Associations of TNF-A-1031TT and -857TT genotypes with Helicobacter pylori seropositivity and gastric atrophy among Japanese Brazilians

Background Our previous study in a Japanese population showed elevated Helicobacter pylori seropositivity in those with tumor necrosis factor (TNF) A -1031TT and -857TT genotypes. This study examined the associations of this seropositivity and serum pepsinogen (PG) levels with these genotypes in Japanese Brazilians. Methods The subjects were 963 individuals (399 males and 564 females), aged 33 to 69 years, from four regions (Sao Paulo, Curitiba, Mogi das Cruzes, and Mirandopolis) in Brazil. Gastric atrophy was evaluated with serum pepsinogens (PGI < 70 ng/dl and PGI/II < 3), and TNF T-1031C and C-857T were genotyped by polymerase chain reaction with confronting two-pair primers (PCR-CTPP). Results The frequency of TNF-A T-1031C was 68.4% TT, 28.4% TC, and 3.3% CC, and that of C-857T was 64.5% CC, 31.7% CT, and 3.8% TT, whose distributions were in Hardy-Weinberg equilibrium. No significant associations of the genotypes with H. pylori seropositivity or gastric atrophy were found. However, male participants with TNF-A -1031CC and -857CC showed the lowest seropositivity (43.8% out of 16), and males with TNF-A -1031TT and -857TT showed the highest (61.5% out of 13). Conclusion This study demonstrated that the associations between H. pylori seropositivity and TNF-A genotypes were not marked for Japanese Brazilians. The genotypes were not associated with gastric atrophy among the seropositive individuals.     

Association of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> infection and environmental factors in non-cardia gastric cancer in Japan

Background Although Helicobacter pylori infection is a major risk factor for gastric cancer, it does not explain the full picture of stomach carcinogenesis. There have been few epidemiological studies, however, which examined both H. pylori and environmental factors simultaneously. The aims of this study were to estimate the association of environmental factors (smoking and dietary factors) with gastric cancer in consideration of H. pylori infection, and to investigate the effects of the interaction between environmental factors and H. pylori infection.Methods A multicenter, hospital-based, case-control study of gastric cancer was conducted at four hospitals in Nagano prefecture, Japan, between October 1998 and March 2002. For 153 newly diagnosed gastric cancer cases, two controls matched by age (within 3 years), sex, and residence area were randomly selected from the participants of a health check-up program during the same period in the same hospitals. We conducted a questionnaire survey and obtained blood samples. Consequently, 122 non-cardia gastric cancer cases and 235 controls were available for this analysis.Results Results. H. pylori infection was strongly associated with non-cardia gastric cancer after adjustment for possible confounding factors (odds ratio [OR], 8.2; 95% confidence interval [CI], 3.7–18.2). Cigarette smoking (OR, 2.8; 95% CI, 1.2–6.5) and frequent intake of miso (fermented soy bean) soup (OR, 2.1; 95% CI, 0.9–5.1) and rice (OR, 2.5; 95% CI, 1.0–6.1) were determined to be risk factors even after adjusting for possible confounding factors, including H. pylori infection. However, no statistically significant interaction between environmental factors and H. pylori infection was detected.Conclusion This finding suggests that although H. pylori infection is clearly an important risk factor for gastric cancer, smoking cessation and dietary modification may be practical strategies for the prevention of non-cardia gastric cancer among both H. pylori-positive and -negative subjects in Japan.     

