Anti‐breast cancer potential of SS1020, a novel antiestrogen lacking estrogenic and genotoxic actions

Long‐term treatment with tamoxifen (TAM) increases the risk of developing endometrial cancer in women. Several antiestrogens developed in last decades have been discontinued from clinical testing because of their undesirable effects on the uterus. To avoid such serious side‐effect while increasing the drug's anti‐breast cancer potential, new triphenylethylene antiestrogens, 2E‐3‐{4‐[(E)‐4‐chloro‐1‐(4‐hydroxyphenyl)‐2‐phenylbut‐1‐enyl]‐phenyl} acrylic acid (SS1020) and 2E‐3‐{4‐[(Z)‐4‐chloro‐1,2‐diphenylbut‐1‐enyl]phenyl}acrylic acid (SS1010), were designed as safer alternatives. Unlike TAM, SS1020 does not present significant uterotrophic potential in rats; in contrast, SS1010, a compound removing a 4‐OH moiety from SS1020, represented weak uterotrophic activity. The structurally related compounds 4‐hydroxytamoxifen, toremifene, ospemifene, raloxifene (RAL) and GW5638 all have uterotrophic activity. In addition, SS1020 and SS1010 exhibit no genotoxic activity to damage hepatic DNA in rats. Therefore, SS1020 was selected as a safer antiestrogen candidate and used for evaluating the antitumor potential in animals. At the human equivalent doses of TAM, SS1020 had antitumor potential much higher than that of TAM, RAL and GW5638 against 7,12‐dimethylbenz(a)anthracene‐induced mammary carcinoma in rats. The growth of human MCF‐7 breast cancer xenograft implanted into athymic nude mice was also effectively suppressed by SS1020. SS1020, lacking estrogenic and genotoxic actions and having strong antitumor potency superior to that of TAM and RAL, could be a safer alternative for breast cancer therapy and prevention.     

An overview of menopausal oestrogen-progestin hormone therapy and breast cancer risk

Results from the Women's Health Initiative (WHI) trial support findings from observational studies that oestrogen-progestin therapy (EPT) use is associated with an increase in breast cancer risk. We conducted a meta-analysis using EPT-specific results from the Collaborative Group on Hormonal Factors in Breast Cancer (CGHFBC) pooled analysis and studies published since that report to obtain an overview of EPT use and breast cancer risk. We also assessed risk by histologic subtype of breast cancer, by schedule of the progestin component of EPT, and by recency of use. We estimate that overall, EPT results in a 7.6% increase in breast cancer risk per year of use. The risk was statistically significantly lower in US studies than in European studies - 5.2 vs 7.9%. There was a significantly higher risk for continuous-combined than for sequential EPT use in Scandinavian studies where much higher total doses of progestin were used in continuous-combined than in sequential EPT. We observed no overall difference in risk for lobular vs ductal carcinoma but did observe a slightly higher risk for current vs past EPT use.     

Forty-year trends in menopausal hormone therapy use and breast cancer incidence among postmenopausal black and white women

After reports from the Women's Health Initiative randomized trial evaluating estrogen plus progestin, there was a sudden, substantial, and sustained decrease in all categories of menopausal hormone therapy, and the first reduction in age-adjusted breast cancer incidence in more than 20 years was seen in 2003-2004 among US women 50 years of age or older. Subsequent trends in breast cancer incidence have been described, but most reports have not focused on the postmenopausal age group or fully engaged the potential influence of reduced hormone therapy on breast cancer incidence trends by race/ethnicity. To address this gap, this commentary examines trends for annual age-adjusted breast cancer incidence over a 40-year period from 1975 to 2015 for white and black women on the basis of findings from the Surveillance, Epidemiology, and End Results 9 registries. Overall, the sharp decline in breast cancer incidence seen in 2003-2004 was followed in the subsequent decade by a continued low breast cancer incidence plateau in white women that has largely persisted. In contrast, a new discordance between breast cancer incidence trends in black and white women has emerged. In the 2005-2015 decade, a sustained increase in breast cancer incidence in black women has resulted in annual incidence rates comparable, for the first time, to those in white women. This commentary explores the hypothesis that the over-decade-long and discordant changes in breast cancer incidence rates in postmenopausal black and white women are, to a large extent, associated with changes in hormone therapy use in these 2 groups.     

