Association between serum concentrations of perfluoroalkyl substances and global DNA methylation levels in peripheral blood leukocytes of Japanese women: A cross-sectional study.

Global DNA methylation levels in peripheral blood leukocytes can be a biomarker for cancer risk; however, levels can be changed by various factors such as environmental pollutants. We investigated the association between serum concentrations of perfluoroalkyl substances (PFASs) and global DNA methylation levels of leukocytes in a cross-sectional study using the control group of a Japanese breast cancer case-control study [397 women with a mean age of 54.1 (SD 10.1) years]. Importantly, our analysis distinguished branched PFAS isomers as different from linear isomers. The serum concentrations of 20 PFASs were measured by in-port arylation gas-chromatography negative chemical ionization mass spectrometry. Global DNA methylation levels in peripheral blood leukocytes were measured using a luminometric methylation assay. Associations between log10-transformed serum PFAS concentrations and global DNA methylation levels were evaluated by regression coefficients in multivariable robust linear regression analyses. Serum concentrations of 13 PFASs were significantly associated with increased global DNA methylation levels in leukocytes. Global DNA methylation was significantly increased by 1.45 %-3.96 % per log10-unit increase of serum PFAS concentration. Our results indicate that exposure to PFASs may increase global DNA methylation levels in peripheral blood leukocytes of Japanese women.

Serum perfluoroalkyl substances and breast cancer risk in Japanese women: A case-control study.

BACKGROUND: Perfluoroalkyl substances (PFASs) may contribute to causing breast cancer; however, associations between exposure to PFASs and risk of breast cancer are controversial. OBJECTIVES: In the present study, we newly distinguished branched isomers of PFASs from their linear isomers and aimed to investigate the association between serum PFAS concentrations and breast cancer risk in Japanese women. METHODS: We used a case-control design to study 405 eligible matched pairs attending four hospitals in Nagano Prefecture, Japan from May 2001 to September 2005. We used in-port arylation gas-chromatography mass spectrometry with negative chemical ionization to measure serum concentrations of 20 PFAS congeners. We calculated multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of breast cancer and its hormone-receptor subtypes by quartiles or tertiles of serum PFASs. RESULTS: After multivariable adjustment for breast cancer risk factors, we found that serum concentrations of 20 PFAS congeners were significantly inversely associated with risk of breast cancer. Comparing the extreme quartiles of linear isomers of perfluorooctane sulfonate or perfluorooctanoic acid, ORs were 0.15 (95% CI: 0.07, 0.33 P for trend <0.0001) and 0.21 95% CI: 0.10, 0.44 P for trend <0.0001). Among postmenopausal women, whereas we found the linear isomer of perfluorotridecanoic acid to be inversely associated with breast cancer risk, a medium degree of exposure to the branched isomer of perfluorotridecanoic acid was associated with a marginally increased risk of breast cancer (OR [95% CI] = 1.74 [0.98, 3.09]). DISCUSSION: In our case-control study, we found overall no association between serum PFAS concentrations and increased risk of breast cancer. Many inverse associations between serum PFAS concentrations and breast cancer risk were found.

Correlation between global methylation level of peripheral blood leukocytes and serum C reactive protein level modified by MTHFR polymorphism: a cross-sectional study.

BACKGROUND: Chronic inflammatory conditions are associated with higher tumor incidence through epigenetic and genetic alterations. Here, we focused on an association between an inflammation marker, C-reactive-protein (CRP), and global DNA methylation levels of peripheral blood leukocytes. METHODS: The subjects were 384 healthy Japanese women enrolled as the control group of a case-control study for breast cancer conducted from 2001 to 2005. Global DNA methylation was quantified by Luminometric Methylation Assay (LUMA). RESULTS: With adjustment for lifestyle-related factors, including folate intake, the global DNA methylation level of peripheral blood leukocytes was significantly but weakly increased by 0.43% per quartile category for CRP (P for trend = 0.010). Estimated methylation levels stratified by CRP quartile were 70.0%, 70.8%, 71.4%, and 71.3%, respectively. In addition, interaction between polymorphism of MTHFR (rs1801133, known as C677T) and CRP was significant (P for interaction = 0.046); the global methylation level was significantly increased by 0.61% per quartile category for CRP in the CT/TT group (those with the minor allele T, P for trend = 0.001), whereas no association was observed in the CC group (wild type). CONCLUSIONS: Our study suggests that CRP concentration is weakly associated with global DNA methylation level. However, this association was observed more clearly in individuals with the minor allele of the MTHFR missense SNP rs1801133. By elucidating the complex mechanism of the regulation of DNA methylation by both acquired and genetic factors, our results may be important for cancer prevention.

