Gene expression profile of gastric carcinoma: identification of genes and tags potentially involved in invasion, metastasis, and carcinogenesis by serial analysis of gene expression.

Gastric carcinoma (GC) is one of the most common malignancies worldwide. To better understand the genetic basis of this disease, we performed serial analysis of gene expression (SAGE) on four primary GC samples and one associated lymph node metastasis. We obtained a total of 137,706 expressed tags (Gene Expression Omnibus accession number GSE 545, SAGE Hiroshima gastric cancer tissue), including 38,903 that were unique. Comparing tags from our GC libraries containing different stages and different histologies, we found several genes and tags that are potentially involved in invasion, metastasis, and carcinogenesis. Among these, we selected 27 genes and measured mRNA expression levels in an additional 46 GC samples by quantitative reverse transcription-PCR. Frequently overexpressed genes (tumor/normal ratio > 2) were COL1A1 (percentage of cases with overexpression, 78.3%), CDH17 (73.9%), APOC1 (67.4%), COL1A2 (58.7%), YF13H12 (52.2%), CEACAM6 (50.0%), APOE (50.0%), REGIV (47.8%), S100A11 (41.3%), and FUS (41.3%). Among these genes, mRNA expression levels of CDH17 and APOE were associated with depth of tumor invasion (P = 0.0060 and P = 0.0139, respectively), and those of FUS and APOE were associated with degree of lymph node metastasis (P = 0.0416 and P = 0.0006, respectively). In addition, mRNA expression levels of FUS, COL1A1, COL1A2, and APOE were associated with stage (P = 0.0414, P = 0.0156, P = 0.0395, and P = 0.0125, respectively). Quantitative reverse transcription-PCR analysis also showed a high level of REGIV expression (>100 arbitrary units) in 14 of 46 GC samples (30.4%) but not in noncancerous tissues. We detected V5-tagged RegIV protein in the culture media of cells transfected with pcDNA-RegIV-V5 by Western blot. Our results provide a list of candidate genes that are potentially involved in invasion, metastasis, and carcinogenesis of GC. REGIV may serve as a specific biomarker for GC.

A single nucleotide polymorphism in the MMP-9 promoter affects tumor progression and invasive phenotype of gastric cancer.

PURPOSE: Matrix metalloproteinase-9 (MMP-9, gelatinase B) plays a key role in cancer invasion and metastasis by degradating the extracellular matrix (ECM) and basement membrane barriers. A cytosine (C)-thymidine (T) single nucleotide polymorphism (SNP) at position -1562 in the MMP-9 promoter is reported to affect expression of this gene. The purpose of this study was to investigate the relation between the -1562 C/T polymorphism and the development and progression of gastric cancer. METHODS: The study population included 177 gastric cancer patients and 224 healthy control subjects. The SNP in the MMP-9 promoter was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing. Genotype frequencies were compared between patients and controls, and the association of genotypes with clinicopathological features was studied. RESULTS: Genotype frequencies in gastric cancer patients were similar to those in control subjects (P = 0.223). However, significant association was found between degree of tumor invasion, clinical stage, and lymphatic invasion and the MMP-9 polymorphism in gastric cancer patients (P<0.05, for each). CONCLUSIONS: Our results indicate that the T allele in the MMP-9 promoter is associated with the invasive phenotype of gastric cancer.

No evidence of correlation between the single nucleotide polymorphism of DNMT3B promoter and gastric cancer risk in a Japanese population.

DNA methylation is a major epigenetic modification in humans, and aberrant DNA methylation may play an important role in the development of various cancers through the silencing of some tumor suppressor genes. DNMT3B is required for the establishment and maintenance of genomic methylation patterns. The -149 C/T single nucleotide polymorphism (SNP) in the promoter of DNMT3B has been identified. This SNP influences DNMT3B promoter function, with the T allele having greater activity than the C allele, and is associated with an increased risk of lung cancer. The purpose of our study was to investigate the correlation between the DNMT3B promoter polymorphism and the development and progression of gastric cancer. We analyzed the SNP of the DNMT3B promoter in 152 gastric cancer patients and 247 controls from a Japanese population using PCR-RFLP and sequencing analysis, and also studied the association between the genotypes of DNMT3B and clinicopathological parameters among cases. Allelic difference was not found between gastric cancer patients and control subjects at the target site, -149 bp from the transcriptional start site in the DNMT3B gene promoter. Only the T/T genotype was detected in all gastric cancer patients and control subjects. We concluded that there was no association between SNP of the DNMT3B promoter and gastric cancer risk in a Japanese population.

