Quantitative analysis of estrogen receptor-alpha and -beta messenger RNA expression in normal and malignant thyroid tissues by real-time polymerase chain reaction

Objectives: We have conducted a quantitative analysis of estrogen receptor- alpha (ER-alpha) and -beta (ER-beta) mRNA expression in normal thyroid and tumor tissues. Methods: Normal thyroid tissues (n = 10) and tumor tissues [ (follicular adenoma (n = 14), follicular carcinoma (n = 8), papillary carci noma (n = 14), anaplastic carcinoma (n = 3) and medullary carcinoma (n = 6) ] were obtained at surgery from 45 female patients. ER-alpha and ER-beta mR NA expression has been studied by a quantitative polymerase chain reaction. Results: ER-alpha mRNA levels in the normal thyroid were not significantly different from those in follicular adenomas, papillary carcinomas and medu llary carcinomas but were marginally (p = 0.08) higher than those in follic ular and anaplastic carcinomas. ER-beta mRNA levels in the normal thyroid t issues were not significantly different from those in any other tumor tissu es. ER-beta to ER-alpha mRNA ratios were significantly (p < 0.05) higher in the normal thyroid tissues than in follicular adenomas. Proportions of ER- beta mRNA variants (ER-beta 1, 2, 5, and 5') did not significantly differ a mong the normal and tumor tissues. Conclusions: A downregulation of ER-alph a mRNA in follicular and anaplastic carcinomas seems to suggest that estrog ens are unlikely to play an important role in the carcinogenesis and progre ssion of these carcinomas. On the other hand, a significant decrease in ER- beta to ER-alpha mRNA ratios in follicular adenomas suggests a possible inv olvement of estrogens in the pathogenesis of this disease since the same ph enomenon has been reported on estrogen-dependent breast cancers. Copyright (C) 2001 S. Karger AG, Basel.