ABO blood type, <Emphasis Type="Italic">Lewis </Emphasis>and <Emphasis Type="Italic">Secretor </Emphasis>genotypes,and chronic atrophic gastritis: a cross-sectional study in Japan

Background: The H type I structure, synthesized by the secretor (Se) enzyme in gastric foveolar cells, and its metabolite, Lewis b (Le ^b ) antigen, mediate the adhesion of Helicobacter pylori ( H. pylori ) to the gastric epithelium, whereas H. pylori does not bind to modified forms of Le ^b specific for blood types A and B. Such host factors as Le and Se genotypes and ABO blood type may affect the establishment of H. pylori infection and, once infected, the risk of chronic atrophic gastritis. Methods: We investigated the cross-sectional relation of ABO blood type and Le and Se genotypes to gastric atrophy, assessed by serum pepsinogen levels, in Japanese residents from two sources. Results: Among the 151 H. pylori -positive participants of the H. pylori eradication program, odds ratios (ORs) for gastric atrophy, adjusted for age, sex, and smoking, were elevated for blood types A (OR = 5.35; 95% confidence interval (CI), 2.11–13.58) and B (OR = 4.79; 95% CI, 1.77–12.93) relative to type O. ORs for blood types A and B were also elevated in H. pylori -negative subjects. These associations were not observed among 250 H. pylori -positive health check-up examinees. The Le genotype was not associated with gastric atrophy in either study population. The se / se genotype was associated with statistically nonsignificant elevation of gastric atrophy risk in both populations. Conclusions: The present data showed a strong association of blood types A and B with gastric atrophy in one, but not the other, study population. Discrepant results between the two populations warrant further investigation. Received: July 29, 2002 / Accepted: September 17, 2002 Acknowledgments The authors thank Dr. Hidemi Ito, Ms. Michiyo Tani, Ms. Naomi Takeuchi, and Ms. Mayumi Kato for their assistance in laboratory assays. This work was supported in part by a Grant-in-Aid for the Second Term Comprehensive 10-Year Strategy for Cancer Control from the Ministry of Health, Labor, and Welfare, Japan, and grant R01CA73011 from the National Cancer Institute, the National Institutes of Health, USA. Offprint requests to: N. Hamajima     

Treatment of low-grade gastric MALT-lymphoma unresponsive to <Emphasis Type="Italic">Helicobacter</Emphasis> <Emphasis Type="Italic">pylori</Emphasis> therapy

The most favourable therapeutic strategy for gastric MALT-lymphoma not responding to Helicobacter pylori eradication still remains unclear, neither official guidelines nor randomised studies being available. We therefore performed a systematic review of the literature to evaluate the efficacy of different therapeutic approaches in these patients. Data regarding 315 patients were valuable, and lymphoma remission following the first therapeutic attempt was achieved in 90.1% cases. The most used therapy was radiotherapy (112 patients), followed by surgery (80 patients) and chemotherapy (68 patients), whilst a combination therapy was less frequent. Radiotherapy achieved a higher remission rate as compared to chemotherapy (97.3 vs. 85.3%; P = 0.007), being similar to surgery (97.3 vs. 92.5%; P = 0.2). No difference emerged when comparing lymphoma remission rate achieved by a single therapy with that of combined treatments (89.6 vs. 96.4%; P = 0.6). This is the first pooled-data analysis assessing the efficacy of different oncologic therapeutic approaches to treat gastric MALT-lymphoma unresponsive to H. pylori eradication. Radiotherapy seems to be the most suitable treatment in these patients.     

<Emphasis Type="Italic">MTHFR</Emphasis> genotypes and breast cancer survival after surgery and chemotherapy: a report from the Shanghai Breast Cancer Study

Summary Methylenetetrahydrofolate reductase (MTHFR) regulates the intracellular folates pool for DNA synthesis and methylation. Sequence variations in MTHFR (nucleotides 677 (CT) and 1298 (AC)) result in allozymes with decreased activity. The 677TT genotype is associated with increased toxicity of methotrexate and increased clinical response to 5-fluorouracil in treatment of cancers including breast cancer. We evaluated MTHFR genotypes and breast cancer survival in a cohort of 1067 Chinese women diagnosed with breast cancer between 1996 and 1998 who received surgery and chemotherapy. Life table method was used to calculate 5-year survival rates. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) after adjusting for potential confounding factors. Median follow-up time was 5.2 years; 5-year survival was 84.6%. Sixty-six percent carried a 677T allele and 31% carried a 1298 C allele. We found that overall 5-year breast cancer survival did not differ significantly across all genotypes (85.3% for 677 CC and 83.8% for 677TT; 83.8% for 1298 AA and 79.1% for 1298 CC). However, carrying the 677T allele was associated with non-significant increased risk of death for subjects with late stage disease (stages III–IV) (HR=1.80, 95% CI: 0.79–4.14 for TT vs. CC, p for trend=0.15), particularly among those who had survived past the second year (HR=2.97, 95% CI: 1.10–7.98, p for trend=0.04). The A1298C genotypes were not significantly associated with risk of death. This study suggests that the MTHFR C677T polymorphisms may affect long-term survival from advanced breast cancer.     

