[Characterization of experimentally induced malignant gastrointestinal tumors of rats using DNA-cytophotometry and karyometry]

The average relative DNA-content, the status of ploidy, the area of the nucleus, the compactness of chromatin and the variability of the shape of the nucleus were determined in 33 experimental induced malignant neoplasms and 5 benign lesions of gastric and intestinal mucosa of rats. The results were compared with diploid controls and divided into 3 types of DNA-histograms. Normal and malignant cells differed significantly in their DNA-content, in the area of the nucleus and in the percentage of hypertetraploid cells. 27 tumors belonged to the aneuploid type of histogram. The dignity was not clear in 6 cases. Diploid carcinomas did not occur. The DNA-cytophotometry gave the decisive hint to diagnosis of malignancy in 8 carcinomas. The various types of tumors differed not in the determined parameters. The problem of differential diagnosis between benign lesions with preneoplastic potential and malignant tumors is discussed.