A functional single nucleotide polymorphism in mucin 1, at chromosome 1q22, determines susceptibility to diffuse-type gastric cancer.

BACKGROUND & AIMS: Two major types of gastric cancer, intestinal and diffuse, develop through distinct mechanisms; the diffuse type is considered to be more influenced by genetic factors, although the mechanism is unknown. Our previous genome-wide association study associated 3 single nucleotide polymorphisms (SNPs) with diffuse-type gastric cancer (DGC); 1 was a functional SNP (rs2294008) in prostate stem cell antigen (PSCA), but the loci of the other 2 were not investigated. METHODS: We performed high-density mapping to explore a linkage disequilibrium status of the 2 SNPs at chromosome 1q22. A DGC case-control study was conducted using DNA from 606 cases and 1264 controls (all Japanese individuals) and validated using DNA from Japanese (304 cases, 1465 controls) and Korean (452 cases, 372 controls) individuals. The effects of SNPs on function were analyzed by reporter assays and analyses of splice variants. RESULTS: A region of a strong linkage disequilibrium with the 2 SNPs contained mucin 1 (MUC1) and other 4 genes and SNPs significantly associated with DGC (rs2070803: P = 4.33 × 10(-13); odds ratio [OR], 1.71 by meta-analysis of the studies on the 3 panels) but not with intestinal-type gastric cancer. Functional studies demonstrated that rs4072037 (P = 1.43 × 10(-11); OR, 1.66 by meta-analysis) in MUC1 affects promoter activity and determines the major splicing variants of MUC1 in the gastric epithelium. Individuals that carry both SNPs rs2294008 in PSCA and rs4072037 in MUC1 have a high risk for developing DGC (OR, 8.38). CONCLUSIONS: MUC1 is the second major DGC susceptibility gene identified. The SNPs rs2070803 and rs4072037 in MUC1 might be used to identify individuals at risk for this type of gastric cancer.

Characteristic methylation profile in CpG island methylator phenotype-negative distal colorectal cancers.

Aberrant DNA methylation is involved in colon carcinogenesis. Although the CpG island methylator phenotype (CIMP) is defined as a subset of colorectal cancers (CRCs) with remarkably high levels of DNA methylation, it is not known whether epigenetic processes are also involved in CIMP-negative tumors. We analyzed the DNA methylation profiles of 94 CRCs and their corresponding normal-appearing colonic mucosa with 11 different markers, including the five classical CIMP markers. The CIMP markers were frequently methylated in proximal CRCs (p < 0.01); however, RASSF1A methylation levels were significantly higher in distal CRCs, the majority of which are CIMP-negative (p < 0.05). Similarly, methylation levels of RASSF1A and SFRP1 in the normal-appearing mucosae of distal CRC cases were significantly higher than those in the proximal CRC cases (p < 0.05). They were also positively correlated with age (RASSF1A, p < 0.01; SFRP1, p < 0.01). Microarray-based genome-wide DNA methylation analysis of 18 CRCs revealed that 168 genes and 720 genes were preferentially methylated in CIMP-negative distal CRCs and CIMP-positive CRCs, respectively. Interestingly, more than half of the hypermethylated genes in CIMP-negative distal CRCs were also methylated in the normal-appearing mucosae, indicating that hypermethylation in CIMP-negative distal CRCs is more closely associated with age-related methylation. By contrast, more than 60% of the hypermethylated genes in CIMP-positive proximal CRCs were cancer specific (p < 0.01). These data altogether suggest that CpG island promoters appear to be methylated in different ways depending on location, a finding which may imply the presence of different mechanisms for the acquisition of epigenetic changes during colon tumorigenesis.

Association of prostate stem cell antigen gene polymorphisms with the risk of stomach cancer in Japanese.

