Effects of lifestyle and single nucleotide polymorphisms on breast cancer risk: a case-control study in Japanese women

Systematic Review and Meta-Analysis of Lifestyle and Reproductive Factors Associated with Risk of Breast Cancer in Asian Women

BACKGROUND

Assessing breast cancer risks from lifestyle and reproductive factors is critical for developing population-specific risk prediction tools. However, limited studies have evaluated these risks in recent Asian birth cohorts.

METHODS

We systematically reviewed articles published from January 2010 to December 2023, examining breast cancer risk factors in Asian women. Data were described narratively, estimates pooled, and prevalence and attributable proportions compared across Asian populations.

RESULTS

Of the 128 studies reviewed, 103 reported adjusted effect sizes for meta-analysis. Lifestyle and reproductive factors were predictive of breast cancer risk in Asian women, with varying impacts on premenopausal and postmenopausal women. Relative risks were similar within Asian populations and in comparison to European populations, except for menarche, menopause, and hormone receptor therapy. However, risk factor distributions differed across populations. While alcohol intake (21%) and oral contraceptive use (20%) emerged as the most attributable modifiable risk factors in Europeans, passive smoking (24%) and higher BMI (17%, ≥24 kg/m2 among postmenopausal women) were predominant in Asians.

CONCLUSIONS

Our study shows that while the effects of lifestyle and reproductive breast cancer risk factors are largely similar across different populations, their distributions vary.

IMPACT

Our analysis underscores the importance of considering population-specific risk factor distributions when developing risk prediction tools for Asian populations.

Seven-plus hours of daily sedentary time and the subsequent risk of breast cancer: Japan Multi-Institutional Collaborative Cohort Study

This study aimed to investigate the association between daily sedentary time and the risk of breast cancer (BC) in a large Japanese population. The participants were 36,023 women aged 35-69 years from the Japan Multi-Institutional Collaborative Cohort Study. Cox proportional hazards analysis was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for BC incidence in relation to time spent sedentarily (categorical variables: <7 and ≥7 hours/day [h/d]). Additionally, the associations of BC incidence to the joint effect of sedentary time with each component of physical activity, such as leisure-time metabolic equivalents (METs), frequency of leisure-time physical activity, and daily walking time, were examined. During 315,189 person-years of follow-up, 554 incident cases of BC were identified. When compared to participants who spent <7 h/d sedentary, those who spent ≥7 h/d sedentary have a significantly higher risk of BC (HR, 1.36; 95% CI, 1.07-1.71). The corresponding HRs among participants who spent ≥7 h/d sedentary with more physical activity, such as ≥1 h/d for leisure-time METs, ≥3 days/week of leisure-time physical activity, and ≥1 h/d of daily walking were 1.58 (95% CI, 1.11-2.25), 1.77 (95% CI, 1.20-2.61), and 1.42 (95% CI, 1.10-1.83), respectively, compared with those who spent <7 h/d sedentary. This study found that spending ≥7 h/d of sedentary time is associated with the risk of BC. Neither leisure-time physical activity nor walking had a BC-preventive effect in those with ≥7 h/d of sedentary time.

Occupational risk factors and breast cancer in Beijing, China: a hospital-based case-control study

INTRODUCTION

Studies on the association between breast cancer and occupational hazards are limited, especially in China. This is the first study to explore the relationship between breast cancer and occupational hazards in Beijing, China.

DESIGN

A hospital-based case-control study.

SETTING

Eight local hospitals in Beijing, China.

PARTICIPANTS

A total of 973 female participants, comprising 495 cases and 478 controls, were recruited in our study. We identified patients who underwent diagnosis for breast cancer at one of the eight local hospitals in Beijing between 1 January 2015 and 31 December 2019; controls were individuals randomly matched from the same hospital where the cases were confirmed.

MAIN OUTCOME AND MEASURE

Least absolute shrinkage and selection operator (LASSO) regression was used to estimate the occupational risk factors associated with breast cancer, including night shift work history and work posture.

RESULTS

In the case group, the breast cancer type was mainly invasive, which accounted for 85.66% of all the breast cancer patients. Five risk factors were included in the final LASSO model, including body mass index (BMI), marital status, menopause, night shift work history and work posture. Furthermore, these risk factors were considered for multivariate logistic regression, and the analyses suggested that the risk of breast cancer was significantly associated with higher BMI (≥28.0 kg/m², OR: 2.85, 95% CI: 1.29 to 6.30); married status: married (OR: 2.67, 95% CI: 1.28 to 5.56) or divorced (OR: 4.51, 95% CI: 1.84 to 11.07); menopause (OR: 6.89, 95% CI: 5.07 to 9.36); night shift work (OR: 1.53, 95% CI: 1.11 to 2.11); and maximum standing or walking, and minimal sitting (OR: 1.80, 95% CI: 1.19 to 2.73).

CONCLUSION

Breast cancer is associated with occupational risk factors. Night shift work, especially in a standing posture, can increase the incidence of breast cancer in women in Beijing, China.

Does coffee, tea and caffeine consumption reduce the risk of incident breast cancer? A systematic review and network meta-analysis

OBJECTIVE

We aimed to evaluate the association between coffee and/or tea consumption and breast cancer (BC) risk among premenopausal and postmenopausal women and to conduct a network meta-analysis.

DESIGN

Systematic review and network meta-analysis.

