Yuki Obata

Aichi Medical University, Japan

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Publications (21)63.94 Total impact

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    ABSTRACT: The relationship between gastric cancer and serum vascular endothelial growth factor receptor-1 (sVEGFR-1) and sVEGFR-2, which are soluble form receptor proteins of vascular endothelial growth factor (VEGF), has not been extensively studied. VEGF, sVEGFR-1 and sVEGFR-2 were measured in the sera obtained before surgical operation from 164 gastric cancer patients and from 164 healthy controls matched for age and gender. Compared with controls, the cases showed elevated VEGF (P < 0.01) and reduced sVEGFR-1 (P = 0.07) and sVEGFR-2 (P = 0.02). The difference in VEGF levels was small among men and when the outcome was early cancer. The difference in sVEGFR-1 levels was significant or borderline significant only in men and when the outcome was diffuse type cancer. The difference in sVEGFR-2 levels was significant only in men and when the outcome was advanced or diffuse type cancer. The sensitivities and specificities of VEGF, sVEGFR-1 and sVEGFR-2 were all approximately 60%. For diffuse type cancer, sVEGFR-2 showed a sensitivity of 62.4% and a specificity of 63.4%, which was similar to serum pepsinogen. In conclusion, elevated VEGF and reduced sVEGFR-1 and sVEGFR-2 in serum are characteristic of gastric cancer patients, and the value of serum sVEGFR-2 in the diagnosis of diffuse type gastric cancer should be further evaluated.
    Cancer Science 01/2011; 102(4):866-9. · 3.48 Impact Factor
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    ABSTRACT: Biliary tract cancer, encompassing gallbladder and bile duct cancers, has a poor prognosis, but little is known of the etiology. A nested case-control study was here conducted to evaluate the association between serum levels of IGF-I, IGF-II and IGFBP-3 and death from biliary tract cancer. In a large scale cohort study, 35 gallbladder and 42 bile duct cancers were observed during the follow-up. For each subject in the case group, 1-3 control subjects (228 in total) were selected randomly, matched for sex, age (as near as possible) and residential area. The subjects were divided into tertiles by circulating levels of IGF-I, IGF-II or IGFBP-3. Using conditional logistic regression, risks among the tertiles were compared adjusted for defecation, smoking and drinking habits. No remarkable differences in risks of gallbladder or bile duct cancer were observed among tertiles of IGF-I or IGF-II, and no remarkable trend was observed. Circulating IGFBP-3 showed an inverse U-shape association with gallbladder cancer and a U-shaped one with bile duct cancer. Associations between IGF-I or IGF-II and gallbladder or bile duct cancer thus were lacking or very weak. The observed U- and inverse U-shaped association of IGFBP-3 with the cancers is not suggestive of any meaningful relationships.
    Asian Pacific journal of cancer prevention: APJCP 12/2009; 10 Suppl:63-7. · 1.50 Impact Factor
  • Pancreas 01/2009; 38(5):593-594. · 2.95 Impact Factor
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    ABSTRACT: Green tea polyphenols have been shown to inhibit tumor growth in animal and in vitro studies. We examined the relationship between green tea consumption and the risk of death from pancreatic cancer in a large Japanese cohort. At baseline (1988-1990), study participants reported the frequency and amount of green tea consumption during the past year. They were followed-up for mortality until December 31, 2003. Relative risk and 95% confidence intervals were calculated from Cox proportional hazard models. During an average follow-up of 13 years, we observed 292 pancreatic cancer deaths. In men and women combined, the relative risk was 1.23 (95% confidence interval, 0.84-1.80) for participants who consumed 7 or more cups of green tea per day as compared with those who consumed less than 1 cup per day, after adjustment for potential confounding factors. No significant trend in risk reduction was noted, with increasing consumption of green tea. We found no inverse association between cups of green tea consumed per day and the risk of pancreatic cancer in either men or women. Our findings do not support the hypothesis that green tea consumption is associated with decreased risk of pancreatic cancer in humans.
