CYP17 genotype is associated with short menstrual cycles, early oral contraceptive use and BRCA mutation status in young healthy women

The Menstrual Cycle and Risk of Breast Cancer: A Review

Cyclic hormonal stimulation of the breast tissue plays a significant role in breast carcinogenesis. Current risk factor models do not include direct measures of cycle characteristics although the effects of possible surrogates of cycle activity such as age at menarche and menopause, parity, and nursing time have been investigated. Future risk models should also include menstrual cycle length, regularity, number of cycles before first full-term pregnancy, and life-time number of cycles. New risk factor models for pre- and postmenopausal breast cancer are proposed here. Furthermore, there is a need for more long-term, prospective studies investigating menstrual cycle characteristics as data currently available are primarily retrospective and collected at one time-point only.

Modulation of estrogen synthesis and metabolism by phytoestrogens in vitro and the implications for women's health

Phytoestrogens are increasingly used as dietary supplements due to their suggested health promoting properties, but also by women for breast enhancement and relief of menopausal symptoms. Generally, phytoestrogens are considered to exert estrogenic activity via estrogen receptors (ERs), but they may also affect estrogen synthesis and metabolism locally in breast, endometrial and ovarian tissues. Considering that accurate regulation of local hormone levels is crucial for normal physiology, it is not surprising that interference with hormonal synthesis and metabolism is associated with a wide variety of women's health problems, varying from altered menstrual cycle to hormone-dependent cancers. Yet, studies on phytoestrogens have mainly focused on ER-mediated effects of soy-derived phytoestrogens, with less attention paid to steroid synthesis and metabolism or other phytoestrogens. This review aims to evaluate the potential of phytoestrogens to modulate local estrogen levels and the implications for women's health. For that, an overview is provided of the effects of commonly used phytoestrogens, i.e. 8-prenylnaringenin, biochanin A, daidzein, genistein, naringenin, resveratrol and quercetin, on estrogen synthesizing and metabolizing enzymes in vitro. The potential implications for women's health are assessed by comparing the in vitro effect concentrations with blood concentrations that can be found after intake of these phytoestrogens. Based on this evaluation, it can be concluded that high-dose supplements with phytoestrogens might affect breast and endometrial health or fertility in women via the modulation of steroid hormone levels. However, more data regarding the tissue levels of phytoestrogens and effect data from dedicated, tissue-specific assays are needed for a better understanding of potential risks. At least until more certainty regarding the safety has been established, especially young women would better avoid using supplements containing high doses of phytoestrogens.

Associations of physical activity and inactivity with body tissue composition among healthy Polish women and women after mastectomy

The aim of the study is to determine the relationship between physical activity and body composition among healthy women and women who have had mastectomy. This is in order to establish whether physical activity of women after breast cancer treatment improves composition and distribution of body mass components to a degree which will allow to achieve the body composition of healthy women. Research material consists of anthropometric measurements (body height, weight) of women and bioelectric impedance analysis (BIA) of body composition (using Akern - BIA 101 composition analyzer). Intensity of activity was assessed using the Physical Activity International Questionnaire. The sample consisted of 76 healthy women (active 44.74%, inactive 55.26%) and 70 females after mastectomy (54.29% and 45.71%, respectively). Mean chronological age of women after mastectomy was 53.40 years, SD=7.55, and of the healthy ones 52.38 years SD=11.01). A significant difference in body composition was noted among active and inactive women after mastectomy; namely the active females had lower weight (by approximately 12 kg), body mass index (BMI), level of fat mass (by approximately 8%) and (by approximately 5%) total body water. The active healthy women had 6% less fat mass, almost 4% more body water and 6% more fat free mass. Programmed physical activity undertaken by women after mastectomy is recommended and produces good results in the form of reduction of excessive body fat tissue. Through physical activity these women are able to achieve the same level of fat mass as healthy women.

Menstrual factors, reproductive factors and lung cancer risk: a meta-analysis

BACKGROUND AND OBJECTIVE

Epidemiological studies have suggested that menstrual and reproductive factors may influence lung cancer risk, but the results are controversial. We therefore carried out a meta-analysis aiming to examine the associations of lung cancer in women with menstrual and reproductive factors.

