The expression of retinoid X receptor γ (RXRγ) and the clinicopathological parameters of total 69 patients with papillary thyroid carcinoma (PTC) larger than 1 cm were examined. The PTCs were classified into two groups according to the presence of loss of cellular polarity/cohesiveness (LOP/C). The expression of RXRγ mRNA was examined by reverse transcriptase polymerase chain reaction and quantitative real-time PCR. The RXRγ mRNA up-regulation was found to be positively correlated with extrathyroid invasion (r = 0.293, P = 0.019), advanced tumor stage (r = 0.318, P = 0.016) and lymph node metastasis (LNM) (r = 0.338, P = 0.005), as well as LOP/C (r = 0.345, P = 0.004), which was proposed as a histological characteristic of poor cellular differentiation. The RXRγ mRNA expression, as well as extrathyroid invasion, LOP/C and advanced tumor stage, was further confirmed to be one of the independent predictive factors (Odds ratio: 6.545; 95% confidence interval: 1.575-27.208) of LNM using multivariate analysis. These results suggest that RXRγ may play a role in the dedifferentiation and metastasis of PTC.
© 2010 The Authors. Pathology International © 2010 Japanese Society of Pathology and Blackwell Publishing Asia Pty Ltd.