    Pancreas 08/2008; 37(1):25-30. · 2.95 Impact Factor
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    ABSTRACT: Gallbladder cancer is a rare cancer with a poor prognosis, and few risk factors have been identified to date. This prospective study was conducted to evaluate the association of cigarette smoking and alcohol consumption with the risk of gallbladder cancer death. A baseline survey in 45 areas throughout Japan was conducted from 1988 to 1990 using a self-administered questionnaire, and a total of 113,496 participants (65,740 women) aged 40-89 years at entry were followed for 15 years. During the follow-up period, 165 gallbladder cancer deaths (95 women) were observed. Among women, the hazard ratio (HR) [95 percent confidence interval: 95% CI] of current smoker was 2.00 [0.91-4.42], when adjusted for age and drinking. There was no clear association between alcohol consumption and the risk. Among men, HR of current smoker was 2.27 [1.05-4.90]. HRs of those who smoked 21 cigarettes or more per day and those with 801-1,000 cigarette-years were 3.18 [1.18-8.53] and 3.44 [1.40-8.45], respectively, and positive linear associations were observed between that risk and the number of cigarettes per day (p for trend = 0.007) or "cigarette-years" (p for trend = 0.012). The alcohol dose was linearly associated with risk (p for trend = 0.004), where the HR among those who consumed 72.0 g or more of alcohol per day was 3.60 [1.29-9.85]. Among both men and women, cigarette smoking may elevate the risk of death from gallbladder cancer. Drinking may pose an elevated risk among men, but that seems to be less true among women.
    International Journal of Cancer 03/2008; 122(4):924-9. · 6.20 Impact Factor
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    ABSTRACT: It is unclear whether body mass index (BMI) and physical activity are associated with the risk of pancreatic cancer in Asian populations. We examined these associations in the Japanese Collaborative Cohort Study for Evaluation of Cancer Risk. Our cohort study included 110,792 Japanese men and women at enrollment (1988-1990). Data on height, body weight (at baseline and at age 20 years) and physical activity were obtained from a questionnaire. Cox proportional hazards models were used to estimate the relative risks of pancreatic cancer mortality. We observed a total of 402 pancreatic cancer deaths during the follow-up period. Men with a BMI of 30 or more at age 20 years had a 3.5-fold greater risk compared with men with a normal BMI. Women with a BMI of 27.5-29.9 at baseline had approximately 60% increased risk compared with women with a BMI of 20.0-22.4. In men, weight loss of 5 kg or more between 20 years of age and baseline age was associated with an increased risk of pancreatic cancer death. In contrast, women with weight loss of 5 kg or more over the same period had a decreased risk. Physical activity was not associated with pancreatic cancer risk in either men or women. Obesity in young adulthood may be associated with an increased risk of death from pancreatic cancer in Japanese men. The risk of pancreatic cancer in relation to BMI seems to differ according to sex and the period over which BMI was measured.
    International Journal of Cancer 07/2007; 120(12):2665-71. · 6.20 Impact Factor
  • Ejc Supplements - EJC SUPPL. 01/2007; 5(4):262-262.
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    ABSTRACT: To examine the relationship of baseline levels of serum TGF-beta1 to the subsequent risk of death from pancreatic cancer in a nested case-control study. The cases were 85 persons who had provided a blood sample at baseline and subsequently died of pancreatic cancer during the study period. For each case, three controls were randomly selected from among the cohort participants, and were matched for each case by sex, age (+/-1 year), and study area. Serum TGF-beta1 levels were measured with enzyme-linked immunosorbent assay (ELISA). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated from conditional logistic models. The mean of serum TGF-beta1 levels was significantly higher among cases than among controls (p = 0.01). Individuals with serum TGF-beta1 levels in the highest quartile had a 2.5-fold increase in risk as compared with those in the lowest quartile (OR, 2.5; 95% CI, 0.9-6.9), after adjustment for month of blood draw, cigarette smoking, body mass index and history of diabetes. Excluding 12 pancreatic cancer deaths that occurred within three years of follow-up did not alter the positive association. Our prospective data indicate that high serum TGF-beta1 levels may be associated with an increased risk of death from pancreatic cancer.