Nimotuzumab combined with concurrent chemoradiotherapy in Japanese patients with esophageal cancer: A phase I study.

Nimotuzumab is a humanized anti-epidermal growth factor receptor IgG1 monoclonal antibody. This phase I study assessed the tolerability, safety, efficacy, and pharmacokinetics of nimotuzumab in combination with chemoradiotherapy in Japanese patients with esophageal cancer. Patients with stage II, III, and IV esophageal cancer were enrolled. Patients were planned to receive nimotuzumab (level 1: 200 mg/wk for 25 weeks; or level 2: 400 mg/wk in the chemoradiation period, 400 mg biweekly in an additional chemotherapy period [8 weeks after the chemoradiation period] and a maintenance therapy period [after chemotherapy to 25 weeks]) combined with cisplatin (75 mg/m2 on day 1) and fluorouracil (1000 mg/m2 on days 1-4) in the chemoradiation and additional chemotherapy periods. Radiotherapy was given concurrently at 50.4 Gy. A total of 10 patients were enrolled in level 1. Dose-limiting toxicities were observed in 2 patients (grade 3 infection and renal disorder). Maximum-tolerated dose was estimated to be at least 200 mg/wk and the dose was not escalated to level 2. The most common grade ≥3 toxicities were lymphopenia (90%), leukopenia (60%), neutropenia (50%), and febrile neutropenia, decreased appetite, hyponatremia, and radiation esophagitis (30% each). Neither treatment-related death nor grade ≥3 skin toxicity was observed in any patient. Complete response rate was 50%. Progression-free survival was 13.9 months. One- and 3-year survival rates were 75% and 37.5%, respectively. Immunogenicity was not reported in any patient. Nimotuzumab in combination with concurrent chemoradiotherapy was tolerable and effective for Japanese patients with esophageal cancer.

An inverse association between serum resistin levels and n-3 polyunsaturated fatty acids intake was strongest in the SNP-420 G/G genotype in the Japanese cohort: The Toon Genome Study.

OBJECTIVE: Resistin is secreted by monocytes/macrophages and is associated with insulin resistance, inflammation and cardiovascular diseases. In the Japanese cohort, serum resistin is tightly associated with a single-nucleotide polymorphism (SNP) at -420 (rs1862513) in the promoter region of the human resistin gene. However, interactions between SNP-420 and environmental factors remain to be elucidated. The aim of this study was to investigate the association between serum resistin levels and nutrient intake, and the effect of SNP-420 on this association. DESIGN, PARTICIPANTS AND MEASUREMENTS: The Toon Genome Study is a cohort study of Japanese community-dwelling subjects. A total of 1981 participants were cross-sectionally analysed. Each nutrient intake was assessed using the semiquantitative food frequency questionnaire and categorized into the quartiles (Q1-Q4). Serum resistin was measured by ELISA. RESULTS: Serum resistin tended to be inversely associated with fish intake and positively associated with meat intake after adjustment for age, sex, BMI and energy intake. Serum resistin was inversely associated with n-3 polyunsaturated fatty acids (PUFA) intake after adjustment for age, sex, BMI and energy intake (Q1 12.5, Q2 12.5, Q3 12.2, Q4 11.5 ng/mL; P for trend = .007). This inverse association was strongest in the G/G genotype of SNP-420, followed by C/G and C/C (G/G, Q1 18.9, Q2 19.5, Q3 18.4, Q4 14.5 ng/mL, P = .001; C/G, 14.4, 13.3, 13.1, 12.9, P = .015; C/C, 9.5, 9.5, 9.2, 8.8, P = .020; P for interaction = .004). CONCLUSIONS: The inverse association between serum resistin and n-3 PUFA intake was strongest in SNP-420 G/G genotype in the Japanese cohort.

