A expressão imuno-histoquímica do marcador molecular Citoqueratina 19 e da proteína Her-2/neu (C-erbB2) em bócios operados na Fundação Hospital Adriano Jorge, em Manaus

Abstract

Cytokeratin 19 (CK 19) is a molecular marker that express cell replication and differentiation, and HER-2 oncogene (Human Epidermal Growth factor receptor-Type 2) is the second member of the human epidermal growth factor receptor (EGFR) family. Its overexpression can mean aggressiveness and poor prognostic in various kinds of tumors, as breast, lung and prostate. In last few decades the diagnostic of morphological changes of the thyroid gland was increased. When being diagnosed with ultrasound, the thyroid nodule prevalence reaches 20% to 30% in the general population. The aim of this prospective study is verify the presence of these markers in thyroid glands in operated non-coastal Amazon inhabitants, and its relationship with pathologic findings. We selected 34 samples of formalin-fixed, paraffin-embedded thyroid tumor tissues, from patients treated at Hospital Adriano Jorge, Manaus, Amazonas. The patients consisted of six men and 28 women, aged between 25 and 76 years, average 47 years. The tissues corresponded to nine multinodular goiter (MNG), seven colloid goiters (CG), five nodular hyperplasia (NH) four adenomatous goiters (AG), three papillary thyroid microcarcinoma (PTMC) and five papillary thyroid carcinomas (PTC). Immunohistochemistry (IHC) staining with CK 19 and HER-2 were performed using the labeled streptavidin biotin peroxidase complex system (LSAB2, DAKO, USA) on all tissues using monoclonal antibodies BA17 mab mouse (Dako M0772, USA) and SP3 rabbit mab (Spring M3034, USA) and inferential statistical analysis applying (Fisher exact test with 5% significance level). HER-2 IHC was not found in all samples. We found a strong positive reactivity for IHC CK19 in all 3 patients with PTMC, in four with PTC, one with MNG, and one with CG. We found focal positivity for CK 19 in one PTC, two MNG, 4 CG and one AG. Statistical significance was found only between CK 19 and histopathology. The results suggest thats HER-2 oncogene has no predictive or prognostic value in thyroid tissues and CK 19 marker showed affinity for PTC, although it is also found in benign tissues with less intensity.