A single nucleotide polymorphism in the extracellular domain of TRAIL receptor DR4 at nucleotide 626 in gastric cancer patients in Japan.

Death receptor 4 (DR4) is a member of the tumor necrosis factor-related apoptosis-inducing ligand receptor genes. A single nucleotide polymorphism (Thr or Arg, C or G) in the extracellular domain was reported to be associated with a risk of lung cancer, head and neck cancer, and bladder cancer. In this study, we examined the association between the DR4 polymorphism and gastric cancer. The Thr/Thr, Thr/Arg and Arg/Arg genotypes were found in 250 (91.2%), 23 (8.4%) and 1 (0.4%) of 274 gastric cancer patients and in 317 (92.2%), 21 (6.1%) and 6 (1.7%) of 344 control subjects, respectively. The OR of Thr/Arg or Arg/Arg genotype did not reveal a significantly enhanced risk of 1.13 (95% CI, 0.63-2.00) compared to Thr/Thr genotype, suggesting that the DR4 polymorphism did not modify the risk of gastric cancer. In patients, no association between the genotype and clinicopathological characteristics (depth of invasion, lymph node metastasis, distant metastasis, stage and grade of differentiation) of gastric carcinoma was found. DR4 was constantly expressed in gastric carcinoma, but not in non-neoplastic gastric epithelium in immunohistochemistry. In conclusion, a Thr to Arg single nucleotide polymorphism in the extracellular domain of DR4 could not be associated with the development and progression of gastric cancer.

A single nucleotide polymorphism in the MMP-1 promoter is correlated with histological differentiation of gastric cancer.

PURPOSE: Matrix metalloproteinase-1 (MMP-1) plays a key role in cancer invasion and metastasis by degradation of extracellular matrix (ECM) and basement membrane barriers. The 1G/2G single nucleotide polymorphism (SNP) in the MMP-1 promoter at position -1607 bp has been reported to affect the transcriptional activity. In the light of these findings, we investigated whether this SNP in the MMP-1 promoter is associated with the development, differentiation, and progression of gastric cancer. METHODS: The 215 gastric cancer patients and 166 controls were used in this study. The SNP of the MMP-1 promoter was analyzed by PCR-RFLP and sequencing. The genotype frequency was compared between cases and controls, and the association with clinicopathological parameters among cases was studied. RESULTS: The frequency of 1G/2G genotypes in gastric cancer patients was similar to those in controls (p=0.57). The degree of tumor invasion, the presence of lymph node metastasis, and clinical stage showed no significant association with the SNP. On the other hand, we found a significant association with histological differentiation and gender among gastric cancer patients (p<0.05, respectively). CONCLUSIONS: The presence of 2G allele in the MMP-1 promoter did not enhance the risk of gastric cancer; however, it may be involved in differentiation of gastric cancer.

Expression of Cbl linking with the epidermal growth factor receptor system is associated with tumor progression and poor prognosis of human gastric carcinoma.

Cbl proteins play important roles in downregulation of growth factor receptors by acting as ubiquitin ligases and multi-adapter proteins. Ligand-induced desensitization of the epidermal growth factor receptor (EGFR) has been shown to be controlled by Cbl. In the present study, we examined the expression of Cbl in gastric carcinomas and studied the correlation of Cbl expression with clinicopathological characteristics as well as EGFR expression. Cbl protein was expressed in 67% (82/122) of gastric carcinomas, and diffuse expression of Cbl was detected in 29% (35/122) of the cases. The incidence of cases with diffuse expression of Cbl was significantly higher in advanced cases (28/70, 40%) than in early cases (7/52, 14%) (P=0.0010). Diffuse expression of Cbl was significantly associated with metastasis of tumor cells in lymph nodes (P=0.0318). Diffuse expression of EGFR was significantly associated with depth of invasion (P=0.0057), lymph-node metastasis (P=0.0371) and tumor stages (P=0.0278). As the grades of Cbl expression became stronger, the cases with diffuse EGFR expression increased, the positive correlation being significant (P=0.049). All the cases with diffuse expression of Cbl and EGFR were found to show nodal metastasis and to be at an advanced stage. Moreover, the prognosis of the patients with synchronous diffuse expression of Cbl and EGFR was significantly poorer than that of the patients negative for Cbl and focal or negative for EGFR (P=0.0086). The expression of Cbl protein was clearly induced in gastric carcinoma cell lines by transforming growth factor-alpha treatment. These results suggest that Cbl in connection with the EGFR system may be associated with stomach carcinogenesis, invasion and metastasis. Cbl may serve as a novel molecular marker for aggressive gastric carcinoma.

