Publications by authors named "Gerson Hamada"

Article Synopsis
  • Gastric cancer is more common in men, and this study explores whether reproductive factors and menopausal hormone therapy (MHT) might protect women from it.
  • The analysis included over 2,000 individuals with gastric cancer and more than 7,000 controls across various studies, revealing that longer fertility duration and MHT use may reduce cancer risk in women.
  • The findings suggest a link between reproductive health and decreased gastric cancer risk, highlighting the need for further research on hormonal effects in different stages of a woman’s life.
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Edible mushrooms have high concentrations of vitamins and minerals. They are considered 'functional foods' for their disease-prevention properties. Mushroom consumption may reduce the risk of gastric cancer, the fifth most common cancer worldwide.

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Background: The causal pathway between high education and reduced risk of gastric cancer (GC) has not been explained. The study aimed at evaluating the mediating role of lifestyle factors on the relationship between education and GC METHODS: Ten studies with complete data on education and five lifestyle factors (smoking, alcohol drinking, fruit and vegetable intake, processed meat intake and salt consumption) were selected from a consortium of studies on GC including 4349 GC cases and 8441 controls. We created an a priori score based on the five lifestyle factors, and we carried out a counterfactual-based mediation analysis to decompose the total effect of education on GC into natural direct effect and natural indirect effect mediated by the combined lifestyle factors.

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Background: Evidence from epidemiological studies on the role of tea drinking in gastric cancer risk remains inconsistent. We aimed to investigate and quantify the relationship between tea consumption and gastric cancer in the Stomach cancer Pooling (StoP) Project consortium.

Methods: A total of 9438 cases and 20,451 controls from 22 studies worldwide were included.

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Purpose: Previous studies show that consuming foods preserved by salting increases the risk of gastric cancer, while results on the association between total salt or added salt and gastric cancer are less consistent and vary with the exposure considered. This study aimed to quantify the association between dietary salt exposure and gastric cancer, using an individual participant data meta-analysis of studies participating in the Stomach cancer Pooling (StoP) Project.

Methods: Data from 25 studies (10,283 cases and 24,643 controls) from the StoP Project with information on salt taste preference (tasteless, normal, salty), use of table salt (never, sometimes, always), total sodium intake (tertiles of grams/day), and high-salt and salt-preserved foods intake (tertiles of grams/day) were used.

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Background: Helicobacter pylori is the most important risk factor for non-cardia gastric cancer (NCGC); however, the magnitude of the association varies across epidemiological studies. This study aimed to quantify the association between H. pylori infection and NCGC, using different criteria to define infection status.

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Background: The prevalence of -negative gastric cancer (HpNGC) can be as low as 1%, when infection is assessed using more sensitive tests or considering the presence of gastric atrophy. HpNGC may share a high-risk profile contributing to the occurrence of cancer in the absence of infection. We estimated the proportion of HpNGC, using different criteria to define infection status, and compared HpNGC and positive cases regarding gastric cancer risk factors.

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Article Synopsis
  • A large study with data from 18 observational studies analyzed the relationship between coffee consumption and gastric cancer, including 8198 cases and 21,419 controls.
  • The results showed that coffee drinkers had a pooled odds ratio (OR) of 1.03 compared to non-drinkers, indicating no significant increase in gastric cancer risk overall.
  • However, high coffee intake (five or more cups per day) was associated with gastric cardia cancer specifically, while no strong link to gastric cancer was found for different amounts of coffee consumed.
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Background: Prior epidemiologic studies on the association between diabetes and gastric cancer risk provided inconclusive findings, while traditional, aggregate data meta-analyses were characterized by high between-study heterogeneity.

Objective: To investigate the association between type 2 diabetes and gastric cancer using data from the 'Stomach Cancer Pooling (StoP) Project', an international consortium of more than 30 case-control and nested case-control studies, which is large and provides harmonized definition of participants' characteristics across individual studies. The data have the potential to minimize between-study heterogeneity and provide greater statistical power for subgroup analysis.

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A low intake of fruits and vegetables is a risk factor for gastric cancer, although there is uncertainty regarding the magnitude of the associations. In our study, the relationship between fruits and vegetables intake and gastric cancer was assessed, complementing a previous work on the association betweenconsumption of citrus fruits and gastric cancer. Data from 25 studies (8456 cases and 21 133 controls) with information on fruits and/or vegetables intake were used.

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Background: Gastric cancer pathogenesis represents a complex interaction of host genetic determinants, microbial virulence factors and environmental exposures. Our primary aim was to determine the association between occupations/occupational exposures and odds of gastric cancer.

Methods: We conducted a pooled-analysis of individual-level data harmonized from 11 studies in the Stomach cancer Pooling Project.

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Article Synopsis
  • * Findings reveal a significant increased risk of gastric cancer linked to the consumption of red meat (OR: 1.24) and processed meat (OR: 1.23), showing that higher meat intake correlates with a greater risk.
  • * The research supports dietary guidelines to limit meat consumption as a strategy to potentially lower the incidence of gastric cancer.
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Low socioeconomic position (SEP) is a strong risk factor for incidence and premature mortality from several cancers. Our study aimed at quantifying the association between SEP and gastric cancer (GC) risk through an individual participant data meta-analysis within the "Stomach cancer Pooling (StoP) Project". Educational level and household income were used as proxies for the SEP.

