Factors associated with breast cancer in Puerto Rican women

Divorce and physical health: A three-level meta-analysis

Divorce is often considered a major and stressful life transition. Given that divorcees are overrepresented in primary care and there is a association between individuals' physical health and psychological adjustment, potential post-divorce health problems are of concern. Yet, empirical evidence is lacking on the magnitude of the overall physical health risk after divorce, on possible differences across specific pathologies, and on factors that may increase or reduce this risk. The current meta-analysis addresses these issues. We identified 94 studies including u = 248 relevant effect sizes, based on N = 1,384,507 participants. Generally, compared to married individuals, divorcees showed significantly worse self-reported health (OR = 1.20, [1.08-1.33]), experienced more physical symptoms (OR = 1.34, [1.17-1.53]), and had a higher risk for diabetes (OR = 1.18 [1.05-1.33]), joint pathologies (OR = 1.24, [1.14-1.34]), cardiovascular (OR = 1.24, [1.09-1.41]) and cerebrovascular conditions (OR = 1.31, [1.14-1.51]), and sexually transmitted diseases (OR = 2.48, [1.32-4.64]). However, they had no increased risk of hypertension, hypercholesterolemia, cancer and cancer development, disabilities or limitations, or cognitive pathologies. Nor did divorcees significantly differ from married individuals when aggregating all pathologies to measure overall physical health problems (OR = 1.14, [0.85 to 1.54]). Yet, moderation analyses revealed that being female, unemployed, childless, or having a lower education constitutes a higher risk for overall physical health problems after divorce. The same applied to having a heavy alcohol consumption, lack of exercise, and being overweight. Our meta-analysis shows that divorcees are at heightened risk of certain pathologies, with sexually transmitted diseases as a particular post-divorce hazard. These findings call for more awareness among counsellors and physicians on divorcees' health conditions and the characteristics that make divorcees even more vulnerable to health problems.

Breast Cancer in Patients with Previous Endometriosis Showed Low Aggressive Subtype

Background and Objectives: The association between endometriosis and breast cancer still remains controversial. The aim of this study was to investigate the different subtypes of breast cancer, immunohistochemical markers, hormone receptors, and ki67 proliferation indexes in patients with and without endometriosis and/or adenomyosis. Materials and Methods: All patients with endometriosis and breast cancer were enrolled. Women with endometriosis and breast cancer (Group BC+EN+) were compared to patients with breast cancer without endometriosis (group BC+EN-) and those with endometriosis without breast cancer (group BC-EN+). General population characteristics and histological and immunohistochemical subtypes of breast cancer were compared between groups. Results: Our study included 41 cases affected by both endometriosis and/or adenomyosis and breast cancer (Group BC+EN+) that were matched (1:2) with 82 patients affected only by breast cancer (group BC+EN-) and 82 patients affected only by endometriosis and/or adenomyosis (group BC-EN+). Group BC+EN+ presented a higher percentage of ER receptor expression (83% vs. 70%, p = 0.02), as well as lower values of Ki 67% (15% vs. 24%, p < 0.0001) and HER2+ (9.8% vs. 28%, p = 0.022). These findings were more evident when comparing patients with premenopausal status, while in postmenopausal patients, this difference was no longer significant. Regarding endometriosis, no statistical differences were observed in type or specific localization of the disease among the groups with and without breast cancer. Conclusions: Patients with endometriosis presented lower aggressive breast cancer rates with higher values of ER% and lower values of Ki 67 and HER2neu+. The type and severity of endometriotic diseases seemed not to influence breast cancer occurrence.

Causal effects of genetically predicted endometriosis on breast cancer: a two-sample Mendelian randomization study

This study used a Mendelian randomization (MR) approach to investigate the causal relationship between genetically predicted endometriosis (EMS) and breast cancer risk. A total of 122,977 cases and 105,974 controls were included in the analysis, with gene-level summary data obtained from the Breast Cancer Association Consortium (BCAC). An inverse variance-weighting approach was applied to assess the causal relationship between EMS and breast cancer risk, and weighted median and MR-Egger regression methods were used to evaluate pleiotropy. Results showed a causal relationship between EMS and a decreased risk of overall breast cancer (odds ratio [OR] 0.95; 95% CI 0.90-0.99, p = 0.02). Furthermore, EMS was associated with a lower risk for estrogen receptor (ER)-positive breast cancer in a subgroup analysis based on immunohistochemistry type (OR 0.91; 95% CI 0.86-0.97, p = 0.005). However, there was no causal association between ER-negative breast cancer and survival (OR 1.00; 95% CI 0.94-1.06, p = 0.89). Pleiotropy was not observed. These findings provide evidence of a relationship between EMS and reduced breast cancer risk in invasive breast cancer overall and specific tissue types, and support the results of a previous observational study. Further research is needed to elucidate the mechanisms underlying this association.

The association between endometriosis and risk of endometrial cancer and breast cancer: a meta-analysis

Purpose

Endometriosis (EMS) is confirmed pathophysiologically to be an estrogen-dependent disease, similar to endometrial hyperplasia/cancer and breast cancer. Epidemiological and biological data on endometriosis might explain links between endometriosis and these cancers. We sought to identify the differences in the risk of endometrial cancer and breast cancer between women with and women without endometriosis.

Methods

We searched PubMed, EMBASE, the Cochrane Library, and four Chinese databases (CNKI, VIP, WanFang, CBM) to identify relevant studies published online between January 2011 and March 2021. In our meta-analysis, we used the Newcastle–Ottawa Scale (NOS) to evaluate the design and quality of all studies, and we calculated the pooled risk ratio (RR) using the random model. The Q test and I2 were used to evaluate the degree of heterogeneity of eligible studies. We used funnel plots and Begg’s and Egger’s tests to assess publication bias.

