Quantitative analysis of estrogen receptor-alpha and -beta messenger RNA expression in normal and malignant thyroid tissues by real-time polymerase chain reaction.
OBJECTIVE
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 carcinoma (n = 14), anaplastic carcinoma (n = 3) and medullary carcinoma (n = 6)] were obtained at surgery from 45 female patients. ER-alpha and ER-beta mRNA 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 medullary carcinomas but were marginally (p = 0.08) higher than those in follicular and anaplastic carcinomas. ER-beta mRNA levels in the normal thyroid tissues were not significantly different from those in any other tumor tissues. 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 among the normal and tumor tissues.


CONCLUSIONS
A downregulation of ER-alpha mRNA in follicular and anaplastic carcinomas seems to suggest that estrogens are unlikely to play an important role in the carcinogenesis and progression of these carcinomas. On the other hand, a significant decrease in ER-beta to ER-alpha mRNA ratios in follicular adenomas suggests a possible involvement of estrogens in the pathogenesis of this disease since the same phenomenon has been reported on estrogen-dependent breast cancers.
Egawa
C
C
Department of Surgical Oncology, Osaka University Medical School, Osaka, Japan.
Miyoshi
Y
Y
Iwao
K
K
Shiba
E
E
Noguchi
S
S
D018263:Adenocarcinoma, Follicular / Q000235:genetics; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002291:Carcinoma, Papillary / Q000235:genetics; D015536:Down-Regulation; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D005260:Female; D005786:Gene Expression Regulation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics*; D011960:Receptors, Estrogen / Q000235:genetics*; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013961:Thyroid Gland / Q000502:physiology*; D013964:Thyroid Neoplasms / Q000235:genetics*; D014158:Transcription, Genetic
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D012333:RNA, Messenger; D011960:Receptors, Estrogen