    Cancer Causes and Control 11/2006; 17(8):1077-82. · 3.20 Impact Factor
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    ABSTRACT: The etiology of pancreatic cancer remains largely unknown. We examined the association of pancreatic cancer deaths with menstrual and reproductive factors in a cohort study involving Japanese women. A total of 63,273 women were followed up for mortality from 1988 to 1999. Information on menstrual and reproductive factors was obtained by a questionnaire survey at baseline. Cox proportional-hazards models were used to estimate the relative risks (RRs) and 95% confidence intervals (CIs) for death from pancreatic cancer in relation to menstrual and reproductive factors. During 631,401 person-years of follow-up, 154 women died from pancreatic cancer. Parity was not significantly associated with the risk of death from pancreatic cancer; the RR was 0.80 (95% CI, 0.31-2.11) for women with six or more births compared with women with zero or one birth. We found no significant overall association with other reproductive factors, including pregnancy, age at first birth, and menopause. The risk appeared to increase with increasing age at menarche; the RR was 1.49 (95% CI, 0.95-2.34) for women who had menarche after 16 years of age compared to those who had menarche before they were 15 years old. Our prospective data indicate that menstrual and reproductive factors are not associated with the risk of death from pancreatic cancer among Japanese women.
    Journal of Gastroenterology 10/2006; 41(9):878-83. · 3.79 Impact Factor
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    ABSTRACT: The significance of serum levels of transforming growth factor (TGF)-beta1 in the development of gastric cancer is unclear. The purpose of this study is to determine whether serum TGF-beta1 correlated with the clinicopathological findings of patients with gastric cancer. Transforming growth factor-beta1 levels in the serum of 275 gastric cancer patients and 275 gender- and age-matched healthy controls were measured with enzyme-linked immunosorbent assay (ELISA) using a commercially available kit. The mean level of serum TGF-beta1 of gastric cancer patients (15.9 +/- 5.9 ng/mL) was significantly higher than that (13.9 +/- 7.4 ng/mL) of healthy controls (P < 0.01). The odds ratio for the subjects in the highest quartile (16.7 ng/mL or more) was 4.03 (95% confidence interval, 2.14-7.58), as compared with that for the subjects in the lowest quartile (0-9.5 ng/mL). Patients with venous invasion compared to those without venous invasion had significantly elevated serum TGF-beta1 (17.3 +/- 7.2 vs 15.0 +/- 5.1 ng/mL; P = 0.04). There were no statistically significant differences between the two groups categorized by histological type, lymph node metastasis and distant metastasis. Logistical regression analysis showed that venous invasion was significantly correlated with elevated serum TGF-beta1 levels (P = 0.02). The present study showed that an elevated serum TGF-beta1 level may be significantly correlated with venous invasion in gastric cancer patients.
    Journal of Gastroenterology and Hepatology 03/2006; 21(2):432-7. · 3.33 Impact Factor
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    ABSTRACT: Few epidemiological studies have examined associations between diet and pancreatic cancer in Japan. In the Japan Collaborative Cohort Study for Evaluation of Cancer Risk, we evaluated the relationship between dietary factors, including meat, vegetable, and fruit intake, and the risk of pancreatic cancer deaths. Among the original cohort established between 1988 and 1990, 46,465 men and 64,327 women aged 40-79 yr were followed-up through December 31,1999. During 1,042,608 person-years of follow-up, we documented 300 deaths from pancreatic cancer. A 33-item food-frequency questionnaire was used to assess dietary intake at the baseline survey. Cox proportional-hazards models were used to estimate the relative risks of pancreatic cancer death in relation to the intake frequency of food items. We did not observe an overall association between meat intake and pancreatic cancer risk. Except for a 50% decrease in risk associated with high fruit intake among men, we did not find other significant inverse relationships between vegetable and fruit intake and pancreatic cancer risk. Smoking did not modify the associations with dietary habits. Our study suggested that high consumption of pickles and wild edible plants, mainly bracken, might be related to increased pancreatic cancer risk; however, this finding should be confirmed in other epidemiological studies.
