Masayoshi Mai

Enhanced production of matrix metalloproteinases and activation of matrix metalloproteinase 2 (gelatinase A) in human gastric carcinomas

We examined the production and tissue localization of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in gastric carcinoma tissues. MMP‐I (tissue collagenase), MMP‐9 (gelatinase B) and TIMP‐2 were immunolocalized in carcinoma cells and MMP‐2 (gelatinase A) on tumor cell membranes, whereas no or little immunostaining for MMP‐3 (stromelysin‐1) and TIMP‐I was seen in carcinoma cells. Stromal cells in carcinoma tissue were also positively stained for these MMPs and TIMPs. MMP‐2 immunostaining was observed exclusively on advanced gastric carcinoma cells and correlated with vascular invasion by tumor cells. Sandwich enzyme immunoassays revealed enhanced production of MMP‐1, MMP‐2, MMP‐3, MMP‐9 and TIMP‐I by carcinoma tissues. Gelatinolytic activities were significantly higher in carcinoma samples than in normal controls. Using gelatin zymography, active forms of MMP‐2 and MMP‐9 were more frequently detected in carcinoma tissue, and the activation rate of the zymogen of MMP‐2 (proMMP‐2), but not that of proMMP‐9, correlated well with degree of local invasion and lymphatic permeation. Our data indicate an enhanced production of 4 MMPs in gastric carcinoma tissue and suggest that activation of pro‐MMP‐2 may be a key step for spreading of gastric carcinoma cells.

Superficial-type adenomas and adenocarcinomas of the colon and rectum: A comparative morphological study

BACKGROUND/AIMS It has been uncertain whether colorectal carcinomas preferentially arise on preexisting adenomas or de novo. However, from a morphological viewpoint, it seems unlikely that pedunculated or exophytic malignant polyps progress to the deeply ulcerated advanced carcinomas usually found clinically. METHODS The morphological features of 26 nonpolypoid, superficial-type colorectal tumors (17 adenomas and 9 adenocarcinomas) were compared to clarify the developmental route of colorectal carcinomas. RESULTS The adenomas and adenocarcinomas were very similar in size and gross appearance; however, examination of the surface appearances of unsectioned tumors by dissecting microscopy was helpful for distinguishing the two. Histologically, no adenomatous tissue was found in any case of superficial-type adenocarcinoma. Five of the nine adenocarcinomas, even including those of small size, invaded the submucosal layer, and two showed lymph node metastasis. CONCLUSIONS These findings suggest that superficial-type adenocarcinomas show rapid growth and aggressive behavior. We suggest that this type of carcinoma may not progress by the adenoma-to-carcinoma pathway but that it may arise from a very small superficial-type adenoma.

Expression and tissue localization of matrix metalloproteinase 7 (matrilysin) in human gastric carcinomas. Implications for vessel invasion and metastasis

We examined the production and tissue localization of matrix metalloproteinase‐7 (MMP‐7 = matrilysin) in human gastric carcinomas and analyzed the data in connection with the clinicopathological factors. Sandwich‐enzyme immunoassay for the zymogen of MMP‐7 (proMMP‐7) showed enhanced production of MMP‐7 in carcinoma tissues compared with control normal gastric mucosa. Immunohistochemical studies demonstrated that MMP‐7 is localized predominantly to the carcinoma cells in 71% of the carcinoma samples (30/42 cases). The percentage of immunoreactive carcinoma cells to total carcinoma cells (positive ratio) was significantly higher in intestinal‐type carcinomas (26%, median) than in diffuse‐type carcinomas (3%, median) (p < 0.05). The positive ratio was markedly higher in carcinoma groups with vascular invasion (28%) or lymphatic permeation (12%) than in those without invasion (6%) or permeation (0%) (p < 0.05). It was also significantly higher in carcinoma groups with liver (49%) or lymph‐node metastases (15%) than in those without metastases (6 and 2% respectively) (p < 0.05). Both proMMP‐7 of 28 kDa and active MMP‐7 of 19 kDa were detected in the carcinoma tissues by immunoblotting. Reverse‐transcription‐PCR showed specific amplification in 50% of the carcinoma cases (6/12 cases) and 8% of the normal control specimens (1/12 cases). In situ hybridization demonstrated that the carcinoma cells almost selectively express MMP‐7 mRNA. These data suggest that enhanced production of proMMP‐7 and its activation are implicated in invasion and metastasis of human gastric carcinomas. Int. J. Cancer (Pred. Oncol.)79:187–194, 1998.© 1998 Wiley‐Liss, Inc.

