The expressions of Cytokeratin7 (CK7) and CK20 have been studied by a lot of cancer researchers, and these 2 protein markers are often used to find the primary foci of metastatic cancers. There have been numerous studies on vimentin, p53 and Ki-67 as prognostic factors for different cancers. However, it seems that there are a few investigations on the expression of CK7 and CK20 in papillary carcinoma of the thyroid. This study aimed to investigate the expressions of CK7, CK20, vimentin, p53 and Ki-67 in papillary thyroid carcinoma, and we wanted to determine whether the expressions of vimentin, p53, and Ki-67 are related to such prognostic factors as age, the tumor size, nodal metastasis or perithyroidal tissue invasion.

Paraffin slices of 44 papillary thyroid carcinomas from 44 patients were used for immunohistochemistry with using monoclonal antibody against CK7, CK20, vimentin, p53 and Ki-67. The expressions of CK7, CK20 and vimentin were determined simply by the staining competence, and more than 5% positive cells out of 1,000 cells in a highpowered microscopic view was considered as positive for the p53 and Ki-67 expressions. The expressions of vimentin, p53 and Ki-67 were investigated for their correlation with age, perithyroidal tissue invasion, the size of the tumor and metastasis to the cervical lymph nodes.

Total of 44 patients (7 men and 37 women) were examined. The average size of tumor was 1.3 cm, and 28 (63.6%) out of 44 patients had perithyroidal tissue invasion. 29 (65.9%) patients had cervical lymph node metastases. The expression of CK7 was observed in all 44 (100%) patients, but only three (6.8%) among them had the expression of CK20. The expression of vimentin was shown in 43 (97.7%) patients. The expressions of p53 and Ki-67 were seen in 33 (75%) patients and 12 (27.7%) patients, respectively. The expressions of vimentin, p53 and Ki-67 were not significantly related with age (P=1.0, 0.084), perithyroidal tissue invasion (P=1.0, 0.798), the size of the tumor (P=0.234, 0.313) and cervical lymph node metastases (P=0.582, 0.948).

As expected, papillary thyroid carcinoma showed a CK7(+)/CK20(-) pattern. Further research is needed to find the meaning of the expression of vimentin because it was meaningless analyzing the relationship between the prognostic factors due to fact that 97.7% of the patients had the expression of vimentin. There was no statistically significant relation between the expressions of p53 and Ki-67 and age, the size of thyroid tumor, perithyroidal tissue invasionand cervical lymph node metastasis.