    Nutrition and Cancer 02/2006; 56(1):40-9. · 2.70 Impact Factor
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    ABSTRACT: We conducted a prospective cohort study to examine the association between alcohol intake and the risk of all-cause mortality among middle-aged and elderly Japanese men and women. At baseline (1988-1990), a total of 110,792 Japanese men and women aged 40 to 79 years were asked to complete a questionnaire that included information on alcohol intake, and were followed up for all-cause mortality through December 31, 1999. Relative risks (95% confidence interval) were calculated using Cox proportional-hazards models. The risk of all-cause mortality was lowest among current drinkers with an alcohol intake of 0.1 to 22.9 g/d (RR, 0.80; 95% CI, 0.72-0.88 for men; and RR, 0.88; 95% CI, 0.77-1.00 for women). Excessive mortality associated with heavy drinking (> or = 69 g/d) was observed for cancer, cardiovascular disease and injuries and other external causes in men, while significantly reduced mortality with light drinking was seen for cancer in men and CVD in women. For men, the benefit associated with light alcohol consumption (< 23 g/d) was more apparent among nonsmokers than among smokers. Our prospective data show a 12% to 20% decreased risk of all-cause mortality in both Japanese men and women who consumed less than 23 g/d of alcohol (approximately 2 drinks), although heavy drinking increased that risk.
    Annals of Epidemiology 10/2005; 15(8):590-7. · 2.48 Impact Factor
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    ABSTRACT: Helicobacter pylori infection and serum pepsinogen values are strongly related with stomach cancer. The aim of this study was to know what were these factors among general population. Subjects were randomly selected 633 control subjects in a nested case-control study for risk of stomach cancer. Most of them were from rural areas of Japan. Using frozen sera, pepsinogen I (PG I) and II (PG II) values and H. pylori antibody were measured. Those with PG I less than 50 ng/mL and the ratio of PG I to PG II (PG I/II) was less than 2.0 were defined as severe, those with PG I less than 70 ng/ml and PG I/II less than 3.0 were defined as mild and the other subjects were defined as no serological atrophy. About 70% of the subjects were H. pylori seropositive and the seroprevalence did not depend on age or sex. Percentages of those with severe serological atrophy increased with age from 10% in those aged 40-49 years to 38% in 70 and more, and percentages of those with mild serological atrophy were about 30% independent of age. The subjects, who were expected to represent populations of rural area of Japan, had high prevalence of both H. pylori infection and serological atrophy of gastric mucosa. These facts should be considered in discussing results of the nested case-control study.
    Journal of Epidemiology 07/2005; 15 Suppl 2:S126-33. · 2.11 Impact Factor
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    ABSTRACT: The role of serum manganese superoxide dismutase (MnSOD) in the development of gastric cancer has not been clearly defined. We conducted a case-control study to address the potential relationship between serum MnSOD levels and gastric cancer. Cases were 275 gastric cancer patients and controls were 275 sex and age-matched healthy persons. Serum MnSOD levels were determined by a commercially available enzyme-linked immunosorbent assay (ELISA). The mean(+/-standard deviation) of serum MnSOD levels was 177.4 +/- 87.3 ng/mL among cases and 169.4 +/- 56.7 ng/mL among controls. Gastric cancer patients had slightly higher serum MnSOD levels than the controls. After adjustment for pack-years of cigarette smoking and Helicobacter pylori infection, the odds ratio was 1.54(95% confidence interval; 0.79-3.01) for subjects in the highest quartile versus the lowest quartile. No significant differences were observed for serum MnSOD levels in gastric cancer patients according to clinicopathological factors such as disease stage, histological type, venous invasion, and lymph node metastasis. Our study suggested that serum MnSOD levels are not significantly associated with the increased risk of gastric cancer, although a weak association may exist.
