Kenji Suga

Publications (7)13.41 Total impact

• Article: Risk Factors for Lung Cancer among Northern Thai Women: Epidemiological, Nutritional, Serological, and Bacteriological Surveys of Residents in High‐ and Low‐incidence Areas

  Kei Nakachi, Porn-ngarm Limtrakul, Prapaisri Sonklin, On-a-nong Sonklin, Chairat Tor Jarern, Suwiwek Lipigorngoson, Kazuaki Arai, Yoshiaki Sone, Kazue Imai, Kenji Suga, Satoru Matsuyama, Hiroyuki Shimizu, Takashi Takahashi, Maitree Suttajit
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  ABSTRACT: Lung cancer incidence among Northern Thai women is one of the highest in Asia (an annual age-adjusted incidence rate of 37.4 per 100,000), and the incidence rate significantly differs by geographical districts. Therefore, we conducted a comparative study of women living in the Sarapee area, which showed the highest (crude incidence rate, 40.9), and the Chom Tong area, which had one of the lowest incidence rates (8.5) in Chiang Mai Province, despite the two areas' geographical and cultural closeness. The women in this study were either family members of lung cancer patients or their neighbors. To find clues to the etiology of lung cancer, this study used various epidemiological and biochemical approaches: interviewing on lifestyle factors, duplicate meals, chemical examination of drinking water, biochemical analysis of sera, mutagenicity test of urine, and monitoring of fungi and bacteria in the living environment. We found that tobacco smoking (Khiyo, local cigars) was less frequently observed in Sarapee (high incidence), compared with Chom Tong (low incidence), and that the history of chronic benign respiratory diseases was the most distinct event among women in Sarapee, resulting in a significantly increased percentage of those with a history of both benign respiratory diseases and tobacco smoking. This population revealed increased levels of serum tumor necrosis factor (TNF)-, an endogenous tumor promoter. Furthermore, significantly increased urine mutagenicity was found to be closely associated with history of benign respiratory disease in Sarapee. The fungus which was most commonly found in the air inside houses in Sarapee was identified as Microsporum canis. Additionally, significantly increased serum concentrations of a constituent of the fungus were found in Sarapee women, compared with those in Chom Tong. Our results suggest that tobacco (Khiyo) smoking alone may not be able to explain the very high incidence of female lung cancer in Northern Thailand, and that chronic benign respiratory disease, possibly caused by the infection of fungi such as M. canis, is likely to be involved in the etiology of female lung cancer in North Thailand.
  Cancer Science 08/2005; 90(11):1187 - 1195. · 3.33 Impact Factor
• Article: Detection of plasma hnRNP B1 mRNA, a new cancer biomarker, in lung cancer patients by quantitative real-time polymerase chain reaction.

  Eisaburo Sueoka, Naoko Sueoka, Kentaro Iwanaga, Akemi Sato, Kenji Suga, Shin-ichiro Hayashi, Kohei Nagasawa, Kei Nakachi
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  ABSTRACT: Circulating cell-free nucleic acids are noninvasive diagnostic tools for cancer detection. Heterogeneous nuclear ribonucleoprotein (hnRNP) B1, an RNA binding protein, has been found overexpressed in the early stage of lung cancer, including bronchial dysplasia, a premalignant lesion of lung squamous cell carcinoma. To determine the utility of plasma hnRNP B1 RNA and as cancer detection markers for lung cancer, we analyzed plasma hnRNP B1 mRNA of lung cancer patients by real-time RT-PCR. Plasma RNA was extracted from plasma of 44 lung cancer patients, 7 lung neoplasm patients, 24 benign lung diseases and 25 healthy volunteers. Mean concentration of plasma hnRNP B1 mRNA in lung cancer patients was 0.99 pg/microg RNA, whereas that in healthy volunteers and in benign lung diseases was 0.23 pg/microg RNA and 0.30 pg/microg RNA, respectively (p<0.05). Twenty of 44 (45.5%) lung cancer patients showed more than 0.70 pg/microg RNA of plasma hnRNP B1 mRNA, compared with only 3 of 25 (12.0%) healthy volunteers. Looking at histological subtype, squamous cell carcinoma patients showed higher hnRNP B1 mRNA in the plasma than did adenocarcinoma patients, which is consistent with our previous immunohistochemistry results. These results indicate that plasma hnRNP B1 mRNA is a useful non-invasive markers for detection of lung cancer.
  Lung Cancer 04/2005; 48(1):77-83. · 3.43 Impact Factor
• Article: [Fatal opportunistic infection following disappearance of antibodies by immunosuppressive therapy in a patient with acquired factor VIII inhibitor].