Dual Effects of a RETN Single Nucleotide Polymorphism (SNP) at -420 on Plasma Resistin: Genotype and DNA Methylation.

CONTEXT: We previously reported that single nucleotide polymorphism (SNP)-420 C>G (rs1862513) in the promoter region of RETN was associated with type 2 diabetes. Plasma resistin was tightly correlated with SNP-420 genotypes. SNP-420 is a CpG-SNP affecting the sequence of cytosine-phosphate-guanine dinucleotides. OBJECTIVE: To examine whether methylation at SNP-420 affects plasma resistin, we analyzed plasma resistin and methylation at RETN SNP-420. DESIGN AND METHODS: Genomic DNA was extracted from peripheral white blood cells in 2078 Japanese subjects. Quantification of the methylation was performed by pyrosequencing after DNA bisulfite conversion. RESULTS: Methylation at SNP-420 was highest in the C/C genotype (36.9 ± 5.7%), followed by C/G (21.4 ± 3.5%) and G/G (2.9 ± 1.4%; P < 0.001). When assessed in each genotype, methylation at SNP-420 was inversely associated with plasma resistin in the C/C (ß = -0.134, P < 0.001) or C/G (ß = -0.227, P < 0.001) genotype. In THP-1 human monocytes intrinsically having the C/C genotype, a demethylating reagent, 5-aza-dC, decreased the methylation at SNP-420 and increased RETN messenger RNA. SNP+1263 (rs3745369), located in the 3' untranslated region of RETN, was also associated with methylation at SNP-420. In addition, highly sensitive C-reactive protein was inversely associated with methylation at SNP-420 in the C/C genotype, whereas body mass index was positively associated. CONCLUSIONS: Plasma resistin was inversely associated with the extent of methylation at SNP-420 mainly dependent on the SNP-420 genotype. The association can also be explained partially independent of SNP-420 genotypes. SNP-420 could have dual, genetic and epigenetic effects on plasma resistin.

Genome-wide association study of plasma resistin levels identified rs1423096 and rs10401670 as possible functional variants in the Japanese population.

Resistin is a cytokine inducing insulin resistance in mice. We previously identified single nucleotide polymorphisms (SNPs) at -420 (rs1862513) and -358 (rs3219175) located in the human resistin gene (RETN) promoter as strong determinants for circulating resistin in the Japanese population. The objective was to identify additional functional variants for circulating resistin. We conducted a genome-wide association study in 448 Japanese subjects. A peak association signal was found on chromosome 19 where RETN is located. The top-hit SNP was SNP -358 G>A, followed by rs1423096 C>T, SNP -420 C>G, and rs10401670 C>T (P = 5.39×10-47, 1.81×10-22, 2.09×10-16, and 9.25×10-15, respectively). Meta-analysis including another two independent general Japanese populations showed that circulating resistin was most strongly associated with SNP-358, followed by SNP-420, rs1423096, and rs10401670. Rs1423096 and rs10401670 were located in the 3'-region of RETN and were in strong linkage disequilibrium. Although these SNPs were also in linkage disequilibrium with the promoter SNPs, conditional and haplotype association analyses identified rs1423096 and rs10401670 as independent determinants for circulating resistin. Functionally, nuclear proteins specifically recognized T but not C at rs10401670 as evidenced by an electrophoretic mobility shift assay. The promoter activity of a luciferase reporter with T at either rs1423096 or rs10401670 was lower than that with C in THP-1 human monocytes. Therefore, rs1423096 and rs10401670, in addition to SNP-420 and SNP-358, were identified as possible functional variants affecting circulating resistin by the genome-wide search in the Japanese population.

Endoplasmic reticulum stress induced by tunicamycin increases resistin messenger ribonucleic acid through the pancreatic endoplasmic reticulum eukaryotic initiation factor 2α kinase-activating transcription factor 4-CAAT/enhancer binding protein-α homologous protein pathway in THP-1 human monocytes.