    Journal of Epidemiology 06/2005; 15(3):90-5. · 2.11 Impact Factor
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    ABSTRACT: Midkine (MK) is one of a family of heparin-binding growth factors, and increased MK expression is reported in various types of human carcinomas. To clarify the association between serum MK (S-MK) concentrations and gastric cancer, we examined S-MK concentrations of gastric cancer patients (n=275) and healthy controls (n=275). S-MK concentrations of all subjects were measured by enzyme-linked immunosorbent assay (elisa). The medians (25th and 75th percentiles) of S-MK were 192 (123 and 314) pg/mL in the cases and 170 (81 and 273) pg/mL in the controls (P <0.01). We also compared S-MK concentrations in each group divided by the progression stage or histological type of cancer. A difference was observed in the median S-MK concentrations between early and advanced cancers [182 (105 and 301) pg/mL vs 203 (139 and 331) pg/mL, P=0.07], but not between intestinal and diffuse type cancers [185 (121 and 306) pg/mL vs 198 (127 and 323) pg/mL, P=0.51]. We found that those progression stages affect S-MK concentration more strongly than the histological types in gastric cancer patients. Because S-MK seems to reflect the progression stage of gastric cancer, it may serve as a useful marker in the clinical follow-up of gastric cancer patients.
    Cancer Science 01/2005; 96(1):54-6. · 3.48 Impact Factor
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    ABSTRACT: Few risk factors for gallbladder cancer have been identified with sufficient statistical power, because this cancer is rare. The present study was conducted to evaluate the association of bowel movement frequency and medical history with the risk of death from gallbladder cancer using the data set from a large-scale cohort study. A total of 113,394 participants (42.0% males), aged 40 to 89 years, were followed up for 11 years. Information on the medical history of selected diseases, history of blood transfusions, frequency of stools, and tendency toward diarrhea at baseline was collected through a self-administered questionnaire. The Cox proportional hazard model was used to estimate the hazard ratio (HR). During the follow-up period, a total of 116 deaths (46 males, 70 females) from gallbladder cancer were identified. After adjustments for age and gender, history of hepatic disease (HR: 2.28; 95% confidence intervals (95% CI): 1.24-4.21), frequency of stool, and tendency toward diarrhea (HR: 0.26; 95% CI: 0.08-0.83) were found to be significantly associated with the risk of death from gallbladder cancer. Compared with those who had a stool at least once a day, the HR was 2.06 (95% CI: 0.82-5.18) for those who had a stool less than once in 6 days (P for trend = 0.050). In this prospective study, constipation and a history of hepatic disease were found to elevate the risk of gallbladder cancer death, whereas a tendency toward diarrhea diminished it.
    Cancer Science 09/2004; 95(8):674-8. · 3.48 Impact Factor
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    ABSTRACT: Recent epidemiological studies have shown that high serum levels of insulin-like growth factor-I (IGF-I) are associated with an increased risk of lung, colon, breast and prostate cancer. Since very few studies have addressed the role of serum levels of IGF-I in the development of pancreatic cancer, we conducted a nested case-control study to examine this association. The analysis involved 69 case subjects who died from pancreatic cancer during the follow-up period of the study, and 207 control subjects matched for sex, age(+/-1 year) and study area, selected randomly from a cohort of 10364 individuals. Serum levels of IGF-I and IGF binding protein-3 (IGFBP-3) were measured by immunoradiometric assay, using commercially available kits. The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic models. The levels of IGF-I were positively correlated with IGFBP-3 (r=0.55). There was a positive, but statistically insignificant association between serum levels of IGF-I and risk of death from pancreatic cancer, with subjects in the highest quartile having an OR of 2.31 (95% CI=0.70-2.64) compared to those in the lowest quartile. The risk of pancreatic cancer death increased significantly with increasing serum levels of IGFBP-3 (trend p=0.03). Further adjustment for IGFBP-3 or IGF-I slightly attenuated the positive associations. This nested case-control study showed that high serum levels of IGF-I and IGFBP-3 may be associated with an increased risk of death from pancreatic cancer.
