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Abstract Objective Depressive symptoms are common comorbidities among breast cancer (BC) patients. Non-pharmacological therapies (NPTs) such as exercise and psychotherapy may reduce depressive symptoms; however, the evidence is inconclusive. The objective of this study is to evaluate if NPTs reduce depressive symptoms among BC patients. Methods A systematic review and meta-analysis of randomized clinical trials (RCTs) of NPTs for BC patients were performed. A literature search was conducted from eight databases in English, Portuguese and Spanish from 2006 to 2017. Inclusion criteria were: RCTs that evaluated depressive symptoms as a primary or secondary outcome that did not include pharmacological interventions and did include a non-intervened control group, with at least 30 participants in non-terminal BC stage with no current psychiatric illness. A meta-analysis for each NPT was performed with DerSimonian and Laird's method for the random effects model. Sensitivity analyses were conducted. Heterogeneity and publication bias were assessed. Results A total of 41 eligible RCTs were identified. Overall, NPTs significantly reduced depressive symptoms (Summary standardized mean difference (SMD) = -0.516; 95%CI: -0.814, −0.218; I2 = 96.2). Of the types of NPTs, psychotherapy significantly reduced depressive symptoms (Summary SMD = −0.819; 95% CI: -1.608, −0.030; I2 = 91.53). A significant difference emerged for Mindfulness (Summary SMD = −0.241; 95% CI: -0.412, −0.070; I2 = 28.6%) and yoga (Summary SMD = −0.305; 95% CI: -0.602, −0.007; I2 = 41.0%) when the heterogeneity was reduced. No evidence of publication bias was observed. Conclusions Psychotherapy and mind-body therapies may reduce depressive symptoms in women with BC. Laughter and couples therapy warrant attention in future studies. Highlights • Psychotherapy and yoga may reduce depressive symptoms in breast cancer patients. • MBSR and imagery reduce depressive symptoms in postmenopausal patients. • Further evidence is needed for laughter and couple therapies. [ABSTRACT FROM AUTHOR]

Objective To evaluate whether the association between breast cancer (BC) and inorganic arsenic (iAs) exposure is modulated by selected polymorphisms in iAs metabolism. Methods A population based case-control (1016/1028) study was conducted in Northern Mexico. Urinary arsenic metabolites were measured by High Performance Liquid Chromatography. Metabolites percentages and methylation ratios, were estimated. Genotypes of selected polymorphisms were determined by allelic discrimination. The interaction between polymorphisms and iAs metabolites percentages and methylation ratios on BC was assessed with unconditional logistic regression models. Results A significant interaction (p = 0.002) between MTR c.2756A>G polymorphism and percentage dimethylarsinic acid (DMA) on BC was found; BC risk related with %DMA was lower in AG + GG carriers than in AA carriers. No other significant interactions were found. Conclusion MTR c.2756A>G polymorphism may confer protection for BC associated with iAs exposure. Further research is warranted to elucidate the potential involvement of other polymorphisms in iAs-related BC. [ABSTRACT FROM AUTHOR]

Breast cancer (BC) is the most frequently diagnosed cancer in women. However, only 58% of cases have been associated with known risk factors (reproductive, hormonal, lifestyles, and genetic), and the rest to unknown causes. Nevertheless, growing evidence suggests that exposure to environmental contaminants is an important risk factor for BC. Polycyclic aromatic hydrocarbons (PAHs) are formed during organic matter combustion, including smoking, grilled meat, and fuels, and are important carcinogenic constituents of environmental pollution. We examined the information generated by epidemiological studies evaluating the association between BC and PAHs exposure from multiple sources. Our work was conducted according to Conducting Systematic Reviews and Meta-Analyses of Observational Studies of Etiology (COSMOS-E) guidelines. We searched PubMed, Web of Science, and Scopus from January 2000 to December 2019. A total of 124 records were identified, and only 23 articles met all inclusion criteria. Occupational and/or environmental exposure to PAHs was significantly associated with BC, irrespective of exposure being assessed by direct or indirect methods. CYP1A1 and CYP1B1 adverse polymorphisms, familial BC history and smoking status, significantly strengthened the association between PAHs exposure and BC, whereas high fruit and vegetable intake had antagonistic associations. The positive relationships obtained in the studies here reviewed indicated that PAHs exposure is a risk factor for BC. Research needs include the improvement of exposure assessment, particularly identification of specific PAHs, reconstruction of time-varying and distant past exposures and further studies on the interaction between known BC factors and modifiable diet and life-style factors allowing BC prevention and control. [Display omitted] • PAHs exposure was significantly and positively associated with BC. • Some CYP1A1 and 1B1 polymorphisms and smoking strengthened PAHs and BC association. • High intakes of fruit and vegetables attenuated PAHs and BC association. [ABSTRACT FROM AUTHOR]

Previously we reported that inorganic arsenic (iAs) methylation capacity was associated with breast cancer (BC). BC risk factors may vary according to immunohistochemical subtype. Here we explored the relationships between the capacity to methylate iAs and the risk of BC by subtype. A population-based case-control study was performed in northern Mexico. Patients with available information about BC subtypes (n = 499) were age-matched with healthy controls. Sociodemographic, reproductive, and lifestyle characteristics were obtained. Tumor marker information was obtained from medical records. Cases were classified as HR+ [estrogen receptor (ER+) and/or progesterone (PR+), and human epidermal growth factor receptor 2 (HER2-)], HER2+, or triple negative (TN). Urinary arsenic species were determined by high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS), and methylation capacity parameters calculated. Conditional logistic regression models were used to estimate BC risk by subtypes. Urinary total arsenic varied from 0.60 to 303.29 μg/L. A significant positive association was found between % monomethylarsonic acid (%MMA) and HR + BC: one percent increase resulted in OR %MMA continuous = 2.73, 95% CI: 1.48, 5.05), and this association remained even when %iAs or % dimethylarsinic acid (%DMA) were added to the models with %MMA. MMA/iAs was positively associated with HR + BC (OR MMA/iAs continuous = 2.03, 95% CI: 1.33–3.10). A significant negative association was observed between DMA/MMA and HR + BC (OR DMA/MMA continuous = 0.43, 95% CI: 0.26, 0.71). MMA/iAs was positively associated with TN BC (OR MMA/iAs continuous = 4.05; 95% CI: 1.63, 10.04). Altered iAs methylation capacity resulting in higher %MMA was associated with HR+ and TN BC but not with HER2+. MMA is the iAs metabolite more likely to be related to BC. Further research is needed to confirm these results and elucidate the underlying biological mechanisms. • BC was associated with alterations in iAs metabolism efficiency in Mexican women. • BC associated with an altered capacity to methylate iAs varies by subtypes. • A higher proportion of MMA was associated with HR+ and TN BC but not with HER2+. [ABSTRACT FROM AUTHOR]