Association of single nucleotide polymorphisms (SNPs) in <Emphasis Type="Italic">TNF-LTA</Emphasis> locus with breast cancer risk in Indian population

Purpose Cytokine milieu of tumor microenvironment affects tumorigenesis in breast cancer. The aim of the present study was to investigate the potential association of functional single nucleotide polymorphisms (SNPs) in TNF-LTA locus with breast cancer. Methods The study included 127 individuals comprising 40 breast cancer cases (35 sporadic & 5 familial) and 87 individuals of high risk group (with family history of breast cancer) along with 150 healthy controls. PCR-RFLP was employed to analyze TNFA promoter polymorphisms at −238 G/A, −308 G/A, −857 C/T, −863 C/A and −1031 T/C along with +252 A/G SNP in LTA. The results were further confirmed by direct sequencing. Results Significant association was established for TNFA −308 G/A and LTA +252 A/G polymorphisms with breast cancer versus controls (P < 0.0001; OR, 9.53; 95% CI, 4.11–22.13; P _c < 0.001) and high risk group versus controls (P < 0.0001; OR, 8.27; 95% CI, 4.28–16.0; P _c < 0.001) respectively. GGACCT haplotype was found to be positively associated with breast cancer (P < 0.0001; OR, 12.17; 95% CI = 5.12–28.92; P _c < 0.001) and high risk group (P, 0.03; OR, 2.95; 95% CI, 1.20–7.26; P _c, 0.005) in relation to controls. While GGGCCT haplotype was significantly related with high risk group in comparison to cancer (P, 0.0002; OR, 5.71; 95% CI, 2.18–14.99; P _c, 0.003) and controls (P, 0.0002; OR, 2.48; 95% CI, 1.55–3.96; P _c, 0.003). Conclusion TNF-LTA locus could serve as an important biomarker for breast cancer predisposition in Indian population.     

Association between Helicobacter pylori seropositivity and NAD(P)H:quinone oxidoreductase 1 (NQO1) C609T polymorphism observed in outpatients and health checkup examinees

Background Significant associations of Helicobacter pylori (H. pylori) seropositivity have been found with several host polymorphisms. This study investigated the associations of functional polymorphisms of the NQO1, GSTM1, and GSTT1 genes of detoxification enzymes, with the seropositivity, as well as with pepsinogen levels, as markers of gastric atrophy.Methods The subjects were 241 noncancer outpatients who had participated in an H. pylori eradication program (HPE) at Aichi Cancer Center Hospital, and 465 health checkup examinees in Nagoya (HCE). The NQO1 C609T, GSTM1, and GSTT1 polymorphisms were determined by triplex polymerase chain reaction with confronting two-pair primers (PCR-CTPP).Results The sex- and age-group-adjusted odds ratio (OR) of NQO1 C/C for H. pylori seropositivity relative to T/T was highly significant; OR, 1.92; 95% confidence interval (95% CI), 1.22–3.03. The ORs of the GSTM1 present type and GSTT1 present type for H. pylori seropositivity were not significant; OR, 0.87; 95% CI, 0.64–1.20 and OR, 1.14; 95% CI, 0.83–1.57, respectively. The association of the NQO1 C/C genotype with H. pylori seropositivity was observed only for never-smokers; OR, 2.25; 95% CI, 1.33–3.79. The genotypes of the NQO1, GSTM1, and GSTT1 genes were not associated with the development of atrophic gastritis among the H. pylori-seropositive subjects.Conclusion This is the first study to report a significant association of the NQO1 C609T polymorphism with H. pylori seropositivity. The biological mechanism explaining the significant association with the seropositivity remains to be elucidated.     