METHODS

Relevant studies were searched from PubMed database, CNKI, WANFANG DATA and VIP INFORMATION up to January 2012, with no language restrictions. References listed from selected papers were also reviewed. We included studies that reported the estimates of relative risks (RRs) with 95% confidence intervals (CIs) for the association between menstrual and reproductive factors and lung cancer risk. The pooled RRs were calculated after the heterogeneity test with the software Stata 11, and publication bias and sensitivity were evaluated at the same time.

RESULTS

Twenty-five articles, representing 24 independent studies, were included in this meta-analysis. Older age at menarche in North America women (RR=0.83; 95%CI: 0.73-0.94) was associated with a significant decreased risk of lung cancer. Longer length of menstrual cycle was also associated with decreased lung cancer risk (RR=0.72; 95%CI: 0.57-0.90). Other exposures were not significantly associated.

CONCLUSIONS

Our analysis provides evidence of the hypothesis that female sex hormones influence the risk of lung cancer in women, yet additional studies are warranted to extend this finding and to clarify the underlying mechanisms.

Association between a common CYP17A1 haplotype and anxiety in female anorexia nervosa

Dehydroepiandrosterone (DHEA), the main brain neurosteroid, has been implicated in various psychiatric disorders especially those including gender differences. We studied genetic variability in the DHEA-producing enzyme CYP17A1 in relation to anorexia nervosa (AN) susceptibility and AN-related co-morbidities. We performed analysis of 100 Israeli AN family trios accounting for CYP17A1 haplotypes characteristic of populations of European origin and studied genotype-phenotype relationships using correlation analyses and transmission disequilibrium test. Although our analysis revealed no evidence of association between CYP17A1 and AN per se, it revealed an association between specific CYP17A1 haplotypes and AN co-morbidity, specifically anxiety. We found that a common CYP17A1 haplotype (H1) was associated with higher anxiety in AN patients (Clinical Global Impression; CGI-anxiety ≥4). Moreover, H1 homozygotes were at higher risk for expressing high CGI-anxiety levels (OR = 3.7), and H1 was preferentially transmitted to AN patients with high CGI-anxiety levels (P = 0. 037). We suggest that CYP17A1 H1 haplotype may contribute to genetic predisposition to higher CGI-anxiety levels in AN patients and that this predisposition may be mediated by reduced CYP17A1 enzymatic activity and corresponding lower DHEA production.

Rare missense P450c17 (CYP17A1) mutation in exon 1 as a cause of 46,XY disorder of sexual development: implications of breast tissue 'unresponsiveness' despite adequate estradiol substitution

17-Alpha-hydroxylase/17,20-lyase deficiency (17OHD) is a rare autosomal recessive disorder resulting from mutations in the CYP17A1 gene, leading to impaired adrenal and gonadal steroidogenesis. We report for the first time a patient with a missense mutation at codon 96 (R96Q) of the CYP17A1 gene causing a 46,XY disorder of sexual development (DSD) that additionally showed lack of breast development despite highly dosed estradiol replacement treatment. This phenomenon could be attributed to irreversible breast tissue alterations following high serum progesterone levels.

Genetic variation in CYP17A1 and pancreatic cancer in a population-based case-control study in the San Francisco Bay Area, California

