Aspirin Use and Risk of Breast Cancer: Systematic Review and Meta-analysis of Observational Studies

Insight into the molecular mechanism of anti-breast cancer therapeutic potential of substituted salicylidene-based compounds using cell-based assays and molecular docking studies

Targeting oxidative stress and inflammatory signaling pathways is an effective cancer prevention and therapy approach. The mechanism of action of synthesized salicylidene-based compounds was investigated in regulating key molecular targets of breast cancer development. Compounds (1), (4), (5), and (7) were found to be more cytotoxic to MCF-7 and 4T1 cells compared to non-cancerous Chang liver cells, while these compounds were cytotoxic to MDA-MB-231 cells, but with poor selectivity. The colony formation assay indicated that bioactive compounds induced significant damage to breast cancer cells, as observed by a reduction in the number of colonies compared to control cells. By inducing a concentration and time-dependent increase of luminescence and fluorescence of phosphatidylserine, and activating the expression of caspases-3, -7, -8, -9 in breast cancer cells, (1) and (7) have shown to induce caspase-dependent apoptosis. The downregulation of NF-kB-p65 and an upregulation of TP53 expression after exposure to bioactive compounds, demonstrated the suppression of two key targets of breast cancer development. Molecular docking studies revealed that selected protein targets strongly interact with bioactive compounds, and the estimated inhibition constants (Ki) of JAK2, STAT3, COX-2, HPV31 E6, EGFR1, TP53, and PARP1 were significantly decreased compared to acetylsalicylic acid. This could be a clear indication that these protein targets are implicated with antiproliferative efficacy, thereby warranting the potential of (1) and (7) to be used as anti-breast cancer drug candidates.

Non-genetic factors and breast cancer: an umbrella review of meta-analyses

BACKGROUND

Previous research has found associations between various non-genetic factors and breast cancer (BrCa) risk. This study summarises and appraises the credibility of the available evidence on the association between non-genetic factors and BrCa risk.

METHODS

We conducted an umbrella review of meta-analyses. Medline, Scopus, and the Cochrane databases were systematically searched for meta-analyses examining non-genetic factors and BrCa incidence or mortality. The strength of the evidence was graded in four categories (i.e., weak, suggestive, highly suggestive, convincing).

RESULTS

A total of 781 meta-analyses from 280 publications were evaluated and graded. We included exposures related to anthropometric measurements, biomarkers, breast characteristics and diseases, diet and supplements, environment, exogenous hormones, lifestyle and social factors, medical history, medication, reproductive history, and pregnancy. The largest number of examined associations was found for the category of diet and supplements and for exposures such as aspirin use and active smoking. The statistically significant (P-value < 0.05) meta-analyses were 382 (49%), of which 204 (53.4%) reported factors associated with increased BrCa risk. Most of the statistically significant evidence (n = 224, 58.6%) was graded as weak. Convincing harmful associations with heightened BrCa risk were found for increased body mass index (BMI), BMI and weight gain in postmenopausal women, oral contraceptive use in premenopausal women, increased androstenedione, estradiol, estrone, and testosterone concentrations, high Breast Imaging Reporting and Data System (BIRADS) classification, and increased breast density. Convincing protective factors associated with lower BrCa risk included high fiber intake and high sex hormone binding globulin (SHBG) levels while highly suggestive protective factors included high 25 hydroxy vitamin D [25(OH)D] levels, adherence to healthy lifestyle, and moderate-vigorous physical activity.

CONCLUSIONS

Our findings suggest some highly modifiable factors that protect from BrCa. Interestingly, while diet was the most studied exposure category, the related associations failed to reach higher levels of evidence, indicating the methodological limitations in the field. To improve the validity of these associations, future research should utilise more robust study designs and better exposure assessment techniques. Overall, our study provides knowledge that supports the development of evidence-based BrCa prevention recommendations and guidance, both at an individual level and for public health initiatives.

TRIAL REGISTRATION

PROSPERO CRD42022370675.

Low-dose acetylsalicylic acid reduces local inflammation and tissue perfusion in dense breast tissue in postmenopausal women

PURPOSE

One major risk factor for breast cancer is high mammographic density. It has been estimated that dense breast tissue contributes to ~ 30% of all breast cancer. Prevention targeting dense breast tissue has the potential to improve breast cancer mortality and morbidity. Anti-estrogens, which may be associated with severe side-effects, can be used for prevention of breast cancer in women with high risk of the disease per se. However, no preventive therapy targeting dense breasts is currently available. Inflammation is a hallmark of cancer. Although the biological mechanisms involved in the increased risk of cancer in dense breasts is not yet fully understood, high mammographic density has been associated with increased inflammation. We investigated whether low-dose acetylsalicylic acid (ASA) affects local breast tissue inflammation and/or structural and dynamic changes in dense breasts.

METHODS

Postmenopausal women with mammographic dense breasts on their regular mammography screen were identified. A total of 53 women were randomized to receive ASA 160 mg/day or no treatment for 6 months. Magnetic resonance imaging (MRI) was performed before and after 6 months for a sophisticated and continuous measure breast density by calculating lean tissue fraction (LTF). Additionally, dynamic quantifications including tissue perfusion were performed. Microdialysis for sampling of proteins in vivo from breasts and abdominal subcutaneous fat, as a measure of systemic effects, before and after 6 months were performed. A panel of 92 inflammatory proteins were quantified in the microdialysates using proximity extension assay.

RESULTS

After correction for false discovery rate, 20 of the 92 inflammatory proteins were significantly decreased in breast tissue after ASA treatment, whereas no systemic effects were detected. In the no-treatment group, protein levels were unaffected. Breast density, measured by LTF on MRI, were unaffected in both groups. ASA significantly decreased the perfusion rate. The perfusion rate correlated positively with local breast tissue concentration of VEGF.

CONCLUSIONS

ASA may shape the local breast tissue microenvironment into an anti-tumorigenic state. Trials investigating the effects of low-dose ASA and risk of primary breast cancer among postmenopausal women with maintained high mammographic density are warranted. Trial registration EudraCT: 2017-000317-22.

Low-dose acetylsalicylic acid for cancer prevention considering risk factors: a retrospective cohort study

PURPOSE

Aspirin (acetylsalicylic acid) has been reported to protect against certain cancers. However, patient-related risk factors may moderate protective effects, including excess weight, smoking, risky alcohol use, and diabetes. We explore the cancer-risk relationship between aspirin intake and those four factors.

METHODS

Retrospective cohort study of cancers, aspirin intake, and four risk factors in persons aged ≥50 years. Participants received medication during 2007-2016, and cancers were diagnosed in 2012-2016. Adjusted hazard ratios (aHR) for 95% confidence intervals (95%CI) were calculated for aspirin intake and risk factors using Cox proportional hazard modeling.

RESULTS

Of 118,548 participants, 15,793 consumed aspirin, and 4003 had cancer. Results indicated a significant protective effect of aspirin against colorectal (aHR: 0.7; 95%CI: 0.6-0.8), pancreatic (aHR: 0.5; 95%CI: 0.2-0.9), prostate (aHR: 0.6; 95%CI: 0.5-0.7) cancers and lymphomas (aHR: 0.5; 95%CI: 0.2-0.9), and also, although not significantly, against esophageal (aHR: 0.5; 95%CI: 0.2-1.8), stomach (aHR: 0.7; 95%CI: 0.4-1.3), liver (aHR: 0.7; 95%CI: 0.3-1.5), breast (aHR: 0.8; 95%CI: 0.6-1.0), and lung and bronchial (aHR: 0.9; 95%CI: 0.7-1.2) cancers. Aspirin intake was not significantly protective against leukemia (aHR: 1.0; 95%CI: 0.7-1.4) or bladder cancer (aHR: 1.0; 95%CI: 0.8-1.3).

CONCLUSIONS

Our results suggest that aspirin intake is associated with a reduced incidence of colorectal, pancreatic, and prostate cancers and lymphomas.