A recent whole-genome association study identified a strong association between polymorphisms in the prostate stem cell antigen (PSCA) gene and stomach cancer risk. In this case-control study, we aimed to validate this association, and further to explore environmental factors possibly interacting with PSCA polymorphisms in 708 incident stomach cancer cases and 708 age-sex matched controls. The association between PSCA polymorphisms and Helicobacter pylori infection was also examined. We found that rs2294008 and rs2976392, which were strongly linked to each other (D' = 1.00), were significantly associated with stomach cancer risk. Per allele odds ratio for rs2994008 was 1.40 (95% confidence interval: 1.19-1.65; p = 3.7 x 10(-5)). We found significant interaction with a family history of stomach cancer in first-degree relatives (p-heterogeneity = 0.009). Similar to originally reported association, we found significant heterogeneity between diffuse and intestinal type (p-heterogeneity = 0.007). No association was seen between PSCA polymorphisms and H. pylori infection. In conclusion, PSCA polymorphisms are associated with stomach cancer risk in Japanese. A possible interaction with family history warrants further evaluation.

Significance of CXCR3 expression in gastric low-grade B-cell lymphoma of mucosa-associated lymphoid tissue type for predicting responsiveness to Helicobacter pylori eradication.

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a distinct low-grade lymphoma that often regresses upon Helicobacter pylori eradication. It was reported that the chemokine receptor CXCR3 is expressed not only on activated T cells, but also on MALT lymphoma cells, and that CXCR3-positive B lymphocytes migrate or home to the MALT of MALT lymphoma. In the present study, we aimed to elucidate the correlation between CXCR3 expression and the clinicopathological features of gastric MALT lymphoma, and to determine whether CXCR3 expression was predictive of responsiveness to H. pylori eradication. Sixty-seven patients with gastric MALT lymphoma in a single-center study were treated with H. pylori eradication therapy. We evaluated the correlation of CXCR3 expression with response to H. pylori eradication therapy by logistic regression stratified according to potential confounders. Immunohistochemical analysis revealed that 28 of 67 cases (42%) were positive for CXCR3 expression. CXCR3 expression was significantly more prevalent in those without H. pylori infection, advanced-stage disease, and in those with API2-MALT1 fusion. In overall analysis, those with CXCR3 expression showed a significantly increased risk of non-responsiveness to H. pylori eradication therapy (odds ratio = 28.6; 95% confidence interval 5.70-143.4) compared to those without CXCR3 expression. This higher risk was observed consistently regardless of sex, API2-MALT1 fusion, H. pylori infection, or clinical stage. We showed that CXCR3 expression was an independent predictive factor for non-responsiveness to H. pylori eradication therapy in patients with gastric MALT lymphoma.

Alcohol drinking and one-carbon metabolism-related gene polymorphisms on pancreatic cancer risk.

Effect of alcohol consumption on pancreatic cancer risk has been investigated in many studies, but results have been inconsistent. We conducted a case-control study to assess the effect of alcohol on pancreatic cancer in conjunction with polymorphisms in one-carbon metabolism enzymes, methylenetetrahydrofolate reductase (MTHFR C677T), methionine synthase (MTR A2756G), methionine synthase reductase (MTRR A66G), and thymidylate synthase (TS) variable number of tandem repeat. A total of 157 pancreatic cancer patients and 785 age- and sex- matched control subjects were genotyped for polymorphisms. Odds ratios (OR) with 95% confidence intervals (95% CI) were estimated using unconditional logistic models adjusted for potential confounders. Heavy alcohol drinking was marginally associated with an increased risk of pancreatic cancer (OR, 1.90; 95% CI, 1.00-3.62). None of the polymorphisms showed any significant effect on pancreatic cancer risk by genotype alone. In stratified analysis, effect of alcohol consumption on pancreatic cancer was observed in individuals with the MTHFR 667 CC, MTR 2756 AA, or MTRR 66 G allele. OR (95% CI) of pancreatic cancer for heavy drinkers compared with never drinkers was 4.50 (1.44-14.05) in the MTHFR 667 CC genotype, 2.65 (1.17-6.00) in the MTR 2756 AA genotype, and 3.35 (1.34-8.36) in the MTRR 66 G allele carriers. These results suggest that the folate-related enzyme polymorphism modifies the association between drinking habit and pancreatic cancer risk.