The usefulness of CEA and/or CA19-9 in monitoring for recurrence in gastric cancer patients: a prospective clinical study

AbstractBackground. Many studies on postoperative carcinoembryonic antigen (CEA) and/or carbohydrate antigen (CA)19-9 monitoring after operation for gastric cancer have been reported, but most have been retrospective. Methods. A nationwide observational study was implemented in 135 leading institutions in Japan to evaluate the significance of CEA and/or CA19-9 in postoperative monitoring for recurrence in patients with advanced gastric cancer. Three hundred and twenty-one patients examined in this analysis underwent radical gastrectomy at one of Japans leading institutions between November 1993 and March 1996 and had been followed up for at least 5 years. Serum levels of CEA and CA19-9 were examined preoperatively and every 3 months postoperatively, with diagnostic imagings, such as chest X-ray, computed tomography (CT), and ultrasonography also being performed every 3 months. Results. Recurrence was observed in 120 patients (peritoneum, 48; liver 16; lymph node, 16; multiple sites, 25; and others, 12). Sensitivities of CEA and either CEA or CA19-9, or both, for recurrence were 65.8% and 85.0%, respectively, both of which values were significantly higher than the preoperative positivities (28.3% and 45.0%, respectively). In most patients with high preoperative levels CEA and/or CA19-9, these tumor markers increased again at recurrence. Recurrent diseases were detected between 5 months after detection by diagnostic imagings and 12 months before detection by diagnostic imagings (mean of 3.1 ± 3.6 months before detection by diagnostic imagings) and between 10 months after detection by diagnostic imagings and 13 months before detection by diagnostic imagings (mean of 2.2 ± 3.9 months before detection by diagnostic imagings) by CEA and CA19-9 monitorings, respectively. Conclusion. These results suggest that CEA and/or CA19-9 monitoring after operation was useful to predict the recurrence of gastric cancer, especially in almost all the patients with high preoperative levels of these markers.

Preparation of specific antibodies against murine IL-1ra and the establishment of IL-1ra as an endogenous regulator of bacteria-induced fulminant hepatitis in mice.

Blocking monoclonal antibodies (mAbs) specific to mouse interleukin‐1 receptor antagonist (IL‐1ra) were prepared by immunizing Armenian hamsters with recombinant mouse IL‐1ra. A sensitive and specific ELISA against mouse IL‐1ra was also established. In Propionibacterium αcnes‐induced liver injury, P. acnes induced transient increase of serum tumor necrosis factor‐α levels but not those of IL‐1ra, IL‐1, and IL‐6. However, subsequent lipopolysaccharide (LPS) challenge induced the increase of serum levels of all these cytokines and the peak serum IL‐1ra level was more than 20 times as high as serum IL‐1 levels. Immunohistochemical analysis demonstrated that IL‐1ra was predominantly produced by hepatocytes during the course of the priming phase by P. acnes and eliciting phase by LPS challenge. Furthermore, the administration of a mAb to mouse IL‐1ra exacerbates the liver injury induced by P. acnes and sublethal dose of LPS, suggesting a protective role of endogenous IL‐1ra in this liver injury model. J. Leukoc. Biol. 58: 90–98; 1995.

Inhibition of metastasis in human gastric cancer cells transfected with tissue inhibitor of metalloproteinase 1 gene in nude mice

Tissue inhibitors of metalloproteinases (TIMPs) act as negative regulators of matrix metalloproteinases (MMPs) that degrade extracellular matrix. We evaluated the metastatic ability of the highly metastatic human gastric cell line KKLS, and that of cells transfected with exogenous TIMP‐1 gene by the orthotopic transplantation model in nude mice.

