dissemination in 10 of 11 (90.9%) cases, whereas parental HPC-3 developed peritoneal dissemination in one of six (16.7%) cases. The metastatic foci in the peritoneum showed essentially the same histologic appearance of parental involvement. The tumorigenicity, motility, and adhesive activity of HPC-3P4a to the extracellular matrix were stronger than were those of the HPC-3. In FACS analysis, HPC-3P4a significantly increased the expression of alpha6 and alpha(v)beta5 integrins, while it decreased alpha2 integrin, hCD44H, and hCD44v 10, as compared with HPC-3. The VEGF production of HPC-3P4a was significantly lower than that of HPC-3. Analysis of gene macroarrays showed a variety of cytokines, interleukin, and other immunomodulatory, and their receptors were up-regulated and down-regulated on an mRNA level in HPC-3P4a cells, compared with HPC-3 cells. Intrasplenic injection of HPC-3P4a produced no liver metastasis. We named our original highly liver metastatic cell line HPC-3H4 (previously reported). This HPC-3H4 cell was established by repeated intrasplenic injection from parental cell HPC-3; thus, it developed high liver metastasis. Moreover, HPC-3H4 developed peritoneal dissemination by intra-abdominal injection. In contrast, HPC-3P4a did not develop liver metastasis by intrasplenic injection. These findings are very interesting and might suggest that the process of hematogenous metastasis differed from that of peritoneal dissemination. Thus, this cell line may be useful for investigating the mechanism of peritoneal dissemination in human pancreatic cancer.

Splenic hamartoma associated with thrombocytopenia.

A case of splenic hamartoma associated with thrombocytopenia is reported. A 70-year-old man was referred to our hospital because of carcinoma of the body of the pancreas. Hematological examination disclosed thrombocytopenia and elevated serum CA19-9 and Span-1 levels. In addition to typical findings of pancreatic carcinoma, a solid mass was observed in the spleen by imaging procedures. On ultrasonography, the splenic mass was well demarcated and slightly hypoechoic. Computed tomography demonstrated a homogeneous low-density mass 5 cm in diameter. On T1- and T2-weighted magnetic resonance images, the splenic mass was demonstrated as low intensity and high intensity, respectively. On selective angiography, the tumor was hypervascular. Distal pancreatectomy plus splenectomy was performed. Microscopically, the splenic tumor consisted of red pulp tissue and was diagnosed as splenic hamartoma.

Segmental groove pancreatitis accompanied by protein plugs in Santorini's duct.

"Groove pancreatitis", a form of segmental pancreatitis affecting the head of the pancreas, is localized within the "groove" between pancreas head, duodenum, and common bile duct. Differentiation between groove pancreatitis and pancreatic head carcinoma is often difficult. We report a case of groove pancreatitis in which a hypoechoic mass between the duodenal wall and pancreas was clearly imaged, and narrowing of the second portion of the duodenum and bile duct stenosis were also found. The diagnosis was confirmed by surgery (pylorus-preserving pancreato duodenectomy). The patient was relieved from abdominal pain post operation. Up to the present, the patient has been good condition. We review the clinicopathologic and radiologic features of groove pancreatitis in the Japanese literature and discuss the possible role of Santorini's duct in its pathogenesis. We consider that impacted protein plugs in Santorini's duct are a pathogenic factor in the development of groove pancreatitis. Therefore, the findings of Santorini's duct on endoscopic retrograde pancreatography are very important in the diagnosis of groove pancreatitis. Groove pancreatitis presents various clinical features, such as biliary stenosis, duodenal stenosis, and pancreatic mass, and often masquerades as pancreatic head carcinoma. This condition should be kept in mind in the differential diagnosis of pancreatic head carcinoma.

Proximal gastrectomy and jejunal pouch interposition: evaluation of postoperative symptoms and gastrointestinal hormone secretion.

Reflux esophagitis, dumping syndrome and malnutrition are included in the postgastrectomy complications. To prevent or minimize such sequelae, proximal gastrectomy with an interposed jejunal pouch has been advocated as an organ-preserving surgical strategy to improve quality of life for the patients. Proximal gastrectomy was performed in 44 patients with tumors in the upper third of the stomach; 21 had reconstruction using jejunal pouch interposition between the esophagus and the remnant stomach (JP group), while 23 had reconstruction by esophagogastrostomy (EG group). Re-construction method was selected by each patient on the basis of the informed consent. Thirty-five patients had early gastric cancer. Postoperative courses of patients were reviewed in terms of symptoms, weight maintenance, nutritional status, blood chemistry values, endoscopic findings, and radiographic appearances after a barium meal. Concentrations of gastrointestinal hormones were measured in response to a test meal. The JP procedure permitted increased dietary volume. The JP group showed fewer severe postoperative symptoms than the EG group. After operation, all patients examined in both groups showed hypergastrinemia and all patients examined in the JP group showed hypersecretinemia. In proximal gastrectomy, the JP procedure improved patient's post-operative quality of life.

Cumulative results of chemosensitivity tests for antitumor agents in Japan. Japan Research Society for Appropriate Cancer Chemotherapy.