AIMS/INTRODUCTION: Resistin, secreted from adipocytes, causes insulin resistance in mice. In humans, the resistin gene is mainly expressed in monocytes and macrophages. Tunicamycin is known to induce endoplasmic reticulum (ER) stress, and reduce resistin gene expression in 3T3-L1 mouse adipocytes. The aim of the present study was to examine whether ER stress affects resistin gene expression in human monocytes. MATERIALS AND METHODS: The relationship between resistin messenger ribonucleic acid (mRNA) and ER stress markers mRNA was analyzed by reverse transcription polymerase chain reaction in isolated monocytes of 30 healthy volunteers. The effect of endotoxin/lipopolysaccharides or tunicamycin on resistin gene expression was analyzed in THP-1 human monocytes. Signaling pathways leading to resistin mRNA were assessed by the knockdown using small interfering RNA or overexpression of key molecules involved in unfolded protein response. RESULTS: Resistin mRNA was positively associated with immunoglobulin heavy chain-binding protein (BiP) or CAAT/enhancer binding protein-α homologous protein (CHOP) mRNA in human isolated monocytes. In THP-1 cells, lipopolysaccharides increased mRNA of BiP, pancreatic endoplasmic reticulum eukaryotic initiation factor 2α kinase (PERK) and CHOP, as well as resistin. Tunicamycin also increased resistin mRNA. This induction appeared to be dose- and time-dependent. Tunicamycin-induced resistin mRNA was inhibited by chemical chaperone, 4-phenylbutyric acid. The knockdown of either PERK, activating transcription factor 4 (ATF4) or CHOP reduced tunicamycin-induced resistin mRNA. Conversely, overexpression of ATF4 or CHOP increased resistin mRNA. CONCLUSIONS: Endoplasmic reticulum stress induced by tunicamycin increased resistin mRNA through the PERK-ATF4-CHOP pathway in THP-1 human monocytes. ER stress could lead to insulin resistance through enhanced resistin gene expression in human monocytes.

Association between serum organochlorines and global methylation level of leukocyte DNA among Japanese women: a cross-sectional study.

While the global methylation level of leukocyte DNA may be a suitable biomarker for cancer risk, the level may be influenced by multiple factors, both environmental and host-related, one of which is exposure to environmental pollutants. To date, three epidemiologic studies have examined associations between serum organochlorine levels and global DNA methylation level, but their findings are not fully consistent, and the associations thus require confirmation in other well-characterized populations. We tested the association between organochlorine exposure and the global DNA methylation level of leukocytes in Japanese women. We conducted a cross-sectional study using the control group of a breast cancer case-control study in Japan. Subjects were 403 Japanese women who provided blood samples. Serum polychlorinated biphenyls (PCBs) and nine pesticide-related organochlorines were measured by gas chromatography isotope-dilution high-resolution mass spectrometry. Further, global methylation level of peripheral leukocyte DNA among 399 women was measured by luminometric methylation assay. Linear trends in the association between methylation and quartile levels of organochlorines were evaluated by regression coefficients in a multivariable linear regression model. We found significant inverse associations between the global methylation level in leukocyte DNA and many of the organochlorine levels measured. Global methylation level was significantly decreased by 0.33-0.83% per quartile category for serum o,p'-dichlorodiphenyltrichloroethane (o,p'-DDT), p,p'-DDT, p,p'-dichlorodiphenyldichloroethylene, trans-nonachlor, oxychlordane, hexachlorobenzene, ß-hexachlorocyclohexane, PCB17, PCB52/69, PCB74, PCB114, and PCB183. Serum organochlorine levels were inversely associated with the global methylation level of leukocyte DNA in a relatively large sample of Japanese women.

Green tea consumption and breast cancer risk in Japanese women: a case-control study.

Although many in vitro and animal studies have suggested a protective effect of green tea against breast cancer, only a few epidemiological studies have examined this association, and findings have been inconsistent. We examined the association between green tea consumption and breast cancer risk in consideration of the hormone receptor status of tumors and investigated whether the association was modified by dietary and genetic factors based on a hospital-based case-control study in Nagano, Japan. A total of 369 pairs completed a validated food frequency questionnaire and provided blood samples. Four single nucleotide polymorphisms (SNPs) were genotyped: CYP19A1 (rs10046), COMT (rs4680), MTHFR C677T (rs1801133), and MTHFR A1298C (rs1801131). We found no inverse association between green tea consumption and breast cancer risk. Compared with women who drank less than 120 ml of green tea per day, the adjusted odds ratio for women who drank more than 600 ml was 1.27 (95% confidence interval = 0.75-2.14; P for trend = 0.20). We also found no inverse association for either tumor subtype. No substantial effect modification was observed for menopausal status, 4 SNPs, or dietary intake of folate or isoflavone. This study provides additional evidence that green tea consumption is not associated with a decreased risk.