Body size and the risk of ovarian cancer by hormone therapy use in the California Teachers Study cohort

Objective  

To investigate whether obesity and hormone therapy (HT) are associated with ovarian cancer risk among women in the California Teachers Study cohort.     

Oral contraceptives, hormone replacement therapy and the risk of colorectal cancer.

The relationship between oral contraceptives (OCs), menopausal hormone replacement therapy (HRT) and the risk of colorectal cancer was investigated in a case-control study conducted in northern Italy between 1985 and 1992 on 709 women with incident colorectal cancer and 992 controls admitted to hospital for a wide spectrum of acute, non-neoplastic, non-digestive tract, non-hormone-related disorders. A reduced risk of colorectal cancer was observed in women who had ever used OCs [multivariate odds ratio (OR) = 0.58; 95% confidence interval (CI): 0.36-0.92]. The OR was 0.52 (95% CI 0.27-1.02) for use over 2 years. For women ever using HRT, the multivariate OR was 0.40 (95% CI 0.25-0.66). The risk was inversely related to duration of use, with ORs of 0.46 for 2 years or less and 0.25 for more than 2 years of use. No consistent pattern of trends was observed with time since first or last use. This study provides further evidence that OC and HRT do not increase, and possibly decrease, the risk of colorectal cancer. These results, if confirmed, would have important implications for the ultimate risk-benefit assessment of female hormone preparations.     

Postmenopausal breast cancer risk and interactions between body mass index,menopausal hormone therapy use,and vitamin D supplementation: Evidence from the E3N cohort

Experimental studies suggest protective effects of vitamin D on breast carcinogenesis, but epidemiological evidence is not conclusive. Body mass index (BMI) has been shown to modulate the effect of supplementation on the vitamin D status, but its potential influence on the relationship with breast cancer risk has been little studied. We investigated a potential interaction between BMI and vitamin D supplementation on breast cancer risk while considering an already reported interaction between vitamin D supplementation and menopausal hormone therapy (MHT) use. Vitamin D supplementation was prospectively investigated in 57,403 postmenopausal women from the French E3N cohort including 2,482 incident breast cancer cases diagnosed between 1995 and 2008. Multivariable hazard ratios (HR) for primary invasive breast cancer and 95% confidence intervals (CI) were estimated using Cox models. Among MHT ever users, vitamin D supplementation was associated with decreased breast cancer risk, similarly across BMI strata (P_homogeneity = 0.83). Among MHT never users, ever vitamin D supplementation was associated with increased postmenopausal breast cancer risk in women with baseline BMI <25 kg/m² (HR = 1.51, 95% CI: 1.13, 2.02), but not in women with higher BMI (0.98, 95% CI: 0.62, 1.56), P_homogeneity = 0.12. In conclusion, our findings suggest that vitamin D supplementation may reduce the excess breast cancer risk in MHT users, but draw attention on a potential risk in postmenopausal women not exposed to high exogenous or endogenous hormones, i.e. non‐overweight MHT‐non users, especially in the present context of increasing vitamin D supplement use and decreasing MHT use.     

The association of polymorphisms in hormone metabolism pathway genes, menopausal hormone therapy, and breast cancer risk: a nested case-control study in the California Teachers Study cohort

Introduction

The female sex steroids estrogen and progesterone are important in breast cancer etiology. It therefore seems plausible that variation in genes involved in metabolism of these hormones may affect breast cancer risk, and that these associations may vary depending on menopausal status and use of hormone therapy.

Methods

We conducted a nested case-control study of breast cancer in the California Teachers Study cohort. We analyzed 317 tagging single nucleotide polymorphisms (SNPs) in 24 hormone pathway genes in 2746 non-Hispanic white women: 1351 cases and 1395 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by fitting conditional logistic regression models using all women or subgroups of women defined by menopausal status and hormone therapy use. P values were adjusted for multiple correlated tests (P_ACT).

Results

The strongest associations were observed for SNPs in SLCO1B1, a solute carrier organic anion transporter gene, which transports estradiol-17β-glucuronide and estrone-3-sulfate from the blood into hepatocytes. Ten of 38 tagging SNPs of SLCO1B1 showed significant associations with postmenopausal breast cancer risk; 5 SNPs (rs11045777, rs11045773, rs16923519, rs4149057, rs11045884) remained statistically significant after adjusting for multiple testing within this gene (P_ACT = 0.019-0.046). In postmenopausal women who were using combined estrogen-progestin therapy (EPT) at cohort enrollment, the OR of breast cancer was 2.31 (95% CI = 1.47-3.62) per minor allele of rs4149013 in SLCO1B1 (P = 0.0003; within-gene P_ACT = 0.002; overall P_ACT = 0.023). SNPs in other hormone pathway genes evaluated in this study were not associated with breast cancer risk in premenopausal or postmenopausal women.