The promoter methylation status of the DNA repair gene O6-methylguanine-DNA methyltransferase in ulcerative colitis.

Patients with long-standing and extensive ulcerative colitis (UC) have an increased incidence of colorectal cancer (CRC). It has been reported that a DNA repair gene, O6-methylguanine-DNA methyltransferase (MGMT) is inactivated by promoter hypermethylation in sporadic CRCs. Hence, we investigated the promoter methylation status of MGMT by methylation specific polymerase chain reaction (PCR) in a total of 67 tissue samples (61 non-cancerous tissues and 6 cancer tissues) from 24 patients with UC. Promoter hypermethylation of MGMT was detected in one well-differentiated adenocarcinoma (16.7%) of 6 cancer samples and not detected in any of adenomas and dysplasias. In non-dysplastic tissues, promoter hypermethylation of MGMT was detected in 2 (3.7%, mucosa with mild inflammation) of 54 samples. The frequency of MGMT promoter hypermethylation in UC-associated CRCs found in this study (16.7%) is obviously lower than previously reported in sporadic CRCs (39.0-42.0%). We also confirmed that 42.9% (6/14) of sporadic CRCs showed the promoter methylation. These findings indicated that promoter hypermethylation of the MGMT gene is infrequent in patients with UC, and may not closely contribute to UC-associated colorectal tumorigenesis. A different genetic pathway for tumor progression may exist between sporadic CRC and UC-associated CRC.

Single nucleotide polymorphism in the hypoxia-inducible factor-1alpha gene in colorectal carcinoma.

Colorectal carcinoma is one of the most common malignancies in the world, and its incidence has increased in recent years. We have reported that expression of hypoxia-inducible factor (HIF)-1alpha correlates with expression of vascular endothelial growth factor (VEGF), tumor stage, lymphatic invasion, venous invasion, and liver metastasis. It has also been reported that a single nucleotide polymorphism (SNP) in exon 12 of HIF-1alpha gene is present in renal cell carcinoma and head and neck squamous cell carcinoma patients. We investigated the C1772T polymorphism in colorectal cancer patients and healthy control subjects to clarify the mechanism of HIF-1alpha activation in colorectal carcinoma. The exon 12 genotype was not associated with sex or age. The distribution of HIF-1alpha genotypes in controls was 89 C/C (89%), 11 C/T (11%), and 0 T/T (0%). The distribution of HIF-1alpha genotypes in colorectal cancer patients was 100 C/C (100%), 0 C/T (0%), and 0 T/T (0%). The difference in genotype distribution between patients and control subjects was significant (p<0.0005). These results suggest that the C1772T polymorphism in HIF-1alpha is not involved in progression or metastasis of colorectal carcinoma.

Angiogenic switch occurs during the precancerous stage of human esophageal squamous cell carcinoma.

We previously reported that vascular endothelial growth factor (VEGF) expression correlates with vessel density in human esophageal squamous cell carcinomas. However, tumor angiogenesis is not controlled simply by the presence of VEGF, and is likely regulated by several angiogenic factors produced by tumor and host cells. The goal of the present study was to determine the angiogenic profile of precancerous and cancerous lesions of the esophagus. Expression of mRNAs for VEGF, platelet derived endothelial cell growth factor (PD-ECGF), basic fibroblast growth factor (bFGF), and interleukin (IL)-8 was examined in six esophageal carcinoma cell lines and fresh biopsy specimens from 16 patients with invasive esophageal carcinoma by RT-PCR. Immunohistochemical analyses with antibodies against VEGF, PD-ECGF, bFGF, and IL-8 were performed on archival specimens of 60 normal esophageal mucosa, 11 dysplasias and 49 carcinomas of the esophagus. Microvessels were stained with anti-CD34 antibody and quantified by counting the number of vessels in a x200 field in the most vascularized areas of the tumor. Esophageal carcinoma cell lines and tumor tissues expressed mRNAs for one or more these angiogenic factors at various levels. An initial increase in vessel density and enhanced expression of PD-ECGF and VEGF were observed in dysplastic epithelium. Vessel density was significantly higher in more advanced lesions. bFGF and IL-8 were not expressed in dysplasias and mucosal carcinomas, but expression was increased in late stage squamous cell carcinoma. These findings suggest that the angiogenic switch is a very early event in the development of invasive carcinoma. Several different angiogenic factors produced by tumor cells and host cells may regulate angiogenesis during different steps of esophageal carcinogenesis.

