Reduced MUTYH, MTH1, and OGG1 expression and TP53 mutation in diffuse-type adenocarcinoma of gastric cardia.

The effects of oxidative stress in adenocarcinomas of gastric cardia (AGCs) have not been fully elucidated. With a strict definition of AGC, we examined the immunohistochemical expressions of inducible nitric oxide synthase; 8-hydroxy-deoxyguanosine; and the base excision repair enzymes such as MUTYH, MTH1, and OGG1, and TP53 mutational status. Sixty-three cases of AGC were characterized by younger patient age (P = .0227) and more frequent venous invasion (P = .0106) compared with the adenocarcinomas of pylorus (APs). 8-hydroxy-deoxyguanosine was accumulated (P = .0011), whereas MUTYH (P = .0325) and OGG1 (P = .0007) were decreased, in the AGCs compared with the adjacent mucosa, but these differences were not detected in the APs. Among the AGCs, lower expressions of MUTYH (P = .0013) and MTH1 (P = .0059) were each significantly associated with diffuse-type histology. A lower expression of OGG1 was correlated with higher T-stage (P = .0011), lymphatic invasion (P = .004), and lymph node metastasis (P = .0094). In addition, the presence of TP53 mutation was associated with diffuse-type histology (P = .0153) and a lower level of MUTYH (P = .0221). The AGCs also showed a relatively high rate of a transversion-type mutation of TP53 (50%), whereas all TP53 mutations in the APs were transition type. Age 62years or older (P = .0073), diffuse-type histology (P = .0020), and TP53 mutation (P = .0066) were each associated with worse survival in the AGC patients. Our results indicate that oxidative stress accumulation and a downregulation of base excision repair enzymes may play an important role in the pathogenesis of AGC, in particular diffuse-type AGCs. Diffuse-type AGC might involve molecular pathways different from those of other subsets of gastric cancer.

Hydrogen sulfide synthesis enzymes reduced in lower esophageal sphincter of patients with achalasia.

The etiology of achalasia remains largely unknown. Considerable evidence reveals that the lower esophageal sphincter dysfunction is due to the lack of inhibitory neurotransmitter, secondary to esophageal neuronal inflammation or loss. Recent studies suggest hydrogen sulfide may act as an inhibitory transmitter in gastrointestinal tract, but study about hydrogen sulfide in human esophagus still lack. The aim of the study was to investigate if hydrogen sulfide synthesis enzymes could be detected in human esophagus and if the synthesis of the endogenous hydrogen sulfide could be affected in achalasia patients. Tissue samples in cardia, lower esophageal sphincter, 2 cm and 4 cm above lower esophageal sphincter were obtained from achalasia patients undergoing peroral endoscopic myotomy. Control tissues in lower esophageal sphincter were obtained from esophageal carcinoma patients. Expression of cystathionine-ß-synthase and cystathionine-γ-lyase in lower esophageal sphincter of achalasia patients and control were detected by immunohistochemical staining. In addition, expression of cystathionine-ß-synthase and cystathionine-γ-lyase were compared among different parts of esophagus in achalasia patients. Compared with control, the expression of cystathionine-ß-synthase and cystathionine-γ-lyase in lower esophageal sphincter of achalasia patients was significantly reduced (χ2 = 11.429, P = 0.010). The expression of cystathionine-ß-synthase and cystathionine-γ-lyase were lower in lower esophageal sphincter than that in 2 cm and 4 cm above lower esophageal sphincter, respectively (all P < 0.05). In conclusion, the expression of hydrogen sulfide synthesis enzymes, cystathionine-ß-synthase and cystathionine-γ-lyase, can be detected in human esophagus and is reduced in patients with achalasia, which implicates the involvement of the two hydrogen sulfide synthesis enzymes in the pathophysiology of achalasia.

Up-regulation of cathepsin X in Helicobacter pylori gastritis and gastric cancer.

