[Measurement of cellular DNA content in thyroid tumors by the flow cytometer]

Cellular DNA contents measured by flow cytometer were analysed in relation to histopathological classification and clinicopathological findings in 94 patients with thyroid tumors. The DNA determination was carried out on both tumor tissues and surrounding thyroid tissues. As an indicator of tumor growth, proliferative index (PI) and DNA index were calculated from DNA histograms. The PI value (mean +/- SD) was 32.5 in medullary carcinoma, 31.3 +/- 10.2 in follicular carcinoma, 28.2 +/- 6.2 in papillary carcinoma, 21.6 +/- 4.4 in follicular adenoma, and 20.6 +/- 4.4 in adenomatous goiter, respectively, whereas the value in normal thyroid tissues was 4.1 +/- 2.2. PI values in the surrounding thyroid tissues in cases of follicular and papillary carcinomas were significantly (p less than 0.01) lower than those of the corresponding cancer tissues, but they were higher than that of the normal tissues. The DNA index and frequencies of aneuploidy were 1.15 and 50.0% in medullary carcinoma; 1.25 +/- 0.27 and 66.7% in follicular carcinoma; 1.19 +/- 0.25 and 64.2% in papillary carcinoma; 1.01 +/- 0.04 and 9.3% in follicular adenoma; and 1.00 +/- 0.00% in adenomatous goiter. The result implies that PI value and DNA index are relatively correlated with clinicopathological criteria of malignancy of individual thyroid tumors, and they may become a putative tool for determination of the biological malignancy.