Conclusions

We found evidence that genetic variation in SLCO1B1 is associated with breast cancer risk in postmenopausal women, particularly among those using EPT.     

Reproductive factors,menopausal hormone therapy,and risk of non-Hodgkin,diffuse large B-cell and follicular lymphomas: a UK case–control study

Background  

Most non-Hodgkin lymphoma (NHL) subtypes occur more among men than women. Since sex hormones may influence immune function, female hormones may be involved. To investigate the relationship between NHL subtypes and reproductive factors, findings from a UK population-based case–control study (1998–2003) are presented.     

Recent diet and breast cancer risk: the California Teachers Study (USA)

Objective: The impact, if any, on breast cancer risk of modifying adult dietary intake is an area of much interest. We take the opportunity to address the relationship between recent adult diet and breast cancer risk during the first two years of follow-up of the large California Teachers Study cohort. Methods: Of the 111,526 at-risk cohort members who resided in California and completed a baseline dietary assessment, 711 were diagnosed with invasive breast cancer after joining the cohort and before January 1998. Average daily nutrient intake was computed based on a food-frequency questionnaire assessing usual dietary intake and portion size during the year prior to joining the cohort. Incident breast cancers were identified through the California Cancer Registry and follow-up for death and confirmation of continued California residence utilized a variety of data sources. Cox proportional hazards models were used to calculate relative hazards. Results: The following components of recent dietary intake were not associated with breast cancer risk: energy, fat, fiber, antioxidant vitamins, and phytoestrogens. Only recent average alcohol consumption of 20 or more grams per day (approximately two or more glasses of wine) was associated with increased risk (RR = 1.5, 95% CI: 1.2–2.0 compared to non-drinkers; p _trend = 0.01 across quintiles). Conclusion: With the exception of alcohol consumption, this study provides no evidence that recent macro- or micronutrient composition of adult diet is likely to have a direct effect on breast cancer risk. Some reduction of alcohol consumption among those consuming more than one drink per day may be beneficial.     

Body size and the risk of endometrial cancer by hormone therapy use in postmenopausal women in the California Teachers Study cohort

Objective  

To investigate whether hormone therapy (HT) and obesity are associated with endometrial cancer risk among postmenopausal women in the California Teachers Study cohort.     

Polymorphisms in genes of the steroid receptor superfamily modify postmenopausal breast cancer risk associated with menopausal hormone therapy

Menopausal hormone therapy (HT) is associated with increased breast cancer risk among postmenopausal women. Nuclear receptors are involved in steroid hormone‐ and xenobiotic‐mediated signal transduction playing a crucial role in regulating gene expression. Therefore, variations within these genes may influence HT‐associated breast cancer risk. We investigated 3,149 postmenopausal breast cancer patients and 5,489 controls from 2 German population‐based case‐control studies. Thirty‐three polymorphisms selected on the basis of known or putative functional relevance located in ESR1, ESR2, PGR, PXR and AR were genotyped. Conditional logistic regression was used to assess multiplicative statistical interaction between polymorphisms and duration of estrogen–progestagen therapy and of estrogen monotherapy with regard to breast cancer risk assuming log‐additive and codominant modes of inheritance. We observed an increased risk for women carrying short AR_(CAG) alleles of <22 repeats associated with combined estrogen–progestagen therapy compared with those with long alleles (≥22 repeats) (p_interaction = 0.03). Additionally, risk associated with combination therapy use was significantly modified by 2 PXR polymorphisms with reduction of risk effects in carriers of the minor PXR_rs6785049_G and PXR_rs1054191_A alleles (p_interaction = 0.04 and 0.05, respectively). Variants in both ESR1 and ESR2 modified risk associated with estrogen monotherapy use. Higher risk were observed in homozygotes for the major ESR1_rs910416_T allele (p_interaction < 0.01) and in homozygotes for the minor ESR2_rs1271572_T, major ESR2_rs4986938_G and minor ESR2_rs928554_G alleles (p_interaction = 0.02, 0.05, 0.02, respectively). Risk effect modification by ESR1_rs910416 and AR_(CAG)n polymorphisms remained significant after correction for multiple testing. We conclude that genetic variants in nuclear receptor genes may modify HT‐associated postmenopausal breast cancer risk.     