SETTING

We conducted a systematic review of electronic publications in the last 30 years to identify case-control studies or prospective cohort studies that evaluated the effects of coffee and tea intake.

RESULTS

Forty-five studies that included more than 3 323 288 participants were eligible for analysis. Network meta-analysis was performed to determine the effects of coffee and/or tea consumption on reducing BC risk in a dose-dependent manner and differences in coffee/tea type, menopause status, hormone receptor and the BMI in subgroup and meta-regression analyses. According to the first pairwise meta-analysis, low-dose coffee intake and high-dose tea intake may exhibit efficacy in preventing ER(estrogen receptor)- BC, particularly in postmenopausal women. Then, we performed another pairwise and network meta-analysis and determined that the recommended daily doses were 2-3 cups/d of coffee or ≥5 cups/d of tea, which contained a high concentration of caffeine, particularly in postmenopausal women.

CONCLUSIONS

Coffee and tea consumption is not associated with a reduction in the overall BC risk in postmenopausal women and is associated with a potentially lower risk of ER- BC. And the highest recommended dose is 2-3 cups of coffee/d or ≥5 cups of tea/d. They are potentially useful dietary protectants for preventing BC.

Abemaciclib in combination with endocrine therapy for East Asian patients with HR+, HER2- advanced breast cancer: MONARCH 2 & 3 trials

This post hoc analysis of MONARCH 2 and MONARCH 3 assesses the efficacy, safety, and pharmacokinetics (PK) of abemaciclib in combination with endocrine therapy (ET) in East Asian patients with hormone receptor positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer. MONARCH 2 and MONARCH 3 are global, randomized, double-blind, phase 3 studies of abemaciclib/placebo + fulvestrant and abemaciclib/placebo + nonsteroidal aromatase inhibitor (NSAI, anastrozole or letrozole), respectively. The East Asian population comprised 212 (31.7%) of the 669 intent-to-treat (ITT) population in the MONARCH 2 trial and 144 (29.2%) of the 493 ITT patients in the MONARCH 3 trial. In the East Asian population, median progression-free survival (PFS) was significantly prolonged in the abemaciclib arm compared with placebo in both MONARCH 2 (hazard ratio [HR], 0.520; 95% confidence interval [CI], 0.362 to 0.747; P < .001; median: 21.2 vs 11.6 months) and MONARCH 3 (HR, 0.326; 95% CI, 0.200 to 0.531, P < .001; median: not reached vs 12.82 months). Diarrhea (MONARCH 2: 90%; MONARCH 3: 88%) and neutropenia (MONARCH 2: 68%; MONARCH 3: 58%) were the most frequent adverse events observed in the East Asian populations. Abemaciclib exposures and PK were similar in East Asians and the non-East Asian populations of both trials. Abemaciclib in combination with ET in the East Asian populations of MONARCH 2 and MONARCH 3 provided consistent results with the ITT populations, demonstrating improvements in efficacy with generally tolerable safety profiles for patients with HR+, HER2- advanced breast cancer.

Higher Mushroom Consumption Is Associated with Lower Risk of Cancer: A Systematic Review and Meta-Analysis of Observational Studies

Mushrooms are rich in bioactive compounds. The potential health benefits associated with mushroom intake have gained recent research attention. We thus conducted a systematic review and meta-analysis to assess the association between mushroom intake and risk of cancer at any site. We searched MEDLINE, Web of Science, and Cochrane Library to identify relevant studies on mushroom intake and cancer published from 1 January, 1966, up to 31 October, 2020. Observational studies (n = 17) with RRs, HRs, or ORs and 95% CIs of cancer risk for ≥2 categories of mushroom intake were eligible for the present study. Random-effects meta-analyses were conducted. Higher mushroom consumption was associated with lower risk of total cancer (pooled RR for the highest compared with the lowest consumption groups: 0.66; 95% CI: 0.55, 0.78; n = 17). Higher mushroom consumption was also associated with lower risk of breast cancer (pooled RR for the highest compared with the lowest consumption groups: 0.65; 95% CI: 0.52, 0.81; n = 10) and nonbreast cancer (pooled RR for the highest compared with the lowest consumption groups: 0.80; 95% CI: 0.66, 0.97; n = 13). When site-specific cancers were examined, a significant association with mushroom consumption was only observed with breast cancer; this could be due to the small number of studies that were conducted with other cancers. There was evidence of a significant nonlinear dose-response association between mushroom consumption and the risk of total cancer (P-nonlinearity = 0.001; n = 7). Limitations included the potential for recall and selection bias in case-control designs, which comprised 11 out of the 17 studies included in this meta-analysis, and the large variation in the adjustment factors used in the final models from each study. The association between higher mushroom consumption and lower risk of cancer, particularly breast cancer, may indicate a potential protective role for mushrooms in the diet.

Relationships of physical and breast cancer phenotypes with three single-nucleotide polymorphisms (rs2046210, rs3757318, and rs3803662) associated with breast cancer risk in Japanese women

BACKGROUND

Recent genome-wide association studies have shown that many single-nucleotide polymorphisms (SNPs) are associated with breast cancer risk. However, it is often unclear how these SNPs are related to breast cancer. Analysis of associations between SNPs and phenotypes may be important for determining mechanisms of action, including carcinogenesis.