Pancreatic cancer is the fourth leading cause of cancer-related death in men and women in the United States. Reproductive factors and steroid hormones have been suspected risk factors for many years, but the results from epidemiologic studies to date have been inconclusive. CYP17A1 encodes cytochrome P450c17alpha, an enzyme with 17alpha-hydroxylase and 17,20-lyase activities in estradiol biosynthesis. A polymorphism in the 5'UTR promoter region of CYP17A1-34T/C(A1/A2) has been associated with circulating estrogens in premenopausal women and with susceptibility to breast, prostate, and endometrial cancer. Questionnaire data and germline DNA collected in a San Francisco Bay Area population-based case-control study of pancreatic cancer (cases = 532, controls = 1701) were used to conduct analyses of pancreatic cancer susceptibility related to the CYP17A1 polymorphism and whether effects associated with smoking and reproductive risk factors were modified by this polymorphism. Mass spectrometry- and TaqMan-based methods were used to determine CYP17A1 genotypes in DNA samples from 308 cases and 964 controls. Results showed that carriers of the A2 allele (vs. A1/A1) were significantly less likely to have been diagnosed with pancreatic cancer (A1/A2, adjusted odds ratio (OR) = 0.77, 95% confidence interval (CI) = 0.58-1.0; A2/A2, OR = 0.63, 95%CI = 0.42-0.93; p-trend = 0.01). ORs for CYP17A1 genotypes did not differ by sex, but the observed inverse association was stronger in postmenopausal women. ORs for smoking and pancreatic cancer were not modified by CYP17A1 genotype. Our results suggest that the CYP17A1 A2 allele may be associated with a lower risk of pancreatic cancer in both men and women.

Chemopreventive actions by enterolactone and 13 VIOXX-related lactone derivatives in H295R human adrenocortical carcinoma cells

Cytochrome P450c17 (CYP17) has been linked to various hormone-related diseases, including breast cancer, thus being a potential target for cancer chemoprevention. We studied the naturally occurring phytochemical enterolactone (ENL) and 13 VIOXX-related lactone derivatives (CRI-1 to CRI-13) for their effects on CYP17 activity and expression and on cell cycle status in the human H295R adrenocorticocarcinoma cell line. Of the tested compounds, only CRI-3, -7, -10 and -12 showed to be inhibitors of CYP17 activity in H295R cells. This inhibition was not due to decreased mRNA expression, but was apparently caused by post-translational modification of the CYP17 enzyme. The MAPK kinase (MEK) inhibitor PD98059 induced CYP17 activity by 24%, while co-incubation of the CRI-s with PD98059, reduced CYP17 activity even further than the reduction caused by the CRI-s alone. In addition, CRI-3, -7, -10 and -12 arrested the cell cycle in the G(2)/M phase. The structure-activity similarities of the CRI-s with known micro-tubule binding agents strongly suggest that cell cycle arrest is a result of interaction with tubulin. We conclude that the proposed cancer chemopreventive actions of ENL are not mediated through interaction with CYP17 or cell cycle status. Of the VIOXX-related lactone derivatives, CRI-7 could prove useful in the prevention of hormone-dependent cancers, such as breast cancer, since in vitro it shows low cytotoxicity, it is a potent inhibitor of CYP17 activity and strong inducer of cell cycle arrest.

Endocrinology of the wild and mutant BRCA1 gene and types of hormonal carcinogenesis

Information related to the BRCA1 gene has increasingly become a subject for analysis by endocrinologists. For example, it is hard to dismiss the fact that, in BRCA1 mutation carriers, tumors develop predominantly in such estrogen-dependent organs as the mammary glands and ovaries but not in the endometrium. Another characteristic feature is that although BRCA1 mutants and knock-downs are unable to inhibit the transcriptional activity of estrogen receptor-alpha, in BRCA1 mutation carriers breast cancers are often estrogen receptor-negative and originate from the basal rather than the luminal epithelium. The latter, together with other data, suggests that BRCA1-positive breast neoplasms could be considered to be a consequence of the genotoxic variant of hormonal carcinogenesis (that is, associated with DNA damaging rather then with pure hormonal/physiological properties of hormones or their derivatives). Of indisputable significance are the data demonstrating that knocking down of the BRCA1 gene is accompanied by aromatase overexpression and the abolishment of IGF-1 receptor expression suppression, thus increasing both steroid and insulin signaling. Importantly, the endocrine-genotoxic 'liberation' found upon transfer from the wild-type to the mutant BRCA1 provides grounds to regard BRCA1 as a modulator of endocrine-genotoxic switching (predominantly into a direction of DNA-damaging hormone effects) and also to ask whether this is a property of only this or some other tumor suppressor's.