Results

Of the 1369 articles, we finally included 14 cohort studies and seven case–control studies. Data from large cohort and case–control studies indicate that women with endometriosis had an increased risk of both endometrial cancer [RR, 1.662; 95% CI, (1.148–2.407)] and breast cancer [RR, 1.082; 95% CI, (1.001–1.169)].

Conclusion

Endometriosis can increase the risk of endometrial cancer and breast cancer, and women with endometriosis are recommended to receive routine screening in long-term management.

Oral Contraceptive Use and Breast Cancer Risk Assessment: A Systematic Review and Meta-Analysis of Case-Control Studies, 2009-2020

To perform a meta-analysis of case-control studies that addressed the association between oral contraceptive pills (OC) use and breast cancer (BrCa), PubMED (MEDLINE), Embase, and the Cochrane Library were searched to identify case-control studies of OC and BrCa published between 2009 and 2020. We used the DerSimonian-Laird method to compute pooled odds ratios (ORs) and confidence intervals (CIs), and the Mantel-Haenszel test to assess the association between OC use and cancer. Forty-two studies were identified that met the inclusion criteria and we included a total of 110,580 women (30,778 into the BrCa group and 79,802 into the control group, of which 15,722 and 38,334 were using OC, respectively). The conducted meta-analysis showed that the use of OC was associated with a significantly increased risk of BrCa in general, OR = 1.15, 95% CI: 1.01 to 1.31, p = 0.0358. Regarding other risk factors for BrCa, we found that increased risk was associated significantly with early menarche, nulliparous, non-breastfeeding, older age at first parity, postmenopause, obesity, smoking, and family history of BrCa. Despite our conclusion that birth control pills increase the cancer risk being supported by extensive previous studies and meta-analyzes, further confirmation is required.

Genetic Contribution of Endometriosis to the Risk of Developing Hormone-Related Cancers

Endometriosis is a common gynecological disorder that has been associated with endometrial, breast and epithelial ovarian cancers in epidemiological studies. Since complex diseases are a result of multiple environmental and genetic factors, we hypothesized that the biological mechanism underlying their comorbidity might be explained, at least in part, by shared genetics. To assess their potential genetic relationship, we performed a two-sample mendelian randomization (2SMR) analysis on results from public genome-wide association studies (GWAS). This analysis confirmed previously reported genetic pleiotropy between endometriosis and endometrial cancer. We present robust evidence supporting a causal genetic association between endometriosis and ovarian cancer, particularly with the clear cell and endometrioid subtypes. Our study also identified genetic variants that could explain those associations, opening the door to further functional experiments. Overall, this work demonstrates the value of genomic analyses to support epidemiological data, and to identify targets of relevance in multiple disorders.

Endometriosis and cancer: a systematic review and meta-analysis

BACKGROUND

Endometriosis is an often chronic, inflammatory gynaecologic condition affecting 190 million women worldwide. Studies have reported an elevated cancer risk among patients with endometriosis. However, prior research has included methodologic issues that impede valid and robust interpretation.

OBJECTIVE AND RATIONALE

We conducted a meta-analysis of studies investigating the association between endometriosis and cancer risk and analysed the results by methodologic characteristics. We discuss the implications of cancer screening in patients and management challenges faced by clinicians.

SEARCH METHODS

We searched PubMed and Embase databases for eligible studies from inception through 24 October 2019. We included cohort and case-control studies examining the association between endometriosis and cancer risk; cross-sectional studies and case reports were excluded. Publications had to present risk/rate/odds estimates with 95% CI. Random effects meta-analysis was used to estimate summary relative risks (SRR) and CIs. Heterogeneity across studies was assessed by the Q test and I2 statistics, and publication bias using Egger's and Begg's tests. Risk of bias and quality of the included studies were assessed using the risk of bias in non-randomized studies of interventions (ROBINS-I) tool.

OUTCOMES

Forty-nine population-based case-control and cohort studies were included. Twenty-six studies were scored as having a 'serious'/'critical' risk of bias, and the remaining 23 'low'/'moderate'. Cancer-specific analyses showed a positive association between endometriosis and ovarian cancer risk (SRR = 1.93, 95% CI = 1.68-2.22; n = 24 studies) that was strongest for clear cell (SRR = 3.44, 95% CI = 2.82-4.42; n = 5 studies) and endometrioid (SRR = 2.33, 95% CI = 1.82-2.98; n = 5 studies) histotypes (Pheterogeneity < 0.0001), although with significant evidence of both heterogeneity across studies and publication bias (Egger's and Begg's P-values < 0.01). A robust association was observed between endometriosis and thyroid cancer (SRR = 1.39, 95% CI =1.24-1.57; n = 5 studies), a very small association with breast cancer (SRR = 1.04, 95% CI =1.00-1.09; n = 20 studies) and no association with colorectal cancer (SRR = 1.00, 95% CI =0.87-1.16; n = 5 studies). The association with endometrial cancer was not statistically significant (SRR = 1.23, 95% CI =0.97-1.57; n = 17 studies) overall and wholly null when restricted to prospective cohort studies (SRR = 0.99, 95% CI =0.72-1.37; n = 5 studies). The association with cutaneous melanoma was also non-significant (SRR = 1.17, 95% CI =0.97-1.41; n = 7 studies) but increased in magnitude and was statistically significant when restricted to studies with low/moderate risk of bias (SRR = 1.71, 95% CI = 1.24-2.36, n = 2 studies). The most robust finding both in terms of statistical significance and magnitude of effect was an inverse association with cervical cancer (SRR = 0.68, 95% CI =0.56-0.82; n = 4 studies); however, this result has a high potential to reflect heightened access to detection of dysplasia for women who reached an endometriosis diagnosis and is thus likely not causal. Several additional cancer types were explored based on <4 studies.