Recently, we identified increased cathepsin X expression in H. pylori-infected gastric mucosa. Here, we describe further up-regulation in gastric cancer and report on the role of inflammatory cytokines required for cathepsin X up-regulation in H. pylori-infected gastric mucosa, as well as on consequences for cellular invasion. Biopsy specimens were taken from the antrum, corpus and cardia of H. pylori-infected and non-infected patients. Gastric cancer samples were obtained from patients undergoing gastric surgery. Cathepsin X was detected in gastric mucosa by quantitative real-time RT-PCR, western blotting and immunohistochemistry. Induction of cathepsin X expression in epithelial and inflammatory cells caused by H. pylori infection was tested in in vitro contact and non-contact co-cultures of AGS cells and monocytic cells. Patients with H. pylori gastritis showed significantly higher cathepsin X mRNA (2.5-fold) and protein (1.6-fold) expression than H. pylori-negative patients. Cathepsin X was also up-regulated in gastric cancer (3-12-fold) compared to non-neoplastic mucosa. Cathepsin X was predominantly expressed by macrophages in the mucosal stroma and in glands of the antral mucosa. In addition, tumour cells stained for cathepsin X in 26 (68%) patients with gastric carcinoma. In general, staining was significantly more common (20 vs. 6 patients) and more intense (3.55 vs. 0.83) in intestinal type gastric cancer than in the diffuse type. In vitro cell culture experiments revealed that intercellular signalling between pathogenicity island (PAI)-positive H. pylori-infected epithelial cells and macrophages via soluble factors in the culture medium seems to be responsible for increased expression of cathepsin X in monocytes. Using antisense oligonucleotides, cathepsin X up-regulation was directly associated with higher invasiveness in vitro. Although no correlation of cathepsin X expression and TNM stage was found, our study demonstrates that cathepsin X plays a role not only in the chronic inflammation of gastric mucosa but also in the tumourigenesis of gastric cancer.

The functional SNP in the matrix metalloproteinase-3 promoter modifies susceptibility and lymphatic metastasis in esophageal squamous cell carcinoma but not in gastric cardiac adenocarcinoma.

The matrix metalloproteinases (MMPs), a family of proteolytic enzymes that degrade different components of the extracellular matrix, play important roles in tumor development and invasion. A single adenine insertion/deletion polymorphism (6A/5A) in the MMP3 promoter region causes transcriptional elevation. The aim of this study was to assess the effects of this single nucleotide polymorphism (SNP) on the development and clinical staging of esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA). The MMP3 SNP was genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis in 417 cancer patients (234 ESCC and 183 GCA) and 350 controls in north China. The overall distribution of the MMP3 SNP in ESCC and GCA patients was not significantly different from that in healthy controls. However, smoking individuals with the 5A/5A or 5A/6A genotype were significantly more common in ESCC patients than in controls (37.5 versus 23.3%, xi(2) = 5.13, P = 0.02). Thus, smokers with at least one 5A allele had a significantly increased risk of ESCC, compared with 6A homozygotes (age and sex adjusted OR = 1.95, 95% CI = 1.08-3.53). The significant difference in the SNP distribution between ESCC patients, GCA patients and controls was not observed when stratified by family history of upper gastrointestinal cancer. In addition, the frequency of the 5A/5A + 5A/6A genotypes in ESCC patients with and without lymphatic metastasis was significantly different (45.8 versus 27.8%, xi(2) = 4.56, P = 0.03). Therefore, patients with at least one 5A allele were significantly more prone to lymphatic metastasis of ESCC. In contrast, no significant difference in the SNP distribution between patients with and without lymphatic metastasis was observed in GCA. The present study suggests that the MMP3 promoter SNP might be associated with a risk of development and lymphatic metastasis in ESCC but not in GCA.

Association of the thymidylate synthase polymorphisms with esophageal squamous cell carcinoma and gastric cardiac adenocarcinoma.

