Comparison of nuclear DNA content in primary and metastatic differentiated thyroid carcinoma

Nuclear DNA content of 20 cases of primary differentiated thyroid carcinoma, 27 corresponding cervical lymph node metastases, and 2 local recurrent tumors was determined by flow cytometry. Evidence of DNA aneuploidy was found in either the primary tumor or in the corresponding metastases in 10 (63%) of the 16 papillary carcinomas, in all 3 follicular carcinomas, and in the case of medullary carcinoma studied. In all but one case, the aneuploid stemlines found in the regional metastases were also found in the primary or in the recurrent tumor. In four cases diploid metastatic tissue was found to originate from a tumor with DNA aneuploidy, and in three other cases two stemlines of tumor cells with different DNA indices could be shown in the primary tumor, further indicating clonal heterogeneity in differentiated thyroid carcinomas. None of the 11 patients with either diploid or aneuploid primary tumor with a DNA index less than 1.2 evaluated for 4-12 years died from thyroid cancer, whereas 5 of the 7 patients with primary tumor DNA index greater than 1.2 died from thyroid cancer (P less than 0.01).