Prognostic significance of co-overexpression of the <Emphasis Type="Italic">EGFR</Emphasis>/<Emphasis Type="Italic">IGFBP-2</Emphasis>/<Emphasis Type="Italic">HIF-2A</Emphasis> genes in astrocytomas

Overexpression of the EGFR, IGFBP-2 and HIF-2A genes has been observed in high-grade astrocytomas and these genes seem to be functionally related to one another. This study aimed to define the profile of their expressions, interactions and correlation with clinical features and prognostic significance in microdissected tumor samples from 84 patients with astrocytomas of different grades and from 6 white matter non-neoplasic brain tissue sample. EGFR, IGFBP-2 and HIF-2A gene expression levels were analyzed by quantitative real-time PCR and differed significantly between grades I–IV astrocytic tumors (P < 0.0001, P < 0.0001 and P: 0.0013, respectively) when analyzed by the Kruskal–Wallis test. Grade I astrocytomas presented gene expression levels similar to those encountered in samples of microdissected white matter of non-neoplastic brain tissue Overexpression of the EGFR, IGFBP-2 and HIF-2A genes was significantly associated with lower 2-year survival (P: 0.009, P: 0.0002 and P: 0.008, respectively). Co-overexpression of these genes was strongly associated with high-grade gliomas and lower survival in univariate (P < 0.0001) and multivariate (P: 0.009) analysis, suggesting that the co-expression of the EGFR/IGFBP-2/HIF-2A pathway genes may have a more important clinical and biological impact than the expression of each individual gene alone. These data support the existence of a common pathway involving these genes that could contribute to the design of new target treatments.     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> infection,but not genetic polymorphism of CYP2E1, is highly prevalent in gastric cancer patients younger than 40 years

Background Gastric cancers in young adults are thought to be associated with risk factors that include Helicobacter pylori infection and genetic polymorphism. The objective of this study was to elucidate the roles of these risk factors in patients younger than 40 years by analyzing clinicopathological data and H. pylori infection, and using molecular epidemiologic techniques. Methods Clinicopathological features, the presence of H. pylori infection, endoscopic characteristics of gastritis, genetic polymorphism of P4502E1 (CYP2E1), and family history of cancer in patients with gastric cancer treated surgically at Nippon Medical School Hospital from 1991 to 2004 were analyzed, based on our medical database. Results Gastric cancer in those younger than 40 years was characterized by a predominance of female patients with poorly differentiated adenocarcinoma who had undergone total gastrectomy with extended lymphadenectomy. H. pylori infection had a higher prevalence in patients with gastric cancer than in patients with normal endoscopic results or chronic gastritis, especially in those younger than 40 years (odds ratio, 13.7). Atrophic gastritis, nodular gastritis, and rugal hyperplastic gastritis were observed by endoscopy as H. pylori-associated gastritis. No difference in the incidence of either CYP2E1 genetic polymorphism or a family history of cancer was observed among different age groups. Conclusion Gastric cancer in patients younger than 40 years is closely associated with H. pylori infection, but not with genetic characteristics. Eradication therapy for H. pylori and endoscopic examination of H. pylori-positive young adults may be anticipated to be adopted as a strategy for the prevention and/or early detection of cancer.     

<Emphasis Type="Italic">BRAF</Emphasis>, <Emphasis Type="Italic">KRAS</Emphasis> and <Emphasis Type="Italic">PIK3CA</Emphasis> mutations in colorectal serrated polyps and cancer: Primary or secondary genetic events in colorectal carcinogenesis?

