Impact of contraception on gynecologic cancers

Low-dose oral contraceptives: protective effect on ovarian cancer risk

Low-dose oral contraceptive (OC) formulations containing 35 microg or less ethinyl estradiol have preferably been prescribed in the last decade, however, few data exist on its relation to ovarian cancer risk. We determined the effects of low-dose OC on the risk of ovarian cancer in a population-based case-control study, including 282 patients ages 20-75 years at diagnosis of incident primary invasive ovarian cancer or borderline tumour between 1993-1996 and 533 control subjects individually matched by age and study area to each case. Analysis excluded women who had undergone a bilateral ovariectomy or had a previous diagnosis of either ovarian cancer or borderline tumour. The association of OC use by ethinyl estradiol dose and ovarian cancer risk was assessed by odds ratios (OR), adjusting simultaneously for the other OC types and determinants of ovarian cancer risk. Ovarian cancer risk was significantly reduced by 52% for ever use of any type of OC. The reduction in risk was 7% per year of use (OR = 0.93, 95% confidence interval [CI] = 0.90-0.96) and was more evident in first-use subjects younger than 25 years. Risk reduction for ovarian cancer was substantial for use of low-dose OC, the odds ratios being 0.86 (95% CI = 0.77-0.94), 0.91 (95% CI = 0.83-1.00), and 0.95 (95% CI = 0.91-0.99) per year of using OC containing <35 microg, 35-<50 microg, and >or=50 microg ethinyl estradiol, respectively. Our study provides evidence that low-dose oral contraceptives confer substantial protection against the development of ovarian cancer.

Regulation of aromatase expression in human ovarian surface epithelial cells

Ovarian cancer originates mainly from surface epithelial cells, which are potential targets of estrogen action. Using immunohistochemistry and RT-PCR analysis, aromatase (estrogen synthetase) can be detected in human ovarian surface epithelial tumors. In this study, we functionally characterized the aromatase expressed in a primary cell culture, normal human ovarian surface epithelial (HOSE) 17. The apparent K(m) and V(max) values were determined to be 5.8 +/- 0.5 nM, and 0.3 +/- 0.0 pmol/mg.h, respectively. The aromatase activity in HOSE 17 cells can be induced effectively by phorbol esters and forskolin, suggesting that estrogen biosynthesis in HOSE 17 cells is mainly regulated through protein kinase C- and protein kinase A-mediated mechanisms. Exon I-specific RT-PCR revealed that phorbol esters predominantly up-regulated promoter II. Whereas forskolin treatment increased exon I.3A-containing messenger RNA, the aromatase activity remained low in the cells treated with this agent. In vitro transcription/translation analysis using plasmids containing T7 promoter and the human snail gene (SnaH) as a reporter capped with different untranslated exon Is revealed that exon PII-containing transcripts were translated more effectively than exon I. 3-containing transcripts. These findings explain why aromatase activity is higher in cells with the PII-containing transcripts than is cells with the I.3-containing transcripts. Our results indicate that aromatase is functionally expressed in human ovarian surface epithelial cells and its expression is regulated at both the transcriptional and translational levels.

Women's health

Symptoms reliably attributable to menopause are vasomotor symptoms and vaginal dryness. Other symptoms are not directly related to the menopause. HRT or ERT are effective in providing symptom relief and preventing disease prevalent in postmenopausal women. HRT or ERT is beneficial in women with RA. Little data concerns safety in SLE patients, but there are theoretical advantages to using HRT or ERT in women with SLE and two studies that indicate it is safe. Other forms of treatment are available to women who cannot or will not use HRT or ERT.

Estrogen action in human ovarian cancer

Evidence is accumulating for a facilitative role for estrogen in ovarian cancer. Although response to antiestrogen therapy has been poor, there is a distinct subset of patients that respond. Strategies for treatment of ovarian cancer would be improved by identification of patients likely to respond to hormonal therapy. Cell culture models that are responsive or resistant to estrogen and antiestrogen may be of value in finding markers that predict responsiveness to hormonal therapy. Several model cell lines have been generated that express ER and proliferate in response to estrogen in vitro. Further studies are needed to better characterize the response of these ER positive cells lines to estrogen in vivo in mouse xenograft models. Expression of many of the same genes are regulated by estrogen in breast and in ovarian cancer cell lines. One exception may be the HER-2/neu oncogene product, which is down-regulated by estrogen in responsive breast carcinoma cells but not in two ovarian carcinoma cell lines. Initial analyses of several estrogen responsive and one resistant cell model suggests the potential value of progesterone receptor presence and low levels of HER-2/neu expression for predicting responsiveness to hormonal therapy. Additional cell models need to be investigated to determine the frequency with which these markers are associated with antiestrogen resistance.