Immunohistochemical Study on the Proliferative Activity of Human Thyroid Tumors

ABSTRACT

For the estimation of the proliferative activity, related to the biologic behaviour, malignant potential, and prognosis, of human thyroid tumors, PCNA(proliferating cell nuclear antigen) immunohistochemical staining was performed on paraffin-embedded sections of 9 normal thyroid tissues, 9 adenomatous goiters, 9 follicular adenomas, 4 Hurthle cell tumors, 12 papillary carcinomas, 4 follicular carcinomas, and 3 anaplastic carcinomas. The results were as follows: 1) The PCNA labeling indices in adenomatous goiter, follicular adenoma, and Hurthle cell tumor were 1.1, 1.5, and 2.4, respectively. They were significantly higher than the labeling index in normal thyroid. 2) The PCNA labeling indices in papillary carcinoma and follicular carcinoma were 3.5 and 4.4, respectively. They were significantly higher than the labeling indices in adenomatous goiter and follicular adenoma, but there was no significant difference between papillary and follicular carcinoma. 3) The PCNA labeling index in anaplastic carcinoma, 14.1, was significantly higher than those in benign and other malignant tumors. According to the results, the PCNA labeling index was well correlated with the malignant potential of a tumor. So the PCNA immunohistochemical staining is thought to be a useful method for the evaluation of the malignant potential and prognosis of a tumor.