Aspirin and Risk of Specific Breast Cancer Subtype in Women with Diabetes

Purpose: Low-dose aspirin was associated with a reduced risk of breast cancer in women with diabetes. However, whether the protective effect of aspirin varies as a function of the hormone receptor status of breast cancer remained an unanswered question. This study aims to explore the association between aspirin use and the risk of specific breast cancer subtypes in women with diabetes. Methods: Population-based retrospective cohort study of women with diabetes, using the Taiwan National Health Insurance reimbursement database (year 1998 to 2011). Patients diagnosed to have diabetes with new low-dose aspirin use (75-165 mg per day) for at least 28 days of prescription were identified as the study population, while patients without low-dose aspirin use were selected as controls. The main outcome measure was breast cancer by aspirin use and hormone receptor status. Results: We studied a total of 148,739 patients with diabetes. Their mean (standard deviation) age was 63.3 (12.8) years. During follow-up, a total of 849 breast cancers occurred, including 329 hormone receptor-positive and 529 hormone receptor-negative tumors. A total of 27,378 patients were taking aspirin. The reduction in risk with aspirin use was seen among those with hormone receptor-positive breast cancer (Hazard ratio [HR]: 0.73; 95% confidence interval [CI]: 0.59-0.91) but not for women with hormone receptor-negative breast cancer (HR: 0.88; 95% CI: 0.74-1.05). A cumulative dose of aspirin use of more than 8,600 mg was found to reduce the risk of hormone receptor-positive breast cancer by 31% (HR: 0.69; 95% CI: 0.50-0.97). A cumulative dose of aspirin use of more than 88,900 mg was found to reduce both the risk of hormone receptor-positive and negative breast cancer. Conclusion: These data add to the growing evidence that supports the use of low-dose aspirin as a potential chemopreventive agent for specific subtypes of breast cancer. Further studies are necessary to confirm these findings.

Benign Breast Disease, NSAIDs, and Postmenopausal Breast Cancer Risk in the CPS-II Cohort

ABSTRACT

Nonsteroidal anti-inflammatory agents (NSAID) are associated with modest inconsistent reductions in breast cancer risk in population-based cohorts, whereas two focused studies of patients with benign breast disease (BBD) have found lower risk with NSAID use. Given that BBD includes fibroinflammatory lesions linked to elevated breast cancer risk, we assessed whether NSAID use was associated with lower breast cancer risk among patients with BBD.Participants were postmenopausal women in the Cancer Prevention Study-II (CPS-II), a prospective study of cancer incidence and mortality, who completed follow-up surveys in 1997 with follow-up through June 30, 2015. History of BBD, NSAID use, and covariate data were updated biennially. This analysis included 23,615 patients with BBD and 36,751 patients with non-BBD, including 3,896 incident breast cancers over an average of 12.72 years of follow-up among participants. NSAID use, overall and by formulation, recency, duration, and pills per month was analyzed versus breast cancer risk overall and by BBD status using multivariable-adjusted Cox models; BBD status and NSAID use were modeled as time-dependent exposures.Patients with BBD who reported using NSAIDs experienced lower breast cancer risk (HR, 0.87; 95% CI, 0.78-0.97), with similar effects for estrogen receptor (ER)-positive breast cancers [HR, 0.85; 95% confidence interval (CI), 0.74-0.97] and ER-negative breast cancers (HR, 0.87; 95% CI, 0.59-1.29); among women without BBD, NSAID use was unrelated to risk (HR, 1.02; 95% CI, 0.92-1.13; Pinteraction = 0.04). Associations stratified by age, obesity, menopausal hormone use, and cardiovascular disease were similar.Among patients with BBD, NSAID use appears linked to lower breast cancer risk. Further studies to assess the value of NSAID use among patients with BBD are warranted.

PREVENTION RELEVANCE

We examined whether NSAID use, a modifiable exposure, is associated with breast cancer risk in postmenopausal women from the Cancer Prevention Study-II with self-reported benign breast disease, an often inflammatory condition associated with higher rates of breast cancer.

Use of Nonsteroidal Anti-Inflammatory Drugs and Risk of Breast Cancer: Evidence from a General Female Population and a Mammographic Screening Cohort in Sweden

A link has been proposed between the use of nonsteroidal anti-inflammatory drugs (NSAIDs) and the risk of breast cancer. There is, however, insufficient data regarding the subtype and stage of breast cancer, and few studies have assessed the interaction between the use of NSAIDs and breast density or previous breast disorders. There is also a lack of data from population-based studies. We first conducted a nested case-control study within the general female population of Sweden, including 56,480 women with newly diagnosed breast cancer during 2006-2015 and five breast cancer-free women per case as controls, to assess the association of NSAID use with the risk of incident breast cancer, focusing on subtype and stage of breast cancer as well as the interaction between NSAID use and previous breast disorders. We then used the Karolinska Mammography Project for Risk Prediction of Breast Cancer (Karma) cohort to assess the interaction between NSAID use and breast density in relation to the risk of breast cancer. Conditional logistic regression was used to estimate the hazard ratio (HR) and a 95% confidence interval (CI) was used for breast cancer in relation to the use of aspirin and non-aspirin NSAIDs. In the nested case-control study of the general population, exclusive use of aspirin was not associated with the risk of breast cancer, whereas exclusive use of non-aspirin NSAIDs was associated with a modestly higher risk of stage 0-2 breast cancer (HR: 1.05; 95% CI: 1.02-1.08) but a lower risk of stage 3-4 breast cancer (HR 0.80; 95% CI: 0.73-0.88). There was also a statistically significant interaction between the exclusive use of NSAIDs and previous breast disorders (p for interaction: <0.001). In the analysis of Karma participants, the exclusive use of non-aspirin NSAIDs was associated with a lower risk of breast cancer among women with a breast dense area of >40 cm² (HR: 0.72; 95% CI: 0.59-0.89). However, the possibility of finding this by chance cannot be ruled out. Overall, we did not find strong evidence to support an association between the use of NSAIDs and the risk of breast cancer.

Microbial dysbiosis and epigenetics modulation in cancer development - A chemopreventive approach

An overwhelming number of research articles have reported a strong relationship of the microbiome with cancer. Microbes have been observed more commonly in the body fluids like urine, stool, mucus of people with cancer compared to the healthy controls. The microbiota is responsible for both progression and suppression activities of various diseases. Thus, to maintain healthy human physiology, host and microbiota relationship should be in a balanced state. Any disturbance in this equilibrium, referred as microbiome dysbiosis becomes a prime cause for the human body to become more prone to immunodeficiency and cancer. It is well established that some of these microbes are the causative agents, whereas others may encourage the formation of tumours, but very little is known about how these microbial communications causing change at gene and epigenome level and trigger as well as encourage the tumour growth. Various studies have reported that microbes in the gut influence DNA methylation, DNA repair and DNA damage. The genes and pathways that are altered by gut microbes are also associated with cancer advancement, predominantly those implicated in cell growth and cell signalling pathways. This study exhaustively reviews the current research advancements in understanding of dysbiosis linked with colon, lung, ovarian, breast cancers and insights into the potential molecular targets of the microbiome promoting carcinogenesis, the epigenetic alterations of various potential targets by altered microbiota, as well as the role of various chemopreventive agents for timely prevention and customized treatment against various types of cancers.

