内分泌細胞腫瘍と免疫組織化学染色

Immunohistochemistry of Endocrine Cell Tumors of the Digestive Tract

要旨●消化管のカルチノイド腫瘍と内分泌細胞癌は，内分泌細胞腫瘍と総称されているが，本態は別の病態の腫瘍である．カルチノイド腫瘍と内分泌細胞癌は異型度をもとに厳密に区別して取り扱うべきである．本稿では，下記とその関連事項について概説した．カルチノイド腫瘍と内分泌細胞癌が内分泌細胞から構成されていることは，内分泌マーカー染色を用いて確認する．カルチノイド腫瘍と内分泌細胞癌の鑑別には，Ki-67染色とp53蛋白染色が役立つ．カルチノイド腫瘍の予後推測に，脈管内皮マーカー染色による脈管侵襲の確認とKi-67染色によるKi-67指数が参考になる．カルチノイド腫瘍の薬物療法の効果予測に，SSTR2A染色やmTOR染色が用いられる．ホルモン染色や胃腸型粘液形質マーカー染色は，腫瘍細胞の特性の解明に有用である．カルチノイド腫瘍・内分泌細胞癌と非内分泌系腫瘍との組織学的鑑別診断は，内分泌マーカー染色と鑑別腫瘍の特異的カーカー染色とを組み合わせて行う．

　Although commonly called as endocrine cell tumors, carcinoid tumors and endocrine cell carcinomas of the digestive tract are different diseases and should be diagnosed distinctively based on atypical grade of tumor cells. Endocrine differentiation of carcinoid tumors and endocrine cell carcinomas is confirmed by immunohistochemistry of endocrine markers. Ki-67 stain and p53 protein stain are useful for differential diagnosis between carcinoid tumors and endocrine cell carcinomas. Vascular invasion detected by endothelial marker stain and Ki-67 index count by Ki-67 stain are used for the prediction factor of tumor behavior and prognosis. SSTR2A and mTOR expression are used immunohistochemically to predict the drug effect to carcinoid tumors, Hormone production and gastrointestinal mucous phenotypes are examined to analyse the tumor cell nature. Carcinoid tumors/endocrine cell carcinomas and non-endocrine tumors are histologically differential diagnosed by combination of endocrine marker stains and specific marker stains for non-endocrine tumors.