DNA ploidy and Cellular Proliferation Activity in Experimentally Induced Malignant Fibrous Histiocytoma

ABSTRACT

To fine out the changes of DNA ploidy and cellular proliferation activity during carcinogenesis and evaluate correlation between flow cytometrically determined S-phase fraction and proportion of proliferation cell nuclear antigen(PCNA, PC10) immunoreactive cells, the authors studied on malignant fibrous histocytoma induced by intra-articular injection of 9, 10-dimethy1-1, 2-benzanthracene(DMBA) in the rats. Forty Wistar rats were used. The results obtained were as follows. 1) Firstly, tumors were palpated 5 weeks after the last injection of DMBA and formed in 27 rats at sacrificed. Histologically, these lesions showed storiform, indicative of malignant fibrous histiocytoma. 2) Three cases of DNA aneuploidy were observed at 4 and 5 months after the last injection of DBMA and one of them, which was DNA diploidy at main mass, was found at daughter mass. 3) Flow cytometrically determined S-phase fraction and proportion of PCNA(PC10) immunoreactive cells in malignant fibrous histiocytoma induced by DMBA were much higher than in control groups and slightly increased according to sequential changes after formation of mass. The comparison of flow cytometrically determined S-phase fraction and proportion of PCNA(PC10) immunoreactive cells showed significant correlation(r=0.6092, p<0.001). Above results strongly suggest that ploidy pattern may evolve into aneuploid type during the development of tumor and proliferation activity increases during the carcinogenesis.