Yonago Acta medica 1996;39:49-58

Frequent Occurrence of Cell Death in Gastric Adenomas: Comparison between Apoptosis and Mitosis

Yoshihito Gomyo, Mitsuhiko Osaki and Hisao Ito

First Department of Pathology, Faculty of Medicine, Tottori University, Yonago 683, Japan

This study examined apoptotic cell death in a total of 45 gastric adenomas consisting of 25 low grade and 20 high grade dysplasia. Formalin-fixed and paraffin-embedded specimens were stained with hematoxylin-eosin, Giemsa and naphthol AS-D chloroacetate. Serial sections were also immunostained for leukocyte common antigen (LCA), Ki-67, P53, P21 and Bax. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling was conducted to confirm apoptotic cells. Obvious apoptotic and mitotic figures were counted in a 10 × 20 magnification field. The apoptotic cells appeared as a single structure separated from surrounding intact cells by a clear halo and frequently showed fragmented nucleus. Most of them seemed to be shed into the glandular lumen, occasionally containing typical apoptotic bodies. Apoptotic cells showed no immunoreactivity for either LCA or Ki-67 antigen. The average number of apoptotic cells per field was 4.5 1.7 in adenomas with low grade dysplasia and 6.4 2.2 in those with high grade dysplasia, the number being significantly higher (P < 0.01) in the latter. There was no significant difference in the number of mitotic figures between the two categories. P53 positive cells were noted in five adenomas, and P21 positive cells, in one adenoma. Bax immunoreactivity was rather faint when compared with adjacent non-neoplastic mucosa. These results indicate the frequent occurrence of apoptotic cell death in gastric adenomas. The process might reflect proliferative activities rather than the slow-growing nature of gastric adenomas. The precise mechanism of apoptosis, however, remains to be elucidated.

Key words: apoptosis; gastric adenoma; mitosis; precancerous lesion