[Nuclear DNA content of thyroid adenocarcinoma]

In order to estimate biological behavior of thyroid adenocarcinoma, the nuclear DNA contents of various thyroid tumors were determined by flow cytometry and microfluorometry. Flow cytometry was performed on 21 patients with benign tumor and 20 with adenocarcinoma. Majority of their modal values in the DNA histograms were diploid or near diploid. There was no obvious difference in ploidy level between benign tumors and adenocarcinomas. However, the mean ratio of cells at a proliferative phase was significantly higher in adenocarcinomas than in benign tumors. Microfluorometry was performed on the surgical specimens taken from 6 patients with anaplastic carcinoma and 25 patients with adenocarcinoma. As to the adenocarcinoma, besides primary lesions, foci of tracheal invasion, lymph nodes with metastatic and recurrent tumors were studied. Most of the DNA histograms of the foci of tracheal invasion showed a wide distribution which was suggestive of dedifferentiation toward anaplastic carcinoma, but other lesions of adenocarcinomas showed no obvious difference from the primary lesions. In patients with recurrent adenocarcinoma, the shorter the interval between the operation and recurrence, the higher the incidence of cells with high ploidy range. From these findings, it was concluded that the nuclear DNA content was estimated as an objective index for the degree of malignancy of thyroid adenocarcinoma.