Aspirin-Based Organoiron Dendrimers as Promising Anti-Inflammatory, Anticancer, and Antimicrobial Drugs

Designing nanocarriers with actions directed at a specific organ or tissue is a very promising strategy since it can significantly reduce the toxicity of a bioactive drug. In this study, an organometallic dendrimer was used to synthesize a biocompatible drug delivery system by attaching aspirin to the periphery of the dendrimer. Our goal is to enhance the bioavailability and anticancer activity of aspirin and reduce its toxicity through successive generations of organoiron dendrimers. The biological activity of aspirin-based dendrimer complexes was evaluated. The result of antimicrobial activity of the synthesized dendrimers also demonstrated an increase in their antimicrobial activity with increased generation of the dendrimers for most types of microorganisms. This study reveals for the first time that organoiron dendrimers linked with aspirin exhibit an excellent Gram-negative activity comparable to the reference drug Gentamicin. All synthesized dendrimers were tested for their anticancer activity against breast cancer cell lines (MCF-7), hepatocellular cell lines (Hep-G2), and a non-cancer cell line, Human Embryonic Kidney (HEK293), using the MTT cell viability assay and compared against a standard anticancer drug, Doxorubicin. Compounds G3-D9-Asp and G4-D12-Asp exhibited noticeable activity against both cell lines, both of which were more effective than aspirin itself. In addition, the in vivo anti-inflammatory activity and histopathology of swollen paws showed that the designed aspirin-based dendrimers displayed significant anti-inflammatory activity; however, G2-D6-Asp showed the best anti-inflammatory activity, which was more potent than the reference drug aspirin during the same period. Moreover, the coupling of aspirin to the periphery of organoiron dendrimers showed a significant reduction in the toxicity of aspirin on the stomach.

Aspirin Use and Risk of Breast Cancer: A Meta-analysis of Observational Studies from 1989 to 2019

BACKGROUND

Some evidence shows that aspirin can reduce the morbidity and mortality of different cancers, including breast cancer. Aspirin has become a new focus of cancer prevention and treatment research at present, however, clinical studies found conflicting conclusions of its anticancer characteristics.

MATERIALS AND METHODS

A systematic literature search was performed in 8 electronic databases. The pooled relative risk (RR) with 95% confidence interval (CI) was calculated using the random effects model to estimate the effect of aspirin on breast cancer.

RESULTS

Forty-two published articles with 99,769 patients were identified. The meta-analysis showed a significant decrease in breast cancer risk with aspirin use (RR, 0.92; 95% CI, 0.89-0.96; I² = 72%). Aspirin use decreased the risk of hormone receptor-positive tumors (estrogen receptor [ER]-positive RR, 0.89; 95% CI, 0.82-0.97; I²=54%; progesterone receptor [PR]-positive RR, 0.86; 95% CI, 0.78-0.95; I²=32%; ER- and PR-positive RR, 0.92; 95% CI, 0.85-1.00; I²=45%) and reduced the risk of breast cancer in postmenopausal women (RR, 0.92; 95% CI, 0.86-0.98; I²=59%). Further analysis showed that for the in situ breast cancer, regular-dose and more than 3 years use of aspirin were associated with the reduced risk of breast cancer.

CONCLUSION

This meta-analysis suggested that aspirin may reduce the overall risk of breast cancer, reduce the risk of breast cancer in postmenopausal women, hormone receptor-positive tumors, and in situ breast cancer. Larger, multicenter clinical studies are needed to find the optimal dose range, frequency, and duration of the aspirin use to explore the best benefit-risk ratio.

COX-2 promotes mammary adipose tissue inflammation, local estrogen biosynthesis, and carcinogenesis in high-sugar/fat diet treated mice

Obesity is a major risk factor for breast cancer, especially in post-menopausal women. In the breast tissue of obese women, cyclooxygenase-2 (COX-2)-dependent prostaglandin E2 (PGE2) production has been correlated with inflammation and local estrogen biosynthesis via aromatase. Using a mouse model of 7,12-dimethylbenz[a]anthracene/medroxyprogesterone-acetate (DMBA/MPA)-induced carcinogenesis, we demonstrated that an obesogenic diet promotes mammary tissue inflammation and local estrogen production, and accelerates mammary tumor formation in a COX-2-dependent manner. High-sugar/fat (HSF) diet augmented the levels of the pro-inflammatory mediators MCP-1, IL-6, COX-2, and PGE2 in mammary tissue, and this was accompanied by crown-like structures of breast (CLS-B) formation and aromatase/estrogen upregulation. Treatment with a COX-2 selective inhibitor, etoricoxib, decreased PGE2, IL-6, MCP-1, and CLS-B formation as well as reduced aromatase protein and estrogen levels in the mammary tissue of mice fed a HSF diet. Etoricoxib-treated mice showed increased latency and decreased incidence of mammary tumors, which resulted in prolonged animal survival when compared to HSF diet alone. Inhibition of tumor angiogenesis also seemed to account for the prolonged survival of COX-2 inhibitor-treated animals. In conclusion, obesogenic diet-induced COX-2 is sufficient to trigger inflammation, local estrogen biosynthesis, and mammary tumorigenesis.

Aspirin as a Potential Geroprotector: Experimental Data and Clinical Evidence

Aging is a biological process with effects at the molecular, cellular, tissue, organ, system, and organismal levels and is characterized by decline in physical function and higher risks of age-related diseases. The use of anti-aging drugs for disease prevention has become a high priority for science and is a new biomedicine trend. Geroprotectors are compounds which slow aging and increase lifespan of the organism in question. The common painkiller aspirin, a member of the non-steroidal anti-inflammatory drug (NSAID) family, is one of the potential geroprotective agents. Aspirin is often used in treatment of mild to moderate pain. It has anti-inflammatory and anti-pyretic properties and acts as an inhibitor of cyclooxygenase which results in inhibition of prostaglandin. Acetylsalicylic acid as an active compound of aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. Aspirin has shown life-extending effects in numerous model organisms. This chapter reviews the evidence for clinical efficacy of aspirin including cardiovascular disease prevention, anti-cancer effects, and improvement of cognitive function. However, there are some limitations of these therapies, including the risk of excessive bleeding. We have also summarized numerous experimental and analytical data that support health and longevity benefits of aspirin treatment by affecting pro-longevity pathways.

Aspirin use and risk of breast cancer in African American women

BACKGROUND

Use of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) has been hypothesized to be associated with reduced risk of breast cancer; however, results of epidemiological studies have been mixed. Few studies have investigated these associations among African American women.

METHODS

To assess the relation of aspirin use to risk of breast cancer in African American women, we conducted a prospective analysis within the Black Women's Health Study, an ongoing nationwide cohort study of 59,000 African American women. On baseline and follow-up questionnaires, women reported regular use of aspirin (defined as use at least 3 days per week) and years of use. During follow-up from 1995 through 2017, 1919 invasive breast cancers occurred, including 1112 ER+, 569 ER-, and 284 triple-negative (TN) tumors. We used age-stratified Cox proportional hazards regression models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of aspirin use with risk of ER+, ER-, and TN breast cancer, adjusted for established breast cancer risk factors.

RESULTS

Overall, the HR for current regular use of aspirin relative to non-use was 0.92 (95% CI 0.81, 1.04). For ER+, ER-, and TN breast cancer, corresponding HRs were 0.98 (0.84, 1.15), 0.81 (0.64, 1.04), and 0.70 (0.49, 0.99), respectively.

CONCLUSIONS

Our findings with regard to ER- and TN breast cancer are consistent with hypothesized inflammatory mechanisms of ER- and TN breast cancer, rather than hormone-dependent pathways. Aspirin may represent a potential opportunity for chemoprevention of ER- and TN breast cancer.

Breast Cancer Risk and Use of Nonsteroidal Anti-inflammatory Agents After a Benign Breast Biopsy

Over one million women in the United States receive biopsy diagnoses of benign breast disease (BBD) each year, which confer a 1.5-4.0-fold increase in breast cancer risk. Studies in the general population suggest that nonsteroidal anti-inflammatory agents (NSAID) lower breast cancer risk; however, associations among women with BBD are unknown. We assessed whether NSAID use among women diagnosed with BBD is associated with lower breast cancer risk. Participants included 3,080 women (mean age = 50.3 ± 13.5 years) in the Mayo BBD surgical biopsy cohort diagnosed between January 1, 1992 and December 31, 2001 who completed breast cancer risk factor questionnaires that assessed NSAID use, and whose biopsies underwent detailed pathology review, masked to outcome. Women were followed from date of BBD biopsy to breast cancer diagnosis (main outcome) or censoring (death, prophylactic mastectomy, reduction mammoplasty, lobular carcinoma in situ or last contact). Median follow-up time was 16.4 ± 6.0 years. Incident breast cancer was diagnosed among 312 women over a median follow-up of 9.9 years. Regular non-aspirin NSAID use was associated with lower breast cancer risk [HR = 0.63; 95% confidence interval (CI) = 0.46-0.85; P = 0.002] with trends of lower risk (highest tertiles of use vs. nonuse) for greater number of years used [HR = 0.55; 95% CI = 0.31-0.97; P _trend = 0.003), days used per month (HR = 0.51; 95% CI = 0.33-0.80; P _trend = 0.001) and lifetime number of doses taken (HR = 0.53; 95% CI = 0.31-0.89; P _trend = 0.003). We conclude that nonaspirin NSAID use is associated with statistically significant lower breast cancer risk after a BBD biopsy, including a dose-response effect, suggesting a potential role for NSAIDs in breast cancer prevention among patients with BBD.