Practical prognostic index for patients with metastatic pancreatic cancer treated with gemcitabine.

AIM: The aim of this study was to identify factors that predict treatment outcome in patients with metastatic pancreatic cancer treated with gemcitabine, and then to use these factors to develop a practical prognostic index. METHODS: A retrospective study was performed on 66 consecutive patients with histologically confirmed pancreatic adenocarcinoma who were treated with gemcitabine. Factors that predicted treatment outcome were identified by univariate and multivariate analyses using the Cox proportional hazards model. RESULTS: Multivariate analysis identified Eastern Cooperative Oncology Group performance status, primary tumor location, and C-reactive protein as important independent predictive factors. Prognostic score was calculated using the following formula: score = (1 if performance status is 0 or 1; 2 if performance status is 2; and 5 if performance status is 3) + (1 if primary site is body or tail, 3 if primary site is head) + (1 if C-reactive protein is <1 mg/dL, 3 if C-reactive protein is 1-3 mg/dL, 6 if C-reactive protein is >3 mg/dL). Patients were accordingly divided into three groups: good (prognostic index = 3 or 4), fair (prognostic index = 5-7), and poor (prognostic index = 8). Median survival was 265, 155, and 65 days for each group, respectively (P < 0.0001). The internally validated c-index (receiver operating characteristics area under the curve) of this model was 0.711. Applied to another data set, the externally validated c-index was 0.692. Prognosis was favorable in the good prognosis group, patients in the fair prognosis group were likely to benefit from gemcitabine, and those in the poor prognosis group were unlikely to benefit. CONCLUSION: This index improved predictive ability in patients with metastatic pancreatic cancer treated with gemcitabine, which may be helpful in counseling patients and making first treatment decisions.

Gastric cancer risk and erythrocyte composition of docosahexaenoic acid with anti-inflammatory effects.

Infection with Helicobacter pylori is linked to inflammation and is the main cause of peptic ulcer, gastritis, and gastric malignancies. To examine associations between gastric cancer risk and the erythrocyte composition of docosahexaenoic acid (DHA), a fatty acid with anti-inflammatory and apoptosis-inducing effects, here we conducted a case-control study of 179 incident gastric cancer cases and 357 noncancer controls (matched by age, sex, and season of sample collection). Dietary information and blood samples were collected from all subjects, and erythrocyte fatty acid levels were measured using accelerated solvent extraction and gas-liquid chromatography. Gastric cancer risk did not seem to be directly associated with dietary intake of fish and n-3 highly unsaturated fatty acids (HUFAs), such as DHA, derived from fish. However, risk was inversely associated with erythrocyte compositions of n-3 HUFAs [the highest to the lowest tertile, odds ratio (OR), 0.39; 95% confidence interval (95% CI), 0.23-0.68; P(trend)<0.005] and DHA (OR, 0.47; 95% CI, 0.28-0.79; P(trend)<0.01). Particularly strong associations were noted for well-differentiated type lesions and n-3 HUFAs (OR, 0.10; 95% CI, 0.03-0.35; P(trend)=0.0005) as well as DHA (OR, 0.20; 95% CI, 0.07-0.58; P(trend)<0.01) values. In conclusion, the erythrocyte composition of DHA was found to be negatively linked to risk of gastric cancer, especially of well-differentiated adenocarcinoma. Further studies are needed to investigate mechanisms of action of DHA relevant to antitumor effects in the stomach.

Gastric MALT lymphomas are divided into three groups based on responsiveness to Helicobacter Pylori eradication and detection of API2-MALT1 fusion.