Background  

BRAF, KRAS and PIK3CA mutations are frequently found in sporadic colorectal cancer (CRC). In contrast to KRAS and PIK3CA mutations, BRAF mutations are associated with tumours harbouring CpG Island methylation phenotype (CIMP), MLH1 methylation and microsatellite instability (MSI). We aimed at determine the frequency of KRAS, BRAF and PIK3CA mutations in the process of colorectal tumourigenesis using a series of colorectal polyps and carcinomas. In the series of polyps CIMP, MLH1 methylation and MSI were also studied.     

Evaluation of cell proliferation and apoptosis in <Emphasis Type="Italic">Helicobacter pylori</Emphasis> gastritis using an image analysis processor

Background: Infection of the gastric mucosa by Helicobacter pylori is primarily responsible for gastritis, gastric ulcer, adenocarcinoma, and lymphoproliferative disorders. H. pylori appears to accelerate apoptosis and the proliferation of the gastric epithelium directly or indirectly. To precisely assess the proliferative and apoptotic profile of H. pylori -infected gastric mucosa, a quantitative imaging system is now required. Methods: Fifty-two patients with H. pylori gastritis were the subjects of the study. Biopsy materials were taken from at least two sites (usually three to five sites) including the antrum and corpus. The grade of gastritis was evaluated by the Updated Sydney System. The proliferative and apoptotic profile was examined by Ki-67 immunohistochemistry and by a terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling method. In addition, Ki-67-positive cells were quantitated by an image processor for analytical pathology (IPAP) system. Results: H. pylori density and polymorphonuclear neutrophil activity were significantly decreased after H. pylori eradication ( P < 0.0001). Chronic inflammation ( P < 0.0001) and lymphoid follicle numbers ( P < 0.0005) were also significantly decreased after the eradication. Glandular atrophy and intestinal metaplasia were slightly decreased after eradication, but the decrease did not reach the significant level. The Ki-67 labeling index was significantly decreased after the eradication ( P < 0.0001). The apoptosis index was also decreased after the eradication, but this decrease did not reach the significant level ( P = 0.06). Conclusion: Our data suggest that the activation of proliferative cells and induction of apoptosis in the gastric mucosa is a response to H. pylori -induced mucosal damage. Moreover, IPAP may be a useful technology for evaluating the results of immunohistochemistry, and it could provide quantitative and reliable data for studying H. pylori gastritis. Received: July 22, 2002 / Accepted: October 10, 2002 Acknowledgments This work was supported in part by a grant from Otsuka Pharmaceutical Company (Tokyo, Japan) and by the Japanese Clinical Study Group of esophagocardiac lesion. We would like to thank Dr. Kaoru Hirabayashi for her helpful suggestion and Ms. Chiaki Sato-Matsuyama, Ms. Ayako Shimizu, and Ms. Takako Ohtsuki for their excellent technical assistance. Offprint requests to: T. Fujimori The first two authors contributed equally to this study.     

Higher occurrence of childhood cancer in families with germline mutations in <Emphasis Type="Italic">BRCA2</Emphasis>, MMR and <Emphasis Type="Italic">CDKN2A</Emphasis> genes