METHODS

In previous case-control studies, we found three SNPs (rs2046210, rs3757318, and rs3573318) associated with breast cancer risk in Japanese women. Among these SNPs, two (rs2046210 and rs3757318) are located at 6q25.1, in proximity to the estrogen receptor 1 gene (ESR1). Using data from these studies, we examined associations between factors related to breast cancer risk, such as height, weight, and breast density, and the three SNPs in cases and controls. We also investigated whether the SNPs correlated with breast cancer features, such as estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor type-2 (HER2) status, and clinical stage.

RESULTS

There was a significant difference in mean height between risk and non-risk allele carriers for rs2046210 (156.0 ± 5.8 vs. 154.3 ± 5.5 cm, p = 0.002), and rs3757318 (155.8 ± 5.7 vs. 154.7 ± 5.6 cm, p = 0.035) in cases, but no significant associations between height and these SNPs in controls. There was also a significant difference in breast density between risk and non-risk allele carriers for rs2046210 (p = 0.040) and rs3757318 (p = 0.044) in cases. rs2046210 and rs3757318 risk allele carriers tended to have higher breast density in all subjects and in controls. In cases, rs3757318 risk allele carriers were also significantly more likely to be ER-negative compared to non-risk allele carriers (ER-positive rate: 77% vs. 84%, p = 0.036).

CONCLUSIONS

SNPs rs2046210 and rs3757318, which are associated with breast cancer risk in Japanese women, were significantly associated with height and high breast density, and this association was particularly strong in those with breast cancer. These findings suggest that SNPs in the ESR1 gene region affect phenotypes such as height and breast density.

A Review of the Epidemiology of Breast Cancer in Asia: Focus on Risk Factors

Background and Aim:

Breast cancer is the most prevalent cancer in women. To date, regional differences in breast cancer risk factors have not been identified. The aim of our review was to gain a better understanding of the role of risk factors in women with breast cancer in Asia.

Methods:

We conducted a PubMed search on 15 March 2016, for journal articles published in English between 2011 and 2016, which reported data for human subjects in Asia with a diagnosis of breast cancer. Search terms included breast neoplasm, epidemiology, Asia, prevalence, incidence, risk and cost of illness. Studies of any design were included, except for review articles and meta-analyses, which were excluded to avoid duplication of data. No exclusions were made based on breast cancer treatment. We reported the results using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines.

Results:

A total of 776 abstracts were retrieved. After screening against the eligibility criteria, 562 abstracts were excluded. The remaining 214 abstracts, which were published between 2013 and 2015, were included in this review. Results were summarized and reported under three categories: incidence, prevalence or outcomes for breast cancer in Asia; modifiable risk factors; and non-modifiable risk factors. We found that the increased risk of breast cancer among participants from Asia was associated with older age, family history of breast cancer, early menarche, late menopause, high body mass index, being obese or overweight, exposure to tobacco smoke, and high dietary intake of fats or fatty foods. In contrast, intake of dietary fruits, vegetables, and plant- and soy-based products was associated with a decreased breast cancer risk. While based on limited data, when compared to women from the United States, women from Asia had a decreased risk of breast cancer.

Conclusions:

This review of 214 abstracts of studies in Asia, published between 2013 and 2015, confirmed the relevance of known non-modifiable and modifiable risk factors for women with breast cancer.

SNHG1 Long Noncoding RNA is Potentially Up-Regulated in Colorectal Adenocarcinoma

Colorectal cancer (CRC) is one of the most common types of cancer worldwide. However, the molecular mechanisms involved in CRC initiation and progression is remained to be unknown. It seems that lncRNAs, as the main and lengthy functional transcripts of the genome, have important roles in different cancers such as CRC. CRC-related lncRNAs are reported to be involved in diverse molecular processes such as metastasis, invasion, cell proliferation, and apoptosis. This study was aimed to analyse the expression level of lncRNA SNHG1 in colorectal adenocarcinoma and normal tissues. We performed an in silico analysis on a large cohort and confirmed the results by experimental analysis of clinical samples through real-time PCR. Our findings demonstrated that that SNHG1 is potentially overexpressed in tumor tissues compared with adjacent normal tissues. The expression level of SNHG1 was shown to be potentially associated with clinicopathological features of tumors. The current study suggests the potential role of SNHG1 in colon cancer progression.

Green tea (Camellia sinensis) for the prevention of cancer

BACKGROUND

This review is an update of a previously published review in the Cochrane Database of Systematic Reviews (2009, Issue 3).Tea is one of the most commonly consumed beverages worldwide. Teas from the plant Camellia sinensis can be grouped into green, black and oolong tea, and drinking habits vary cross-culturally. C sinensis contains polyphenols, one subgroup being catechins. Catechins are powerful antioxidants, and laboratory studies have suggested that these compounds may inhibit cancer cell proliferation. Some experimental and nonexperimental epidemiological studies have suggested that green tea may have cancer-preventative effects.

OBJECTIVES

To assess possible associations between green tea consumption and the risk of cancer incidence and mortality as primary outcomes, and safety data and quality of life as secondary outcomes.

SEARCH METHODS

We searched eligible studies up to January 2019 in CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and reference lists of previous reviews and included studies.

SELECTION CRITERIA

We included all epidemiological studies, experimental (i.e. randomised controlled trials (RCTs)) and nonexperimental (non-randomised studies, i.e. observational studies with both cohort and case-control design) that investigated the association of green tea consumption with cancer risk or quality of life, or both.