Antibiotic use and the risk of breast cancer: A systematic review and dose-response meta-analysis

OBJECTIVE

Oral antibiotics are posed as a possible risk factor for breast cancer. Evidence is insufficient to determine whether the choice of antibiotic class could effect this potential association, and non-linearity has not been studied. We aimed to fill these important knowledge gaps.

METHODS

PubMed, Web of Science, Embase and a trial registry were searched from inception until January 2020, without any restrictions. Additionally, extensive manual searches were undertaken. Random-effects meta-analyses provided pooled risk estimates with 95 % confidence intervals (CI). Dose-response analyses modeling the relationship between number of antibiotic prescriptions and breast cancer risk were extended to non-linear models. Heterogeneity, publication bias and small-study effects were assessed.

RESULTS

Of 7805 identified publications ten were eligible, including 3,719,383 individuals and 84,485 breast cancer cases. The pooled breast cancer risk was modestly increased among individuals who ever used antibiotics (relative risk RR = 1.18, 95 %CI 1.08-1.29), also after excluding the last year prior diagnosis. This excess risk was seen among penicillin (RR = 1.09, 95 %CI 1.01-1.18), tetracycline (RR = 1.13, 95 %CI 1.04-1.24) and nitrofuran users (RR = 1.26, 95 %CI 1.05-1.52), whilst nitroimidazole and metronidazole use (RR = 1.05, 95 %CI 1.00-1.11) indicated for marginal association. No apparent association was found for other antibiotics. Data suggested for a non-linear dose-dependent relationship, with a seemingly protective effect after at least 35 prescriptions. However, these findings might partly be explained by limited power of dose-response analyses.

CONCLUSIONS

The association of antibiotics with breast cancer risk appears to differ between the various antibiotic classes. Whether this association is causal remains unclear, requiring further clarification and mechanistic studies.

Different associations of tumor PIK3CA mutations and clinical outcomes according to aspirin use among women with metastatic hormone receptor positive breast cancer

Introduction

The relationships among PIK3CA mutations, medication use and tumor progression remains poorly understood. Aspirin use post-diagnosis may modify components of the PI3K pathway, including AKT and mTOR, and has been associated with lower risk of breast cancer recurrence and mortality. We assessed time to metastasis (TTM) and survival with respect to aspirin use and tumor PIK3CA mutations among women with metastatic breast cancer.

Methods

Patients with hormone receptor positive, HER2 negative (HR+/HER2-) metastatic breast cancer treated in 2009–2016 who received tumor genotyping were included. Aspirin use between primary and metastatic diagnosis was extracted from electronic medical records. TTM and survival were estimated using Cox proportional hazards regression.

Results

Among 267 women with metastatic breast cancer, women with PIK3CA mutated tumors had longer TTM than women with PIK3CA wildtype tumors (7.1 vs. 4.7 years, p = 0.008). There was a significant interaction between PIK3CA mutations and aspirin use on TTM (p = 0.006) and survival (p = 0.026). PIK3CA mutations were associated with longer TTM among aspirin non-users (HR = 0.60 95% CI:0.44–0.82 p = 0.001) but not among aspirin users (HR = 1.57 0.86–2.84 p = 0.139). Similarly, PIK3CA mutations were associated with reduced mortality among aspirin non-users (HR = 0.70 95% CI:0.48–1.02 p = 0.066) but not among aspirin users (HR = 1.75 95% CI:0.88–3.49 p = 0.110).

Conclusions

Among women who develop metastatic breast cancer, tumor PIK3CA mutations are associated with slower time to progression and mortality only among aspirin non-users. Larger studies are needed to confirm this finding and examine the relationship among aspirin use, tumor mutation profile, and the overall risk of breast cancer progression.

Aspirin and Its Potential Preventive Role in Cancer: An Umbrella Review

Background: Aspirin is one of the most commonly prescribed drugs worldwide and has been reported to possess anti-cancer properties in addition to antipyretic and analgesic effects. This umbrella review summarizes systematic reviews and meta-analyses that investigate the association between aspirin and cancer risk, aiming to help clinical and public health decision-makers interpret the results of these studies when re-positioning aspirin. Methods: An umbrella review of systematic reviews and meta-analyses. Results: The associations that reached statistical significance (17 in total) indicated potential preventive effects of aspirin on certain cancers or precancerous lesions. We found that no association was supported by strong evidence. Only one association (aspirin and overall cancer risk) was supported by highly suggestive evidence. The evidence supporting the association between aspirin and the risk of breast cancer, non-cardia gastric cancer, or prostate cancer was considered to be highly suggestive. The remaining 23 associations were supported by weak (13) or not suggestive evidence (10). Conclusions: The association between aspirin and a reduced risk of esophageal squamous cell carcinoma is supported by strong evidence, researchers and policy makers should pay more attention to the potential merit of repositioning aspirin to prevent esophageal squamous cell carcinoma.

Compound C enhances the anticancer effect of aspirin in HER-2-positive breast cancer by regulating lipid metabolism in an AMPK-independent pathway

Various clinical studies have determined that aspirin shows anticancer effects in many human malignant cancers, including human epidermal growth factor receptor-2 (HER-2)-positive breast cancer. However, the anti-tumor mechanism of aspirin has not been fully defined. The aim of this study was to determine the role of Compound C in enhancing the anticancer effect of aspirin. HER-2-positive breast cancer cell lines were treated with aspirin with or without Compound C pre-treatment; their phenotypes and mechanisms were then analyzed in vitro and in vivo. Aspirin exhibited anticancer effects in HER-2-positive breast cancer by inhibiting cell growth and inducing apoptosis through the activation of AMP-activated protein kinase (AMPK). Unexpectedly, pre-treatment with Compound C, a widely used AMPK inhibitor, induced robust anticancer effects in cells compared to aspirin monotherapy. This anticancer effect was not distinct in HER-2 negative breast cancer MDA-MB-231 cells and may be due to the inhibition of lipid metabolism mediated by c-myc. Besides, c-myc re-expression or palmitic acid supply could partially restored cell proliferation. Aspirin exhibits anticancer effects in HER-2-positive breast cancer by regulating lipid metabolism mediated by c-myc, and Compound C strengthens these effects in an AMPK-independent manner. Our results potentially provide a novel therapeutic strategy exploiting combined aspirin and Compound C therapy for HER-2-positive breast cancer, which acts by reducing de novo lipid synthesis.

The Role of Adipokines in Breast Cancer: Current Evidence and Perspectives

PURPOSE

The current review shows evidence for the role of adipokines in breast cancer (BC) pathogenesis summarizing the mechanisms underlying the association between adipokines and breast malignancy. Special emphasis is given also on intriguing insights into the relationship between obesity and BC as well as on the role of novel adipokines in BC development.

RECENT FINDINGS

Recent evidence has underscored the role of the triad of obesity, insulin resistance, and adipokines in postmenopausal BC. Adipokines exert independent and joint effects on activation of major intracellular signal networks implicated in BC cell proliferation, growth, survival, invasion, and metastasis, particularly in the context of obesity, considered a systemic endocrine dysfunction characterized by chronic inflammation. To date, more than 10 adipokines have been linked to BC, and this catalog is continuously increasing. The majority of circulating adipokines, such as leptin, resistin, visfatin, apelin, lipocalin 2, osteopontin, and oncostatin M, is elevated in BC, while some adipokines such as adiponectin and irisin (adipo-myokine) are generally decreased in BC and considered protective against breast carcinogenesis. Further evidence from basic and translational research is necessary to delineate the ontological role of adipokines and their interplay in BC pathogenesis. More large-scale clinical and longitudinal studies are awaited to assess their clinical utility in BC prognosis and follow-up. Finally, novel more effective and safer adipokine-centered therapeutic strategies could pave the way for targeted oncotherapy.