Polymorphisms in the untranslated regions (UTRs) of the thymidylate synthase (TS) gene, which may modulate TS transcription and expression, have been associated with susceptibility and prognosis of several tumors. However, their effects on the development and clinical staging of esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA) have not been assessed so far. In this study, the 28-bp tandem repeat and the G/C single nucleotide polymorphism in the TS 5'UTR, the 6-bp deletion (6 bp-) polymorphism in the TS 3'UTR, were genotyped in 465 cancer patients (232 ESCC, 233 GCA) and 348 control subjects in North China. The genotype and allelotype distribution of the TS variants in ESCC, GCA patients and controls did not show significant difference. However, the frequency of the 6 bp-/2R haplotype in ESCC and GCA patients was marginally or significantly lower than that in controls (P = 0.05 and 0.006, respectively). Thus, the 6 bp-/2R significantly reduced the risk to ESCC and GCA, compared with the 6 bp-/3G haplotype [odds ratio (OR) = 0.61 and 0.48, 95% confidence interval (CI) = 0.37-1.00 and 0.28-0.81, respectively]. In addition, the 6 bp+/3G haplotype in ESCC patients was also significantly less common than in controls (P = 0.002). Compared with the 6 bp-/3G haplotype, the 6 bp+/3G significantly reduced the risk to ESCC (OR = 0.30, 95% CI = 0.14-0.67). Moreover, the TS 2R/3G genotype frequency in ESCC patients with and without lymphatic metastasis was significantly different (27.1 versus 4.9%, P < 0.001). Therefore, the 2R/3G genotype had an approximately 11-fold increase in the risk of lymphatic metastasis of ESCC, compared with the 3G/3G genotype (95% CI = 2.67-49.74). The results suggested that the TS polymorphisms might be associated with the susceptibility to ESCC and GCA, and the 2R/3G genotype might be a candidate marker to predict the potential of lymphatic metastasis in ESCC.

Comparison of cyclooxygenase 2 expression in adenocarcinomas of the gastric cardia and distal oesophagus.

BACKGROUND: Adenocarcinomas of the gastric cardia and distal oesophagus are at present often considered as one clinical entity because of their comparable increasing incidence, prognosis, and optimal treatment options. However, it is still a matter of debate whether these malignancies have the same pathogenesis and genotype. AIMS: The aim of this study was to analyse expression of cyclooxygenase 2 (COX-2) in cardia carcinomas, and correlate this expression with clinicopathological parameters and survival. The results were compared with the prognostic value of COX-2 found for Barrett carcinomas. METHODS: Tumour sections of 134 consecutive patients undergoing potentially curative surgery for an adenocarcinoma of the gastric cardia and substantially invading the distal oesophagus were immunohistochemically stained using a COX-2 monoclonal antibody. Specimens were blindly scored based on intensity and extent of COX-2 immunopositivity. RESULTS: COX-2 expression was negative to weak in 59% ("COX-2 low") and moderate to strong in 41% ("COX-2 high") of tumours. This was significantly lower than in Barrett carcinomas (p<0.0001). COX-2 expression was not correlated with any clinicopathological parameter. A correlation between elevated COX-2 expression and reduced survival, as described for Barrett carcinomas, was not identified for cardiac carcinomas. CONCLUSIONS: There is a difference in COX-2 expression with respect to intensity and prognostic significance between adenocarcinomas of the gastric cardia and distal oesophagus. This suggests a different pathogenesis and different genetic constitution of these two cancers. Based on these findings, the role of selective COX-2 inhibitors in the treatment of adenocarcinomas of the gastric cardia is less promising than in Barrett carcinomas.

Polymorphisms of 5,10-methylenetetrahydrofolate reductase and risk of gastric cancer in a Chinese population: a case-control study.