DATA COLLECTION AND ANALYSIS

Two or more review authors independently applied the study criteria, extracted data and assessed methodological quality of studies. We summarised the results according to diagnosis of cancer type.

MAIN RESULTS

In this review update, we included in total 142 completed studies (11 experimental and 131 nonexperimental) and two ongoing studies. This is an additional 10 experimental and 85 nonexperimental studies from those included in the previous version of the review. Eleven experimental studies allocated a total of 1795 participants to either green tea extract or placebo, all demonstrating an overall high methodological quality based on 'Risk of bias' assessment. For incident prostate cancer, the summary risk ratio (RR) in the green tea-supplemented participants was 0.50 (95% confidence interval (CI) 0.18 to 1.36), based on three studies and involving 201 participants (low-certainty evidence). The summary RR for gynaecological cancer was 1.50 (95% CI 0.41 to 5.48; 2 studies, 1157 participants; low-certainty evidence). No evidence of effect of non-melanoma skin cancer emerged (summary RR 1.00, 95% CI 0.06 to 15.92; 1 study, 1075 participants; low-certainty evidence). In addition, adverse effects of green tea extract intake were reported, including gastrointestinal disorders, elevation of liver enzymes, and, more rarely, insomnia, raised blood pressure and skin/subcutaneous reactions. Consumption of green tea extracts induced a slight improvement in quality of life, compared with placebo, based on three experimental studies. In nonexperimental studies, we included over 1,100,000 participants from 46 cohort studies and 85 case-control studies, which were on average of intermediate to high methodological quality based on Newcastle-Ottawa Scale 'Risk of bias' assessment. When comparing the highest intake of green tea with the lowest, we found a lower overall cancer incidence (summary RR 0.83, 95% CI 0.65 to 1.07), based on three studies, involving 52,479 participants (low-certainty evidence). Conversely, we found no association between green tea consumption and cancer-related mortality (summary RR 0.99, 95% CI 0.91 to 1.07), based on eight studies and 504,366 participants (low-certainty evidence). For most of the site-specific cancers we observed a decreased RR in the highest category of green tea consumption compared with the lowest one. After stratifying the analysis according to study design, we found strongly conflicting results for some cancer sites: oesophageal, prostate and urinary tract cancer, and leukaemia showed an increased RR in cohort studies and a decreased RR or no difference in case-control studies.

AUTHORS' CONCLUSIONS

Overall, findings from experimental and nonexperimental epidemiological studies yielded inconsistent results, thus providing limited evidence for the beneficial effect of green tea consumption on the overall risk of cancer or on specific cancer sites. Some evidence of a beneficial effect of green tea at some cancer sites emerged from the RCTs and from case-control studies, but their methodological limitations, such as the low number and size of the studies, and the inconsistencies with the results of cohort studies, limit the interpretability of the RR estimates. The studies also indicated the occurrence of several side effects associated with high intakes of green tea. In addition, the majority of included studies were carried out in Asian populations characterised by a high intake of green tea, thus limiting the generalisability of the findings to other populations. Well conducted and adequately powered RCTs would be needed to draw conclusions on the possible beneficial effects of green tea consumption on cancer risk.

Variants in the 8q24 region associated with risk of breast cancer: Systematic research synopsis and meta-analysis

Breast cancer is a molecularly heterogeneous disorder associated with high lethal malignant tumors among women worldwide. Genetic factors play an important role in breast cancer development. Several single nucleotide polymorphisms in the 8q24 region associated with risk of breast cancer have been identified. Fifteen studies including 32,955 cases and 43,716 controls were collected to conduct a meta-analysis to evaluate the associations between variants in 8q24 region and risk of breast cancer. Our study showed that only rs13281615 is associated with breast cancer risk in this large-scale research synopsis and meta-analysis. Further studies are needed to explore the role of the 8q24 variants in the development of breast cancer.

New Educational Model to Promote Breast Cancer-Preventive Behaviors (ASSISTS): Development and First Evaluation

BACKGROUND

The prevalence of breast cancer in Iran has increased. An effective approach to decrease the burden of breast cancer is prevention.

OBJECTIVE

The aim of this study was to develop and evaluate an educational model, called the ASSISTS, for promoting breast cancer-preventive behaviors in women.

METHODS

A multiphase method was used to develop the model designed to promote breast cancer prevention behaviors. A conceptual model was generated based on a secondary analysis of qualitative data. Then, a structural equation model technique was used to test the relationships among the model constructs.

RESULTS

The analysis revealed that 7 constructs could be extracted, namely, perceived social support, attitude, motivation, self-efficacy, information seeking, stress management, and self-care. Based on these constructs, a conceptual model was built and tested using structural equation modeling. The model fit was good, and the model confirmed significant relationships among the 7 constructs of breast cancer prevention.

CONCLUSION

Findings revealed that self-care behavior and stress management are influenced directly by attitude, motivation, self-efficacy, information seeking, and social support. In addition, women seek more information when they are motivated, have more self-efficacy, have a more positive attitude toward breast cancer prevention, and experience more social support.

IMPLICATION FOR PRACTICE

Cancer nurses can be at the forefront of breast cancer prevention. Because they can play a pivotal role in providing information, they can reduce women's stress and increase their self-care behavior. In addition, their social support can positively influence Iranian women's attitude, motivation, and self-care behavior. Furthermore, implementing educational programs based on this model might encourage women to practice preventive behaviors.

