Helicobacter pylori感染と胃癌―血清診断（pepsinogen，Hp抗体）からみた胃癌ハイリスクグループ

Helicobacter pylori Infection and Gastric Cancer : the Serology-based Stratification According to Anti-H. pylori Antibody and Pepsinogen Levels can Predict the Risk of Gastric Cancer Development

要旨　胃癌をはじめ胃疾患のリスクはH. pylori（Helicobacter pylori）感染と深く関わっており，これを踏まえた背景胃粘膜分類を提案した．血清H. pylori抗体価（Hp）と血清pepsinogen値（PG）でABC（D）分類を行うと胃癌のリスクが層別化され，血清A群：Hp（－）PG（－）はローリスク，血清A′群：H. pylori除菌後Hp（－）PG（－），血清B群：Hp（＋）PG（－）は中等度リスク群，血清C群：Hp（＋）PG（＋），血清D群：Hp（－）PG（＋）はハイリスク群と考えられた．胃癌ハイリスク群を囲い込むと同時に，ローリスク群（H. pylori未感染，血清A群）を特定し，日常診療や検診の場に応用することが大切である．

　The infection of Helicobacter pylori（H. pylori）is the strongest known risk factor for developing gastroduodenal ulcers and the first bacterium to be classified as a carcinogen in the development of gastric adenocarcinoma. Based on a patient's being H. pylori infected or not, we proposed a new endoscopic classification of gastric mucosal status. The serology-based stratification ABC（D）according to anti-H. pylori antibody（Hp）and pepsinogen levels（PG）proved to be effective in predicting the risk of gastroduodenal disease. Concerning gastric cancer development, group A ; Hp（－）PG（－）individuals are at low-risk. In group A′;（H. pylori eradicated）and group B ; Hp（＋）PG（－）individuals are moderate-risk. In group C ; Hp（＋）PG（＋）and group D ; Hp（－）PG（＋）individuals are high-risk. Accurately and noninvasively identifying the low-risk group（non-infected H. pylori, group A）, for gastroduodenal disease will be of great benefit for patient management in clinical practice and mass screening for gastric cancer.