The Japan Research Society for Appropriate Cancer Chemotherapy set out to summarize the present status of chemosensitivity testing for antitumor agents in Japan. Two different questionnaires were sent to 122 and 94 institutes, respectively, whilst responses were received from 87 (71.3%) and 41 (43%) institutes, respectively. The results showed that chemosensitivity tests were performed in 42 institutes where a total of 2 in vivo and 10 in vitro different assays were performed. Actual cases of chemosensitivity detected by the tests varied from 1 to 368 cases/year/institute with a median of 15 cases and mean +/- standard deviation of 48 +/- 65 cases. The total number of tested cases increased from 1,747 cases in 1993 to 1,934 cases in 1994 and to 2,147 cases in 1995, resulting in an average of 1,891 cases year. The assays used included the adenosine triphopsphate inhibition assay,/the collagen droplet embed drug response assay, the fluorescent dye assay, the growth chamber assay, the histoculture drug response assay, human tumor clonogenic assay, the MTT assay (SDI test), the nuclear damage assay, the nude mouse model, the subrenal capsule assay and the thymidine incorporation assay (scintillation assay). The correlation of in vitro and in vivo results revealed 215 true positive (S/S), 246 false positive (S/R), 45 false negative (R/S) and 595 true negative (R/R) cases, resulting in rates of 47% for true positives and 93% for true negatives, with a 74% accuracy. We concluded that chemosensitivity testing is widely applied in this country and has a high accurate predictive value for advanced carcinomas.

Isolation and partial characterization of a novel amino sugar-containing fucan sulfate from commercial Fucus vesiculosus fucoidan.

Commercial crude fucoidan (Sigma) from the brown seaweed Fucus vesiculosus was fractionated into its polysaccharide components by gel filtration and anion-exchange chromatography to clarify the structure-anticoagulant activity relationship. The products comprised a wide spectrum of fucans ranging from typical fucoidans (major components) containing mainly fucose, sulfate, and no uronic acid to low sulfate-containing heteropolysaccharide-like fucans (minor components) being composed of neutral sugars other than fucose and a high content of uronic acid(s). The polysaccharide components also had a wide range of molecular weight. The typical fucoidans showed a potent anticoagulant activity, whereas the other fucans had no or only slight activity. One of the fractions found as a minor component, was a novel polysaccharide containing an appreciable amount (11.5%) of glucosamine and a small amount (5.2%) of protein in addition to fucose and sulfate, and having a low apparent molecular weight of 6800. This is the first report that a proteoglycan-like, amino sugar-containing fucan sulfate, composed of fucose, galactose, glucose, mannose, xylose, uronic acid, glucosamine, and sulfate in the molar ratio of 1.00:0.04:0.01:0.48:0.24:0.18:0.56:1.90, could be obtained from brown seaweed. However, this polysaccharide showed no anticoagulant activity.

Immunohistochemical analysis of p53 expression in human pancreatic carcinomas.

Alterations in the p53 tumor suppressor gene are involved in the pathogenesis of diverse human cancers. Immunohistochemical detection of the p53 protein has been strongly correlated with mutations in the p53 gene. Fifty-four human exocrine pancreatic tumors of American, Japanese, and Senegalese origin and six xenotransplanted human pancreatic carcinoma cell lines were investigated immunohistochemically with monoclonal anti-p53 antibodies pAb 1801 and BP53-12. Positive nuclear p53 immunoreactivity was detected in 37% of paraffin-embedded primary tumors (21.8% in the Japanese group, 52.6% in the American group) and in 50% of xenotransplanted carcinoma cell lines. Since several intraductal papillary adenocarcinomas exhibited positive p53 immunostain, it seems probable that alterations in this tumor suppressor gene occur relatively early in the process of pancreatic carcinogenesis. No clear correlation was established between p53-positive immunohistochemical staining and tumor stage and histologic appearance, nor with patient age, sex, or survival time. In contrast to ductal carcinomas and intraductal papillary adenocarcinomas, none of the mucinous or adenosquamous pancreatic carcinomas exhibited positive nuclear staining for p53. The fact that more than half of the ethanol-fixed fine-needle aspirates were positive for p53 suggests that this type of immunostain may be of potential diagnostic significance. An investigation of a large series of pancreatic tumors is needed to further evaluate the relationship between p53 alterations and clinicopathologic features in human pancreatic cancer.

Establishment and characterization of a human gastric carcinoma cell line that is highly metastatic to lymph nodes.