Green tea consumption and risk of breast cancer: A systematic review and updated meta-analysis of case-control studies

BACKGROUND

As the most popular beverage in East Asia, green tea (GT) has various biological activities effects such as anti-mutation, anti-oxidation, and anti-tumor. In this study, we aimed to evaluate whether GT consumption could be an effective way to decrease the risk of breast cancer.

METHODS

We had performed a systematic review and updated meta-analysis of published case-control studies to evaluate the association between GT intake and the risk of breast cancer. Searching strategies were performed by the following keywords "Breast cancer," "breast neoplasm," and "green tea," with derivations and different combinations. The following databases were searched: PubMed, Cochrane Library, EMBASE, Web of science, China National Knowledge Infrastructure, WanFang, and China Biology Medicine disc. Studies published in both English and Chinese were considered for inclusion. Risk of bias was assessed through the Newcastle-Ottawa Scale (NOS). All data were analyzed through using Review Manager 5.1 software.

RESULTS

Fourteen studies fulfilled inclusion criteria for meta-analysis, yielding a total of 14,058 breast cancer patients and 15,043 control subjects. Individuals with the habit of drinking GT were found to have a negative association with the risk of future breast cancer (odds ratio 0.83; 95% confidence interval: 0.72-0.96) despite significant heterogeneity. In subgroup analyses, the negative correlation was still found in studies using registry-based controls, NOS grades ≥6 and the number of cases <500.

CONCLUSIONS

GT consumption may have a decreased incidence of breast cancer despite significant heterogeneity. However, owing to the quality of available studies, more properly designed trials are warranted to clarify the association between GT consumption and breast cancer.

Mushroom Consumption and Risk of Total and Site-Specific Cancer in Two Large U.S. Prospective Cohorts

Several case-control studies have reported that mushroom consumption may be associated with reduced risk of certain cancers. However, epidemiologic studies have not yet prospectively examined the association of mushroom consumption with total and various site-specific cancer risks. This prospective cohort study included 68,327 women (Nurses' Health Study, 1986-2012) and 44,664 men (Health Professionals Follow-up Study, 1986-2012) who were free of cancer at baseline. Mushroom consumption was assessed at baseline using a validated food frequency questionnaire. Covariates were assessed using biennial questionnaires during the follow-up. We used Cox proportional hazards models to estimate hazard ratios (HR) and 95% confidence intervals (CI) of total and 17 site-specific cancers associated with mushroom consumption. During up to 26 years of follow-up, we documented 22,469 incident cancer cases (15,103 in women and 7,366 in men). In the pooled multivariable analysis, participants who consumed five or more servings of mushrooms per week had no significantly different risk of total cancer (HR, 1.06; 95% CI, 0.98-1.14) than participants who almost never consumed mushrooms. We consistently found no association between mushroom consumption and risk of 16 site-specific cancers. However, there was a marginal positive association between mushroom consumption and risk of lung cancer (P _trend = 0.05). In conclusion, we found no association between mushroom consumption and total and site-specific cancers in U.S. women and men. More prospective cohort studies are needed to examine the associations for specific cancer types in diverse racial/ethnic groups.

The association between green tea consumption and breast cancer risk: A systematic review and meta-analysis

This systematic review and meta-analysis aimed to critically evaluate the relation between green tea (GT) consumption and the risk of breast cancer. Popular electronic databases were systematically searched for papers in English language. All case-control and cohort studies in addition to randomized clinical trials were included if they assessed the chemopreventive effects of GT on breast cancer. The quality of included studies was assessed using the Newcastle-Ottawa and Jadad scale. This systematic review comprised 14 studies: 9 case-control studies, 4 cohort studies, and 1 clinical trial. Odds ratio (OR) in case-control studies suggested that women in the group receiving the highest level of GT had 19% reduction in breast cancer risk compared with those who received the lowest level of GT (summary OR = 0.81, p = .031; 95% CI [0.66, 0.981]; heterogeneity, I²  = 71.53, p < .001, random effect model; 9 studies). OR in cohort studies also showed no significant difference (OR = 0.99, p = .94; 95% CI [0.81, 1.138]; heterogeneity, I²  = 19.06, p = .29; fixed-effect model; 4 studies). According to the only clinical trial, treatment with GT could not alter the mammographic density compared with placebo (26% vs. 25%). It cannot be concluded that GT consumption may decrease the risk of breast cancer. Due to high heterogeneity, a pooled analysis of case-control and cohort studies was not performed.

Breast cancer risk associated with genes encoding DNA repair MRN complex: a study from Punjab, Pakistan

BACKGROUND

Variants of DNA repair genes are extensively reported to cause genetic instability and increase the risk of breast cancer. In combination with NBS1, MRE11 and RAD50 constitute an MRN (MRE11-RAD50-NBS1) complex that repairs DNA damage. However, certain genetic alterations in MRE11 and RAD50 produce abnormal protein that affects the repairing process and may result in malignancy. We aimed to investigate the association of MRE11 and RAD50 polymorphisms with breast risk in the female population of Punjab, Pakistan.