Gastric MALT lymphoma shows unique features including regression by Helicobacter pylori eradication and API2-MALT1 fusion. We performed a molecular and clinicopathologic study for 115 cases. All eradication-responsive cases were devoid of API2-MALT1 fusion. All tumors positive for the fusion and all negative for H. pylori infection were nonresponsive to the eradication. Consequently, gastric MALT lymphomas were divided into three groups: Eradication-responsive and fusion-negative (group A, n = 72), eradication-nonresponsive and fusion-negative (group B, n = 22), and eradication-nonresponsive and fusion-positive (group C, n = 21). Group A tumors were characterized by low clinical stage and superficial gastric wall involvement, and group C tumors by low H. pylori infection rate, advanced clinical stage, and nuclear BCL10 expression. All group C tumors showed exclusively low-grade histology. Group B tumors, which have not been well recognized, frequently showed nodal involvement, deep gastric wall involvement, and advanced clinical stage, and sometimes an increased large cell component. A multivariate discriminant analysis revealed that responsiveness to the eradication could be predicted accurately by negative API2-MALT1 fusion, positive H. pylori infection, low clinical stage, and superficial gastric wall invasion, the former being the most important factor for the prediction. This 3-group categorization may be helpful for a comprehensive understanding of gastric MALT lymphoma.

No associations of p73 G4C14-to-A4T14 at exon 2 and p53 Arg72Pro polymorphisms with the risk of digestive tract cancers in Japanese.

A case-control study was conducted to examine the possible association between digestive tract cancers and p73 G4C14-to-A4T14 at exon 2 and p53 Arg72Pro polymorphisms in Japanese. Cases were 102 esophageal cancer patients, 144 stomach cancer patients, and 147 colorectal cancer patients, and controls were 241 non-cancer outpatients. The genotype frequencies among controls were 55.3% for p73 GG at position 4, 40.4% for GA, and 4.3% for AA, and 37.7% for p53 ArgArg, 44.4% for ArgPro, and 18.0% for ProPro. No significant differences in the genotype frequencies were observed between the controls and each case group or cases as a whole.

Gastric low-grade B-cell MALT lymphoma: treatment, response, and genetic alteration.

Approximately 10% of gastric low-grade B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) type are unresponsive to Helicobacter pylori ( H. pylori) eradication treatment, and many of them contain an API2-MALT1 chimeric transcript mediated by t(11;18)(q21;q21) translocation. We here review the current status on the interrelationship among clinical features, H. pylori infection status, responsiveness to antibacterial treatment, and API2-MALT1 chimeric transcript of gastric MALT lymphoma in a unicenter study experience and discuss the clinicopathologic significance of API2-MALT1 chimeric transcript in gastric MALT lymphoma. We enrolled 59 patients with gastric MALT lymphoma in a unicenter study. H. pylori infection status and clinical stages were investigated. Antibacterial treatment and subsequent follow-up endoscopy were performed for the assessment of responsiveness of MALT lymphoma in every patient. All cases were examined for API2-MALT1 chimeric transcript by means of RT-PCR and sequencing analyses using RNA extracted from tissues. H. pylori infection status was assessed as positive in 50 patients and negative in 9. Antibacterial treatment achieved complete or partial remission in 41 patients and no change in 12. API2-MALT1 chimeric transcript was detected in 9 patients, all of whom showed no change in response to treatment. Notably, responsiveness to H. pylori eradication treatment most clearly delineated the enrolled cases into two groups, indicating that six factors ( H. pylori infection, API2-MALT1 chimeric transcript, cobblestone mucosa and submucosal tumor in gross appearance, nodal involvement, and clinical stage) were statistically significant. On the other hand, comparison of two groups from the standpoint of H. pylori or API2-MALT1 chimeric transcript status revealed a lesser number of the statistically significant factors (two and three, respectively). Gastric MALT lymphoma characterized by unresponsiveness to antibacterial treatment contains all API2-MALT1 chimeric transcript-positive cases and may constitute a distinct group often seen with nodal involvement and an advanced clinical stage. This group is thought to be unrelated to H. pylori infection in its pathogenesis, and might share a unifying feature of genetic alteration such as involving the MALT1 locus on chromosome 18. Investigation in the future will clarify this issue and establish the clinical implication of such genetic alteration as the predictive factor for gastric MALT lymphoma.

Risk factors for vitamin D deficiency in patients with Crohn's disease.