Antiplatelet Agents for Cancer Prevention: Current Evidences and Continuing Controversies

Over the past two decades, aspirin has emerged as a promising chemoprotective agent to prevent colorectal cancer (CRC). In 2016, the mounting evidence supporting its chemoprotective effect, from both basic science and clinical research, led the US Preventive Services Task Force to recommend regular use of low-dose aspirin in some subgroups of patients for whom the benefits are deemed to outweigh the risks. In contrast, data on the chemoprotective effect of aspirin against other cancers are less clear and remain controversial. Most data come from secondary analyses of cardiovascular prevention trials, with only a limited number reporting cancer outcomes as a prespecified endpoint, and overall unclear findings. Moreover, the potential chemoprotective effect of aspirin against other cancers has been recently questioned with the publication of 3 long-awaited trials of aspirin in the primary prevention of cardiovascular diseases reporting no benefit of aspirin on overall cancer incidence and cancer-related mortality. Data on the chemoprotective effects of other antiplatelet agents remain scarce and inconclusive, and further research to examine their benefit are warranted. In this narrative review, we summarize current clinical evidence and continuing controversies on the potential chemoprotective properties of antiplatelet agents against cancer.

The effect of NSAIDs exposure on breast cancer risk in female patients with autoimmune diseases

Both breast cancer and autoimmune diseases (ADs) are predominant in women. NSAIDs are common medications for AD. Evidence on the association between NSAIDs use and breast cancer risk is controversial. We investigated the association between NSAIDs exposure and breast cancer risk in female patients with AD. AD patients older than 18 years of age were enrolled from Taiwan Longitudinal Health Insurance Database 2005. The NSAID users were defined as AD patients who had ever taken NSAIDs for at least 3 months between 2000 and 2009. All individuals were followed from the date of first diagnosis of AD to the end of 2013 to evaluate the risk of breast cancer. We estimated the adjusted hazard ratio (HR) using Cox proportional hazard regression after adjusting for age, comorbidities and medications. A total of 12 331 NSAID users and 12 331 non-NSAID users were included in this study after 1: 1 individual matching. The NSAID users were less likely to develop breast cancer than the non-NSAID users (adjusted HR: 0.37; 95% confidence interval: 0.27-0.50; P < 0.001), even if they used NSAIDs with low cumulative defined daily doses (adjusted HR: 0.42; 95% confidence interval: 0.34-0.53; P < 0.001). The incidence of new-onset breast cancer in NSAID users was significantly decreased in users taking selective cyclooxygenase 2 inhibitors, diclofenac, ibuprofen and piroxicam. Lower cumulative hazard rates were found in the AD patients who used NSAIDs (P < 0.001). NSAID exposure is associated with a decreased risk of breast cancer in female AD patients.

Prediagnosis aspirin use, DNA methylation, and mortality after breast cancer: A population-based study

BACKGROUND

The authors hypothesized that epigenetic changes may help to clarify the underlying biologic mechanism linking aspirin use to breast cancer prognosis. To the authors' knowledge, this is the first epidemiologic study to examine whether global methylation and/or tumor promoter methylation of breast cancer-related genes interact with aspirin use to impact mortality after breast cancer.

METHODS

Prediagnosis aspirin use was assessed through in-person interviews within a population-based cohort of 1508 women diagnosed with a first primary breast cancer in 1996 and 1997. Global methylation in peripheral blood was assessed by long interspersed elements-1 (LINE-1) and the luminometric methylation assay. Promoter methylation of 13 breast cancer-related genes was measured in tumor by methylation-specific polymerase chain reaction and the MethyLight assay. Vital status was determined by the National Death Index through December 31, 2014 (N = 202/476 breast cancer-specific/all-cause deaths identified among 1266 women with any methylation assessment and complete aspirin data). Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% CIs, and the likelihood ratio test was used to evaluate multiplicative interactions.

RESULTS

All-cause mortality was elevated among aspirin users who had methylated promotor of BRCA1 (HR, 1.67; 95% CI, 1.26-2.22), but not among those with unmethylated promoter of BRCA1 (HR, 0.99; 95% CI, 0.67-1.45; P for interaction ≤.05). Decreased breast cancer-specific mortality was observed among aspirin users who had unmethylated promotor of BRCA1 and PR and global hypermethylation of LINE-1 (HR, 0.60, 0.78, and 0.63, respectively; P for interaction ≤.05), although the 95% CIs included the null.

CONCLUSIONS

The current study suggests that the LINE-1 global methylation and promoter methylation of BRCA1 and PR in tumor may interact with aspirin use to influence mortality after breast cancer.

Health Benefits of Anti-aging Drugs

Aging, as a physiological process mediated by numerous regulatory pathways and transcription factors, is manifested by continuous progressive functional decline and increasing risk of chronic diseases. There is an increasing interest to identify pharmacological agents for treatment and prevention of age-related disease in humans. Animal models play an important role in identification and testing of anti-aging compounds; this step is crucial before the drug will enter human clinical trial or will be introduced to human medicine. One of the main goals of animal studies is better understanding of mechanistic targets, therapeutic implications and side-effects of the drug, which may be later translated into humans. In this chapter, we summarized the effects of different drugs reported to extend the lifespan in model organisms from round worms to rodents. Resveratrol, rapamycin, metformin and aspirin, showing effectiveness in model organism life- and healthspan extension mainly target the master regulators of aging such as mTOR, FOXO and PGC1α, affecting autophagy, inflammation and oxidative stress. In humans, these drugs were demonstrated to reduce inflammation, prevent CVD, and slow down the functional decline in certain organs. Additionally, potential anti-aging pharmacologic agents inhibit cancerogenesis, interfering with certain aspects of cell metabolism, proliferation, angioneogenesis and apoptosis.

Regular use of aspirin and other non-steroidal anti-inflammatory drugs and breast cancer risk for women at familial or genetic risk: a cohort study

Background

The use of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) has been associated with reduced breast cancer risk, but it is not known if this association extends to women at familial or genetic risk. We examined the association between regular NSAID use and breast cancer risk using a large cohort of women selected for breast cancer family history, including 1054 BRCA1 or BRCA2 mutation carriers.

Methods

We analyzed a prospective cohort (N = 5606) and a larger combined, retrospective and prospective, cohort (N = 8233) of women who were aged 18 to 79 years, enrolled before June 30, 2011, with follow-up questionnaire data on medication history. The prospective cohort was further restricted to women without breast cancer when medication history was asked by questionnaire. Women were recruited from seven study centers in the United States, Canada, and Australia. Associations were estimated using multivariable Cox proportional hazards regression models adjusted for demographics, lifestyle factors, family history, and other medication use. Women were classified as regular or non-regular users of aspirin, COX-2 inhibitors, ibuprofen and other NSAIDs, and acetaminophen (control) based on self-report at follow-up of ever using the medication for at least twice a week for ≥1 month prior to breast cancer diagnosis. The main outcome was incident invasive breast cancer, based on self- or relative-report (81% confirmed pathologically).

Results

From fully adjusted analyses, regular aspirin use was associated with a 39% and 37% reduced risk of breast cancer in the prospective (HR = 0.61; 95% CI = 0.33–1.14) and combined cohorts (HR = 0.63; 95% CI = 0.57–0.71), respectively. Regular use of COX-2 inhibitors was associated with a 61% and 71% reduced risk of breast cancer (prospective HR = 0.39; 95% CI = 0.15–0.97; combined HR = 0.29; 95% CI = 0.23–0.38). Other NSAIDs and acetaminophen were not associated with breast cancer risk in either cohort. Associations were not modified by familial risk, and consistent patterns were found by BRCA1 and BRCA2 carrier status, estrogen receptor status, and attained age.

