2023 Fiscal Year Final Research Report

Associations of bacterial contamination in drinking waters and aflatoxin B1 with developing gallbladder cancer

Research Project

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Project/Area Number	19K10607
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 58020:Hygiene and public health-related: including laboratory approach
Research Institution	Niigata University
Principal Investigator	Ikoma Toshikazu 新潟大学, 医歯学総合研究科, 客員研究員 (60612744)
Co-Investigator(Kenkyū-buntansha)	土屋康雄新潟大学, 医歯学総合研究科, 客員研究員 (60334679) 浅井孝夫順天堂大学, 医療科学部, 准教授 (60612736) 中村和利新潟大学, 医歯学系, 教授 (70207869)
Project Period (FY)	2019-04-01 – 2024-03-31
Keywords	胆嚢がん / インド / 飲料水 / 細菌汚染 / アフラトキシンB1
Outline of Final Research Achievements	Metagenomic analysis of bacterial flora indigenous in well water used for eating and drinking in the homes of 10 patients with gallbladder cancer in northern India detected bacterial species such as Acinetobacter and Flavobacterium. The concentration of aflatoxin B1-lysine adduct in serum collected from 45 patients with gallbladder cancer, 57 patients with cholecystitis, and 55 healthy subjects was measured using a commercial ELISA test kit, and aflatoxin B1 was detected in 32 (71%) patients with gallbladder cancer, 22 (39%) patients with cholecystitis, and 4 (7%) healthy subjects. From the above, the expected Typhoid fever bacteria and Helicobacter pylori were not detected in drinking water. On the other hand, the detection rate of aflatoxin B1 in patients with gallbladder cancer was significantly higher than that in cholecystitis patients and healthy subjects, suggesting a relationship between aflatoxin B1 exposure and developing gallbladder cancer.
Free Research Field	疫学
Academic Significance and Societal Importance of the Research Achievements	胆嚢がんは世界的には稀な悪性腫瘍であるが、特定の国や地域、あるいは民族で多発しており、5年生存率が低い予後不良のがんである。胆嚢がん多発国、インド北部の胆嚢がん患者、胆嚢炎患者、及び健常者を対象とした本症例対象研究において、アフラトキシンB1‐リジン付加体の血清レベルに基づくアフラトキシンB1への曝露と胆嚢がんとの関連が明らかとなった。我々の知見が、他の方法、例えばHPLC法などで検証されれば、アフラトキシンB1への曝露を減らすことでインド北部における胆嚢がんの発生率、死亡率を減らせる可能性が示唆された。今後、アフラトキシンB1汚染源を解明する追加研究が必要である。