鋸歯状癌に関する最新知見

The Latest Advances in Knowledge on Serrated Carcinoma

要旨●鋸歯状腺癌（SAC）は大腸癌の10%を占める組織型であり，鋸歯状病変から発生し，主に右側結腸に多くみられる．高齢者や女性に多く，喫煙や西洋型の食生活がリスク因子とされ，他臓器癌の合併のリスクも高い．SACは内視鏡所見で鋸歯状領域内に発赤や二段隆起などが認められることが特徴的で，拡大観察で複数のpitが混在する．分子病理学的にはKRAS/BRAF変異やMSI-Hが特徴で，特にCMS分類ではMSI-immune（CMS1）に分類される可能性が高い．左側結腸発生のSACは予後不良であり，さらなる研究が必要とされる．

　Serrated adenocarcinoma（SAC）accounts for 10% of colorectal cancers and arises from serrated lesions, predominantly occurring in the right colon. SAC is more common in the elderly and females, with smoking and a Western-style diet identified as risk factors. SAC is also associated with an elevated risk of developing cancers in other organs. Endoscopically, SAC often presents features such as erythema and two-tiered elevations within the serrated regions. Magnified observations revealed the presence of mixed pits. Molecularly, SAC is characterized by KRAS/BRAF mutations and microsatellite instability-high（MSI-H）and is likely to be classified as MSI-Immune（CMS1）under the CMS classification. SAC arising in the left colon has a poorer prognosis. Further research is needed.