WIDER IMPLICATIONS

Endometriosis was associated with a higher risk of ovarian and thyroid, and minimally (only 4% greater risk) with breast cancer, and with a lower risk of cervical cancer. However, this meta-analysis confirms that: a majority of studies had severe/critical risk of bias; there is impactful heterogeneity across studies-and for ovarian cancer, publication bias; and causal inference requires temporality, which in many studies was not considered. We discuss the implications of these potential associations from the perspectives of patients with endometriosis, clinicians involved in their care, and scientists investigating their long-term health risks.

Does marital status correlate with the female breast cancer risk? A systematic review and meta-analysis of observational studies

Objective

To investigate that whether an association between marital status and the female breast cancer risk exists.

Methods

The MEDLINE, EMBASE and PsycINFO databases were searched from their inception to July 2019. The Newcastle-Ottawa Scale was used to rate the methodological quality of included studies. Study data were pooled using random-effects meta-analyses to compare the breast cancer risk between unmarried, widowed, divorced or lifelong single women and married women. This study is registered with PROSPERO (number CRD42018112368).

Results

Forty-nine publications were included in the meta-analysis. Compared with married women, unmarried and lifelong single women had an elevated risk of breast cancer, and the pooled ORs of case-control studies were 1.20 (95% CI: 1.07 to 1.35) and 1.24 (95% CI: 1.05 to 1.45), respectively. In the subgroup analyses under these two comparisons, hospital-based estimates and multivariate-adjusted estimates demonstrated a strong association, while population-based estimates and age-adjusted estimates produced nonsignificant results. The pooled OR of cohort studies examining the effect of being a lifelong single woman was 1.10 (95% CI: 1.04 to 1.16). Heterogeneity was moderate to substantial across case-control studies (I²: 46% to 82%), which may be partially explained by differences in geographic regions, publication years and control types. Possible publication bias was indicated by the funnel plot and Egger’s test (P = 0.03).

Conclusions

Marital status may correlate with the risk of developing female breast cancer. However, suboptimal selection of controls, insufficient exploration of confounding effects, inadequate ascertainment of marital status, and possible publication bias may have limited the quality of the available evidence. Overall, conclusions that marital status is an independent risk factor for breast cancer could not be drawn, and further prospective rigorous cohort studies are warranted.

Breast Cancer in a Caribbean Population in Transition: Design and Implementation of the Atabey Population-Based Case-Control Study of Women in the San Juan Metropolitan Area in Puerto Rico

Global breast cancer incidence varies considerably, particularly in comparisons of low- and high-income countries; rates may vary even within regions. Breast cancer rates for Caribbean countries are generally lower than for North America and Europe. Rates in Puerto Rico are in the middle of the range between the highest and the lowest Caribbean countries. Populations in transition, with greater variability in risk factor exposures, provide an important opportunity to better understand breast cancer etiology and as potential sources of variation in rates. Understanding of exposures across the life span can potentially contribute to understanding regional differences in rates. We describe here the design and implementation of a population-based, case-control study in the San Juan Metropolitan Area (SJMA) of Puerto Rico, the Atabey Epidemiology of Breast Cancer Study. We describe steps taken to ensure that the study was culturally appropriate, leveraging the Atabey researchers’ understanding of the culture, local health system, and other required resources to effectively recruit participants. A standardized, in-person interview was developed, with attention to life course events customized to the study population. In order to understand variation in global breast cancer rates, studies customized to the populations outside of North America and Europe are required.

Association between endometriosis and gynecological cancers: a critical review of the literature

BACKGROUND

Endometriosis is one of the most common benign gynecological diseases with an occurrence approximately 10% in reproductive age. Endometriosis has been proposed as a possible precursor of certain ovarian carcinomas such as clear cell and endometrioid ovarian carcinomas. In addition to this pathogenic link, the association with other gynecological tumors and breast cancer has been studied on an epidemiological basis in several studies.

OBJECTIVE

The aim of this review was to critically present the recent published evidence on the association of endometriosis with gynecological cancer, and with a special emphasis on ovarian cancer.

MATERIALS AND METHODS

A search for eligible studies was conducted in three electronic databases, MEDLINE, EMBASE and CINAHL, for original research in humans published in any language.

RESULTS

The present review includes studies examining the association between endometriosis and different types of gynecological cancer (i.e., 25 studies on ovarian cancer, 8 studies on breast cancer, 8 studies on endometrial cancer and 2 studies on cervical cancer).

CONCLUSION

The present literature supports the pre-existing evidence suggesting an association between ovarian cancer and endometriosis and specifically its two histologic subtypes (endometrioid and ovarian clear cell cancer). The most recent population-based epidemiological studies cannot provide a clear association between endometriosis and endometrial, cervical or breast cancer.

Burden of Breast Cancer in the Arab World: Findings from Global Burden of Disease, 2016

Epidemiology of breast cancer in the Arab region is understudied as compared with Western countries. We aimed to examine breast cancer epidemiology in Arab countries from 1990 to 2016. We analyzed the Global Burden of Disease, 2016 data for breast cancer among women in 22 Arab countries. Epidemiological measures including incidence, mortality, and disability adjusted life years (DALYs) were analyzed for breast cancer in women from 1990 to 2016. We also measured the burden of breast cancer stratified by the sociodemographic index (SDI). Our analysis indicates that the incidence of breast cancer in Arab women has risen over the past 26 years, but is still lower than global averages. In 2016, there were 45,980 new cases (28/100,000) and 20,063 deaths (11/100,000) in the region. The burden of breast cancer as estimated by DALYs was also lower than the global rates and tended to increase with increasing SDI. Although some studies have reported that Arab women present with breast cancer at a younger age, our analysis of age-specific rates, indicates that this is not statistically significant. Our findings indicate that a comprehensive plan to improve public awareness, screening, diagnosis, and treatment is required to reduce the growing burden of breast cancer in the Arab world.