DNA demethylation of vascular endothelial growth factor-C is associated with gene expression and its possible involvement of lymphangiogenesis in gastric cancer.

Previous studies have indicated that lymphangiogenesis in solid tumors is associated with lymphatic metastasis. Overexpression of Vascular endothelial growth factor (VEGF)-C plays a major role in lymphangiogenesis in cancers. In the present study, DNA methylation and expression of the VEGF-C gene was investigated in gastric cancer (GC). Four GC cell lines (MKN-45, MKN-74, HSC-39 and HSC-43) showed no expression of VEGF-C, and the VEGF-C gene was found to be methylated in these cells. In contrast, 7 GC cell lines (MKN-1, MKN-7, MKN-28, TMK-1, KATO-III, SH101-P4 and HSC-44PE) expressed VEGF-C, and the VEGF-C gene was found to be unmethylated in these cell lines. In addition, expression of VEGF-C mRNA was retrieved by treatment with a demethylating agent, Aza-2'-deoxycytidine. In GC tissue samples, bisulfite DNA sequencing analysis revealed that VEGF-C was not methylated in 9 (29.0%) of 31 GC samples, whereas demethylation was not observed in corresponding non-neoplastic mucosa samples. Overexpression of VEGF-C mRNA was observed in 16 (51.6%) of 31 GC samples by quantitative reverse transcription-polymerase chain reaction. Of the 9 GC cases with VEGF-C demethylation, 8 (88.9%) overexpressed VEGF-C. In contrast, of the 22 GC cases without VEGF-C demethylation, 8 (36.4%) overexpressed VEGF-C (p = 0.0155). Furthermore, lymphatic vessel density determined by immunostaining of podoplanin in GC tissues was associated with overexpression of VEGF-C (p < 0.0001). These results suggest that demethylation and activation of the VEGF-C gene is likely involved in lymphangiogenesis in GC.

Accumulation of DNA methylation is associated with tumor stage in gastric cancer.

BACKGROUND: The authors purpose in this study was to clarify the difference in terms of clinicopathologic features between gastric cancer (GC) with high numbers of DNA methylated genes and CpG island methylator phenotype (CIMP)-positive GC as originally defined. METHODS: We analyzed DNA methylation of 12 tumor-related genes (hMLH1, MGMT, p16(INK4a), CDH1, RAR-beta, HLTF, RIZ1, TM, FLNc, LOX, HRASLS, HAND1) in 75 samples of GC from 75 patients, 25 samples of corresponding nonneoplastic mucosa from 25 patients, and 10 samples of normal gastric mucosa from 10 healthy young individuals by methylation-specific polymerase chain reaction (PCR) and bisulfite PCR. We also investigated CIMP status by examining the methylation of five MINT loci and p53 mutation status by PCR single-strand conformation polymorphism. We measured levels of expression of mRNAs for these 12 genes by quantitative reverse transcription PCR in 50 GC specimens. RESULTS: The average number of methylated genes per tumor was 4.83. DNA methylation of each gene was correlated with low expression of the respective mRNA. High methylation (GC with 5 or more methylated genes) was detected in 39 (52.0%) of 75 GCs. Twenty-nine (37.8%) of 75 GCs were CIMP-positive. DNA methylation of each of the 12 genes was observed more frequently in the high-methylation group than in the low-methylation group. Methylation of 6 specific genes occurred more frequently in CIMP-positive GC than in CIMP-negative GC. Methylation of the remaining 6 genes was not correlated with CIMP-status. High methylation was found more frequently in Stage III/IV GC (26 of 40 cases, 65.0%) than in Stage I/II GC (13 of 35 cases, 37.1%, P = 0.029).CONCLUSIONS.These findings indicate that GCs with higher numbers of methylated genes have more distinct DNA methylation profiles than the originally defined CIMP-positive GCs. DNA methylation of tumor-related genes accumulates in conjunction with tumor progression.

Molecular-pathological prognostic factors of gastric cancer: a review.