Long-term and baseline recreational physical activity and risk of endometrial cancer: the California Teachers Study

Background:

Physical activity may be associated with decreasing endometrial cancer risk; it remains unclear whether the association is modified by body size.

Methods:

Among 93 888 eligible California Teachers Study participants, 976 were diagnosed with incident endometrial cancer between 1995–1996 and 2007. Cox proportional hazards regression methods were used to estimate relative risks (RRs) and 95% confidence intervals (CIs) for endometrial cancer associated with long-term (high school through age 54 years) and baseline (3 years prior to joining the cohort) strenuous and moderate recreational physical activity, overall and by body size.

Results:

Increased baseline strenuous recreational physical activity was associated with decreased endometrial cancer risk (P_trend=0.006) with approximately 25% lower risk among women exercising >3 h per week per year than among those exercising <1/2 h per week per year (RR, 0.76; 95% CI, 0.63–0.92). This inverse association was observed among overweight/obese women (body mass index ≥25 kg m⁻²; P_trend=0.006), but not among thinner women (P_trend=0.12). Baseline moderate activity was associated with lower risk among overweight/obese women.

Conclusion:

Increasing physical activity, particularly strenuous activity, may be a lifestyle change that overweight and obese women can implement to reduce their endometrial cancer risk.     

The role of menopausal hormone therapy in women with or at risk of ovarian and breast cancers: Misconceptions and current directions

For women who are candidates for menopausal hormone therapy (MHT), estrogen can provide relief from symptomatic menopause, decrease rates of chronic illnesses, and improve health-related quality of life. However, confusion surrounds the evidence regarding the impact of exogenous estrogen and progesterone on the breast and ovary. Available data regarding the risks of MHT (estrogen and/or progestin) related to the development of breast and ovarian cancer are often inconsistent or incomplete. Modern molecular and genetic techniques have improved our understanding of the heterogeneity of breast and ovarian cancer. This enhanced understanding of the disease has impacted our understanding of carcinogenesis. Treatment options have evolved to be more targeted toward hormonal therapy for certain subtypes of disease, whereas cytotoxic chemotherapy remains the standard for other histological and molecular subtypes. The role of MHT in the breast and ovarian cancer survivor, as well as women who are at high risk for the development of hereditary breast and ovarian cancer, remains controversial despite evidence that this treatment can improve quality of life and survival outcomes. Through this article, we examine the evidence for and against the use of MHT with a focus on women who have or are at high risk for breast and ovarian cancer.     

Postmenopausal hormone therapy and breast cancer risk: the Multiethnic Cohort

Epidemiological studies indicate that menopausal estrogen-progestin therapy (EPT) use is associated with an increase in breast cancer risk. Further data are needed on whether this association varies by specific prognostic factors and ethnicity. We conducted a cohort study among 55,371 African-American, Native Hawaiian, Japanese-American, Latina and White postmenopausal women aged 45-75 years old in the Multiethnic Cohort Study (MEC). A total of 1,615 incident invasive breast cancer cases were identified over an average of 7.3 years. Adjusted relative risks (RRs) were computed for the various forms of hormone therapy (HT). Assuming current users continued HT use to the end of follow-up, current EPT use was associated with a 29% increased risk of breast cancer per 5 years of use (95% confidence interval (CI) = 23-35%), and current estrogen therapy (ET) use with a 10% increase in risk per 5 years of use (95% CI = 5-16%). These figures increased to only a very small extent when we adjusted for the estimated 3% of such women who stop HT use per year of follow-up. EPT and ET use were associated with greater risk among leaner women, but the increase in risk with EPT use was still very evident in women with BMI > or =30 kg/m(2). Current EPT use was associated with increased risk for ER+/PR+, ER+/PR- and ER-/PR- tumors. There was little difference in risk by stage of disease or histologic subtype. The increase with EPT use was clearly seen in all 5 ethnic groups; and the increase with ET in 4 of the 5 groups.     