METHODS

We collected blood samples of 100 breast cancer patients and 100 tumor-free females selected as controls. Extracted DNA was genotyped by tetra ARMS-PCR followed by gel electrophoresis. Results were analyzed by SPSS and SNPstats to analyze the association of different clinical factors and SNPs (single nucleotide polymorphisms) with the risk of breast cancer.

RESULTS

We found that the increased risk of breast cancer is associated with MRE11 variant rs684507 (odds ratio-OR 3.71, 95% confidence interval-CI 1.68-8.18, p value < 0.0001), whereas, RAD50 variant rs28903089 appeared to have protective effect (OR 0.55, CI 0.29-1.02, p value = 0.003). Additionally, clinical factors such as positive family history, life style, and marital status also play significant roles in breast cancer development.

CONCLUSION

In the present study, strong risk of breast cancer was associated with MRE11 gene. However, RAD50 showed protective effect. Additionally, clinical factors are also pivotal in risk assessment. We anticipate that targeting specific genetic variations confined to ethnic groups would be more effective in future therapeutic approaches for prevention and treatment of breast cancer.

Association between 8q24 (rs13281615 and rs6983267) polymorphism and breast cancer susceptibility: a meta-analysis involving 117,355 subjects

Published data on the association between 8q24 polymorphism and breast cancer (BC) risk are inconclusive. Thus, we conducted a meta-analysis to evaluate the relationship between 8q24 (rs13281615 and rs6983267) polymorphism and BC risk. We searched PubMed, EMBASE, Web of Science and the Cochrane Library up to August 13, 2015 for relevant studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the strength of associations. Twenty-six studies published from 2008 to 2014, with a total of 52,683 cases and 64,672 controls, were included in this meta-analysis. The pooled results showed that there was significant association between 8q24 rs13281615 polymorphism and BC risk in any genetic model. In the subgroup analysis by ethnicity, the effects remained in Asians and Caucasians. However, no genetic models reached statistical association in Africans. There was no association in any genetic model in rs6983267. This meta-analysis suggests that 8q24 rs13281615 polymorphism is a risk factor for susceptibility to BC in Asians, Caucasians and in overall population, While, there was no association in Africans. The rs6983267 polymorphism has no association with BC risk in any genetic model. Further large scale multicenter epidemiological studies are warranted to confirm this finding.

Association of three single nucleotide polymorphisms of ESR1with breast cancer susceptibility: a meta-analysis

Expression of estrogen receptors is correlated with breast cancer risk, but inconsistent results have been reported. To clarify potential estrogen receptor (ESR)-related breast cancer risk, we analyzed genetic variants of ESR1 in association with breast cancer susceptibility. We performed a meta-analysis to investigate the association between rs2234693, rs1801132, and rs2046210 (single nucleotide polymorphisms of ESR1 ), and breast cancer risk. Our analysis included 44 case-control studies. For rs2234693, the CC genotype had a higher risk of breast cancer compared to the TT or CT genotype. For rs2046210, the AA, GA, or GA+ GG genotype had a much higher risk compared to the GG genotype. No significant association was found for the rs1801132 polymorphism with breast cancer risk. This meta-analysis demonstrates association between the rs2234693 and rs2046210 polymorphisms of ESR1 and breast cancer risk. The correlation strength between rs2234693 and breast cancer susceptibility differs in subgroup assessment by ethnicity.

Development and psychometric testing of a new instrument to measure factors influencing women's breast cancer prevention behaviors (ASSISTS)

BACKGROUND

Breast cancer preventive behaviors have an extreme effect on women's health. Despite the benefits of preventive behaviors regarding breast cancer, they have not been implemented as routine care for healthy women. To assess this health issue, a reliable and valid scale is needed. The aim of the present study is to develop and examine the psychometric properties of a new scale, called the ASSISTS, in order to identify factors that affect women's breast cancer prevention behaviors.

METHODS

A multi-phase instrument development method was performed to develop the questionnaire from February 2012 to September 2014. The item pool was generated based on secondary analyses of previous qualitative data. Then, content and face validity were applied to provide a pre-final version of the scale. The scale validation was conducted with a sample of women recruited from health centers affiliated with Tehran University of Medical Sciences. The construct validity (both exploratory and confirmatory), convergent validity, discriminate validity, internal consistency reliability and test-retest analysis of the questionnaire were tested.

RESULTS

Fifty-eight items were initially extracted from the secondary analysis of previous qualitative data. After content validity, this was reduced to 49 items. The exploratory factor analysis revealed seven factors (Attitude, supportive systems, self-efficacy, information seeking, stress management, stimulant and self-care) containing 33 items that jointly accounted for 60.62 % of the observed variance. The confirmatory factor analysis showed a model with appropriate fitness for the data. The Cronbach's alpha coefficient for the subscales ranged from 0.68 to 0.85, and the Intraclass Correlation Coefficient (ICC) ranged from 0.71 to 0.98; which is well above the acceptable thresholds.

CONCLUSION

The findings showed that the designed questionnaire was a valid and reliable instrument for assessing factors affecting women's breast cancer prevention behaviors that can be used both in practice and in future studies.