Conclusion

Regular use of aspirin and COX-2 inhibitors might reduce breast cancer risk for women at familial or genetic risk.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1135-y) contains supplementary material, which is available to authorized users.

Use of statins or NSAIDs and survival of patients with high-grade glioma

Background

High-grade glioma (HGG) is associated with a limited prognosis. Drug repurposing has become of increasing interest to improve standard therapy. Statins and NSAIDs inhibit glioma cell growth in vitro and in vivo, but data on statin and NSAID treatment in relation to survival of patients with HGG are sparse.

Methods

We performed multivariable adjusted Cox-regression analyses among 1,093 patients with HGG from a regional cancer registry to obtain Hazard Ratios (HRs) with 95% Confidence Intervals (CIs) for overall survival (OS) and progression-free survival (PFS) according to treatment with statins or NSAIDs. Data on dose and duration of treatment was mostly lacking in our analysis, therefore we were not able to perform dose-response analyses.

Results

Use of statins was unrelated to OS or PFS of glioma patients. Use of aspirin was associated with prolonged OS and PFS in patients with WHO grade III, but not WHO grade IV glioma. Use of other NSAIDs (diclofenac, ibuprofen) or non-NSAID analgesics (paracetamol) was mostly unrelated to survival of glioma patients. Use of selective COX-2 inhibitors and metamizol was related to inferior patient survival in parts of the analyses.

Conclusions

Use of statins or NSAIDS, including aspirin, was not associated with prolonged OS or PFS of patients with WHO grade IV glioma in our selected cohort. There was an indication for improved survival in patients with WHO grade III glioma using aspirin, but further studies are needed to confirm our first observation.

Low-dose aspirin use and risk of contralateral breast cancer: a Danish nationwide cohort study

Observational studies of aspirin use and breast cancer risk have provided inconsistent results. The occurrence of contralateral breast cancer (CBC) among breast cancer survivors may serve as a useful high-risk model to identify preventive drug effects. Using this model, we examined the association between post-diagnosis use of low-dose aspirin and risk of CBC. We identified all women recorded with a first primary breast cancer in the Danish Breast Cancer Cooperative Group Database between 1996 and 2012. Information on drug use, tumor and patient characteristics, treatment, and CBC was obtained from nationwide registries. In the main analysis, we defined time-varying post-diagnosis low-dose aspirin use as two or more prescriptions filled during follow-up and applied a one-year exposure lag. Cox proportional hazard regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between post-diagnosis low-dose aspirin use and CBC risk. Among 52,723 breast cancer patients, 1,444 women developed CBC during a median follow-up of 4.8 years. The adjusted HR for CBC associated with post-diagnosis use of low-dose aspirin was 0.91 (95% CI: 0.75-1.09). We observed no substantial variation in HRs according to pattern of low-dose aspirin use or estrogen receptor status of the first or the contralateral breast cancer. In conclusion, this large nationwide cohort study of breast cancer survivors does not provide strong evidence suggesting an association between post-diagnosis use of low-dose aspirin and risk of CBC.

Nonsteroidal anti-inflammatory drug use and breast cancer risk in a European prospective cohort study

Experimental studies have shown a protective effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on breast cancer development. However, results from epidemiological cohort studies are less consistent. Our objective was to assess the association between NSAID use and breast cancer risk within the European Prospective Investigation into Cancer and Nutrition (EPIC). EPIC is a prospective cohort study initiated in 1992 in 10 European countries. Self-reported information on NSAID use at baseline has been collected in five EPIC countries. Multivariable Cox regression models were used to estimate hazard ratios for the association of NSAID use with breast cancer incidence with adjustment for potential confounders. We also assessed effect modification by breast cancer risk factors and examined the associations within specific breast cancer subtypes. Among the 140,981 women included in the analysis, 7% were regularly using NSAIDs at baseline. During a median follow-up time period of 13 years, 7,379 incident breast cancer cases were diagnosed (816 in situ and 6,563 invasive). There were no statistically significant associations between NSAID use and breast cancer risk, overall and by subtypes. However, a statistically significant interaction was observed for invasive cases between NSAID use and ever use of menopausal hormonal therapy (MHT) among postmenopausal women [MHT users: HRNSAID use  = 0.84 (0.73-0.96); non MHT users: HRNSAID use  = 1.08 (0.93-1.25); pinteraction  = 0.05]. Our results indicate potential effect modification of MHT use on the association between use of NSAIDs and breast cancer risk which deserves in-depth investigation in studies with accurate data on both NSAID and MHT use.

Breast Cancer and Its Relationship with the Microbiota

The microorganisms that live symbiotically in human beings are increasingly recognized as important players in health and disease. The largest collection of these microorganisms is found in the gastrointestinal tract. Microbial composition reflects both genetic and lifestyle variables of the host. This microbiota is in a dynamic balance with the host, exerting local and distant effects. Microbial perturbation (dysbiosis) could contribute to the risk of developing health problems. Various bacterial genes capable of producing estrogen-metabolizing enzymes have been identified. Accordingly, gut microbiota is capable of modulating estrogen serum levels. Conversely, estrogen-like compounds may promote the proliferation of certain species of bacteria. Therefore, a crosstalk between microbiota and both endogenous hormones and estrogen-like compounds might synergize to provide protection from disease but also to increase the risk of developing hormone-related diseases. Recent research suggests that the microbiota of women with breast cancer differs from that of healthy women, indicating that certain bacteria may be associated with cancer development and with different responses to therapy. In this review, we discuss recent knowledge about the microbiome and breast cancer, identifying specific characteristics of the human microbiome that may serve to develop novel approaches for risk assessment, prevention and treatment for this disease.

Aspirin Disrupts the Crosstalk of Angiogenic and Inflammatory Cytokines between 4T1 Breast Cancer Cells and Macrophages

The tumor microenvironment is rich in multiple cell types that influence tumor development. Macrophages infiltrate tumors, where they are the most abundant immune cell population and secrete a number of cytokines. Aspirin acts as a chemopreventive agent against cancer development. This study investigated whether aspirin regulates crosstalk between breast cancer cells and macrophages. To study these interactions in a tumor microenvironment, a conditioned media was employed using 4T1 breast cancer cells cultured in RAW 264.7 cell-conditioned medium (RAW-CM), and a cocultured model of both cells was used. When 4T1 cells were cultured in the RAW-CM, there were increases in cell viability and secretion of the cytokines VEGF, PAI-1, TNF-α, and IL-6. Treatment with aspirin inhibited 4T1 cell growth and migration and MCP-1, PAI-1, and IL-6 production. In the coculture of both cells, aspirin inhibited secretion of MCP-1, IL-6, and TGF-β. Furthermore, aspirin significantly decreased the M2 macrophage marker CD206, but increased M1 marker CD11c expression. In summary, aspirin treatment inhibited the crosstalk of 4T1 and RAW 264.7 cells through regulation of angiogenic and inflammatory mediator production and influenced the M1/M2 macrophage subtype. This highlighted that aspirin suppresses the tumor favorable microenvironment and could be a promising agent against triple-negative breast cancer.

Cancer and platelet crosstalk: opportunities and challenges for aspirin and other antiplatelet agents

Platelets have long been recognized as key players in hemostasis and thrombosis; however, growing evidence suggests that they are also significantly involved in cancer, the second leading cause of mortality worldwide. Preclinical and clinical studies showed that tumorigenesis and metastasis can be promoted by platelets through a wide variety of crosstalk between platelets and cancer cells. For example, cancer changes platelet behavior by directly inducing tumor-platelet aggregates, triggering platelet granule and extracellular vesicle release, altering platelet phenotype and platelet RNA profiles, and enhancing thrombopoiesis. Reciprocally, platelets reinforce tumor growth with proliferation signals, antiapoptotic effect, and angiogenic factors. Platelets also activate tumor invasion and sustain metastasis via inducing an invasive epithelial-mesenchymal transition phenotype of tumor cells, promoting tumor survival in circulation, tumor arrest at the endothelium, and extravasation. Furthermore, platelets assist tumors in evading immune destruction. Hence, cancer cells and platelets maintain a complex, bidirectional communication. Recently, aspirin (acetylsalicylic acid) has been recognized as a promising cancer-preventive agent. It is recommended at daily low dose by the US Preventive Services Task Force for primary prevention of colorectal cancer. The exact mechanisms of action of aspirin in chemoprevention are not very clear, but evidence has emerged that suggests a platelet-mediated effect. In this article, we will introduce how cancer changes platelets to be more cancer-friendly and highlight advances in the modes of action for aspirin in cancer prevention. We also discuss the opportunities, challenges, and opposing viewpoints on applying aspirin and other antiplatelet agents for cancer prevention and treatment.

