胃と腸38巻8号

2003年07月発行

今月の主題 経過観察からみた大腸癌の発育・進展sm癌を中心に

主題研究

表面型大腸腫瘍の遺伝子解析

著者： 藤井博昭¹ 坂本直人² 折田創³ 味岡洋一⁴ 渡辺英伸⁴ 下田忠和⁵

所属機関： ¹順天堂大学医学部病理学第2講座 ²順天堂大学医学部消化器内科 ³順天堂大学医学部第1外科 ⁴新潟大学大学院医歯学細胞機能講座分子病態病理学分野 ⁵国立がんセンター中央病院臨床検査部

ページ範囲：P.1180 - P.1188

文献概要

要旨　表面型大腸腫瘍の発育進展を遺伝子レベルで明らかにするため，腫瘍病変部からマイクロディセクションを行い，loss of heterozygosity(LOH)を検索した．de novoで多数のLOHが均一に発生する症例が存在する可能性が示された．また，粘膜内で腫瘍クローンが拡がる過程でLOHが順次あるいは枝分かれしつつ蓄積進展し，浸潤癌に至る経路も明らかにした．17pLOHは早期に起きる症例が多く，またp53免疫染色と多くは一致していた．隆起型腫瘍とは異なり，腫瘍発生早期からp53異常が関与することを示唆している．3p LOHはhomogeneous LOHが32％と，ある症例では腫瘍発生早期から関与する傾向があった．genome wideのLOH検索，特定の癌抑制遺伝子異常，およびその獲得時期を発育進展経路や組織異型度と対比して解析することにより，従来の隆起型腫瘍でのadenoma-carcinoma sequenceとは異なるgenetic pathwayが次第に明らかにされよう．

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