The contribution of hereditary factors for development of childhood tumors is limited to some few known syndromes associated with predominance of tumors in childhood. Occurrence of childhood tumors in hereditary cancer syndromes such as BRCA1/2 associated breast and ovarian cancer, DNA-mismatch repair (MMR) genes associated hereditary non polyposis colorectal cancer and CDKN2A associated familial malignant melanoma are very little studied. Herein we report the prevalence of childhood tumors (diagnosed ≤18 years of age) in families identified with mutation in the BRCA1/2, MMR and CDKN2A genes. Using pedigrees at the Regional Oncogenetic Clinic at Lund University Hospital, the prevalence of childhood cancer was estimated in families with mutations in the BRCA1 (n = 98), BRCA2 (n = 43) MMR (MLH1, MSH2 MSH6) (n = 31) and CDKN2A (n = 15) genes in comparison with population based control families (n = 854). Compared with the control group, a significantly higher prevalence of childhood cancer was found in families with mutations in BRCA2 (9.3% vs. 0.8% P = 0.001), MMR genes (19.4% vs. 0.8% P < 0.001) and CDKN2A (20.0% vs. 0.8% P < 0.001), but not in families with BRCA1 mutations (1.0% vs. 0.8% P = 0.6). Further analyses showed an increased risk for childhood tumors in families with mutations in BRCA2 (OR 12.4; 95% CI 3.5–44.1), MMR genes (OR 29.0; 95% CI 9.1–92.6), and CDKN2A (OR 30.2; 95% CI 7.0–131.1). This study suggests that the risk for childhood tumors is increased in families with germline mutations in the BRCA2, MMR and CDKN2A genes.     

Genetic mutations of <Emphasis Type="Italic">p53</Emphasis> and <Emphasis Type="Italic">k-ras</Emphasis> in gastric carcinoma patients from Hunan,China

This case–control study investigated the mutations in p53 and k-ras genes of 123 gastric carcinoma patients and 129 normal individuals from Hunan, China. By isolating genomic DNA from peripheral blood and employing polymerase chain reaction–single strand conformation polymorphism and DNA sequencing, the mutations of p53 exons-5, 6, 7, and 8 and k-ras were detected. The overall mutation frequency of p53 was 29.3%, and mutation was found in all four exons studied. The point mutations were predominant and among them, G:C→A:T was the highest (41.7%), followed by A:T→G:C (25%), G:C→C:G (11.1%), G:C→T:A (8.3%), and A:T→T:A (2.8%). The frameshift mutation was 11.1%. Mutations were detected in codons-131, 132, 133, 135, 149, 151, 162, 167, 173, 174, and 175 of exon 5, codons-193, 197, 213, and 215 of exon 6, codons-245, 246, 248, 249, and 270 of exon 7, and codons-271, 272, 273, and 282 of exon 8 of p53. The overall frequency of mutation in k-ras was 9.8%, mostly in codon-12 (91.7%) and in codon-13 (8.3%). There was no significant relationship between p53 and k-ras gene mutation in gastric carcinoma patients. Also, the relationships between p53 mutation and age, sex, smoking or drinking, and tumor metastasis were not significant. However, the patients with high/high-middle differentiated gastric carcinoma had a higher association with of p53 mutations. This study identified some novel p53 mutations in gastric cancer and showed mutation pattern and frequency of p53 and k-ras in the population of the central southern region of China.     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> infection in association with cell proliferation,apoptosis and prostaglandin E<Subscript>2</Subscript> levels

Objective:To evaluate the relationship between H.pylori infection with cell proliferation,apoptosis and PGE2 levels.Methods:A population-based study was conducted in Linqu,a high-risk area of gastric cancer in China.A total of 1523 subjects,aged 35-64,participating in a gastric cancer screening survey were investigated.H.pylori status were determined by 13C-urea breath test,expressions of Ki-67 were assessed by immunohistochemistry,apoptotic cells were detected by terminal deoxynucleotide transferase mediated dUTP nick end-labeling(TUNEL)method,and PGE2 levels were measured by enzyme immunoassay.Results:H.pylori infection was positively associated with cell proliferation activity.The mean and median percentage of Ki-67 labeling index(LI)in subjects with H.pylori positive were 14.1±10.3 and 12.0,significantly higher than those with H.pylori negative(?x±s:8.4±7.0;median:5.8;P<0.0001).Moreover,the prevalence rates of H.pylori infection showed a tendency to increase according to severity score of cell apoptosis(Ptrend <0.0001),from score 0 to 3,the percentage of H.pylori positivity increased from 67.5% to 96.7%.Furthermore,The mean and median of PGE2 concentration were 628.84±726.40 pg/mL and 411.33 pg/mL among subjects with H.pylori positive compared with 658.19±575.91pg/mL and 455.97 pg/mL among those with H.pylori negative(P=0.209).Conclusion:H.pylori infection was positively associated with increased cell proliferation and apoptosis activity,suggesting that H.pylori infection plays an important role in the gastric epithelial cell malignant transformation.     