Dual antiplatelet therapy with clopidogrel and aspirin increases mortality in 4T1 metastatic breast cancer-bearing mice by inducing vascular mimicry in primary tumour

Platelet inhibition has been considered an effective strategy for combating cancer metastasis and compromising disease malignancy although recent clinical data provided evidence that long-term platelet inhibition might increase incidence of cancer deaths in initially cancer-free patients. In the present study we demonstrated that dual anti-platelet therapy based on aspirin and clopidogrel (ASA+Cl), a routine regiment in cardiovascular patients, when given to cancer-bearing mice injected orthotopically with 4T1 breast cancer cells, promoted progression of the disease and reduced mice survival in association with induction of vascular mimicry (VM) in primary tumour. In contrast, treatment with ASA+Cl or platelet depletion did reduce pulmonary metastasis in mice, if 4T1 cells were injected intravenously. In conclusion, distinct platelet-dependent mechanisms inhibited by ASA+Cl treatment promoted cancer malignancy and VM in the presence of primary tumour and afforded protection against pulmonary metastasis in the absence of primary tumour. In view of our data, long-term inhibition of platelet function by dual anti-platelet therapy (ASA+Cl) might pose a hazard when applied to a patient with undiagnosed and untreated malignant cancer prone to undergo VM.

Associations between aspirin use and the risk of cancers: a meta-analysis of observational studies

Background

Epidemiological studies have clarified the potential associations between regular aspirin use and cancers. However, it remains controversial on whether aspirin use decreases the risk of cancers risks. Therefore, we conducted an updated meta-analysis to assess the associations between aspirin use and cancers.

Methods

The PubMed, Embase, and Web of Science databases were systematically searched up to March 2017 to identify relevant studies. Relative risks (RRs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

Results

A total of 218 studies with 309 reports were eligible for this meta-analysis. Aspirin use was associated with a significant decrease in the risk of overall cancer (RR = 0.89, 95% CI: 0.87–0.91), and gastric (RR = 0.75, 95% CI: 0.65–0.86), esophageal (RR = 0.75, 95% CI: 0.62–0.89), colorectal (RR = 0.79, 95% CI: 0.74–0.85), pancreatic (RR = 0.80, 95% CI: 0.68–0.93), ovarian (RR = 0.89, 95% CI: 0.83–0.95), endometrial (RR = 0.92, 95% CI: 0.85–0.99), breast (RR = 0.92, 95% CI: 0.88–0.96), and prostate (RR = 0.94, 95% CI: 0.90–0.99) cancers, as well as small intestine neuroendocrine tumors (RR = 0.17, 95% CI: 0.05–0.58).

Conclusions

These findings suggest that aspirin use is associated with a reduced risk of gastric, esophageal, colorectal, pancreatic, ovarian, endometrial, breast, and prostate cancers, and small intestine neuroendocrine tumors.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4156-5) contains supplementary material, which is available to authorized users.

Pre-diagnostic aspirin use and mortality after breast cancer

BACKGROUND

Whether aspirin or other nonsteroidal anti-inflammation drug (NSAID) use is associated with mortality following breast cancer remains unclear. Consideration of use patterns and interaction with obesity may help to clarify the inconsistent results.

METHODS

Pre-diagnosis NSAID use, weight, and height were assessed ~ 3 months after diagnosis through in-person interviews with a population-based cohort of 1,442 women with first primary breast cancer. Vital status was determined through the national death index after ~ 18 years of follow-up (N = 237/597 breast cancer-specific/all-cause deaths). We used Cox proportional hazards regression to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Multiplicative interaction by body mass index (BMI) was evaluated using the likelihood ratio test.

RESULTS

Ever aspirin use was inversely associated with breast cancer-specific mortality (HR 0.87, 95% CI 0.59-1.29), but positively associated with all-cause mortality (HR 1.21, 95% CI 0.99-1.48); the CIs included the null values. The HRs, however, were more pronounced for the highest level of duration, frequency, regularity, and timing for all-cause, but not breast cancer-specific mortality. Interactions with BMI revealed no significant heterogeneity (p_interaction = 0.37 and p_interaction = 0.36, respectively).

CONCLUSION

Pre-diagnosis aspirin use was not strongly associated with mortality following breast cancer. The all-cause mortality associations, however, were slightly stronger when we considered patterns of use.

Postmenopausal breast cancer and oestrogen associations with the IgA-coated and IgA-noncoated faecal microbiota

Background:

The diversity and composition of the gut microbiota may affect breast cancer risk by modulating systemic levels of oestrogens and inflammation. The current investigation tested this hypothesis in postmenopausal women by identifying breast cancer associations with an inflammation marker, oestrogen levels, and faecal microbes that were or were not coated with mucosal immunoglobulin A (IgA).

Methods:

In this population-based study, we compared 48 postmenopausal breast cancer cases (75% stage 0–1, 88% oestrogen-receptor positive) to 48 contemporaneous, postmenopausal, normal-mammogram, age-matched controls. Microbiota metrics employed 16S rRNA gene amplicon sequencing from IgA-coated and -noncoated faecal microbes. High-performance liquid chromatography/mass spectrometry (HPLC/MS) and radioimmunoassay were used to quantify urine prostaglandin E metabolite (PGE-M), a possible marker of inflammation; urine oestrogens and oestrogen metabolites were quantified by HPLC/MS-MS.

Results:

Women with pre-treatment breast cancer had non-significantly elevated oestrogen levels; controls’ (but not cases’) oestrogens were directly correlated with their IgA-negative microbiota alpha diversity (P=0.012). Prostaglandin E metabolite levels were not associated with case status, oestrogen levels, or alpha diversity. Adjusted for oestrogens and other variables, cases had significantly reduced alpha diversity and altered composition of both their IgA-positive and IgA-negative faecal microbiota. Cases’ faecal microbial IgA-positive imputed Immune System Diseases metabolic pathway genes were increased; also, cases’ IgA-positive and IgA-negative imputed Genetic Information Processing pathway genes were decreased (P⩽0.01).

Conclusions:

Compared to controls, breast cancer cases had significant oestrogen-independent associations with the IgA-positive and IgA-negative gut microbiota. These suggest that the gut microbiota may influence breast cancer risk by altered metabolism, oestrogen recycling, and immune pressure.

Age-Specific Indicators of a Healthy Lifestyle and Postmenopausal Breast Cancer

INTRODUCTION

Modifiable lifestyle factors have been consistently associated with breast cancer, and risk may vary by menopausal status. However, whether these associations vary according to age among postmenopausal women remains unresolved.

METHODS

Using postmenopausal women from a population-based case-control study (990 cases and 1006 frequency-matched controls), we conducted multivariable-adjusted unconditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for lifestyle factors (lifetime alcohol intake, body mass index [BMI] in the year before diagnosis, lifetime recreational physical activity [RPA], and nonsteroidal anti-inflammatory drug use) in association with breast cancer stratified by age (<65 vs. 65+). We examined estrogen-related subgroups by (1) further stratifying by hormone replacement therapy (HRT) use and (2) restricting cases to estrogen receptor (ER)+/progesterone receptor (PR)+ cancers.