Oral contraceptives and the risk of endometrial cancer

The relationship between the use of combbination oral contraceptives (OCs) and the risk of endometrial cancer was assessed in a case-control study conducted in the Swiss Canton of Vaud between 1 January 1988 and 31 July 1990. Subjects included 122 women aged 75 or less with histologically confirmed endometrial cancer, and 309 control women in hospital for acute conditions unrelated to OC use. Overall, 14 percent of cases and 27 percent of controls had ever used OCs, corresponding to a multivariate relative risk (RR) of 0.5 (95 percent confidence interval [CI]: 0.3. 0.8). The risk of endometrial cancer was found to be related inversely to duration of OC use: RR=1.0 for less than two years of OC use; 0.5 for two to five years; and 0.3 (95 percent CI: 0.1, 0.7) for more than five years. The protection appeared greater within 20 years since last use, and the RR rose to 0.8 after 20 or more years since last use; numbers are too small, however, for reliable inference from these subanalyses. No significant interaction or modifying effect was observed with other major factors related to endometrial cancer, including parity, body mass index, estrogen replacement therapy, and cigarette smoking. While this study provides further evidence for the protective effect of OCs against risk of endometrial cancer, the relationship requires continued evaluation to assess the long-term implications and public health impact of OC use.This work was supported in part by the Swiss National Science Foundation Grant No. 3.866-0.88.     

Inverse associations of dietary fiber and menopausal hormone therapy with colorectal cancer risk in the Multiethnic Cohort Study

In the Multiethnic Cohort Study, we previously reported that dietary fiber intake was inversely associated with colorectal cancer risk in men only. In women, the inverse relationship was weaker and appeared to be confounded by menopausal hormone therapy (MHT). We re‐examined this observation with a greatly increased power. Using Cox proportional hazards models, we analyzed data from 187,674 participants with 4,692 cases identified during a mean follow‐up period of 16 years. In multivariable‐adjusted models, dietary fiber intake was inversely associated with colorectal cancer risk in both sexes: HR = 0.73, 95% CI: 0.61–0.89 for highest vs. lowest quintile, p_trend = 0.0020 in men and HR = 0.76, 95% CI: 0.62–0.91, p_trend = 0.0067 in women. Postmenopausal women who ever used MHT had a 19% lower risk of colorectal cancer (95% CI: 0.74–0.89) compared with MHT never users. In a joint analysis of dietary fiber and MHT, dietary fiber intake was associated with a lower colorectal cancer risk in MHT never users (HR = 0.75, 95% CI: 0.59–0.95, p_trend = 0.045), but did not appear to further decrease the colorectal cancer risk of MHT ever users (p_trend = 0.11). Our results support the overall protective roles of dietary fiber and MHT against colorectal cancer and suggest that dietary fiber may not lower risk further among women who ever used MHT. If confirmed, these results would suggest that MHT and dietary fiber may share overlapping mechanisms in protecting against colorectal cancer.     

Oral contraceptives,menopausal estrogens,and the risk of breast cancer: A case-control study in greece

In a hospital-based case-control study in Athens, we examined the association between the use of oral contraceptives and menopausal estrogens and the risk of breast cancer. Eight hundred and twenty patients with confirmed breast cancer were compared with 795 orthopedic patient controls and 753 healthy visitor controls, matched to the cases by age and interviewer. The data were modeled through logistic regression, controlling for demographic and reproductive variables. Odds ratio patterns were similar for the 2 control series, which were therefore combined to increase precision of the estimates. The risk for breast cancer was not elevated among ever-users of oral contraceptives, regardless of age at diagnosis of breast cancer, duration of oral contraceptive use or timing of use in relation to first full-term pregnancy. Among peri- and post-menopausal women who ever used menopausal estrogens, with never-users as the baseline, a statistically significant elevated odds ratio was found after adjusting for age at menopause. © 1995 Wiley-Liss, Inc.     

Oral contraceptives and prognosis of breast cancer in women aged 35 to 50

Among 193 breast cancer patients aged 35-50 years, there was no appreciable difference in the extent of disease at diagnosis between 53 oral contraceptive (OC) users and 140 OC non-users. There was no overall significant difference between OC users and non-users for either the disease-free interval (P = .81), metastatic period (P = .41), or survival (P = .79), either alone or when adjusted for stage or family history. The survival rate of OC users of more than 2 years was similar to the survival rate of those of shorter duration (P = .36). Patients who began the use of OC 10 years or more before diagnosis showed no statistical difference from those beginning more recently (P = .69). Recent OC users within a year of diagnosis had a survival rate similar to that of other users who stopped the pills at least 1 year prior to diagnosis (P = .14). Our data suggest no adverse effects of OC use on the prognosis of breast cancer, regardless of duration of use, latency or recency period.