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Intake of heterocyclic amines (HCAs) and other mutagenic compounds formed during cooking has been hypothesized to be responsible for the positive association observed between red meat and colorectal cancer. We evaluated whether well-done/very well-done preferences for various meat and fish items, higher intakes of meat and fish, and meat-derived and fish-derived HCA are associated with the risk of colorectal adenoma (CRA) in a Japanese-Brazilian population. We selected 302 patients with adenoma and 403 control individuals who underwent total colonoscopy between 2007 and 2013, and collected information on aspects of meat intake using a detailed questionnaire.

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Background: Helicobacter pylori (H. pylori) infection is more frequent among men, though the magnitude of the association might be inaccurate due to potential misclassification of lifetime infection and publication bias. Moreover, infection is common, and most studies are cross-sectional.

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Smoking has been associated with acquisition and increased persistence of Helicobacter pylori infection, as well as with lower effectiveness of its eradication. A greater prevalence of infection among smokers could contribute to the increased risk for gastric cancer. We aimed to estimate the association between smoking and seropositivity to H.

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Glycoprotein-A repetitions predominant (GARP) is a transmembrane protein that is highly expressed in breast cancer. Its overexpression correlates with worse survival, and antibodies to GARP appear to play a protective role in a mouse model. No large-scale studies of immunity to GARP in humans have yet been undertaken.

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High levels of naturally occurring IgG antibodies to mucin 1 (MUC1), a membrane-bound glycoprotein that is overexpressed in patients with breast cancer, are associated with good prognosis. This suggests that endogenous anti-MUC1 antibodies have a protective effect and, through antibody-mediated host immunosurveillance mechanisms, might contribute to a cancer-free state. To test this possibility, we characterized a large number of multiethnic patients with breast cancer and matched controls for IgG antibodies to MUC1.

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Increasing evidence implicates human cytomegalovirus (HCMV) in the etiopathogenesis of breast cancer. Antibodies to this virus in patients with breast cancer have been reported, but no large-scale studies have been conducted to determine whether the antibody levels differ between patients and matched controls. Using specimens from a large (1712 subjects) multiethnic case-control study, we aimed to determine whether the levels of antibodies to the HCMV glycoprotein B (gB) differed between patients and controls and whether they were associated with particular immunoglobulin γ marker (GM), κ marker (KM), and Fcγ receptor (FcγR) genotypes.

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Although Japanese in Japan and the USA are high-risk populations for colorectal cancer, the prevalence of obesity, one of the established risk factors for this disease, is low in these populations compared with other high-risk populations. To understand this inconsistency, we compared plasma obesity-related biomarkers in cross-sectional studies carried out in Tokyo, São Paulo, and Hawaii. We measured plasma levels of insulin-like growth factor-I (IGF-I), insulin-like growth factor-binding protein (IGFBP)-1, IGFBP-3, C-peptide, adiponectin, leptin, tumor necrosis factor-α, and interleukin-6 by immunoassay and total C-reactive protein, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides using a clinical chemistry autoanalyzer.

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Previous studies of Japanese migrants have suggested that the increase in colorectal cancer rates occurring after migration is slower among Japanese Brazilians than among Japanese Americans. We hypothesized that this difference may partly reflect differences in vegetable and fruit intake between the populations. Using data from validation studies of food frequency questionnaires being used in comparative case-control studies of colorectal adenoma in Tokyo, São Paulo, and Hawaii, plasma carotenoid, retinol, tocopherol, and coenzyme Q10 levels were measured by high-performance liquid chromatography, and 25-hydroxy vitamin D levels were estimated by enzyme-linked immunosorbent assay.

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Immunoglobulin κ constant (IGKC) gene has recently been identified as a strong prognostic marker in several human solid tumors, including breast cancer. Although the mechanisms underlying the IGKC signature are not yet known, identification of tumor-infiltrating plasma cells as the source of IGKC expression strongly suggests a role for humoral immunity in breast cancer progression. The primary aim of the present investigation was to determine whether the genetic variants of IGKC, KM (κ marker) allotypes, are risk factors for breast cancer, and whether they influence the magnitude of humoral immunity to epidermal growth factor receptor 2 (HER2), which is overexpressed in 25-30% of breast cancer patients and is associated with poor prognosis.

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Immunoglobulin GM allotypes, antigenic determinants of γ chains, are encoded by three very closely linked codominant genes on chromosome 14q32. Particular GM alleles/haplotypes are associated with antibody responses to certain tumor antigens and contribute to the cytotoxicity of breast cancer cells, but their possible role in susceptibility to this malignancy has not been adequately examined. Using a matched case-control design, we genotyped a large (1710 subjects) study population from Japan and Brazil for several GM alleles to determine whether these determinants are associated with susceptibility to breast cancer.

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Background: Differences in sex hormone levels among populations might contribute to the variation in breast cancer incidence across countries. Previous studies have shown higher breast cancer incidence and mortality among Japanese Brazilians than among Japanese. To clarify the difference in hormone levels among populations, we compared postmenopausal endogenous sex hormone levels among Japanese living in Japan, Japanese Brazilians living in the state of São Paulo, and non-Japanese Brazilians living in the state of São Paulo.

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Previous studies showing the presence of antibodies against tumor-associated antigens in healthy individuals suggest that antibody-dependent cell cytotoxicity (ADCC) might play a role in the development of breast cancer. We hypothesized that functional polymorphisms in fragment c gamma receptor (FcgR) genes were associated with breast cancer risk. We conducted hospital-based case-control studies of patients aged 20-74 years with invasive breast cancer, and matched controls from medical checkup examinees in Nagano, Japan and from cancer-free patients in São Paulo, Brazil.

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