Proliferative markers in diagnosis of thyroid tumors: a comparative study of MIB-1 and topoisomerase II-a immunostaining.
BACKGROUND
The differential diagnosis of well-differentiated tumors of follicular cell origin remains a most problematic task in thyroid pathology. Therefore, various diagnostic/prognostic thyroid markers are currently being studied. The aim of our study was to evaluate the proliferative MIB-1 and topoisomerase II-alpha markers in both oncocytic and non-oncocytic epithelial thyroid tumors.


METHODS
Proliferative activity was analyzed by means of immunohistochemistry in 215 thyroid tumors and the evaluated proliferative indices (PI) were correlated with morphological diagnosis. Comparison of both proliferative markers was made. The results were statistically analyzed using Wilcoxon tests (significance level p<0.05) and the Spearman correlation coefficient.


RESULTS
Carcinomas generally showed significantly higher PI than adenomas, irrespective of their oncocytic or non-oncocytic features. Moreover, PI in oncocytic adenomas was significantly higher than in non-oncocytic ones. However, PI in both oncocytic and non-oncocytic carcinomas, including papillary microcarcinomas, were similar. The studied proliferative markers correlated with each other.


CONCLUSIONS
PI can help the differential diagnosis of morphologically difficult cases of thyroid tumors. Oncocytic adenomas have higher malignant potential and should be promptly surgically removed. Both MIB-1 and topoisomerase II-alpha are recommended for the evaluation of thyroid tumor cell proliferation.
Ludvíková
M
M
Sikl's Department of Pathology, Charles University Medical Faculty Hospital, Plzen, Czech Republic. ludvikova@fnplzen.cz
Holubec
L
L
Ryska
A
A
Topolcan
O
O
D000951:Antigens, Neoplasm; D002455:Cell Division; D004250:DNA Topoisomerases, Type II; D004268:DNA-Binding Proteins; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000201:enzymology / Q000276:immunology / Q000473:pathology
D000951:Antigens, Neoplasm; D004268:DNA-Binding Proteins; D019394:Ki-67 Antigen; D004250:DNA Topoisomerases, Type II