Medullary carcinoma with lymphocytic infiltration of the stomach. Clinicopathologic study of 27 cases and immunohistochemical analysis of the subpopulations of infiltrating lymphocytes in the tumor

The current study attempts to clarify the possible immune response that occurs in medullary carcinoma with lymphocytic infiltration of the stomach by an immunohistochemical analysis of the subpopulations of tumor‐infiltrating lymphocytes. This carcinoma was histologically characterized by the sparse population of small nests consisting of poorly differentiated carcinoma cells, widely separated by intervening nondesmoplastic stroma infiltrated uniformly with abundant lymphocytes frequently accompanied by lymph follicles. An immunohistochemical analysis revealed that T‐cells were evenly distributed throughout the tumor with intimate contact with individual carcinoma cells, except the lymph follicles consisted mainly of B‐cells. Because of the similarities of morphologic features and subpopulations of tumor‐infiltrating lymphocytes of this carcinoma to the normal lymphoid tissue, an organized immune response combined with cell‐mediated and humoral immunities against the invading carcinoma cells seemed to occur in this type of gastric carcinoma, resulting in a excellent prognosis compared with that in ordinary gastric carcinoma.

Alpha-fetoprotein (AFP)-producing gastric carcinoma: is it hepatoid differentiation?

Biochemical and immunohistochemical analyses were done on five cases of gastric carcinoma with excessive production of alpha‐fetoprotein (AFP). Histologic and ultrastructural examination of these cases showed conventional poorly differentiated adenocarcinoma of cuboidal or polygonal tumor cells in the medullary area with scattered AFP‐positive cancer cells. Comparative studies on serum AFP between these cases and in hepatocellular carcinoma (HCC) or in testicular yolk sac tumor cases using concanavalin A (ConA)‐affinity and lens culinalis agglutinin A (LCA)‐affinity sepharose columns revealed that the AFP derived from four cases had a high ConA nonadsorping rate and high LCA‐reactive fraction similar to that of yolk sac tumor. The AFP from one case had a small LCA‐reactive fraction similar to that of HCC. Further immunohistochemical study using several markers for liver cells or germ cell tumor did not show additional evidence of these tumor cells to differentiate into liver cells or yolk sac tumor cells. Thus, this study indicates that AFP‐producing gastric carcinomas are not always derived from hepatoid differentiation of the foregut. These gastric carcinomas might be categorized into medullary tumor with gastrointestinal tract‐specific AFP.

α-Difluoromethylornithine induces apoptosis as well as anti-angiogenesis in the inhibition of tumor growth and metastasis in a human gastric cancer model

Polyamines are essential in various biological systems such as cellular proliferation including tumor growth, differentiation and neoplastic transformation including carcinogenesis. α‐Difluoromethylornithine (DFMO) is a specific irreversible inhibitor of ornithine decarboxylase, a key enzyme in polyamine biosynthesis, and has been used for clinical chemotherapy and chemoprevention trials against several tumors with various effects. The cellular mechanisms of DFMO action are unclear. Because our hypothesis with regard to polyamine‐directed chemoprevention includes anti‐angiogenesis and apoptosis as essential parts of the cellular mechanism of action of DFMO, we examined these effects in our human gastric cancer model. In our initial experiments, DFMO inhibited the growth of both human umbilical vein endothelial cells (HUVEC), angio‐endothelial cells in vitro, and KKLS, a gastric cancer cell line, in culture, and also the growth of KKLS cells transplanted into nude mice. DFMO also inhibited liver metastasis of KKLS orthotransplanted in the stomach of nude mice. The vessel density of DFMO‐treated tumors was significantly lower than that of non‐treated tumors. The apoptotic index was significantly greater in DFMO‐treated tumors than in non‐treated tumors. These results suggest that anti‐angiogenesis and apoptosis play significant roles in the DFMO inhibition of the growth and metastasis in this human gastric cancer model and provide evidence that DFMO induces apoptosis. Int. J. Cancer 85:243–247, 2000. ©2000 Wiley‐Liss, Inc.

Mutant K-ras in apparently normal mucosa of colorectal cancer patients. Its potential as a biomarker of colorectal tumorigenesis.

Background. The best way to reduce the incidence of colorectal cancer mortality would be to prevent this cancer. However, none of the biomarkers proposed can accurately identify persons at increased risk of colorectal cancer or those at low risk. As a possible genetic biomarker, K‐ras mutations, which are frequently found in colorectal cancers, were analyzed in apparently normal colorectal mucosa.