Genetic variation in <Emphasis Type="Italic">IGF1</Emphasis>, <Emphasis Type="Italic">IGFBP3</Emphasis>, <Emphasis Type="Italic">IRS1</Emphasis>, <Emphasis Type="Italic">IRS2</Emphasis> and risk of breast cancer in women living in Southwestern United States

Background An insulin-related pathway to breast cancer has been hypothesized. Methods We examine the 19 CA repeat of the IGF1 gene, the -202 C > A IGFBP3, the G972R IRS, and the G1057D IRS2 polymorphisms among 1,175 non-Hispanic white (NHW) and 576 Hispanic newly diagnosed breast cancer cases and 1,330 NHW and 727 Hispanic controls living in Arizona, Colorado, New Mexico, and Utah. Results Among post-menopausal women not recently exposed to hormones, not having the 19 CA repeat of IGF1 gene was associated with breast cancer among NHW women [odds ratio (OR) 2.14, 95% confidence interval (CI) 1.21–3.79] and having an R allele of G972R IRS1 increased breast cancer risk among Hispanic women (OR 2.70, 95% CI 1.13–6.46). Among post-menopausal Hispanic women recently exposed to hormones the A allele of the -202 C > A IGFBP3 polymorphism increased risk of breast cancer (OR 1.57, 95% CI 1.06–2.33). The IGF1 19 CA repeat polymorphism interacted with hormone replacement therapy (HRT) among NHW post-menopausal women; women who had the 19/19 IGF1 genotype were at reduced risk of breast cancer (OR 0.64, 95% CI 0.47–0.88) if they did not use HRT. We also observed interaction between body mass index and IGF1 19 CA repeat (p=0.06) and between weight gain and the -202 C > A IGFBP3 polymorphism (p=0.05) in NHW post-menopausal women not recently exposed to hormones. Conclusions Our data suggest that associations between insulin-related genes and breast cancer risk among women living in the Southwestern United States may be dependent on estrogen exposure and may differ by ethnicity.     

The Biology of <Emphasis Type="Italic">K-Ras</Emphasis> and <Emphasis Type="Italic">B-Raf</Emphasis> Mutations in Colorectal Cancer

Ras and Raf proteins are two major players in the MAP kinase pathway. They are crucial downstream regulators of multiple receptor tyrosine kinase-mediated cell growth, transformation, and maintenance of the malignant phenotype in human cancers. Mutations have been identified in K-Ras and B-Raf in patients with colorectal cancer. Clinical studies in colorectal cancers demonstrate that the therapeutic efficacy of cetuximab, a chimeric monoclonal antibody against epidermal growth factor receptor, depends on the presence of wild-type K-Ras. However, mutations in B-Raf do not predict cetuximab resistance. These observations have led to the use of K-Ras as a predictive biomarker, allowing clinicians to direct the therapy of cancer patients based on their K-Ras mutational status.     

Induction of apoptosis by <Emphasis Type="Italic">p53</Emphasis>, <Emphasis Type="Italic">bax</Emphasis>, <Emphasis Type="Italic">bcl-2</Emphasis>, and <Emphasis Type="Italic">p21</Emphasis> expressed in colorectal cancer

Background We investigated the influence of genes on the apoptosis of colorectal tumor cells, based on DNA and mRNA kinetics.Methods In 30 colorectal cancer patients, we examined the mRNA expression of p53, bax, bcl-2, and p21 ^WAF1 , and we also investigated the development of tumor cell apoptosis, using a terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end labeling (TUNEL) method.Results TUNEL-positive cells showed a positive correlation with bax (P = 0.010) and a negative correlation with p21 (P = 0.04). We also investigated the relationship between p53 point mutation, p21 immunostaining degree, and apoptosis, based on DNA ladder expression. A remarkable correlation (P = 0.0090) was found between p21 and apoptosis.Conclusions The present study findings suggest that tumor cell apoptosis is (1) strongly inhibited by p21, (2) induced by bax, and (3) influenced by bcl-2, which, presumably, inhibits tumor cell apoptosis.     