Sedentary Behavior and Alcohol Consumption Increase Breast Cancer Risk Regardless of Menopausal Status: A Case-Control Study

Identification of modifiable risk factors for breast cancer is critical for primary prevention of the disease. The aim of this study was to evaluate how certain lifestyle variables modify the chances of developing breast cancer based on menopausal status. A case-control study was performed in a group of 542 women, 197 who were diagnosed with breast cancer and 344 control individuals. The groups were matched by age, body mass index, and menopausal status. Participants were evaluated for level of physical activity, alcohol consumption, smoking habit, weight, height, and waist circumference (WC). A multivariate logistic regression model was used to estimate odds ratios and 95% confidence intervals (95% CI). Regular consumption of alcoholic beverages (2.91, 95% CI 1.58–5.38 and 1.86, 95% CI 1.15–3.03) and sedentary behavior (2.08; 95% CI 1.12–3.85 and 1.81; 95% CI 1.12–2.94) were associated with breast cancer risk in pre- and postmenopausal women, respectively. High WC (3.31, 95% CI 1.45–7.55) was associated with an increased risk of developing breast cancer in premenopausal women. While in postmenopausal women, current smoking (2.43, 95% CI 1.01–5.83) or previous history of smoking (1.90; 95% CI 1.14–3.14) increased the chances of developing breast cancer. Sedentary behavior and current consumption of alcoholic beverages were more likely to increase the risk of developing breast cancer regardless of menopausal status.

MicroRNA Expression Changes in Women with Breast Cancer Stratified by DNA Repair Capacity Levels

Breast cancer (BC) is the most commonly diagnosed cancer in women worldwide and is the leading cause of death among Hispanic women. Previous studies have shown that women with a low DNA repair capacity (DRC), measured through the nucleotide excision repair (NER) pathway, have an increased BC risk. Moreover, we previously reported an association between DRC levels and the expression of the microRNA (miRNA) let-7b in BC patients. MiRNAs can induce genomic instability by affecting the cell's DNA damage response while influencing the cancer pathobiology. The aim of this pilot study is to identify plasma miRNAs related to variations in DRC levels in BC cases. Hypothesis. Our hypothesis consists in testing whether DRC levels can be correlated with miRNA expression levels. Methods. Plasma samples were selected from 56 (27 cases and 29 controls) women recruited as part of our BC cohort. DRC values were measured in lymphocytes using the host-cell reactivation assay. The samples were divided into two categories: low (≤3.8%) and high (>3.8%) DRC levels. MiRNAs were extracted to perform an expression profile analysis. Results. Forty miRNAs were identified to be BC-related (p<0.05, MW), while 18 miRNAs were found to be differentially expressed among BC cases and controls with high and low DRC levels (p<0.05, KW). Among these candidates are miR-299-5p, miR-29b-3p, miR-302c-3p, miR-373-3p, miR-636, miR-331-5p, and miR-597-5p. Correlation analyses revealed that 4 miRNAs were negatively correlated within BC cases with low DRC (p<0.05, Spearman's correlation). Results from multivariate analyses revealed that the clinicopathological characteristics may not have a direct effect on specific miRNA expression. Conclusion. This pilot study provides evidence of four miRNAs that are negatively regulated in BC cases with low DRC levels. Additional studies are needed in order to have a complete framework regarding the overall DRC levels, miRNA expression profiles, and tumor characteristics.

Breast Cancer Research in the Caribbean: Analysis of Reports From 1975 to 2017

Purpose

Breast cancer is among the leading causes of death resulting from cancer in Caribbean women. Studies examining exogenous and genetically predetermined endogenous risk factors are critical to define breast cancer susceptibility in Caribbean women. The purpose of this systematic review is to assess the existing scientific literature in the last 42 years (1975 to 2017) to describe the body of research generated for the population of this region and determine future research directions.

Methods

We selected published research articles using a combination of definite keyword searches in PubMed. Only articles presenting the Caribbean population as the focus of their research objectives were included in this analysis.

Results

Studies on breast cancer in the Caribbean are limited. A majority of publications on Caribbean populations were descriptive, focusing on cancer trends and clinicopathologic factors. High incidence and mortality rates for breast cancer are reported for the region, and there seem to be some differences between countries in the frequency of cases according to age at presentation. A limited number of epidemiologic, behavioral, and genetic and molecular studies were conducted in more recent years.

Conclusion

A regional strategy for cancer registration is needed for the Caribbean to address possible underestimates of breast cancer incidence. Furthermore, behavioral, molecular, genetic, and epidemiologic investigations of breast cancer are critical to address the concerns related to currently described high incidence and mortality rates in the Caribbean.

The risk of extra-ovarian malignancies among women with endometriosis: A systematic literature review and meta-analysis

We conducted a meta-analysis of studies reporting on the risk of extra-ovarian malignancies among women with endometriosis. Summary relative risk (SRR) and 95% confidence intervals (CI) were calculated through random effect models. We explored causes of between-studies heterogeneity and assessed the presence of publication bias. We included 32 studies published between 1989 and 2018. We found an increased risk of endometrial (SRR 1.38, 95%CI 1.10-1.74) and thyroid cancer (SRR 1.38, 95%CI 1.17-1.63), and inverse association with cervical cancer (SRR 0.78, 95%CI 0.60-0.95). No association emerged for breast cancer (SRR 1.04, 95%CI 0.99-1.09) and melanoma (SRR 1.31, 95%CI 0.86-1.96). Between-study heterogeneity was large for breast and endometrial cancer and melanoma. Associations were generally stronger in case-control, cross-sectional, and cohort studies with internal control group, compared to cohort studies with external control group. No indication for publication bias was found. Our conclusions need to be confirmed in properly designed cohort studies with clinical confirmation of endometriosis.

Prevalence of breast and ovarian cancer subtypes in Hispanic populations from Puerto Rico

Background

Previous epidemiological studies aimed at describing characteristics of breast (BC) and ovarian cancer (OC) patients tend to examine Hispanic populations using a mix of individuals that come from ethnically different Hispanic backgrounds. Since most USA cancer statistics do not include cancer data from Puerto Rico (PR), there is a lack of historical and descriptive data analysis for Hispanic women in the island that suffer from these diseases. Therefore, the aim of our study is to provide a comprehensive clinicopathological characterization of BC and OC cases in PR.

