Expression of Estrogen Receptor-beta and Its Variants in Normal Mammary and Tumor Tissues / 한국유방암학회지
Journal of Korean Breast Cancer Society
;
: 161-167, 2003.
Article
in Korean
| WPRIM
| ID: wpr-209921
ABSTRACT
PURPOSE:
Since the discovery of estrogen receptor-beta(ER-beta, five C-terminal variants of ER-beta were identified. We designed this study to investigate the pattern and clinical implications of ER-betaand its splicing variants expression in normal and malignant mammary tissues.METHODS:
Using reverse transcription polymerase chain reaction (RT-PCR), we examined the expression levels of ER-alpha and ER-betaand its five splicing variants (beta1, beta2, beta3, beta4, beta5) in 50 paired normal and cancer tissues. We measured the densities of RT-PCR products using Tina version 2.10 (Raytest, Germany). Firstly, the incidence and intensity of ER-alpha and ER-beta and its five splicing variants were compared. Then the expression of ER-betamRNA splicing variants was also analyzed with regard to the ER-alphaprotein expression measured by immuno-histochemical staining and the menopausal status of the patients. Chi-square test and paired samples t-test were used for statistical analysis. Differences were considered to be significant with a p-value of less than 0.05.RESULTS:
The expression of ER-betamRNA variants in normal breast and cancer tissues were as follows ER-beta2 (100%/100%), ER-beta4 (76%/74%), ER-beta5 (32%/58%), and ER-beta1 (14%/16%). ER-beta3 was not detected at all. In terms of intensity, we observed a significant decrease of ER-beta2 (P<0.001) and an increase of ER-beta5 (P=0.004) in the mRNA expression levels among breast cancers compared to the corresponding normal breast tissues. Compared to the corresponding normal tissues, a significant decrease of ER-beta2 in cancer tissues was observed in patients with ER-alpha-positive (P<0.001), with age over 50 (P=0.01), and under 50 (P=0.04) as well, but not in patients with ER-alpha-negative (P=0.48). ER-beta4 also significantly decreased in patients with ER-alpha-positive (P=0.004) and with age over 50 (P=0.07). ER-beta5 showed a significant increment only in patient aged over 50 (P=0.04).CONCLUSION:
ER-alpha mRNA expression significantly increases but ER-beta mRNA expression decreases in the cancer tissues compared to the corresponding normal tissues. Among ER-beta variant forms, ER-beta2 is predominant in both normal and malignant mammary tissues and ER-beta4, ER-beta5, and ER-beta1 in descending order but ER-beta3 does not express in mammary tissues. The decrease of ER-beta2 and ER-beta4 expression is prominent in cancer tissue especially in ER-alpha-positive cancers, which suggests that ER-beta2 and ER-beta4 may possess a regulatory function in mammary carcinogenesis. Further investigations to verify the roles of ER-beta variants are mandatory.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Breast
/
Breast Neoplasms
/
RNA, Messenger
/
Receptors, Estrogen
/
Polymerase Chain Reaction
/
Incidence
/
Reverse Transcription
/
Estrogens
/
Carcinogenesis
Type of study:
Incidence study
/
Prognostic study
Limits:
Humans
Language:
Korean
Journal:
Journal of Korean Breast Cancer Society
Year:
2003
Type:
Article
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