Phase 1 study of efatutazone, a novel oral peroxisome proliferator-activated receptor gamma agonist, in combination with FOLFIRI as second-line therapy in patients with metastatic colorectal cancer.

BACKGROUND: Efatutazone, a novel oral highly-selective peroxisome proliferator-activated receptor gamma (PPARγ) agonist, has demonstrated some inhibitory effects on disease stabilization in patients with metastatic colorectal cancer (mCRC) enrolled in previous phase I studies. Here, we evaluate the safety and pharmacokinetics of efatutazone combined with FOLFIRI (5-fluorouracil, levo-leucovorin, and irinotecan) as second-line chemotherapy in Japanese patients with mCRC. METHODS: Dose-limiting toxicities (DLTs) were evaluated at 2 efatutazone dose levels of 0.25 and 0.50 mg (the recommended dose [RD] of efatutazone monotherapy) twice daily in combination with FOLFIRI in a 3-9 patient cohort. Furthermore, tolerability at the RD level was assessed in additional patients, up to 12 in total. Blood samples for pharmacokinetics and biomarkers and tumor samples for archival tissues were collected from all patients. RESULTS: Fifteen patients (0.25 mg, 3; 0.5 mg, 12) were enrolled. No DLTs were observed. Most patients experienced weight increase (100 %) and edema (80.0 %), which were manageable with diuretics. Common grade 3/4 toxicities were neutropenia (93.3 %), leukopenia (46.7 %), and anemia (33.3 %). Stable disease was observed in 8 of the 14 patients evaluable for tumor response. The plasma adiponectin levels increased over time and increased dose. No clear relationship was detected between treatment efficacies and plasma levels of adiponectin as well as the expression levels of PPARγ and the retinoid X receptor in tumor tissues. CONCLUSIONS: Efatutazone combined with FOLFIRI demonstrates an acceptable safety profile and evidence of disease stabilization in Japanese patients with mCRC. The RD for efatutazone monotherapy can be used in combination with FOLFIRI.

Dietary cadmium intake and breast cancer risk in Japanese women: a case-control study.

Cadmium, an environmental pollutant, may act like an estrogen and be a potential risk factor for estrogen-dependent diseases such as breast cancer. We examined the hypothesis that higher dietary cadmium intake is associated with risk of overall and hormone receptor-defined breast cancer in Japanese women, a population with a relatively high cadmium intake. The study was conducted under a case-control design in 405 eligible matched pairs from May 2001 to September 2005 at four hospitals in Nagano Prefecture, Japan. Dietary cadmium intake was estimated using a food frequency questionnaire. Multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of breast cancer and its hormone-receptor-defined subtypes were calculated by tertile of dietary cadmium intake. We found no significant association between dietary cadmium and risk of total breast cancer in either crude or multivariable-adjusted analysis. Adjusted ORs for tertiles of cadmium intake were 1.00, 1.19, and 1.23 (95% CI, 0.76-2.00; P for trend=0.39) for whole breast cancer. Further, no significant associations were seen across strata of menopausal status, smoking, and diabetes in multivariable-adjusted models except for adjusted OR for continuous cadmium intake in postmenopausal women. A statistically significant association was found for estrogen receptor-positive (ER+) tumors among postmenopausal women (adjusted OR=1.00, 1.16, and 1.94 [95% CI, 1.04-3.63; P for trend=0.032]). Although the present study found no overall association between dietary cadmium intake and breast cancer risk, higher cadmium intake was associated with increased risk of ER+ breast cancer in postmenopausal women, at least at regular intake levels in Japanese women in the general population. Further studies are needed to confirm this association.

Plasma resistin is associated with single nucleotide polymorphisms of a possible resistin receptor, the decorin gene, in the general Japanese population.