Methods

Our study consisted of a longitudinal retrospective review of archived pathology reports at Southern Pathology Services (SPS), which mostly serves southwestern PR, from years 2000–2015. After filtering SPS records with pre-established criteria, tumor samples from 3451 BC and 170 OC cases were used for descriptive statistics and analysis using R program.

Results

In our cohort, the mean age of diagnosis for BC was 60.5 years and 60.3 years for OC. Available data for subtype characterization from BC cases, exhibited an expected subtype distribution that remained stable over time (Luminal A = 68.8%, Luminal B = 9.7%, HER-2 = 6.1% and Triple negative = 15.4%). Additionally, tumor grades distribution varied within different BC subtypes in which the majority of Luminal A tumors were G2 and most Triple negative tumors were G3. For OC cases, available subtype and tumor grade information identified serous histology in 64.71% of all cases and G3 as being the most prevalent tumor grade. Pathology reports revealed that 39.42% of all OC cases were described as late stage, while 50.5% as early stage (by pathological staging).

Conclusion

Our data suggests that OC and BC subtypes distribution in Hispanic populations from PR are in-line with national averages. In a significant number of BC cases, subtype could not be determined due to study limitations, health insurance coverage, or other reasons described here and may constitute a health disparity. Altogether, and despite these gaps, this study represents one of the most complete reviews of BC and OC in PR and provides an opportunity to further study this population separate from other US Hispanic populations.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5077-z) contains supplementary material, which is available to authorized users.

No Evidence for the Pathogenicity of the BRCA2 c.6937 + 594T>G Deep Intronic Variant: A Case-Control Analysis

BACKGROUND

The role of deep intronic variants in hereditary cancer susceptibility has been largely understudied. Previously, the BRCA2 c.6937 + 594T>G variant has been shown to preferentially promote the inclusion of a 95 nucleotide cryptic exon and to introduce a premature termination codon. Our objective was to further assess the pathogenicity of the BRCA2 c.6937 + 594T>G deep intronic variant.

PATIENTS AND METHODS

We examined the association between BRCA2 c.6937 + 594T>G and breast cancer (BC) risk in 464 BC cases and 497 noncancer controls from Puerto Rico.

RESULTS

The overall frequency of the G allele was 2.1% in this population. There was no association between the TG/GG genotypes and BC risk in the uncorrected model and after correcting for confounders. There was only one carrier of the GG genotype. This individual did not have personal or family history of cancer and did not meet the National Comprehensive Cancer Network criteria for hereditary cancer genetic testing.

CONCLUSIONS

Although previous work has demonstrated that the BRCA2 c.6937 + 594T>G variant affects splicing, this association study does not support a pathogenic role for the BRCA2 c.6937 + 594T>G intronic variant in breast and ovarian cancer syndrome susceptibility. Furthermore, it emphasizes the need to take into account multiple diverse populations in association studies for the assessment of variant pathogenicity.

Variability in DNA Repair Capacity Levels among Molecular Breast Cancer Subtypes: Triple Negative Breast Cancer Shows Lowest Repair

Breast cancer (BC) is a heterogeneous disease which many studies have classified in at least four molecular subtypes: Luminal A, Luminal B, HER2-Enriched, and Basal-like (including triple-negative breast cancer, TNBC). These subtypes provide information to stratify patients for better prognostic predictions and treatment selection. Individuals vary in their sensitivities to carcinogens due to differences in their DNA repair capacity (DRC) levels. Although our previous case-control study established low DRC (in terms of NER pathway) as a BC risk factor, we aim to study this effect among the molecular subtypes. Therefore, the objectives of this study include investigating whether DRC varies among molecular subtypes and testing any association regarding DRC. This study comprised 267 recently diagnosed women with BC (cases) and 682 without BC (controls). Our results show a substantial variability in DRC among the molecular subtypes, with TNBC cases (n = 47) having the lowest DRC (p-value < 0.05). Almost 80 percent of BC cases had a DRC below the median (4.3%). Low DRC was strongly associated with the TNBC subtype (OR 7.2; 95% CI 3.3, 15.7). In conclusion, our study provides the first report on the variability among the molecular subtypes and provides a hypothesis based on DRC levels for the poor prognosis of TNBC.

Laparoscopically Confirmed Endometriosis and Breast Cancer in the Nurses' Health Study II

OBJECTIVE

To investigate the association between laparoscopically confirmed endometriosis and the risk of breast cancer. Previous research on endometriosis and breast cancer has reported mixed results.

METHODS

Our prospective cohort study included 116,430 women from the Nurses' Health Study II cohort followed from 1989 until 2013. Our primary analysis investigated the association between self-reported laparoscopically confirmed endometriosis and the risk of breast cancer. Breast cancer diagnosis was verified through medical records. Multivariable adjusted Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). Breast cancer was further classified by menopausal status at the time of diagnosis and tumor hormone receptor status verified through tissue microarrays when available and medical records.

RESULTS

At baseline, 5,389 (5%) women reported laparoscopically confirmed endometriosis. Over 24 years of follow-up, 4,979 (3%) incident breast cancer cases were diagnosed. Women with endometriosis were not at higher risk for overall (adjusted HR 0.96, 95% CI 0.88-1.06), premenopausal (adjusted HR 1.05, 95% CI 0.89-1.23), or postmenopausal breast cancer (adjusted HR 0.93, 95% CI 0.80-1.07). However, associations varied by tumor hormone receptor status (P value, test for heterogeneity: .001), although women with endometriosis were not at increased risk of estrogen- and progesterone receptor-positive (ER+/PR+) tumors (adjusted HR 1.00, 95% CI 0.87-1.14) or ER- and PR- tumors (adjusted HR 0.90, 95% CI 0.67-1.21). Women with endometriosis reported 2.87 ER+/PR- breast cancer cases per 10,000 person-years compared with women without endometriosis (1.32/10,000 person-years), which resulted in nearly a twofold increased risk of ER+/PR- breast cancers (adjusted HR 1.90, 95% CI 1.44-2.50).