<Emphasis Type="Italic">BRAF</Emphasis>/K-<Emphasis Type="Italic">ras</Emphasis> mutation,microsatellite instability,and promoter hypermethylation of <Emphasis Type="Italic">hMLH1</Emphasis>/<Emphasis Type="Italic">MGMT</Emphasis> in human gastric carcinomas

Background The BRAF and K-ras genes are the most frequently mutated oncogenes in various human malignancies. We examined BRAF and K-ras mutations in human gastric cancer, and investigated their relationship with microsatellite instability (MSI) and the hypermethylation of promoter regions in hMLH1 and O ⁶ -methylguanine DNA methyltransferase (MGMT).Methods Sixteen gastric cancer cell lines and 62 gastric cancer tissue samples were screened for BRAF and K-ras mutations by direct sequencing. We also performed a microsatellite assay and investigated methylation status in the promoter regions of hMLH1 and MGMT.Results mutation was not found in any of the cancer cell lines examined. One (1.6%) cancer tissue sample showed a point mutation in the BRAF gene (GT_G GA_G; V599E). K-ras mutation (GG_T GA_T, G12D) was detected in five (31%) gastric cancer cell lines and in 1 (1.6%) gastric cancer tissue sample. In the gastric cancer tissue samples examined, MSI was detected in 23 (37%) samples. Hypermethylated promoter regions in hMLH1 and MGMT, respectively, were detected in 6 (10%) and 13 (21%) gastric cancer tissue samples. Microsatellite stable (MSS) tumors showed frequent lymphatic invasion (P = 0.050).Conclusion Although BRAF mutation has been reported in a variety of other human cancers, it is a rare event in the carcinogenesis and progression/development of gastric cancer.     

Analysis of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> genotypes in clinical gastric wash samples

Helicobacter pylori is a key factor in the development of gastric cancer; indeed, clearance of H. pylori helps prevent gastric cancer. However, the relationship between gastric cancer and the abundance and diversity of H. pylori genotypes in the stomach remains unknown. Here, we present, for the first time, a quantitative analysis of H. pylori genotypes in gastric washes. A method was first developed to assess diversity and abundance by pyrosequencing and analysis of single nucleotide polymorphisms in 23S ribosomal RNA (rRNA), a gene associated with clarithromycin resistance. This method was then validated using arbitrarily mixed plasmids carrying 23S rRNA with single nucleotide polymorphisms. Multiple strains were detected in many of 34 clinical samples, with frequency 24.3?±?24.2 and 26.3?±?33.8 % for the A2143G and A2144G strains, respectively. Importantly, results obtained from gastric washes were similar to those obtained from biopsy samples. The method provides opportunities to investigate drug resistance in H. pylori and assess potential biomarkers of gastric cancer risk, and should thus be validated in large-scale clinical trials.     

Gene expression deregulation by <Emphasis Type="Italic">KRAS</Emphasis> G12D and G12V in a <Emphasis Type="Italic">BRAF</Emphasis> V600E context

Background  

KRAS and BRAF mutations appear of relevance in the genesis and progression of several solid tumor types but the co-occurrence and interaction of these mutations have not yet been fully elucidated. Using a microsatellite stable (MSS) colorectal cancer (CRC) cell line (Colo741) having mutated BRAF and KRAS ^WT , we also aimed to investigate the KRAS-BRAF interaction. Gene expression profiles for control KRAS ^WT , KRAS ^G12V and KRAS ^G12D transfected cells were obtained after cell clone selection and RT-PCR screening. Extensive qPCR was performed to confirm microarray data.