胃型分化型腺癌―新しい抗体を用いた免疫染色による癌の形質判定

The Phenotypes of the Gastric Carcinoma: Evaluation by a New Immunohistochemical Method

要旨　CD10による刷子縁，MUC2による杯細胞，human gastric mucin（HGM）による腺窩上皮，paradoxical concanavalin A（ConA）による幽門腺への分化を評価することで胃癌の形質分類を行い，癌の形質を分類し従来の方法と比較した．対象は通常の単発分化型腺癌の52症例と超高分化型腺癌4症例（胃型2例，腸型2例）を用いた．通常の単発高分化型腺癌の形質は，胃型12例（23％），不完全腸型33例（64％），完全腸型7例（14％）に分類された．不完全腸型のHGM陰性群は従来は単に腸型と分類されていたが，今回の検討ではこの群は背景粘膜との対比から，不完全腸型のHGM陽性性群（従来の混合型）と同様であり，これら二群は不完全腸型としてひとまとめにするほうが妥当であると考えられた．そして，超高分化型腺癌（胃型）の2例ともAB陽性で従来の判定法では腸型形質の発現と判定されることになるが，新しい判定法では，AB陽性の杯細胞様に見える細胞が多数みられる腺管もMUC2陰性でHGM陽性であるので完全胃型と判定され，H・E染色の形態とも合致した．この評価法では従来の分類と比較すると，胃癌の形質判定をより簡便かつ客観的に行うことができ，また腸上皮化生の分類に対応した胃癌の形質を評価でき背景粘膜と癌の形質がより対応すると考えられた．

　The phenotypes of the gastric carcinoma were evaluated by a new method using immunohistochemistory with CD10 for intestinal brush border, MUC2 for intestinal goblet cells, human gastric mucin (HGM) for gas-tric foveolar cells and paradoxical concanavalin A (ConA) for gastric pyloric glands. For this study, fiftytwo cases of well differentiated adenocarcinoma were randomly selected from our files, and four cases of extremely well differentiated adenocarcinomas were specially selected. Randomly selected well differentiated adenocarcinomas were classified into 12 cases (23%) of gastric phenotype, 33 (64%) of incomplete intestinal phenotype and 7 (14%) of complete intestinal (small intestinal) phenotype. Incomplete intestinal phenotype with HGM (－) used to be simply classified as intestinal phenotype, but it was very similar to incomplete intestinal phenotype with HGM(＋). Therefore, it is reasonable that they should be classified as belonging to the same phenotypic group of incomplete intestinal type, distinguishing then from complete intestinal type. In addition, the phenotype of extremely well differentiated adenocarcinoma classified by the new method was consistent with morphological features revealed by H・E stain. By the new method, the phenotypes can be more easily and objectively evaluated. This classification is based on that of intestinal metaplasia, and it is considered to be useful for analyzing the correlation between background mucosa and carcinogenesis.