Invasion and metastasis are critical determinants of cancer morbidity. Genes and molecules participating in these steps must be regarded as potential prognostic factors. Growth factors and their receptors, cell-cycle regulators, cell-adhesion molecules and matrix-degrading enzymes are those to be used as prognostic factors, including epidermal growth factor (EGF), EGF receptor, K-sam, HER-2, interleukin (IL)-8, vascular endothelial growth factor (VEGF), cyclin E, p27, E-cadherin, CD44v6, matrix metalloproteinase-1 (MMP-1), and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1). Alterations in epigenetics, such as aberrant DNA methylation and histone modification that are, in part, associated with the tumor progression of gastric cancer, can be candidate prognostic factors. The number of methylated genes may serve as a marker of tumor progression. Genetic polymorphism not only affects cancer susceptibility but also influences malignant phenotype; examples include single-nucleotide polymorphism in the HER-2 and MMP-9 genes. Comprehensive gene expression analyses are useful to search for novel genes related to invasion and metastasis and potential prognostic factors. Serial analysis of gene expression (SAGE) has identified several these genes, such as CDH17, APOE, FUS, COL1A1, COL1A2, GW112, and MIA. Overexpression of MIA is found to be associated with poor prognosis. Microarray analysis has great potential for identifying the characteristics of individual cancers, from the view point of gene expression profiles. A combination of these examinations can not only foretell a patient's prognosis but can also give information directly connected with personalized cancer medicine and prevention.

Histone H3 acetylation is associated with reduced p21(WAF1/CIP1) expression by gastric carcinoma.

Histone acetylation appears to play an important role in transcriptional regulation. Inactivation of chromatin by histone deacetylation is involved in the transcriptional repression of several tumour suppressor genes, including p21(WAF1/CIP1). However, the in vivo status of histone acetylation in human cancers, including gastric carcinoma, is not well understood. This study shows that histone H3 in the p21(WAF1/CIP1) promoter region is hypoacetylated and that this hypoacetylation is associated with reduced p21(WAF1/CIP1) expression in gastric carcinoma specimens. Chromatin immunoprecipitation assays revealed that histone H3 was hypoacetylated in the p21(WAF1/CIP1) promoter and coding regions in 10 (34.5%) and 10 (34.5%) of 29 gastric carcinoma specimens, respectively. Hypoacetylation of histone H4 in the p21(WAF1/CIP1) promoter and coding regions was observed in 6 (20.7%) and 16 (55.2%) of 29 gastric carcinoma specimens, respectively. p21(WAF1/CIP1) mRNA levels were associated with histone H3 acetylation status in the p21(WAF1/CIP1) promoter region (p = 0.047) but not p53 mutation status (p = 0.460). In gastric carcinoma cell lines, expression of p21(WAF1/CIP1) protein was induced by trichostatin A, a histone deacetylase inhibitor. This induction was associated with hyperacetylation of histone H3 in the p21(WAF1/CIP1) promoter region. Hyperacetylation of histone H4 in the p21(WAF1/CIP1) promoter region did not appear to be associated with increased expression. Induction of p21(WAF1/CIP1) protein expression was associated with hyperacetylation of histones H3 and H4 in the p21(WAF1/CIP1) coding region. Expression of a dominant-negative mutant of p53 reduced expression of p21(WAF1/CIP1) protein. Histone H4 acetylation in both the promoter and coding regions of the p21(WAF1/CIP1) gene in cells expressing dominant-negative p53 was less than half of that in cells expressing wild-type p53, whereas histone H3 acetylation in both the promoter and coding regions was slightly reduced (by approximately 20%) in cells expressing the dominant-negative p53. These findings provide evidence that alteration of histone acetylation occurs in human cancer tissue specimens such as those from gastric carcinoma.

A single nucleotide polymorphism in the 5' untranslated region of the EGF gene is associated with occurrence and malignant progression of gastric cancer.

OBJECTIVE: Epidermal growth factor (EGF) has many biological functions and plays an important role in the progression of various tumors including gastric cancer. An A-G single nucleotide polymorphism (SNP) at position 61 in the 5'-untranslated region (UTR) of the EGF gene has recently been reported to be associated with different levels of EGF production. We examined whether this polymorphism is correlated with the development and malignant phenotypes of gastric cancer. METHODS: The study population included 200 gastric cancer patients and 230 healthy control subjects. The SNP in the 5'-UTR of the EGF gene was analyzed by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: The A allele was significantly less frequent in patients than in controls (p = 0.01). Individuals with the A/A or A/G genotype showed a significantly lower risk of gastric cancer than those with the G/G genotype [adjusted odds ratio (OR) = 0.56], whereas the same genotypes were associated with malignant progression of this cancer, e.g. deeper tumor invasion, increased lymph node metastasis and advanced clinical stage, and histological classification in gastric cancer patients (adjusted OR = 1.80, 1.98, 2.26 and 1.89, respectively). CONCLUSIONS: Our findings suggest that the A-G polymorphism of EGF is involved not only in the occurrence but also in the malignant progression of gastric cancer.

