胃印環細胞癌の組織化学的研究

Histochemical Studies on Signet-ring Cell Carcinoma of the Stomach

　胃のスキルスは若年者または女性に比較的多く，その激しい浸潤性の増殖のために予後の悪い癌とされている．その組織発生や進展様式については，すでに長与ら¹⁾，中村ら²⁾，佐野ら³⁾等の研究があり，粘膜内の印環細胞癌巣がスキルスの発生母地として重要視されているが，この印環細胞の発生起源や生物学的特徴についてはいまだ不明な点が多く，またスキルスの発生機序との関係についても多くの疑問が残されている．

　われわれは，印環細胞癌について一連の組織化学的検索を行ない印環細胞の生物学的特徴の一端を明らかにしえたので報告したい．

　Signet-ring cell carcinoma of the stomach shows following histological features; (i) cancer cells tend to be isolated from one another, showing minimal glandular formation, (ii) they diffusely infiltrate throughout the gastric wall and evoke scirrhous reaction in the affected stroma, (iii) periodic acid-Schiff (PAS) positive mucin is almost always detected in the cytoplasm and the nuclei are pressed toward the periphery of the cells as a result of abundant mucin production.

　Histochemical studies on sigent-ring cell carcinoma with these histological features were carried out with 64 surgically resected cases.

　Based on PAS reactivity of intracellular mucin, the signet-ring cells were classified into three types; Type A (immature), Type B (intermediate) and Type C (mature), and, according to different staining reaction to alcian blue at pH 2.5, Type C cells were further subclassified into C-1 and C-2.

　Among 6 enzymes studied, leucine aminopeptidase showed its intense activity in 63 cases (98.4％). The activity was found in the cytoplasm of nearly all cells except Type C-2 cells. Alkaline phosphatase activity, which was also found in the cytoplasm of the cells of all types except Type C-2, was present in 24 cases (37.5％) but the positive cells were usually scattered throughout the cancerous tissues. The 4 dehydrogenases (glucose-6-phosphate dehydrogenase, lactate dehydrogenase, succinate dehydrogenase and isocitrate dehydrogenase) similarly showed their definite or intense activities in all cases but the activities were not detected in Type C-2 cells.