Evaluation of epithelial-to-mesenchymal transition and Ki-67 index in aggressive papillary thyroid cancer

Abstract

ObjectivesThe present study aims to characterize immunohistochemical features of markers associated with Epithelial-Mesenchymal Transition (EMT) and proliferative activity that could lead to death in Papillary Thyroid Cancer (PTC). MethodsClinical data and tumor material were retrospectively collected. The patients were separated into death from PTC (Group 1), metastatic cases with indolent behavior (Group 2) and non-metastatic indolent PTC (Group 3). Immunohistochemical assessment of E-cadherin, β-catenin, Vimentin, ZEB-1 and Ki-67 was performed in each tumor and a semiquantitative estimation of the percentage of expression was fulfilled on the best marking area at high of the tumor invasion front. Results31 patients were included, 15 that died from PTC (Group 1), 6 in Group 2 and 10 in Group 3. The proliferative marker Ki-67 showed a significant difference in its expression in the tumor invasion front between the groups, specifically between groups 1 and 3 (p = 0.006). On the other hand, EMT-related immunohistochemical markers didn’t show significant difference in their percentage of expression, since loss of E-cadherin, β-catenin and Vimentin was observed in most cases at the invasion front. ConclusionPatients that died from PTC had a significantly higher Ki-67 labelling index compared to patients with indolent disease (cutoff of 11%). Ki-67 may have a role as a prognostic marker and could be considered for routine use in PTC. Level of evidence4.