  Yasushi Kubota, Masayuki Sano, Sachie Nakazato, Naoko Tsuneyoshi, Rika Tomimasu, Nobuo Kuwahara, Noriyasu Fukushima, Noriko Funai, Kenji Suga, Eisaburo Sueoka
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  ABSTRACT: An 83-year-old man without history of the hemorrhagic diathesis was admitted to our hospital with a 4-months history of purpura and subcutaneous hematoma. He had an extraordinarily prolonged activated partial thromboplastin time, and his factor VIII (F VIII) activity level was 0.2%. A study revealed the existence of an IgG type anti-F VIII inhibitor at a titer of 1004 Bethesda units/ml. He received recombinant factor VIIa and immunosuppressive therapy with cyclophosphamide, prednisolone and cyclosporin, but despite this the titer of F VIII inhibitor remained high. Although the inhibitor disappeared after methylprednisolone mini-pulse therapy, the patient died of opportunistic infections with cytomegalovirus and pneumocystis carinii. The majority of patients with acquired F VIII inhibitor belong to the elderly population, and the standard therapeutic strategy to eliminate the acquired F VIII inhibitor has not been established. Those patients with high titers of F VIII inhibitor require particularly long term immunosuppressive therapy. Therefore, it is important to bear in mind treatment-related opportunistic infections in a case with a high titer of acquired F VIII inhibitor.
  [Rinshō ketsueki] The Japanese journal of clinical hematology 10/2004; 45(9):1023-7.
• Article: Mechanistic Findings of Green Tea as Cancer Preventive for Humans

  Hirota Fujiki, Masami Suganuma, Sachiko Okabe, Eisaburo Sueoka, Kenji Suga, Kazue Imai, Kei Nakachi, Shunsaku Kimura
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  ABSTRACT: Based on our initial work with green tea, in which repeated topical applications of (−)-epigallocatechin gallate (EGCG), the main green tea polyphenol, inhibited tumor promotion in a two-stage carcinogenesis experiment on mouse skin (Phytother Res 1, 44–47, 1987), numerous scientists have since provided so much additional evidence of the benefits of drinking green tea that it is now an acknowledged cancer preventive in Japan, and will possibly soon be recognized as such in other countries. Our work has so far produced several important results with EGCG and green tea: a wide range of target organs in animal experiments for cancer prevention, wide bioavailability of 3H-EGCG in various organs of mice, delayed cancer onset of patients with a history of consuming over 10 cups of green tea per day, and absence of any severe adverse effects among volunteers who took 15 green tea tablets per day (2.25 g green tea extracts, 337.5 mg EGCG, and 135 mg caffeine) for 6 months. This paper introduces three new findings: 1) EGCG interacted with the phospholipid bilayer membrane resulting in confirmation of the sealing effect of EGCG; 2) EGCG inhibited TNF- gene expression in the cells and TNF- release from the cells; 3) high consumption of green tea was closely associated with decreased numbers of axillary lymph node metastases among premenopausal Stage I and II breast cancer patients, and with increased expression of progesterone and estrogen receptors among postmenopausal ones. These results provide new insights into our understanding of the mechanisms of action of tea polyphenols and green tea extract as a cancer preventive.
  Proceedings of The Society for Experimental Biology and Medicine 11/2003; 220(4):225 - 228.
• Article: Molecular Significance of Excess Body Weight in Postmenopausal Breast Cancer Patients, in Relation to Expression of Insulin‐like Growth Factor I Receptor and Insulin‐like Growth Factor II Genes

