Claire Templeman

BACKGROUND: Endometriosis is a risk factor for epithelial ovarian cancer; however, whether this risk extends to all invasive histological subtypes or borderline tumours is not clear. We undertook an international collaborative study to assess the association between endometriosis and histological subtypes of ovarian cancer. METHODS: Data from 13 ovarian cancer case-control studies, which were part of the Ovarian Cancer Association Consortium, were pooled and logistic regression analyses were undertaken to assess the association between self-reported endometriosis and risk of ovarian cancer. Analyses of invasive cases were done with respect to histological subtypes, grade, and stage, and analyses of borderline tumours by histological subtype. Age, ethnic origin, study site, parity, and duration of oral contraceptive use were included in all analytical models. FINDINGS: 13 226 controls and 7911 women with invasive ovarian cancer were included in this analysis. 818 and 738, respectively, reported a history of endometriosis. 1907 women with borderline ovarian cancer were also included in the analysis, and 168 of these reported a history of endometriosis. Self-reported endometriosis was associated with a significantly increased risk of clear-cell (136 [20·2%] of 674 cases vs 818 [6·2%] of 13 226 controls, odds ratio 3·05, 95% CI 2·43-3·84, p<0·0001), low-grade serous (31 [9·2%] of 336 cases, 2·11, 1·39-3·20, p<0·0001), and endometrioid invasive ovarian cancers (169 [13·9%] of 1220 cases, 2·04, 1·67-2·48, p<0·0001). No association was noted between endometriosis and risk of mucinous (31 [6·0%] of 516 cases, 1·02, 0·69-1·50, p=0·93) or high-grade serous invasive ovarian cancer (261 [7·1%] of 3659 cases, 1·13, 0·97-1·32, p=0·13), or borderline tumours of either subtype (serous 103 [9·0%] of 1140 cases, 1·20, 0·95-1·52, p=0·12, and mucinous 65 [8·5%] of 767 cases, 1·12, 0·84-1·48, p=0·45). INTERPRETATION: Clinicians should be aware of the increased risk of specific subtypes of ovarian cancer in women with endometriosis. Future efforts should focus on understanding the mechanisms that might lead to malignant transformation of endometriosis so as to help identify subsets of women at increased risk of ovarian cancer. FUNDING: Ovarian Cancer Research Fund, National Institutes of Health, California Cancer Research Program, California Department of Health Services, Lon V Smith Foundation, European Community's Seventh Framework Programme, German Federal Ministry of Education and Research of Germany, Programme of Clinical Biomedical Research, German Cancer Research Centre, Eve Appeal, Oak Foundation, UK National Institute of Health Research, National Health and Medical Research Council of Australia, US Army Medical Research and Materiel Command, Cancer Council Tasmania, Cancer Foundation of Western Australia, Mermaid 1, Danish Cancer Society, and Roswell Park Alliance Foundation.

OBJECTIVE: To test the hypothesis that increasing the intake of isoflavones by dietary supplementation may produce a therapeutic effect in reducing the incidence and severity of hot flushes in menopausal women. METHODS: Fifty-one postmenopausal women were randomized to placebo and active (one tablet per day of a 40-mg isoflavone supplement) groups in a cross-over design trial. After a 1-week run-in period, subjects were commenced on a 12-week period of treatment (active or placebo), followed by a 1-month placebo wash-out period, then crossed over to the alternative treatment regimen for a further 14 weeks. Symptom diaries were maintained throughout the trial and at the start and end of treatment. Plasma sex hormone binding globulin (SHBG) assay, full blood count, biochemical profiles, vaginal swabs and vaginal ultrasound scans were performed and isoflavones determined in 24-h urine collections by high-pressure liquid chromatography (HPLC) analysis. RESULTS: There was no significant difference between active and placebo groups in the reduction in hot flushes between start and finish time-points. Analysis performed on interim data time-points revealed a substantially greater reduction in flushing in the active group than placebo at 4 and 8 weeks after commencement of treatment, but this was not statistically significant. There were no significant differences between groups for Greene scores or in SHBG levels, hematological or biochemical parameters and vaginal swab or ultrasound findings. The combined values for all subjects, regardless of treatment group, revealed a strong negative correlation between the level of urinary isoflavone excretion and the incidence of hot flushes. CONCLUSIONS: These data do not indicate a therapeutic benefit from dietary supplementation with isoflavones in women experiencing menopausal symptoms, but do indicate that the apparent placebo effect in many studies of menopausal symptoms may be attributable to dietary sources of isoflavones. The study also demonstrates that 3 months of isoflavone supplementation did not cause adverse events or endometrial changes.

HNF1B is overexpressed in clear cell epithelial ovarian cancer, and we observed epigenetic silencing in serous epithelial ovarian cancer, leading us to hypothesize that variation in this gene differentially associates with epithelial ovarian cancer risk according to histological subtype. Here we comprehensively map variation in HNF1B with respect to epithelial ovarian cancer risk and analyse DNA methylation and expression profiles across histological subtypes. Different single-nucleotide polymorphisms associate with invasive serous (rs7405776 odds ratio (OR)=1.13, P=3.1 × 10−10) and clear cell (rs11651755 OR=0.77, P=1.6 × 10−8) epithelial ovarian cancer. Risk alleles for the serous subtype associate with higher HNF1B-promoter methylation in these tumours. Unmethylated, expressed HNF1B, primarily present in clear cell tumours, coincides with a CpG island methylator phenotype affecting numerous other promoters throughout the genome. Different variants in HNF1B associate with risk of serous and clear cell epithelial ovarian cancer; DNA methylation and expression patterns are also notably distinct between these subtypes. These findings underscore distinct mechanisms driving different epithelial ovarian cancer histological subtypes. HNF1B is overexpressed in the clear cell subtype and epigenetically silenced in the serous subtype of ovarian cancer. Pearce and colleagues now show that genetic variants in HNF1B are differentially associated with risks of developing these two cancer subtypes, possibly through an epigenetic mechanism.