CONCLUSION

Endometriosis was not found to be associated with overall risk of breast cancer in this study; however, endometriosis was significantly associated with an increased risk of ER+/PR- breast tumors, which should be interpreted cautiously.

Breastfeeding Mode and Risk of Breast Cancer: A Dose-Response Meta-Analysis

BACKGROUND

Breastfeeding reduces women's risk of breast cancer. Since exclusive breastfeeding has a stronger hormonal effect, it could theoretically result in a greater reduction in breast cancer risk than any breastfeeding mode. No meta-analysis has examined breast cancer risk by breastfeeding mode. Research aim: The authors conducted a meta-analysis for breast cancer risk in parous women who breastfed exclusively or in any mode versus parous women who formula fed their infants, and they estimated the summary dose-response association by the accumulated duration of any breastfeeding mode.

METHODS

A systematic review of studies published between 2005 and 2015 analyzing breastfeeding and breast cancer risk in women was conducted in PubMed and EBSCOhost. A meta-analysis ( n = 65 studies) with fixed effects (or random effects, if heterogeneity existed) was carried out stratified by breastfeeding mode and menopausal and parity status. A summary dose-response association was estimated using the generalized least-squares method.

RESULTS

The summary relative risk (SRR) for breast cancer in parous women who breastfed exclusively was 0.72, 95% confidence interval (CI) [0.58, 0.90], versus parous women who had never breastfed. For parous women who breastfed in any mode, the SRR was lower in both premenopausal women (0.86, 95% CI [0.80, 0.93]) and postmenopausal women (0.89, 95% CI [0.83, 0.95]). There was no heterogeneity or publication bias. There is weak evidence of a difference between exclusive and any breastfeeding mode ( p = .08). The summary dose-response curve was nonlinear ( p < .001).

CONCLUSION

Exclusive breastfeeding among parous women reduces the risk of breast cancer compared with parous women who do not breastfeed exclusively.

Social determinants of breast cancer in the Caribbean: a systematic review

BACKGROUND

Breast cancer is the leading cause of cancer deaths among women in the Caribbean and accounts for >1 million disability adjusted life years. Little is known about the social inequalities of this disease in the Caribbean. In support of the Rio Political Declaration on addressing health inequities, this article presents a systematic review of evidence on the distribution, by social determinants, of breast cancer risk factors, frequency, and adverse outcomes in Caribbean women.

METHODS

MEDLINE, EMBASE, SciELO, CINAHL, CUMED, LILACS, and IBECS were searched for observational studies reporting associations between social determinants and breast cancer risk factors, frequency, or outcomes. Based on the PROGRESS-plus checklist, we considered 8 social determinant groups for 14 breast cancer endpoints, which totalled to 189 possible ways ('relationship groups') to explore the role of social determinants on breast cancer. Studies with >50 participants conducted in Caribbean territories between 2004 and 2014 were eligible for inclusion. The review was conducted according to STROBE and PRISMA guidelines and results were planned as a narrative synthesis, with meta-analysis if possible.

RESULTS

Thirty-four articles were included from 5,190 screened citations. From these included studies, 75 inequality relationships were reported examining 30 distinct relationship groups, leaving 84% of relationship groups unexplored. Most inequality relationships were reported for risk factors, particularly alcohol and overweight/obesity which generally showed a positive relationship with indicators of lower socioeconomic position. Evidence for breast cancer frequency and outcomes was scarce. Unmarried women tended to have a higher likelihood of being diagnosed with breast cancer when compared to married women. While no association was observed between breast cancer frequency and ethnicity, mortality from breast cancer was shown to be slightly higher among Asian-Indian compared to African-descent populations in Trinidad (OR 1.2, 95% CI 1.1-1.4) and Guyana (OR 1.3, 95% CI 1.0-1.6).

CONCLUSION

Study quantity, quality, and variability in outcomes and reporting limited the synthesis of evidence on the role of social determinants on breast cancer in the Caribbean. This report represents important current evidence on the region, and can guide future research priorities for better describing and understanding of Caribbean breast cancer inequalities.

A prospective study of endometriosis and risk of benign breast disease

PURPOSE

Given the altered hormonal and inflammatory environment of women with endometriosis, several studies have suggested a positive association between endometriosis and breast cancer, although findings have been mixed. This study investigates the relationship between endometriosis and benign breast disease (BBD), benign lesions that are associated with an increased risk of breast cancer.

METHODS

Among women in the Nurses' Health Study II followed from 1991-2003 (n = 76,393), we investigated the association between laparoscopically confirmed endometriosis and biopsy-confirmed BBD. Cox proportional hazard models, adjusted for a priori potential confounding factors, were used to calculate hazard ratios (HR) and 95 % confidence intervals (CI). Across follow-up, 2011 BBD biopsies were collected and centrally reviewed by study pathologists (nonproliferative = 675, proliferative = 1336). Effect modification by infertility history and use of screening mammography was investigated.

RESULTS

Endometriosis was associated with a modest increased risk of biopsy-confirmed BBD in crude and multivariable adjusted models (HR 1.20, 95 % CI 1.00-1.43). When evaluating subtypes of BBD, we did not see different associations for nonproliferative or proliferative BBD lesions, as endometriosis was associated with a modest increased risk for both (HR nonproliferative 1.15, 95 % CI 0.84-1.57; HR proliferative 1.22, 95 % CI 0.98-1.52). The association between endometriosis and proliferative BBD appeared strongest among women who had ever experienced infertility (HR 1.50, 95 % CI 1.12-2.03; P value, test for heterogeneity = 0.05). Sensitivity analyses investigating screening behaviors between those with and without endometriosis did not significantly alter results.