Resistin is an adipokine secreted from adipocytes in mice. We previously reported that a single nucleotide polymorphism (SNP) -420 (rs1862513) in the human resistin gene (RETN), is correlated with plasma resistin. Decorin is a multifunctional proteoglycan, and its isoform, lacking 14 amino acids from the N terminal region of mature core decorin, recently was identified as a resistin receptor in mice. To examine whether SNPs in the vicinity of the human decorin gene (DCN) are associated with plasma resistin, we cross-sectionally analyzed six tag SNPs selected around DCN in the same linkage disequilibrium block in 2,078 community-dwelling Japanese subjects. Plasma resistin was associated with the rs7139228, rs7956537, rs516115, and rs3138167 genotypes in DCN. A multiple regression analysis revealed that the genotype of rs7308752 (G/G) or rs516115 (C/C) was associated with decreased plasma resistin after adjusted for age, sex, BMI, and the RETN SNP rs1862513. The effect of rs7139228 and rs1862513 seemed to be additive without synergistic interaction. Therefore, plasma resistin was associated with some tag SNPs around DCN in the general Japanese population. The possibility that human decorin is a human resistin receptor should be pursued.

Association of dietary and genetic factors related to one-carbon metabolism with global methylation level of leukocyte DNA.

Global hypomethylation of leukocyte DNA has been associated with an increased risk of cancer. As dietary and genetic factors related to one-carbon metabolism may influence both the methylation and synthesis of DNA, we investigated associations between these factors and the global methylation level of peripheral blood leukocyte DNA based on a cross-sectional study of 384 Japanese women. Dietary intake of folate and vitamins B2, B6, and B12 was assessed with a validated semiquantitative food frequency questionnaire. Five polymorphisms in methylenetetrahydrofolate reductase (MTHFR) (rs1801133 and rs1801131), methionine synthase (MTR) (rs1805087), and methionine synthase reductase (MTRR) (rs10380 and rs162049) were genotyped. Global DNA methylation of leukocyte DNA was quantified using Luminometric Methylation Assay. A linear trend of association between methylation and dietary and genetic factors was evaluated by regression coefficients in a multivariable linear regression model. Mean global methylation level (standard deviation) was 70.2% (3.4) and range was from 59.0% to 81.2%. Global methylation level significantly decreased by 0.36% (95% confidence interval, 0.03-0.69) per quartile category for folate level. Subgroup analysis suggested that alcohol drinking modified the association between folate intake and global methylation level (P(interaction)  = 0.01). However, no statistically significant association was observed for intake of vitamins B2, B6, and B12, alcohol consumption, or five single nucleotide polymorphisms of MTHFR, MTR, and MTRR. We found that higher folate intake was significantly associated with a lower level of global methylation of leukocyte DNA in a group of healthy Japanese females.

Association of postmenopausal endogenous sex hormones with global methylation level of leukocyte DNA among Japanese women.

BACKGROUND: Although global hypomethylation of leukocyte DNA has been associated with an increased risk of several sites of cancer, including breast cancer, determinants of global methylation level among healthy individuals remain largely unexplored. Here, we examined whether postmenopausal endogenous sex hormones were associated with the global methylation level of leukocyte DNA. METHODS: A cross-sectional study was conducted using the control group of a breast cancer case-control study in Nagano, Japan. Subjects were postmenopausal women aged 55 years or over who provided blood samples. We measured global methylation level of peripheral blood leukocyte DNA by luminometric methylation assay; estradiol, estrone, androstenedione, dehydroepiandrosterone sulfate, testosterone and free testosterone by radioimmunoassay; bioavailable estradiol by the ammonium sulfate precipitation method; and sex-hormone binding globulin by immunoradiometric assay. A linear trend of association between methylation and hormone levels was evaluated by regression coefficients in a multivariable liner regression model. A total of 185 women were included in the analyses. RESULTS: Mean global methylation level (standard deviation) was 70.3% (3.1) and range was from 60.3% to 79.2%. Global methylation level decreased 0.27% per quartile category for estradiol and 0.39% per quartile category for estrone while it increased 0.41% per quartile category for bioavailable estradiol. However, we found no statistically significant association of any sex hormone level measured in the present study with global methylation level of leukocyte DNA. CONCLUSIONS: Our findings suggest that endogenous sex hormones are not major determinants of the global methylation level of leukocyte DNA.