Low dietary folate intake has been associated with increased risk of gastric cancer. The 5,10-methylenetetrahydrofolate reductase (MTHFR) involved in folate metabolism has 2 variants, C677T and A1298C, that result in decreased MTHFR activity and lower plasma folate levels. Therefore, we hypothesized that these 2 variants play a role in gastric carcinogenesis. We tested this hypothesis in a Chinese population-based case-control study of 187 histopathologically confirmed gastric cancer cases and 166 healthy controls frequency-matched by age (+/-5 years), gender and residential area. The 677TT genotype was associated with increased risk for gastric cancer [adjusted odds ratio (OR) = 1.87, 95% confidence interval (CI) = 1.00-3.48] compared to the 677CC genotype. This association was more pronounced for gastric cardia cancer (adjusted OR = 2.47, 95% CI = 1.14-5.32). However, no evidence was found for risk associated with the MTHFR A1298C polymorphism. Our findings support the hypothesis that MTHFR C677T variants contribute to gastric carcinogenesis, particularly in gastric cardia. Larger studies incorporating dietary folate intake and serum levels are needed to confirm our findings.

Glutathione S-transferases in esophageal cancer.

Glutathione content and glutathione S-transferase enzyme activity as well as isoenzyme composition were studied in normal gastric cardia, normal squamous esophageal epithelium and corresponding malignant tumor of 10 patients with esophageal cancer. Mean values of glutathione (38 +/- 6 versus 36 +/- 12 nmol/mg protein) and glutathione S-transferase activity (532 +/- 44 versus 532 +/- 108 nmol/min mg protein) did not differ significantly between normal esophageal and tumor tissue. However, great individual differences exist. In two patients, glutathione S-transferase activity was much higher in the tumor (1081 and 1381 nmol/min mg protein) due to overexpression of class alpha, mu and pig glutathione S-transferases in one case, and of class mu and pi in the other case. In the other patients, glutathione S-transferase activity was equal (one case) or lower (seven cases) in the tumor. In normal gastric cardia glutathione content as well as glutathione S-transferase activity was significantly lower as compared to normal esophageal epithelium. In conclusion, in contrast to other gastrointestinal tumors, glutathione S-transferases are overexpressed in esophageal tumors in only a limited number of patients.

Gastric lipase and pepsinogen during the ontogenesis of rabbit gastric glands.

In rabbit stomach, gastric lipase activity level was found to increase from birth to 30 days old (weaning), and then decreased. In contrast, pepsin activity only appeared between 30 to 45 days old, and increased till to the adult level. It was observed that maturation of gastric glands in cardial mucosa was a downward elongation process from the mitotic cell pool. These mitotic cells were always found in the neck of the gastric glands, corresponding to the bottom of the gland at 6 days old and to the mid-zone of the gland in adult. Location of rabbit gastric lipase (RGL) cells in cardial glands varied with age and was found along the pit of the gastric glands at 6 days old. The extent of this cellular location decreased with age, whereas a second RGL cell zone appeared below the mitotic cell area at 18 and 30 days old. At 45 days old, the pepsinogen cells appeared in the bottom of the gland, and consequently the RGL cells were located in the mid-zone of the gastric glands, between mitotic cells (neck of the gland) and pepsinogen cells (lower part of the gland). Ultrastructural study of cardial gastric glands revealed different morphologies of the secretion granules in the cells along the gastric glands. In 6-day-old rabbits, secretory granules were found uniformly electron dense in the bottom of the glands and were RGL-labeled by the immunogold technique. In the medium part of the glands, granules appeared biphasic, with a clear and a dense part, and RGL labeling was confined to the electron-dense part.(ABSTRACT TRUNCATED AT 250 WORDS)

Distribution of lysozyme, alpha 1-Antichymotrypsin and alpha 1-Antitrypsin in adenocarcinomas of the stomach and large intestine. An immunohistochemical study.

Lysozyme, alpha 1-Antichymotrypsin and alpha 1-Antitrypsin were demonstrated by an immunoperoxidase technique (PAP) in malignant cells of adenocarcinomas of the stomach but not of the large intestine. Lymph-node metastases showed identical immunoreactivity to that of the primary tumour. Neoplasms arising from the cardia, the body and the pyloric antrum of the stomach showed different immunostaining reactions. It seems that these differences partly reflect the distribution of lysozyme, alpha 1-Antichymotrypsin and alpha 1-Antitrypsin in the normal gastric mucosa. The usefulness of our findings in the identification of the primary tumour in cases of lymph node metastases of unknown origin, is also discussed.