CONCLUSION

Endometriosis was associated with a modest increased risk of both proliferative and nonproliferative BBD, although future work should replicate this novel finding.

Endometriosis and mammographic density measurements in the Nurses' Health Study II

PURPOSE

Endometriosis and mammographic density have been hypothesized to be influenced by sex steroid hormonal exposures in adolescence and early adulthood. We investigated the association between endometriosis and mammographic density, a consistent and independent risk factor for breast cancer.

METHODS

We conducted a cross-sectional analysis among 1,581 pre- and postmenopausal women not previously diagnosed with breast cancer in the Nurses' Health Study II cohort. We measured average percent mammographic density and absolute dense and non-dense breast area using a validated computer-assisted method. Multivariable linear regression was used to estimate the association between endometriosis and mammographic density among pre- and postmenopausal women separately.

RESULTS

Among premenopausal women, average percent mammographic density was 43.1 % among women with endometriosis (n = 91) and 40.5 % among women without endometriosis (n = 1,150). Endometriosis was not associated significantly with mammographic density among premenopausal (% difference = 2.00 percentage points 95 % CI -1.33, 5.33) or among postmenopausal women (% difference = -0.89 percentage points 95 % CI -5.10, 3.33). Among premenopausal women, there was heterogeneity by BMI at age 18 (p value = 0.003), with a suggested association among those who were lean at age 18 (BMI < 20.6 kg/m(2)) (% difference = 3.74 percentage points 95 % CI -0.29, 7.78).

CONCLUSION

Endometriosis was not found to be associated with overall measurements of mammographic density.

Estrogen Receptor Expression Is Associated with DNA Repair Capacity in Breast Cancer

Estrogen-receptor-positive (ER+) tumors employ complex signaling that engages in crosstalk with multiple pathways through genomic and non-genomic regulation. A greater understanding of these pathways is important for developing improved biomarkers that can better determine treatment choices, risk of recurrence and cancer progression. Deficiencies in DNA repair capacity (DRC) is a hallmark of breast cancer (BC); therefore, in this work we tested whether ER signaling influences DRC. We analyzed the association between ER positivity (% receptor activation) and DRC in 270 BC patients, then further stratified our analysis by HER2 receptor status. Our results show that among HER2 negative, the likelihood of having low DRC values among ER- women is 1.92 (95% CI: 1.03, 3.57) times the likelihood of having low DRC values among ER+ women, even adjusting for different potential confounders (p<0.05); however, a contrary pattern was observed among HER2 positives women. In conclusion, there is an association between DRC levels and ER status, and this association is modified by HER2 receptor status. Adding a DNA repair capacity test to hormone receptor testing may provide new information on defective DNA repair phenotypes, which could better stratify BC patients who have ER+ tumors. ER+/HER2- tumors are heterogeneous, incompletely defined, and clinically challenging to treat; the addition of a DRC test could better characterize and classify these patients as well as help clinicians select optimal therapies, which could improve outcomes and reduce recurrences.

Endometriosis and breast cancer: A survey of the epidemiological studies

Endometriosis is a chronic gynecological disease with a wide spectrum of clinical manifestations that affects approximately 10% of women of reproductive age. Recent reviews have demonstrated the connection between endometriosis and breast cancer, which represents the most frequently diagnosed female cancer and the most common cause of cancer-related mortality among women worldwide. The aim of this study was to conduct a survey of available published epidemiological studies indicating the association between endometriosis and breast cancer, and simultaneously to categorize the results based on the strength of the association, with the intention of the critical evaluation of the existing data. We performed a rigorous search of the PubMed/Medline database, using the key words 'endometriosis' and 'breast cancer' for all studies published in the English language until September 2015. We found 4 retrospective cohort studies, 4 case-control studies and 3 case-cohort studies that demonstrated a notable risk for developing breast cancer among women with endometriosis. By contrast, we also found 5 case-control studies, 1 prospective cohort study, 1 case-cohort study and 1 cross-sectional study that demonstrated a negative association between endometriosis and breast cancer. In conclusion, as regards the clarification of a 'robust' or 'weak' association between endometriosis and breast cancer, no definite conclusions could be drawn, due to the limited number of studies and the limitations of each of these studies. New well-designed, prospective cohort or randomized control trials with long-term follow-up are warranted in order to provide evidence-based clinical recommendations for proper counseling, screening and treatment strategies for patients with endometriosis, and hence to improve public health.

Breastfeeding and maternal health outcomes: a systematic review and meta-analysis

AIM

To evaluate the effect of breastfeeding on long-term (breast carcinoma, ovarian carcinoma, osteoporosis and type 2 diabetes mellitus) and short-term (lactational amenorrhoea, postpartum depression, postpartum weight change) maternal health outcomes.

METHODS

A systematic literature search was conducted in PubMed, Cochrane Library and CABI databases. Outcome estimates of odds ratios or relative risks or standardised mean differences were pooled. In cases of heterogeneity, subgroup analysis and meta-regression were explored.

RESULTS

Breastfeeding >12 months was associated with reduced risk of breast and ovarian carcinoma by 26% and 37%, respectively. No conclusive evidence of an association between breastfeeding and bone mineral density was found. Breastfeeding was associated with 32% lower risk of type 2 diabetes. Exclusive breastfeeding and predominant breastfeeding were associated with longer duration of amenorrhoea. Shorter duration of breastfeeding was associated with higher risk of postpartum depression. Evidence suggesting an association of breastfeeding with postpartum weight change was lacking.

CONCLUSION

This review supports the hypothesis that breastfeeding is protective against breast and ovarian carcinoma, and exclusive breastfeeding and predominant breastfeeding increase the duration of lactational amenorrhoea. There is evidence that breastfeeding reduces the risk of type 2 diabetes. However, an association between breastfeeding and bone mineral density or maternal depression or postpartum weight change was not evident.

