Quantitative analysis of estrogen receptor-α and -β messenger RNA expression in breast carcinoma by real-time polymerase chain reaction
✍ Scribed by Kyoko Iwao; Yasuo Miyoshi; Chiyomi Egawa; Noriko Ikeda; Fumine Tsukamoto; Shinzaburo Noguchi
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 134 KB
- Volume
- 89
- Category
- Article
- ISSN
- 0008-543X
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✦ Synopsis
Background:
Estrogen action is mediated not only through a classic estrogen receptor (er) (er-alpha) but also through a second er (er-beta) that has a structure and function similar to er-alpha. a correlation between er-beta mrna expression with er and progesterone receptor (pr) protein levels as well as prognostic factors remains to be established in breast carcinoma.
Methods:
The authors conducted a quantitative analysis of er-alpha and er-beta mrna expression in 116 breast tumors using real-time polymerase chain reaction (pcr), and investigated a possible correlation between er-alpha and er-beta mrna expression and er and pr status as determined by enzyme immunoassay as well as with various prognostic factors.
Results:
Er-alpha mrna levels were significantly (p < 0.01) higher in er positive compared with er negative tumors. conversely, er-beta mrna levels were significantly (p < 0.01) lower in er positive compared with er negative tumors. accordingly, the ratio of er-beta to er-alpha was significantly (p < 0.01) higher in er negative compared with er positive tumors. a subset analysis based on er and pr status showed that er-beta mrna levels as well as the ratios of er-beta to er-alpha mrna level were highest in er negative and pr negative tumors (p < 0.05). er-alpha mrna levels were significantly (p < 0.05) higher in postmenopausal compared with premenopausal tumors. histologic grade 3 tumors showed a significant decrease in er-alpha mrna levels compared with grade 1 and 2 tumors (p < 0.01 and p < 0.05, respectively). no significant correlation between er-alpha and er-beta mrna levels and histologic type, tumor size, or lymph node status was observed.
Conclusions:
An absolute and relative increase in er-beta mrna levels in er negative and pr negative breast tumors, which rarely respond to endocrine therapy, suggests the possible involvement of up-regulation of er-beta mrna in the development of estrogen-independent tumors.