The actual mechanisms by which carcinoma cells metastasize to lymph nodes are still unclear, and there is a need to establish in vivo experimental models suitable for the investigation of lymph node metastasis. For the purpose, we established a highly lymph node-metastasizing line, designated AZL5G, derived from a human gastric cancer cell line, AZ521, which had low capacity for lymph node metastasis. AZL5G cells transplanted orthotopically in the nude mouse stomach metastasize predominantly to the regional lymph nodes, showing little potential for hematogenous metastasis. AZL5G tumors developing in the stomach and regional lymph nodes showed poorly differentiated adenocarcinoma with medullary growth, and their histologic appearance strongly resembled that of parental AZ521. The growth activities in vitro of low-metastatic AZ521 and high-metastatic AZL5G were almost the same, but the tumorigenicity in vivo of AZL5G was significantly higher than that of AZ521. AZL5G cells also showed clearly higher abilities of cell locomotion and adhesion to type IV collagen and fibronectin in vitro as compared with AZ521 cells. Flow cytometric analysis demonstrated that the expression of integrin beta1 subfamily except for alpha6 integrin was generally increased in AZL5G cells than in AZ521 cells. Especially, the expression of alpha1 and alpha2 integrins in AZL5G cells was clearly higher than in AZ521, while alpha(v)beta3 integrin, E-cadherin, ICAM-1 and CD44H were not expressed by either cell line. The cell adhesion blocking assay showed that DGEA-containing peptide, which is composed of alpha2 integrin recognition sequence, significantly reduced the adhesiveness of AZL5G cells to type IV collagen as well as to type I collagen and laminin. Furthermore, the administration of anti-alpha2 integrin mAb or DGEA peptide in AZL5G-transplanted nude mice produced a significant reduction in the number of lymph node metastases. These data suggest that the up-regulation of alpha2 integrin expression by gastric cancer cells may play a critical role in the process of lymph node metastasis through the increased adhesiveness to type IV collagen. In conclusion, we established a gastric cancer cell line, AZL5G, with a highly metastatic potential to lymph nodes. This well-characterized line and its in vivo experimental model should be useful for investigation of the mechanisms of lymph node metastasis and for establishment of a new therapeutic approach for human gastric cancer.

Effects of formaldehyde on xenotransplanted human respiratory epithelium.

A laboratory animal model that permits the exposure of xenotransplanted human respiratory epithelium to formaldehyde was used to study the effects of formaldehyde alone or in combination with the ultimate carcinogenic metabolite of benzo[a]pyrene, benzo[a]pyrene diol epoxide. Epithelial cells obtained from autopsies of full-term human fetuses or infants less than one year old were isolated, amplified in primary cultures, and then inoculated into rat tracheas from which the epithelial layer had been removed. These tracheas then were sealed and transplanted subcutaneously into irradiated athymic nude mice. Four weeks after transplantation, the tracheal lumen was completely covered by epithelium, most of which was of the mucociliary respiratory type. At this stage, tracheal transplants containing tracheobronchial epithelium from 20 different human infant donors were exposed to silastic devices containing 0, 0.5, 1, or 2 mg of formaldehyde. The tracheal transplants were examined histologically 2, 4, 8, or 16 weeks after transplantation. Before being killed, all animals were injected with a single pulse of tritiated thymidine. Important epithelial alterations were seen in the transplants treated with formaldehyde, with a maximum effect visible two weeks after exposure. In most cases, the highest dose of 2 mg produced numerous areas of epithelial erosion and inflammation; however, this effect was not as evident with the lower doses. All doses produced areas of hyperplastic epithelium alternating with areas of atrophic epithelium. Although the differences in predominance of different types of epithelium were not clearly dependent on dose, the labeling index showed dose dependence between two and four weeks after the initiation of exposure. The maximum mean labeling index was three to four times higher than normal, although in some focal hyperplastic-metaplastic lesions the labeling index increased up to 20 times. These studies show that formaldehyde, although toxic at higher doses, is able to elicit at lower doses a proliferative response of the human infant tracheobronchial epithelium that is not preceded by a massive toxic effect. Similar studies were performed using xenotransplanted human adult nasal respiratory epithelium (Study 2). The response pattern was very similar to that of the xenotransplanted human tracheobronchial epithelium from human infants (Study 1). In Study 3, using cells obtained from 11 human infant tracheobronchial epithelia, the formaldehyde applied simultaneously or sequentially with benzo[a]pyrene diol epoxide did not induce epithelial alterations different from those observed with formaldehyde treatments alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Urokinase-type plasminogen activator and plasminogen activator inhibitor-1 as a prognostic factor in human colorectal carcinomas.

BACKGROUND/AIMS: The urokinase pathway of plasminogen activation is known to be involved in proteolytic degradation of the extracellular matrix during carcinoma invasion. METHODOLOGY: We immunohistochemically examined 97 colorectal carcinomas for the expression of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) to investigate whether uPA and PAI-1 expressions could serve as prognostic parameters; the gene expression of uPA and PAI-1 in human colon cancer tissues was also analyzed using reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The relative expression levels of uPA and PAI-1 mRNAs were well correlated with immunoreactivities of uPA and PAI-1, respectively (p < 0.05). In immunohistochemical staining, diffuse specific staining was observed in the cytoplasm of carcinoma cells. uPA expression was detected in 57 carcinoma specimens (58.8%) and PAI-1 expression was detected in 36 specimens (37.1%). With regard to 5-year overall survival rate, patients whose tumors had positive uPA and negative PAI-1 immunoreactivities had a significantly poorer prognosis (p < 0.05). In multivariate analysis, the combined variable of uPA and PAI-1 was shown to be an independent prognostic indicator. CONCLUSIONS: Our results suggest that immunohistochemical combined analysis of uPA and PAI-1 may be a useful prognostic factor in colorectal carcinoma patients.