Genotype risk score of common susceptible variants for prediction of type 2 diabetes mellitus in Japanese: the Shimanami Health Promoting Program (J-SHIPP study). Development of type 2 diabetes mellitus and genotype risk score.

Recent genomewide association studies have successfully identified several genotypes susceptible to type 2 diabetes mellitus (T2DM). However, only a few studies have investigated whether these variations confer a risk of the future development of T2DM. We conducted a longitudinal genetic epidemiological study to clarify the prognostic significance of the T2DM-associated variants. The sample population consisted of 2037 middle-aged to elderly community residents. Personal health records were obtained from a clinical database administered by the local government. Genotype risk score was calculated by the following variants, namely, KCNQ1, TCF7L2, CDKAL1, HHEX, IGF2BP2, CDKN2AB, SLC30A8, KCNJ11, PPARG, and GCKR. Susceptibility of these variants in Japanese has been confirmed by association analysis. Among the 1824 subjects who did not have T2DM at baseline, 95 cases of T2DM were newly diagnosed during the 9.4-year follow-up period. Mean genotype risk score in these subjects was significantly higher than that in the subjects who remained nondiabetic (9.5 ± 1.8 vs 9.1 ± 2.0, P = .042). Although the initial mean body mass index (24.7 ± 3.2 vs 23.0 ± 2.8, P < .001) and initial glucose (106 ± 18 vs 90 ± 13, P < .001) were also significantly higher in those subjects who developed T2DM, the genotype risk score remained an independent determinant of the development of T2DM even after adjustment for these parameters and possible confounding factors. Per-allele odds ratio for the development of T2DM was 1.12 (95% confidence interval, 1.00-1.25; P = .049). Type 2 diabetes mellitus-susceptible genetic variants identified by a cross-sectional genomewide association study were significantly associated with the future development of T2DM in a general population sample.

Comparison of postmenopausal endogenous sex hormones among Japanese, Japanese Brazilians, and non-Japanese Brazilians.

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. METHODS: A cross-sectional study was conducted using a control group of case-control studies in Nagano, Japan, and São Paulo, Brazil. Participants were postmenopausal women older than 55 years of age who provided blood samples. We measured estradiol, estrone, androstenedione, dehydroepiandrosterone sulfate (DHEAS), testosterone and free testosterone by radioimmunoassay; bioavailable estradiol by the ammonium sulfate precipitation method; and sex hormone-binding globulin (SHBG) by immunoradiometric assay. A total of 363 women were included for the present analyses, comprising 185 Japanese, 44 Japanese Brazilians and 134 non-Japanese Brazilians. RESULTS: Japanese Brazilians had significantly higher levels of estradiol, bioavailable estradiol, estrone, testosterone and free testosterone levels, and lower SHBG levels, than Japanese. Japanese Brazilians also had significantly higher levels of bioavailable estradiol, estrone and DHEAS and lower levels of SHBG and androstenedione than non-Japanese Brazilians. Levels of estradiol, testosterone and free testosterone, however, did not differ between Japanese Brazilians and non-Japanese Brazilians. These differences were observed even after adjustment for known breast cancer risk factors. We also found an increase in estrogen and androgen levels with increasing body mass index, but no association for most of the other known risk factors. CONCLUSIONS: We found higher levels of estrogens and androgens in Japanese Brazilians than in Japanese and levels similar to or higher than in non-Japanese Brazilians. Our findings may help explain the increase in the incidence and mortality rate of breast cancer among Japanese Brazilians.

Fragment c gamma receptor gene polymorphisms and breast cancer risk in case-control studies in Japanese, Japanese Brazilians, and non-Japanese Brazilians.