Association of single nucleotide polymorphism rs3803662 with the risk of breast cancer

Large scale association studies have identified the single nucleotide polymorphism rs3803662 associated with breast cancer risk. However, the sample size of most studies is too small. Here, we performed this meta-analysis to make the result more convincing. Relevant articles published up to 2016 were identified by searching the PubMed database. 13 studies, involving a total of 29405 participants, were included in the meta-analysis. Odds Ratios (ORs) with 95% confidence intervals (CIs) was calculated with random or fixed effects model. All data analyses were analyzed by Review Manger 5.3 software. In Caucasian subgroup: Dominant model (TT + CT vs CC): OR = 1.17 (1.06, 1.29), Recessive model (TT vs CT + CC): OR = 1.25 (1.13, 1.39) and Allele frequency (T vs C): OR = 1.15 (1.08, 1.22). The present meta-analysis suggests that rs3803662 polymorphism is significantly associated with breast cancer risk in Caucasian women, and we did not find the association in Asian women.

Evaluation of potential regulatory function of breast cancer risk locus at 6q25.1

In a genome-wide association study conducted among Chinese women, we identified the single nucleotide polymorphism (SNP) rs2046210 at 6q25.1 for breast cancer risk. To explore a potential regulatory role for this risk locus, we measured expression levels of nine genes at the locus in breast cancer tissue and adjacent normal tissue samples obtained from 67 patients recruited in the Shanghai Breast Cancer Study. We found that rs2046210 had a statistically significant association with the expression levels of the AKAP12 and ESR1 genes in adjacent normal breast tissues. Women who carry the AA/AG risk genotypes had higher expressions of these two genes compared to those who carry G/G genotypes (P = 0.02 and 0.04 for the AKAP12 and ESR1, respectively). However, no significant differences of SNP rs2046210 with gene expression levels were found in tumor tissues. In The Cancer Genome Atlas samples, the AA/AG risk genotypes of SNP rs2046210 were associated with a significantly higher expression level of the AKAP12 gene and a lower level of the ESR1 gene in tumor tissue. Functional analysis using ENCODE data revealed that SNP rs7763637, which is in strong linkage disequilibrium with SNP rs2046210, is likely a potential functional variant, regulating the AKAP12 gene. Taken together, these results from our study suggest that the association between the 6q25.1 locus and breast cancer risk may be mediated through SNPs that regulate expressions of the AKAP12 gene.

Association of three SNPs in TOX3 and breast cancer risk: Evidence from 97275 cases and 128686 controls

The associations of SNPs in TOX3 gene with breast cancer risk were investigated by some Genome-wide association studies and epidemiological studies, but the study results were contradictory. To derive a more precise estimate of the associations, we conducted a meta-analysis. ORs with 95% CI were used to assess the strength of association between TOX3 polymorphisms and breast cancer risk in fixed or random effect model. A total of 37 publications with 97275 cases and 128686 controls were identified. We observed that the rs3803662 C > T, rs12443621 A > G and rs8051542 C > T were all correlated with increased risk of breast cancer. In the stratified analyses by ethnicity, significantly elevated risk was detected for all genetic models of the three SNPs in Caucasians. In Asian populations, there were significant associations of rs3803662 and rs8051542 with breast cancer risk. Whereas there was no evidence for statistical significant association between the three SNPs and breast cancer risk in Africans. Additionally, we observed different associations of rs3803662 with breast cancer risk based on different ER subtype and BRCA1/BRCA2 mutation carriers. In conclusion, the meta-analysis suggested that three SNPs in TOX3 were significantly associated with breast cancer risk in different populations.

Association of five single nucleotide polymorphisms at 6q25.1 with breast cancer risk in northwestern China

CCDC170 and ESR1, located at 6q25.1, were associated with breast cancer (BC) risk by genome-wide association studies. Our goal was to validate the association between CCDC170-ESR1 polymorphisms and BC risk in the population of northwestern China. A case-control study of 551 patients with BC and 577 control individuals was conducted from January 2011 to November 2014. We analyzed five BC-associated single nucleotide polymorphisms (SNPs) identified in CCDC170-ESR1 by previous studies. Logistic regression models were used to derive odds ratios (ORs) and 95% confidence intervals after adjusting for body mass index and age. The minor alleles of rs3757318, rs3734805, and rs2046210 were associated with increased BC risk (OR = 1.30, p = 0.005; OR = 1.28, p = 0.006; OR = 1.20, p = 0.033, respectively) in an allelic model analysis. Those three SNPs had a coincident significant association with increased BC risk in genetic models and stratification analyses. A new haplotype, "CT", was associated with a 1.31-fold increased risk of BC (OR = 1.31, p = 0.006). The "C" allele of rs9383951 was associated with a reduced risk of BC (OR = 0.69, p = 0.048) in estrogen receptor-positive individuals under the log-additive model. Our data provide new evidence of the association between CCDC170-ESR1 and BC susceptibility in the population of northwestern China.