RESULTS

Postmenopausal breast cancer incidence in women 65 years and older was positively associated with alcohol intake (OR = 1.79 for 15-30 g/day vs. nondrinkers, 95% CI: 1.03-3.12) and BMI (OR = 1.83 for BMI ≥30 vs. <25, 95% CI: 1.29-2.60), and inversely with RPA (OR = 0.69 for fourth quartile vs. inactive, 95% CI: 0.47-1.03). For postmenopausal women younger than 65, ORs were closer to the null. Tests for heterogeneity by age were significant at the p < 0.10 level for BMI and RPA, but not alcohol. Among older women, associations were stronger among never users of HRT and for those with ER+/PR+ cancers. The inverse associations with aspirin use did not differ by age.

CONCLUSIONS

Interventions targeting modifiable lifestyle factors may reduce the burden of postmenopausal breast cancer among older women.

Cardiac glycosides use and the risk and mortality of cancer; systematic review and meta-analysis of observational studies

BACKGROUND

Cardiac glycosides (CGs) including digitalis, digoxin and digitoxin are used in the treatment of congestive heart failure and atrial fibrillation. Pre-clinical studies have investigated the anti-neoplastic properties of CGs since 1960s. Epidemiological studies concerning the association between CGs use and cancer risk yielded inconsistent results. We have performed a systematic review and meta-analysis to summarize the effects of CGs on cancer risk and mortality.

METHODS

PubMed, Scopus, Cochrane library, Medline and Web of Knowledge were searched for identifying relevant studies. Summary relative risks (RR) and 95% confidence intervals (CI) were calculated using random-effects model.

RESULTS

We included 14 case-control studies and 15 cohort studies published between 1976 and 2016 including 13 cancer types. Twenty-four studies reported the association between CGs and cancer risk and six reported the association between CGs and mortality of cancer patients. Using CGs was associated with a higher risk of breast cancer (RR = 1.330, 95% CI: 1.247-1.419). Subgroup analysis showed that using CGs increased the risk of ER+ve breast cancer but not ER-ve. Using CGs wasn't associated with prostate cancer risk (RR = 1.015, 95% CI: 0.868-1.87). However, CGs decreased the risk in long term users and showed a protective role in decreasing the risk of advanced stages. CGs use was associated with increased all-cause mortality (HR = 1.35, 95% CI: 1.248-1.46) but not cancer-specific mortality (HR = 1.075, 95% CI: 0.968-1.194).

CONCLUSION

The anti-tumor activity of CGs observed in pre-clinical studies requires high concentrations which can't be normally tolerated in humans. However, the estrogen-like activity of CGs could be responsible for increasing the risk of certain types of tumors.

Regular and low-dose aspirin, other non-steroidal anti-inflammatory medications and prospective risk of HER2-defined breast cancer: the California Teachers Study

BACKGROUND

Regular users of aspirin may have reduced risk of breast cancer. Few studies have addressed whether risk reduction pertains to specific breast cancer subtypes defined jointly by hormone receptor (estrogen and progesterone receptor) and human epidermal growth factor receptor 2 (HER2) expression. This study assessed the prospective risk of breast cancer (overall and by subtype) according to use of aspirin and other non-steroidal anti-inflammatory medications (NSAIDs) in a cohort of female public school professionals in California.

METHODS

In 1995 - 1996, participants in the California Teachers Study completed a baseline questionnaire on family history of cancer and other conditions, use of NSAIDs, menstrual and reproductive history, self-reported weight and height, living environment, diet, alcohol use, and physical activity. In 2005-2006, 57,164 participants provided some updated information, including use of NSAIDs and 1457 of these participants developed invasive breast cancer before January 2013. Multivariable Cox proportional hazards regression models provided hazard rate ratios (HRR) for the association between NSAID use and risk of invasive breast cancer as well as hormone receptor- and HER2-defined subtypes.

RESULTS

Developing breast cancer was associated inversely with taking three or more tablets of low-dose aspirin per week (23% of participants). Among women reporting this exposure, the HRR was 0.84 (95% confidence interval (CI) 0.72-0.98) compared to those not taking NSAIDs and this was particularly evident in women with the hormone receptor-positive/HER2-negative subtype (HRR = 0.80, 95% CI 0.66-0.96). Use of three or more tablets of "other" NSAIDs was marginally associated with lower risk of breast cancer (HRR = 0.79, 95% CI 0.62-1.00). Other associations with NSAIDs were generally null.

CONCLUSION

Our observation of reduced risk of breast cancer, among participants who took three or more tablets of low-dose aspirin weekly, is consistent with other reports looking at aspirin without differentiation by dose. This is the first report to suggest that the reduction in risk occurs for low-dose aspirin and not for regular-dose aspirin and only among women with the hormone receptor-positive/HER2-negative subtype. This preliminary study builds on previous knowledge and further supports the need for formal cancer chemoprevention studies of low-dose aspirin.

ADAM17 in tumor associated leukocytes regulates inflammatory mediators and promotes mammary tumor formation

The presence of inflammatory cells within the tumor microenvironment has been tightly linked to mammary tumor formation and progression. Specifically, interactions between tumor cells and infiltrating macrophages can contribute to the generation of a pro-tumorigenic microenvironment. Understanding the complex mechanisms that drive tumor cell-macrophage cross-talk will ultimately lead to the development of approaches to prevent or treat early stage breast cancers. As described here, we demonstrate that the cell surface protease a disintegrin and metalloproteinase 17 (ADAM17) is expressed by macrophages in mammary tumors and contributes to regulating the expression of pro-inflammatory mediators, including inflammatory cytokines and the inflammatory mediator cyclooxygenase-2 (Cox-2). Furthermore, we demonstrate that ADAM17 is expressed on leukocytes, including macrophages, within polyoma middle T (PyMT)-derived mammary tumors. Genetic deletion of ADAM17 in leukocytes resulted in decreased onset of mammary tumor growth, which was associated with reduced expression of the Cox-2 within the tumor. These findings demonstrate that ADAM17 regulates key inflammatory mediators in macrophages and that leukocyte-specific ADAM17 is an important promoter of mammary tumor initiation. Understanding the mechanisms associated with early stage tumorigenesis has implications for the development of preventive and/or treatment strategies for early stage breast cancers.

Aspirin Breaks the Crosstalk between 3T3-L1 Adipocytes and 4T1 Breast Cancer Cells by Regulating Cytokine Production

Breast cancer is one of the most common cancers in women worldwide. The obesity process is normally accompanied by chronic, low-grade inflammation. Infiltration by inflammatory cytokines and immune cells provides a favorable microenvironment for tumor growth, migration, and metastasis. Epidemiological evidence has shown that aspirin is an effective agent against several types of cancer. The aim of this study is to investigate the anti-inflammatory and anti-cancer effects of aspirin on 3T3-L1 adipocytes, 4T1 murine breast cancer cells, and their crosstalk. The results showed that aspirin treatment inhibited differentiation and lipid accumulation by 3T3-L1 preadipocytes, and decreased the secretion of the inflammatory adipokine MCP-1 after stimulation with tumor necrosis factor (TNF)-α or conditioned medium from RAW264.7 cells. In 4T1 cells, treatment with aspirin decreased cell viability and migration, possibly by suppressing MCP-1 and VEGF secretion. Subsequently, culture of 4T1 cells in 3T3-L1 adipocyte-conditioned medium (Ad-CM) and co-culture of 3T3-L1 and 4T1 cells using a transwell plate were performed to clarify the relationship between these two cell lines. Aspirin exerted its inhibitory effects in the transwell co-culture system, as well as the conditioned-medium model. Aspirin treatment significantly inhibited the proliferation of 4T1 cells, and decreased the production of MCP-1 and PAI-1 in both the Ad-CM model and co-culture system. Aspirin inhibited inflammatory MCP-1 adipokine production by 3T3-L1 adipocytes and the cell growth and migration of 4T1 cells. It also broke the crosstalk between these two cell lines, possibly contributing to its chemopreventive properties in breast cancer. This is the first report that aspirin’s chemopreventive activity supports the potential application in auxiliary therapy against obesity-related breast cancer development.