[The evaluation of cellular proliferating activity in gastric carcinoma with the proliferating cell nuclear antigen (PCNA) expressive rate: its fundamental examination of the immunohistochemical procedures and its clinical applications].

PCNA is known as a cell cycle-related nuclear antigen. We stained PCNA immunohistochemically, and examined whether or not PCNA expressive rate could be applied clinically for a biological parameter of the histopathological effects in preoperative chemotherapy. PCNA was stained in proliferating cell by measuring nuclear DNA simultaneously. The most suitable fixation time in PCNA expression was 24 hours. On the examination of fixation fluid, ethanol was considered to be more suitable than buffer formaldehyde because PCNA expressive rate in ethanol correlated to BrdU labeling index with statistical significance. We examined PCNA expressive rate in gastric carcinomas. In the group whose histopathological effects of preoperative chemotherapy was recognized to be positive, PCNA expressive rate was significantly lower than in the group of negative effect. We measured thymidylate synthetase inhibition rate (TSIR) in the cases of preoperative oral administration of 5-FU, and the significantly negative correlation was seen between TSIR and PCNA expressive rate in the cases of differentiated adenocarcinoma (p < 0.05). The proliferating activity was recognized to be lower in the cases of higher inhibitional effect for DNA synthesis. PCNA expressive rate was considered to be a more effective and objective biological parameter on the evaluation of malignant potential in gastric carcinoma.