BACKGROUND: Although the pathogenesis of osteopenia in Crohn's disease is not established, vitamin D deficiency is thought to be an important risk factor. However, little is known about the prevalence of vitamin D deficiency in patients with Crohn's disease in Japan. This study aimed to clarify the prevalence of vitamin D deficiency in patients with Crohn's disease in Japan and to examine the possible causes of the deficiency. METHODS: We investigated serum 25-hydroxyvitamin D (25-OHD) levels, various laboratory parameters, and patient histories in 33 outpatients (25 men, 8 women; median age, 37 years; range, 26-57 years) and 15 age- and sex-matched healthy controls (8 men, 7 women; median age, 37 years; range, 24-57 years) and assessed risk factors for vitamin D deficiency. RESULTS: Although patients with Crohn's disease did not have significantly lower serum concentrations of 25-OHD than controls, 9 of 33 patients (27.3%) were considered vitamin D deficient (serum 25-OHD level 15 years) and who have been in the active stage of the disease for long periods.

Endoscopic ultrasound-guided fine-needle aspiration biopsy for the diagnosis of gastrointestinal stromal tumors in the stomach.

BACKGROUND: For the diagnosis of gastric submucosal tumors (SMTs), endoscopic ultrasound (EUS) alone does not reveal the complete pathology, such as the degree of malignancy, and EUS-guided fine-needle aspiration biopsy (EUS-FNAB) has been reported to be more useful. Recently, most cases initially diagnosed as leiomyosarcomas have received further study with immunohistochemical staining and have been given the new diagnosis of gastrointestinal stromal tumors (GISTs). The degree of malignancy of GISTs differs widely in clinical aspects. In this study, we examined whether EUS-FNAB was useful in diagnosing GISTs and differentiating their degrees of malignancy. METHODS: From January 1997 to March 2002, 21 cases of gastric GISTs were diagnosed from the immunohistochemical staining of specimens resected at Aichi Cancer Center Hospital. Of these 21 patients, 14 (5 with high-grade malignancy and 9 with low-grade malignancy) underwent EUS-FNAB preoperatively, and were examined further: their EUS-FNAB specimens were submitted for additional immunohistochemical testing. RESULTS: The EUS-FNAB specimens from all patients were positive for c-kit and CD34 immunohistochemical testing, coinciding with the staining results of the resected specimens. The MIB-1 labeling indices in specimens of high-grade malignancy were significantly higher than those of low-grade malignancy. If we assumed that a tumor with an MIB-1 labeling index of more than 5% was a high-grade malignancy, the diagnostic accuracy was 85.7%. CONCLUSIONS: The EUS-FNAB procedure is a useful tool for diagnosing GISTs of the stomach with immunohistochemical staining. When used with MIB-1 staining, the procedure may indicate GIST prognosis and influence decisions regarding therapeutic strategies.

A pilot study of imatinib mesylate (STI571) on gastrointestinal stromal tumors in Japanese patients.

BACKGROUND: Gastrointestinal stromal tumor (GIST) is the most common type of nonepithelial tumor in the gastrointestinal tract. The gastrointestinal stromal tumor is defined immunohistologically as a c-Kit-positive tumor. For those GISTs that are malignant, the only effective treatment modality has been surgical. Early clinical reports have shown that imatinib mesylate (STI571) produces substantial anticancer activity in patients with metastatic or unresectable GIST. METHODS: Nine Japanese patients who were found clinically and immunohistochemically to have inoperable GISTs were entered into this study. These patients were given 400 mg STI571 orally once daily. We then evaluated the tumor response and the safety of the drug. RESULTS: Five of the nine patients achieved partial responses, two had stable disease, and two had progressive disease. The main side effects were skin rash, edema, periorbital edema, diarrhea, nausea, and vomiting. Mild anemia, leukocytopenia, and neutropenia were also noted. No patients required dose reduction or cessation because of adverse events. CONCLUSIONS: This study demonstrates that STI571 might be an active agent against malignant GIST in Japanese patients with manageable toxicities. Gastrointestinal stromal tumor (GIST) is the most common type of nonepithelial tumor in the gastrointestinal tract. The gastrointestinal stromal tumor is defined immunohistologically as a c-Kit-positive tumor. For those GISTs that are malignant, the only effective treatment modality has been surgical. Early clinical reports have shown that imatinib mesylate (STI571) produces substantial anticancer activity in patients with metastatic or unresectable GIST.