C6ORF97-ESR1 breast cancer susceptibility locus: influence on progression and survival in breast cancer patients

Genome-wide association studies have identified a single-nucleotide polymorphism (SNP) to be associated with an increased risk of breast cancer. The biology of one of the susceptibility locus C6ORF-ESR1 and whether it also contributes to progression of established disease has not yet been ascertained. We examined the association of rs2046210 and its six linkage disequilibrium SNPs with clinicopathological characteristics, prognosis, and gene expression levels of ESR1 and the C6ORFs (C6ORF97:CCDC170, C6ORF211, C6ORF96:RMND1) in 344 breast cancer tissue samples and 253 corresponding samples of adjacent normal tissue. Tumor genotypes with homozygous risk alleles were more frequent than normal tissues. The tumor genotypes of rs2046210 and rs6929137 with homozygous risk alleles showed worse relapse-free survival (RFS, P=0.038 and P=0.031, respectively), whereas no notable associations were observed with either clinicopathological characteristics or expression of the peripheral genes. Higher C6ORF97 expression correlated with ER negativity (P<0.0001), highly proliferative characteristics (P=0.0005 for Ki67, P<0.0001 for nuclear grade) and worse RFS in the ER+/HER2- cohort (P=0.013), whereas the other two C6ORFs showed the inverse associations. Furthermore, C6ORF97 showed significant worse prognostic values especially in luminal B subtype in the publically available data sets. rs2046210 and the upstream gene C6ORF97 might have substantial roles not only in carcinogenesis but also in progression toward a more aggressive phenotype in breast cancer patients, which suggests that functional studies of this locus are imperative.

Association of H3K9me3 and H3K27me3 repressive histone marks with breast cancer subtypes in the Nurses' Health Study

Repressive histone tail modifications have been associated with molecular breast cancer subtypes. We investigated whether histone 3 lysine 9 trimethylation (H3K9me3) and histone 3 lysine 27 trimethylation (H3K27me3) were associated with tumor features and subtypes while adjusting for prospectively collected reproductive and lifestyle breast cancer risk factors. We have tissue microarray data with immunohistochemical marker information on 804 incident cases of invasive breast cancer diagnosed from 1976-2000 in the Nurses' Health Study. Tissue microarray sections were stained for global H3K9me3 and H3K27me3, and scored into four categories. Multivariate odds ratios (OR) and 95 % confidence intervals (CI) were calculated using logistic regression models for tumor features and subtypes, adjusting for breast cancer risk factors. While there were no significant associations between H3K9me3 and tumor features, H3K27me3 was significantly associated with lower grade tumors compared to high grade tumors in the multivariate model (OR = 1.95, 95 % CI 1.35-2.81, p = 0.0004). H3K27me3 was suggestively associated with estrogen receptor-positive (ER+) tumors (OR = 1.47, 95 % CI 0.97-2.23, p = 0.07). In subtype analyses, H3K27me3 was positively associated with the luminal A subtype compared to all other subtypes (OR = 1.42, 95 % CI 1.14-1.77, p = 0.002), and was inversely associated with HER2-type (OR = 0.58, 95 % CI 0.37-0.91, p = 0.02) and basal-like breast cancer (OR = 0.52, 95 % CI 0.36-0.76, p = 0.0006). In the largest immunohistochemical examination of H3K9me3 and H3K27me3 in breast cancer, we found that H3K27me3 positivity, but not H3K9me3, was associated with lower grade tumors and the luminal A subtype after adjusting for reproductive and lifestyle breast cancer risk factors.

Dietary mushroom intake may reduce the risk of breast cancer: evidence from a meta-analysis of observational studies

Epidemiological studies have investigated the potential anticancer effects of mushroom intake. This review aims to clarify the evidence on the association of dietary mushroom intake with breast cancer risk and to quantify its dose-response relationship. Relevant studies were identified by a search of PubMed, Web of Science and Google Scholar up to December 31, 2013. Observational studies with relative risks (RRs) or hazard ratios (HRs) or odd ratios (ORs) and 95% confidence intervals (CIs) of breast cancer for three or more categories of mushroom intake were eligible. The quality of included studies was assessed by using Newcastle-Ottawa Scale. A dose-response meta-analysis was performed by utilizing generalized least squares trend estimation. Eight case-control studies and two cohort studies with a total of 6890 cases were ultimately included. For dose-response analysis, there was no evidence of non-linear association between mushroom consumption and breast cancer risk (P = 0.337) and a 1 g/d increment in mushroom intake conferred an RR of 0.97 (95% CI: 0.96–0.98) for breast cancer risk, with moderate heterogeneity (I² = 56.3%, P = 0.015). Besides, available menopause data extracted from included studies were used to evaluate the influence of menopausal statues. The summary RRs of mushroom consumption on breast cancer were 0.96 (95% CI: 0.91–1.00) for premenopausal women and 0.94 (95% CI: 0.91–0.97) for postmenopausal women, respectively. Our findings demonstrated that mushroom intake may be inversely associated with risk of breast cancer, which need to be confirmed with large-scale prospective studies further.

Breast cancer-preventive behaviors: exploring Iranian women's experiences

Background

Breast cancer-preventive behaviors are critical for community and women’s health. Although many studies have addressed women’s knowledge and attitudes toward breast cancer, little information is available about their experiences of breast cancer preventive behaviors. This study aimed to explore the experiences of Iranian women regarding preventive behaviors.

Methods

This was a qualitative study. A sample of Iranian women aged 30 years and over was selected purposefully. Data collected through focus group and semi-structured audiotaped interviews and were analyzed by conventional content analysis.

Results

The following five main themes emerged from the analysis: attitude toward breast cancer and preventive behaviors, stress management, healthy lifestyle, perceived social support and individual/environmental barriers. The findings showed that women were highly motivated to preventive behaviors of breast cancer but faced considerable challenges.

Conclusions

The findings indicated that increased awareness, positive attitudes, stronger motivational factors, and fewer barriers toward preventive behaviors are most important parameters that might encourage women to practice breast cancer-preventive behaviors.