    International Journal of Cancer 08/2004; 110(4):584-8. · 6.20 Impact Factor
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    ABSTRACT: Although age-adjusted mortality from gastric cancer has been decreasing in Japan, the crude incidence of gastric cancer shows a slight increase. We have observed trends in the incidence of gastric cancer by sex and 20-year age groups over the past two decades (1976-1996). Source data were obtained from the cancer statistics materials provided by the Research Group for Population-Based Cancer Registration in Japan. Simultaneously, we observed changes in the prevalence of Helicobacter pylori infection and in serological atrophy of the gastric mucosa, and compared the results with those involving changes in the incidence of gastric cancer. A slight decline was observed in all age groups over 40 years old, in both men and women, between 1986 and 1996. However, a marked decline in incidence was observed for those aged 20-39 years. The prevalence of H. pylori infection declined in both sexes between 1989 and 1998. The frequency of serological atrophy of the gastric mucosa significantly declined in all age groups between 1989 and 1996, with young age groups experiencing a more marked decrease. The marked decline in gastric cancer incidence observed in the young population will also begin to occur in the elderly population in the future.
    Gastric Cancer 02/2004; 7(4):233-9. · 3.99 Impact Factor
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    ABSTRACT: Helicobacter pylori infection is thought to be a causal risk factor for gastric carcinoma. Recently, diagnostic accuracy of serological kits for H. pylori infection that were made in Western countries has been reported to be lower when used among Oriental populations. Diagnostic accuracy of two serological kits [HM-CAP and HM-CAP with antigens extracted from clinically isolated Japanese H. pylori strains (J-HM-CAP)] was investigated in 440 samples from a Japanese patient population by using the (13)C-urea breath test as gold standard. According to the original optimal cut-off value, HM-CAP provided 87.5 % sensitivity and 84.8 % specificity with 86.8 % accuracy and J-HM-CAP provided 95.5 % sensitivity and 81.9 % specificity with 92.3 % accuracy. This study suggests that antigens from HM-CAP are satisfactory for examining a Japanese patient population, but that using local antigens improves accuracy.
    Journal of Medical Microbiology 11/2003; 52(Pt 10):889-92. · 2.30 Impact Factor
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    ABSTRACT: We conducted a case-control study to evaluate the association between serum levels of copper/zinc superoxide dismutase (Cu/Zn SOD) and the risk of gastric cancer. Cases were 214 patients who had been diagnosed with gastric cancer and controls were 120 persons who underwent medical checkups. Serum levels of Cu/Zn SOD were determined by enzyme-linked immunosorbent assay (ELISA). Compared with the lowest quartile, the OR (odds ratio) was 4.54 (95% CI (confidence interval), 1.62 - 12.66) for the third quartile and 15.75 (95% CI, 5.84 - 42.46) for the highest quartile. With both early and advanced cancers, as well as with the intestinal and diffuse types, a significant increase in risk was observed with increasing levels of serum Cu/Zn SOD. Our case-control study showed that serum levels of Cu/Zn SOD were significantly elevated in gastric cancer patients compared with apparently healthy controls, and higher Cu/Zn SOD levels may be associated with an increased risk of gastric cancer.
    Japanese journal of cancer research: Gann 11/2002; 93(10):1071-5.