Clinical relevance of telomerase activity in primary gastric lymphoma.

BACKGROUND: To distinguish between low-grade lymphoma and reactive lymphoid infiltrate can be demanding for pathologists. Demonstration of B-cell monoclonality by polymerase chain reaction (PCR) analysis of immunoglobulin heavy chain is useful as referential data. Telomerase activity, which is frequently detected in malignant tumors while being undetectable in normal tissues, may also have a supportive role in the diagnostic procedure, but has not been investigated in specimens of primary gastric lymphoma. METHODS: Telomerase activity was qualitatively and quantitatively evaluated, using fluorescence-based telomeric amplification assay protocol (TRAP) analysis, in 16 malignant lymphoma and related specimens, including 7 specimens of low-grade mucosa-associated lymphoid tissue (MALT) lymphoma, among which specimens before and after Helicobacter pylori eradication were evaluated from five patients. RESULTS: Telomerase activity was detected more frequently (6 of 7 specimens) at higher levels in high-grade lymphoma compared with low-grade MALT lymphoma. It was detected in 3 of 7 specimens of low-grade MALT lymphoma, but was undetectable either at the stage of Helicobacter pylori-induced gastritis or after H. pylori eradication therapy. CONCLUSION: Telomerase activity evaluated by fluorescence-based TRAP analysis was detectable late in the process of evolution of MALT lymphoma and was undetectable early in the process of regression. It was frequently and overtly elevated in high-grade lymphoma. Telomerase activity may have a role in confirming the histologic diagnosis of primary gastric lymphoma.

Pancreaticobiliary maljunction in monozygotic twins--a case report.

We experienced a case of pancreaticobiliary maljunction in monozygotic twins. While one of the twins suffered from gallbladder cancer with poor prognosis, the other was not associated with biliary malignancy. Ultrasonography, endoscopic ultrasonography, and magnetic resonance cholangiopancreatography are effective in diagnosis of this disorder before occurrence of biliary cancers. This case is not only of academic interest for familial occurrence, but also of clinical interest in the early detection of pancreaticobiliary maljunction.

Risk of second malignancies in patients with gastric marginal zone lymphomas of mucosa associate lymphoid tissue (MALT).

BACKGROUND: It is controversial whether patients with gastric marginal zone lymphomas of mucosa associated lymphoid tissue (MALT) have higher risk of second malignancies. The aim of this study was to define the risk of second malignancies in these patients. METHODS: We analyzed prospective follow-up data of 146 consecutive patients with gastric MALT lymphoma treated at Aichi Cancer Center Hospital and compared the incidence of second malignancies with that in the general population. We calculated the standardized incidence ratio (SIR), using age- and sex-specific incidence rates from the Aichi Cancer Registry. RESULTS: The median follow-up period was 74 months. A total of 27 tumors occurred in 22 patients (15.1%), including 19 solid tumors. Of these, nine tumors were detected concomitantly with, and 18 tumors following, the diagnosis of gastric MALT lymphoma. Four patients had two second malignancies each. For the entire group, the SIR of an additional malignancy was 3.39 (95% confidence interval [CI] 2.11-4.66). An increased incidence of solid tumors (SIR 2.91 [1.60-4.22]) and hematologic malignancies (SIR 5.54 [1.70-9.38]) were seen. In addition, there was increased risk for development of second malignancies during follow up (SIR 2.26 [1.21-3.30]). Chemotherapy for treatment of MALT was an independent risk factor for second malignancies (age-sex adjusted hazard ratio 3.98 [1.47-10.79]. CONCLUSIONS: Compared with the general population, patients with gastric MALT lymphoma are at increased risk for second malignancies, including gastric cancer.