Quantitative analysis of lymphangiogenic markers for predicting metastasis of human gastric carcinoma to lymph nodes.

The spread of tumor cells to regional lymph nodes is an early event of gastric cancer metastasis. In our study, we assessed the expression of lymphangiogenic factors and lymphatic endothelial markers in gastric carcinoma tissues and compared expression levels with the status of lymph node metastasis. We also examined the correlation between lymphatic vessel density (LVD) in primary tumors and lymph node metastasis. Paired biopsy samples (tumor and corresponding normal mucosa) of gastric tissue were obtained from 39 patients with gastric carcinoma. The expression of VEGF-C, VEGF-D, VEGFR-3 and podoplanin mRNAs was assessed by real-time quantitative PCR. The expression of VEGF-C (but not of VEGF-D) was significantly greater in patients with lymph node metastasis than in those without metastasis. The expression of lymphatic endothelial markers VEGFR-3 and podoplanin was also significantly greater in the node-positive group. LVD, as assessed by immunohistochemistry for podoplanin, was correlated with lymph node metastasis. These results indicate that quantitative analysis of lymphangiogenic markers in gastric biopsy specimens may be useful in predicting metastasis of gastric cancer to regional lymph nodes.

Reduced expression of the TSP1 gene and its association with promoter hypermethylation in gastric carcinoma.

Thrombospondin-1 (TSP1) is a potent peptide shown in some tumor systems to be linked with angiogenesis. Epigenetic alteration of TSP1 has been reported in various primary tumors. However, the expression pattern of TSP1 has not been characterized in gastric carcinoma. We measured levels of TSP1 mRNA expression using quantitative RT-PCR in 30 gastric carcinomas and 10 non-neoplastic mucosae. In addition, we examined the correlation of the levels of TSP1 mRNA expression levels with promoter methylation status of TSP1 monitored by methylation-specific PCR as well as P53 mutation status detected by PCR-single-strand conformation polymorphism. Promoter hypermethylation of the TSP1 gene was found in 10 (33%) of 30 gastric carcinomas, and TSP1 mRNA expression levels were associated with promoter hypermethylation of TSP1 (p = 0.017; Mann-Whitney U test). P53 mutation was found in 5 (17%) of 30 gastric carcinomas, however, TSP1 mRNA expression was not associated with P53 mutation status (p = 0.858; Mann-Whitney U test). There was no correlation between TSP1 mRNA expression levels and T grade, N grade, tumor stage, or histological type. Our results suggest that transcriptional inactivation of TSP1 by aberrant DNA methylation of the promoter region may participate partly in stomach carcinogenesis through TSP1 down-regulation.

A single nucleotide polymorphism in the transmembrane domain coding region of HER-2 is associated with development and malignant phenotype of gastric cancer.

Alterations of the HER-2 (erbB-2/neu) proto-oncogene have been associated with carcinogenesis and poor prognosis of certain cancers. A single nucleotide polymorphism (Ile/Val, A/G) in the transmembrane domain was reported to be associated with a risk of breast cancer. In our study, we examined the association between the HER-2 polymorphism and gastric carcinoma. The Ile/Ile, Ile/Val and Val/Val genotypes were found in 146 (68.9%), 56 (26.4%) and 10 (4.7%) of 212 gastric cancer patients and in 234 (81.5%), 48 (16.7%) and 5 (1.8%) of 287 control subjects, respectively. The Ile/Val or Val/Val genotype was significantly more frequent in patients than in controls (p = 0.005 and 0.033, respectively). The OR of Val/Val genotype then revealed a significantly enhanced risk of 3.25 (95% CI 1.09-9.70) compared to Ile/Ile genotype; heterozygous Ile/Val genotype showed an intermediate risk of 1.97 (1.27-3.06). In patients, carcinomas of advanced stage were significantly more frequent in patients with Ile/Val or Val/Val genotype than those with Ile/Ile genotype (p < 0.001). The logistic regression analysis for tumor invasion, lymph node metastasis and distant metastasis revealed that lymph node metastasis was most closely associated with the HER-2 genotype. These results suggest that this nucleotide polymorphism in the transmembrane domain-coding region of HER-2 could be associated with development of gastric carcinoma and may serve as a predictor of risk for a malignant phenotype of gastric cancer. The association of HER-2 genotype with clinicopathologic characteristics of gastric cancer was also suggested, which has to be confirmed with a larger sample size.