Clinicopathological and prognostic significance of mucin phenotype in gastric cancer.

BACKGROUND AND OBJECTIVES: Gastric and intestinal mucin phenotype cell markers are widely expressed in gastric carcinoma cells, irrespective of their tumor histological type. In the present study, we tried to reveal the clinicopathological significance of mucin phenotype in human gastric carcinomas. Moreover, we investigated the clinical significance of RUNX3 in association with mucin phenotype. METHODS: The mucin expression of MUC5AC, MUC6, MUC2, and CD10 was evaluated in 97 gastric carcinomas by immunohistochemistry. Tumors were classified into gastric (G), gastric and intestinal mixed (GI), intestinal (I), and null (N) phenotype according to combination of mucin expression. RESULTS: The rate of G, GI, I, and N phenotype was 40.0%, 38.1%, 10.3%, and 19.6%, respectively. Mucin phenotype was also significantly correlated with several clinicopathological findings. Patients with I phenotype had a significantly poorer prognosis than those with any other phenotypes. They also had a higher rate of postoperative liver metastasis. Multivariate analysis revealed that mucin phenotype was a significant independent prognostic factor. We suggested that Loss of RUNX3 expression might correlate with intestinal phenotype and postoperative outcome. CONCLUSIONS: Mucin phenotype has a significant prognostic value and may be a useful marker for the treatment of human gastric carcinoma.

Prognostic significance of platelet-derived growth factor-BB expression in human esophageal squamous cell carcinomas.

BACKGROUND: Cancer metastases are commonly found in the lymphatic system and tumor lymphangiogenesis requires the interplay of several growth factors. The expression of platelet-derived growth factor (PDGF)-BB and vascular endothelial growth factor (VEGF)-C in esophageal cancer was investigated to define their clinicopathological significance. MATERIALS AND METHODS: Using immunohistochemistry, the expression of PDGF-BB and VEGF-C was examined, along with lymphatic vessel density (LVD) in 53 patients with esophageal cancer. RESULTS: PDGF-BB and VEGF-C expression was positive in 31 cases (58.5%) and 38 cases (71.7%), respectively, and expression correlated with lymph node metastasis and lymphatic invasion. Furthermore, PDGF-BB expression correlated with the depth of tumor invasion and the size of the tumor, and PDGF-BB-positive patients had a significantly poorer prognosis than PDGF-BB-negative patients. The LVD in positive PDGF-BB or VEGF-C tumors was higher than in negative tumors. CONCLUSION: PDGF-BB may play a pivotal role in lymphangiogenesis and tumor growth in esophageal cancer.

Clinical significance of programmed death-1 ligand-1 and programmed death-1 ligand-2 expression in human esophageal cancer.

PURPOSE: The negative regulatory programmed death-1/programmed death-1 ligand (PD-1/PD-L) pathway in T-cell activation has been suggested to play an important role in tumor evasion from host immunity. In this study, we investigated the expression of PD-L1 and PD-L2 in human esophageal cancer to define their clinical significance in patients' prognosis after surgery. EXPERIMENTAL DESIGN: PD-L1 and PD-L2 gene expression was evaluated in 41 esophagectomy patients by real-time quantitative PCR. The protein expression was also evaluated with newly generated monoclonal antibodies that recognize human PD-L1 (MIH1) and PD-L2 (MIH18). RESULTS: The protein and the mRNA levels of determination by immunohistochemistry and real-time quantitative PCR were closely correlated. PD-L-positive patients had a significantly poorer prognosis than the negative patients. This was more pronounced in the advanced stage of tumor than in the early stage. Furthermore, multivariate analysis indicated that PD-L status was an independent prognostic factor. Although there was no significant correlation between PD-L1 expression and tumor-infiltrating T lymphocytes, PD-L2 expression was inversely correlated with tumor-infiltrating CD8(+) T cells. CONCLUSIONS: These data suggest that PD-L1 and PD-L2 status may be a new predictor of prognosis for patients with esophageal cancer and provide the rationale for developing novel immunotherapy of targeting PD-1/PD-L pathway.

A clinical and immunohistochemical study on gastrointestinal mesenchymal tumor (GIMT): RCAS1 as a predictor for recurrence of GIMT.

