BACKGROUND AND OBJECTIVES: Studies investigating the molecular pathogenesis of common thyroid neoplasms have shown some association between oncogenes expression and histological aggressiveness of thyroid tumors. We have investigated molecular changes in variants of thyroid papillary carcinoma (TPC), by analyzing the expression of proteins related to its tumorigenesis, and further, its own relationship to the prognosis. METHODS: We examined 32 surgical specimens of TPC obtained from 5 males and 27 females (mean ages of 52.6 and 46.5 years, respectively). Monoclonal antibodies anti-MIB-1, p53, c-erb-B2, TSH receptors, TGFb receptors and bcl-2 were detected by immunohistochemistry. RESULTS: 11 of the 32 cases had a better prognosis (microcarcinoma and encapsulated tumors), with high expression of TSHR2 and TGFbR2 (100%), bcl-2 (81.8%), c-erb-B2 (90.9%) and lesser expression of p53 and MIB-1 (18.2%). In the 13 cases with intermediate prognosis (classic and folicular), the expression of TSHR2 reached 100%; TGFbR2 and bcl-2, 92.3%; c-erb-B2, 76.9%; p53, 23.1%; and MIB-1, 69.2%. The 8 cases with the worst prognosis (tall and columnar cells) expressed TSHR2, bcl-2, c-erb-B2, in 100% of them; TGFbR2 in 87.5%; p53 in 75%; and MIB-1 in 37.5%. CONCLUSIONS: These neoplasias have shown to be well differentiated, due to the high expression of TSH and TGFb receptors, and low expression of p53. In all groups, the proliferation rate was absent or very low (<1.5%), with high positives in the group of intermediate prognosis. Proliferation rate was higher among the most aggressive variants. Furthermore, the positivity to bcl-2 was highly related to the worsening of prognosis.
Papillary carcinoma; Immunohistochemistry; Thyroid cancer; Prognosis; Tumor markers