Association of endometriosis and breast cancer: mini review of the literature

BACKGROUND

Endometriosis is a common, estrogen-dependent, gynecological disease, which is defined as the presence of endometrial tissue outside the uterine cavity. Current data have associated endometriosis with specific malignancies, including ovarian and breast cancer.

PURPOSE

The purpose of our study is to summarize and present published literature providing evidence regarding the possible relationship between endometriosis and breast cancer.

METHODS

Pubmed and Scopus databases were searched systematically for studies that sought to identify a potential association of endometriosis and breast cancer. 15 relevant articles were retrieved and included in the present review.

RESULTS

A small number of observational studies have shown a correlation of endometriosis and breast cancer. Other studies found that the risk of breast cancer increases with age. The scenario of an early interruption of the inflammatory process, derived from endometriosis, by oophorectomy and a possible consequent decrease in the risk of breast cancer has also been proposed. The hypothesis that both conditions could be related through common mutations on BRAC1 and BRAC2 genes has also been investigated.

CONCLUSION

The available published evidence is inconclusive. Further studies are needed to evaluate the association of endometriosis and breast cancer and the possible pathogenetic pathways that relate the two disorders.

Association between breastfeeding and breast cancer risk: evidence from a meta-analysis

BACKGROUND

Quantification of the association between breastfeeding and breast cancer risk is still conflicting. Therefore, we conducted a meta-analysis to summarize the evidence from epidemiological studies of breastfeeding with the risk of breast cancer.

MATERIALS AND METHODS

Pertinent studies were identified by a search of PubMed between January 1, 2008 and July 31, 2014. The random-effect model was used. Sensitivity analysis, subgroups analysis, and publication bias were conducted.

RESULTS

Twenty-four articles with 27 studies involving 13,907 breast cancer cases were included in this meta-analysis. Pooled results suggested that breastfeeding was inversely [corrected] associated with the risk of breast cancer. The summary relative risk (RR) of breast cancer for the ever compared with never categories of breastfeeding was 0.613 (95% confidence interval [CI], 0.442-0.850). An inverse association was also found for the longest compared with the shortest categories of breastfeeding with the risk of breast cancer (RR=0.471; 95% CI, 0.368-0.602). No evidence of publication bias was found.

CONCLUSIONS

Findings from this meta-analysis suggest that breastfeeding, particularly a longer duration of breastfeeding, was inversely associated with risk of breast cancer.

Breast cancer risk after full-term pregnancies among African women from Nigeria, Cameroon, and Uganda

BACKGROUND

The breast cancer (BC) risk profiles of African women differ significantly from those of women of European ancestry. African women are younger at the age of onset and tend to have high parity. The purpose of this study was to examine the relationship between full‐term pregnancy (FTP) and the risk of BC.

METHODS

A case‐control study was conducted among 1995 women with invasive BC and 2631 controls in Nigeria, Cameroon, and Uganda. Odds ratios (ORs) for individual ages at FTP according to the time since delivery were calculated and adjusted for confounders. A fitted spline model was used to assess the impact of the number of pregnancies on BC risk.

RESULTS

In comparison with a nulliparous woman, a parous woman with her first FTP at 20 years showed an OR of 0.76 (95% confidence interval [CI], 0.57‐0.99) for developing BC in the following 5 years. Ten years later, this risk was 0.76 (95% CI, 0.58‐0.99) and 0.76 (95% CI, 0.58‐0.98) for women aged 25 and 30 years, respectively. Similarly, a parous woman with 1 pregnancy had an OR of 0.69 (95% CI, 0.49‐0.96), whereas the OR was 0.66 (95% CI, 0.48‐0.91) with 2 or 5 pregnancies and 0.67 (95% CI, 0.47‐0.94) with 6 pregnancies in comparison with nulliparous women.

CONCLUSIONS

In contrast to studies in women of European ancestry, this study showed no transient increase in the risk of developing BC after FTP among African women. Further studies are needed to examine the impact of reproductive factors on early‐onset BC in African women. Cancer 2015;121:2237–2243. © 2015 American Cancer Society.

There is no transient increase in breast cancer risk after a full‐term pregnancy among African women. The protection conferred by pregnancy occurs immediately after the first full‐term pregnancy regardless of the age at that pregnancy and the number of pregnancies.

Differential promoter methylation of kinesin family member 1a in plasma is associated with breast cancer and DNA repair capacity

Methylation alterations of CpG islands, CpG island shores and first exons are key events in the formation and progression of human cancer, and an increasing number of differentially methylated regions and genes have been identified in breast cancer. Recent studies of the breast cancer methylome using deep sequencing and microarray platforms are providing a novel insight on the different roles aberrant methylation plays in molecular subtypes of breast cancer. Accumulating evidence from a subset of studies suggests that promoter methylation of tumor-suppressor genes associated with breast cancer can be quantified in circulating DNA. However, there is a paucity of studies that examine the combined presence of genetic and epigenetic alterations associated with breast cancer using blood-based assays. Dysregulation of DNA repair capacity (DRC) is a genetic risk factor for breast cancer that has been measured in lymphocytes. We isolated plasma DNA from 340 participants in a breast cancer case control project to study promoter methylation levels of five genes previously shown to be associated with breast cancer in frozen tissue and in cell line DNA: MAL, KIF1A, FKBP4, VGF and OGDHL. Methylation of at least one gene was found in 49% of the cases compared to 20% of the controls. Three of the four genes had receiver characteristic operator curve values of ≥0.50: MAL (0.64), KIF1A (0.51) and OGDHL (0.53). KIF1A promoter methylation was associated with breast cancer and inversely associated with DRC. This is the first evidence of a significant association between genetic and epigenetic alterations in breast cancer using blood-based tests. The potential diagnostic utility of these biomarkers and their relevance for breast cancer risk prediction should be examined in larger cohorts.