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. A total of 869 pairs (403 Japanese, 80 Japanese Brazilians and 386 non-Japanese Brazilians) were genotyped for two single nucleotide polymorphisms (SNPs): a histidine (H)/arginine (R) polymorphism at position 131 of FcgRIIa (FcgRIIa H131R) and a valine (V)/phenylalanine (F) polymorphism at position 158 of FcgRIIIa (FcgRIIIa F158V). We found no statistically significant association between either of the two SNPs and breast cancer risk regardless of population. In analyses of the three populations combined, adjusted odds ratio (OR) was 0.93 [95% confidence interval (CI) 0.66-1.32] for women with the R/R versus H/H genotype of the FcgRIIa H131R polymorphism and 1.04 (95% CI 0.69-1.57) for the V/V versus F/F genotype of the FcgRIIIa F158V polymorphism. On combination of the two SNPs, compared to women with both the R/R genotype of the FcgRIIa H131R polymorphism and F/F genotype of the FcgRIIIa F158V polymorphism, the adjusted OR for women with both the H/H and V/V genotype was 0.68 (95% CI 0.37-1.27). In conclusion, our findings suggest that ADCC might not play a major role in the etiology of breast cancer.

Leisure-time physical activity and breast cancer risk by hormone receptor status: effective life periods and exercise intensity.

OBJECTIVE: Physical activity may decrease breast cancer risk. However, it is unclear what intensity of exercise and during which life periods this effect on decreasing risk is efficiently expressed, and whether the associations differ by the estrogen-/progesterone- receptor (ER/PR) status of tumors. We investigated associations between age- and intensity-specific leisure-time physical activity and ER/PR-defined breast cancer risk. METHODS: We conducted a hospital-based case-control study in Nagano, Japan. Subjects were 405 cases newly diagnosed (>99% known ER/PR) from 2001 to 2005, who were age-/area-matched with 405 controls. Activity was assessed with a self-reported questionnaire which considered intensity level (moderate and/or strenuous) at different ages (at 12 and 20 years, and in the previous 5 years). Odds ratios (ORs) and 95% confidence intervals were calculated using logistic regression. RESULTS: Strenuous but not moderate physical activity at age 12 was inversely associated with pre- and postmenopausal breast cancer risk across ER/PR subtypes [overall OR(≥ 5 days/week vs. none) = 0.24 (0.14-0.43)]. Moderate physical activity in the previous 5 years was significantly associated with a decrease in risk for postmenopausal ER + PR + tumors only [OR(≥ 1 day/week vs. none) = 0.35 (0.18-0.67)]. CONCLUSION: Strenuous activity in teens and moderate activity after menopause may contribute to a reduction in breast cancer risk.

Dietary isoflavone intake, polymorphisms in the CYP17, CYP19, 17beta-HSD1, and SHBG genes, and risk of breast cancer in case-control studies in Japanese, Japanese Brazilians, and non-Japanese Brazilians.

We tested the hypothesis that polymorphisms in cytochrome P450c17alpha (CYP17), aromatase (CYP19), 17beta-hydroxysteroid dehydrogenase type I (17beta-HSD1) and sex hormone-binding globulin (SHBG) genes may modify the association between isoflavone intake and breast cancer risk. We conducted hospital-based, case-control studies in Nagano, Japan and Sao Paulo, Brazil. A total of 846 pairs (388 Japanese, 79 Japanese Brazilians, and 379 non-Japanese Brazilians) completed validated food frequency questionnaires. Four single nucleotide polymorphisms (SNPs) in CYP17 (rs743572), CYP19 (rs10046), 17beta-HSD1 (rs605059), and SHBG (rs6259) genes were genotyped. We found no association between the 4 SNPs and breast cancer risk. In combination analyses of isoflavone intake and SNPs, an inverse association between intake and risk was limited to women with at least one A allele of the rs605059 polymorphism for all 3 populations, albeit without statistical significance. For the rs6259 polymorphism, the inverse association was limited to postmenopausal Japanese with the GG genotype (odds ratio [OR] for highest vs. lowest tertile = 0.50, 95% confidence interval [CI] = 0.29-0.87; P for trend < 0.01), and to non-Japanese Brazilians with at least one A allele (OR for consumers vs. nonconsumer = 0.21, 95% CI = 0.06-0.77). We found no remarkable difference for the rs743572 and rs10046 polymorphisms. Our findings suggest that polymorphisms in the 17beta-HSD1 and SHBG genes may modify the association between isoflavone intake and breast cancer risk.