Topoisomerase II α and telomerase expression in papillary thyroid carcinomas

Background. Altered topoisomerase II alpha (Topo II alpha) expression and telomerase activity (TA) reflect tumour cell growth and malignant transformation. Methods. We examined TA by using a TRAP assay and expression of Topo 11 (X by immunohistochemical analysis in a series of 27 cases of papillary thyroid carcinoma (PTC). Results. Topo II alpha labelling index (LI) ranged from 0.1 to 4.2% and was significantly associated with patient age (r = -0.42, p = 0.003), with higher levels of Topo II alpha in patients under 40 years. There was no relationship between Topo II alpha Ll, AGES score or other clinical outcome. TA was detected in 14 PTC, with relative levels ranging from 1.2 to 102 units. A significant positive correlation between the multiplicity of tumoral foci and the TA levels (p < 10(-2)) was noted. Conclusion. We concluded that Topo II alpha cannot be used as a marker of tumour aggressiveness. Furthermore, enhanced Topo II alpha expression in PTCs from patients less than 40 years old suggests that this age group might benefit from Topo II inhibitor chemotherapy. (C) 2003 Elsevier Ltd. All rights reserved.