Gastrointestinal mesenchymal tumors (GIMTs) are the most common mesenchymal tumors of the gastrointestinal tract. RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) is a cancer cell-surface antigen and has been identified as a prognostic factor in several cancer types. It is thought that tumor cells escape immune attack by expressing RCAS1, which induces apoptosis in receptor-positive immune cells. The current study was designed to elucidate the histogenesis of these tumors by using various immunohistochemical markers, and identify parameters that will help to establish the criteria of malignancy in the GIMT. We also discuss the clinicopathological significance of RCAS1 expression in the diagnosis and prognosis of GIMTs. A total of 70 cases of GIMTs were reviewed. Immunohistochemistry was performed between 1990 and 2000, with the avidin-biotin-peroxidase complex method on 3 microm-thick sections of formalin-fixed paraffin-embedded specimens of GIMTs. Antibodies to the following antigens were used: KIT (CD117), CD34 alpha-SMA, Desmin, cytokeratin, S-100 protein, p53, and RCAS1. Recurrence-free survival analysis was done with Stat View-J 5.0 statistical packages. Univariate analysis for a recurrence-free prognosis demonstrated that antibody detection of p53 expression (p=0.0333) and expression of RCAS1 (p=0.0008) is correlated with a significantly higher potential of recurrence. On multivariate analysis, tumor size and RCAS1 expression were independently and inversely correlated with recurrence-free survival. The expression of RCAS1 has not previously been reported in GIMT; indeed, our study suggests that the expression of RCAS1 is correlated with recurrence not only in carcinomas, but also in mesenchymal tumors.

High lymphatic vessel density correlates with overexpression of VEGF-C in gastric cancer.

Lymph node metastasis is one of the most important prognostic factors in malignant tumors. In this study, we investigated vascular endothelial growth factor (VEGF)-C expression in human gastric cancer using immunohistochemical techniques and determined the number of microvessels in peritumoral tissue. VEGF-C expression was positive in 22 of 79 cases (27.8%), and correlated with the presence of lymphatic invasion and lymph node metastasis. We confirmed by reverse transcription-polymerase chain reaction (RT-PCR) that VEGF-C mRNA expression is observed more commonly in cancer tissues than normal tissues. For 59 gastric tumors, we examined lymphatic vessel density (LVD) using the specific lymphatic vessel endothelial hyaluronan receptor (LYVE) -1 antibody. VEGF-C expression was observed in 10 of 25 cases (40%) that exhibited a high LVD. Furthermore, high LVD exhibited a significant correlation with VEGF-C expression. Our findings suggest that VEGF-C plays a pivotal role for lymphangiogenesis and tumor growth in gastric cancer.

Tumor suppression effect using NK4, a molecule acting as an antagonist of HGF, on human gastric carcinomas.

Hepatocyte growth factor (HGF) is involved in malignant behavior of cancers as a mediator of tumor-stromal interactions, facilitating tumor invasion and metastasis. We have investigated whether a blockade of HGF using recombinant NK4, an HGF antagonist, would lead to growth inhibition of the human gastric carcinoma cell line, TMK1. To evaluate the function of endogenous NK4 and investigate its potential inhibitory effect, TMK1 cells were transfected with NK4 plasmid. After selection, NK4-expressing cells (T11) were obtained, and cell growth was evaluated. Significant growth inhibition was observed in the T11-group compared to the control both in vitro and in vivo. Moreover, we investigated the effect of exogenous NK4 transferred by an adenovirus vector (AdCMV.NK4). Cell proliferation of AdCMV.NK4 infected TMK1 cells was significantly inhibited compared with the control group. We also assessed the in vivo tumor suppression effect of AdCMV.NK4. The tumor volume following treatment with AdCMV.NK4 was significantly inhibited compared to that of the control group. These findings indicate that NK4 gene expression has a potential role in controlling proliferation of cancer cells. In conclusion, NK4 is a promising therapeutic agent and its gene delivery may be a new approach to treating patients with advanced gastric cancer.

Amplification/overexpression of Aurora-A in human gastric carcinoma: potential role in differentiated type gastric carcinogenesis.

