BBN Ratにおける膀胱癌とヒト膀胱癌の組織学的検討

Abstract

BBNラットの膀胱発癌の経時的変化を病理組織学的および発癌した組織のDNA量について経時的変化を調べた.ヒト膀胱癌と比較するために膀胱全摘標本の多発性乳頭状癌と非乳頭状の浸潤癌についての病理組織およびDNA量を比較検討した.BBNの膀胱発癌の過程はヒト乳頭状癌と発育様相が似ており, 乳頭状腫瘍の有効なモデルとなるが, 非乳頭状浸潤癌のgrowth patternとは著しい違いが見られた

Male Fisher rats were treated with 0.5% BBN, and the appearance of cancer in the rat's bladder was observed successively. The quantities of DNA in the normal and tumorous tissues were compared with those in the bladder cancer excised from man; and, the bladder cancer produced in the rat and that occurring in man were compared. 96 rats were divided into 4 groups, and given 8, 16, 24 or 32 weeks of treatment with BBN. Papillomas appeared after administration for 8 weeks, and with subsequent increase in the period of administration the rate of canceration increased. The cancerous tissue proliferated papillarily , the malignancy was grade 1 to 2, no case showed infiltration into the muscle layer, and the quantity of DNA scarcely changed with time, always showing a peak near 2c. In the papillary type of bladder cancer in man, the quantity of DNA showed little change at any stage, and little tendency of infiltration; and, the growth pattern was similar to that of the BBN-induced cancer in rats. On the other hand, non-papillary cancer in man showed a flat histogram of DNA, had a strong tendency of infiltration, and showed a growth pattern different from that of the BBN-induced cancer in rats, thus the BBN-induced cancer in the rat cannot be used as a model of non-papillary infiltrative cancer.