  Kenji Suga, Kazue Imai, Hidetaka Eguchi, Shin-ichi Hayashi, Yasuhiro Higashi, Kei Nakachi
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  ABSTRACT: A number of epidemiological and clinical studies have revealed that excess body weight increases the risk of postmenopausal breast cancer and also adversely affects subsequent malignant progression. To elucidate the molecular mechanisms underlying these observations, we examined mRNA expression of various genes in normal (non-cancerous) mammary gland and cancer tissue of Japanese patients with primary breast cancer, in association with their body mass index (BMI). On the basis of analysis of 106 breast cancer patients, we found that mRNA expression of insulin-like growth factor I receptor (IGF-IR) and insulin-like growth factor II (IGF-II) in the normal mammary gland showed a significant and positive association with increased BMI among postmenopausal patients. Furthermore, the positive association of increased BMI with IGF-IR mRNA expression was also found in postmenopausal breast cancer tissue, while this association was not observed among premenopausal patients. In addition, increased mRNA expression of cyclin Dl and bcl-2 was observed in association with increased mRNA levels of IGF-IR among the patients regardless of menopausal status. These findings suggest that the molecular consequence of the increased BMI is the increased expression of IGF-II and IGF-IR, resulting in development of postmenopausal breast cancer and its progression mediated through modulation of the cell cycle and apoptosis.
  Cancer Science 01/2001; 92(2):127 - 134. · 3.33 Impact Factor
• Article: Phase I Clinical Trial With Green Tea Tablets in a Japanese Healthy Population

  Kenji Suga, Kazue Imai, Naoko Sueoka, Kei Nakachi
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  ABSTRACT: Based on our prospective cohort study of healthy volunteers in a town in Saitama prefecture, Japan, we previously reported that drinking green tea prevents cancer. To apply our results to the general population, we conducted a Phase I trial with green tea tablets in 108 Japanese healthy volunteers for 6 months. Each volunteer took 15 green tea tablets per day, a total of 2.25 g of crude green tea extract or 337.5 mg of (-)-epigallocatechin gallate. The dose is equivalent to 10 cups of green tea per day. Effects of green tea tablets on volunteers were examined by various tests on blood samples, such as blood cell counts, serum lipids, hepatologic markers, and body iron; a questionnaire was also used to determine any symptoms experienced. The results of blood examination indicated that none of the volunteers experienced any strong adverse effects. Specifically, 24 volunteers (22%) complained of mild or moderate disorders, such as stomach discomfort or heartburn. Our study provided significant evidence that a Phase I clinical trial with green tea tablets is applicable to healthy Japanese for the purpose of cancer prevention.
  Cancer Prevention International. 03/1998; 3(2):79-88.
• Article: Influence of Drinking Green Tea on Breast Cancer Malignancy among Japanese Patients

  Kei Nakachi, Kimito Suemasu, Kenji Suga, Takeshi Takeo, Kazue Imai, Yasuhiro Higashi
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  ABSTRACT: Inhibitory effects of green tea on carcinogenesis have been investigated in numerous laboratory studies using (–)-epigallocatechin gallate (EGCG) or crude green tea extract, and there is also some epidemiologic evidence. Further, EGCG has been reported to inhibit the growth of cancer cells, lung metastasis in an animal model, and urokinase activity. In this study, we first examined the association between consumption of green tea prior to clinical cancer onset and various clinical parameters assessed at surgery among 472 patients with stage I, II, and III breast cancer. We found that increased consumption of green tea was closely associated with decreased numbers of axillary lymph node metastases among premenopausal patients with stage I and II breast cancer and with increased expression of progesterone receptor (PgR) and estrogen receptor (ER) among postmenopausal ones. Since these are potential prognostic factors, we then investigated the prognosis of breast cancer with special reference to consumption of green tea, in a follow-up study of these patients. We found that increased consumption of green tea was correlated with decreased recurrence of stage I and II breast cancer (P<0.05 for crude disease-free survival); the recurrence rate was 16.7 or 24.3% among those consuming ≥5 cups or ≥4 cups per day, respectively, in a seven-year follow-up of stage I and II breast cancer, and the relative risk of recurrence was 0.564 (95% confidence interval, 0.350–0.911) after adjustment for other lifestyle factors. However, no improvement in prognosis was observed in stage III breast cancer. Our results indicate that increased consumption of green tea prior to clinical cancer onset is significantly associated with improved prognosis of stage I and II breast cancer, and this association may be related to a modifying effect of green tea on the clinical characteristics of the cancer.
  Cancer Science 02/1998; 89(3):254 - 261. · 3.33 Impact Factor