Aurora-A encodes a cell cycle regulated serine/threonine kinase that has essential functions for centrosome maturation and chromosome segregation. Aurora-A is amplified and overexpressed in various human carcinomas and is suggested to be a potential oncogene. To clarify the potential role of Aurora-A in human gastric carcinoma, we examined the amplification and expression in both tumor cell lines and primary carcinoma. We examined the amplification and overexpression of Aurora-A in 9 gastric carcinoma cell lines and 88 primary gastric carcinomas using Southern and Northern blot analysis, and confirmed a protein expression by immunohistochemical staining. We also investigated the relationship between Aurora-A overexpression and clinicopathological features of the tumors. Aurora-A amplification and overexpression was observed in 29% and 44.4% of cell lines and 12.5% and 41% of primary carcinomas, respectively. There was discordance between gene amplification and transcript expression, since in a previous study DNA amplification was the main mechanism for Aurora-A activation. Aurora-A overexpression exhibited significant association with increasing age and differentiated type gastric carcinoma. It was also detected in early stage gastric cancer as well as in gastric intestinal metaplasia, which is considered as a common precursor lesion for the differentiated type gastric carcinoma, and severe dysplastic cells showed stronger protein expression. We concluded that Aurora-A overexpression may well be involved in differentiated type gastric carcinogenesis. Further evaluation of the possible roles of Aurora-A and the regulation of Aurora-A expression in malignant cells will be critically important for the development of new strategies aimed at controlling the growth of malignant cells.

Frequent and preferential infection of Treponema denticola, Streptococcus mitis, and Streptococcus anginosus in esophageal cancers.

Multiple cancers frequently occur in the upper digestive tract. One possible explanation is that specific bacterial infection stimulates the normal epithelium to initiate inflammation and/or promotes carcinogenesis. This study was undertaken to determine which bacterial species is predominantly associated with esophageal cancer. We examined the bacterial diversity in this type of cancer and in the saliva from healthy people by using a culture-independent molecular method. Here we report the preferential and frequent infection of the oral periodontopathic spirochete Treponema denticola (T. denticola), Streptococcus mitis (S. mitis), and Streptococus anginosus (S. anginosus) in esophageal cancer from different regions of the world, and we also describe the induction of inflammatory cytokines by infection of S. anginosus and S. mitis. Our present data suggest that these three bacteria could have significant roles in the carcinogenic process of many cases of esophageal cancer by causing inflammation and by promoting the carcinogenic process, and that eradication of these three bacteria may decrease the risk of recurrence.

The prognostic significance of overexpression of the decoy receptor for Fas ligand (DcR3) in patients with gastric carcinomas.

BACKGROUND: The FasL-Fas system has an important role in mediating immune-cytotoxic killing of cells such as virus-infected or tumor cells. It was recently reported that there is a soluble decoy receptor (DcR3), which binds to FasL and inhibits FasL-induced apoptosis, and certain tumors may escape FasL-dependent immune-cytotoxic attack by expressing a decoy receptor that blocks FasL. We evaluated whether DcR3 has clinical relevance in actual human gastric cancers. METHODS: : The expression of DcR3 was investigated by Northern blot analysis in a series of 84 primary gastric carcinomas and compared with clinicopathological features and prognosis. The DcR3 expression level was analyzed and quantified densitometrically. The location of DcR3 mRNA in gastric carcinoma tissue was detected by in situ hybridization. RESULTS: The frequency of DcR3 overexpression was 26% (22 of 84 surgical specimens). The DcR3 expression level was significantly associated with lymph node metastasis and pathological stage, but did not correlate with tumor size, metastatic status, or histological type. In situ hybridization demonstrated that DcR3 mRNA was expressed in tumor cells. When the patients were followed up for 63 months, DcR3 overexpression was found to be associated with a significantly shortened duration of overall survival compared with findings in patients having normal DcR3 expression. CONCLUSION: The DcR3 decoy receptor for FasL may be involved in the progression of gastric cancer. Further evaluation of these possible roles of DcR3 and the regulation of DcR3 expression in malignant cells will be critically important for the development of new strategies for controlling the growth of malignant cells that escape host immune surveillance.