Abstract BACKGROUND Although the identification of the BRCA1 and BRCA2 genes have been of great interest, these genes account for less than 5% of all breast carcinoma cases. The remaining cases are sporadic. Reanalysis of a large twin study suggested that genetic factors may play a significant role in sporadic breast and other carcinomas. Sporadic breast carcinoma is polygenically inherited. Multiple genes are likely to have an additive effect, each gene accounting for a fraction of the variance. One factor that may have an impact on the development of hormonally responsive breast tumors is the duration of exposure of the breast to estrogen.

Therefore, one of the demographic risk factors for breast carcinoma is an early age of onset of menarche. The current study was based on the hypothesis that genes that play a role in demographic risk factors may be breast carcinoma risk genes in their own right.

The authors hypothesized that six genes relevant to the timing of the onset of menarche and related risk factors might be candidate genes for breast carcinoma. Adobe Muse Media Queries Using Em. These were the leptin gene ( LEP), the leptin receptor gene ( LEPR), the catechol-0-methyltransferase gene ( COMT), the dopamine D 2 receptor gene ( DRD2), the estrogen 1 receptor gene ( ESR1), and the androgen receptor gene ( AR). METHODS The authors examined 67 women with postmenopausal sporadic breast carcinoma and 145 gender and race-matched controls. Download Game Yugioh Ps1 Untuk Pc.