Endogenous hormones and risk of invasive breast cancer in pre- and post-menopausal women: findings from the UK Biobank

Non-occupational exposure to cadmium and breast cancer: A comprehensive and critical review

Breast cancer (BC) is a multifactorial disease with unresolved etiology. Environmental pollutants, primarily trace metals, play a pivotal role in the pathophysiological cascade of malignant tumors, including BC. In this up-to-date review, we comprehensively and critically examined the relationship between cadmium (Cd) and BC. For this purpose, peer-reviewed studies from relevant databases (PubMed, SCOPUS, and Cochrane Library) over the last 40 years were retrieved and analyzed. We found that in vitro and in vivo studies strongly support the view that Cd has harmful effects on breast health. According to the human studies, we found that Cd could be responsible for the development and progression of malignant breast tumors due to markedly higher levels in clinical matrices of cases (whole blood, urine, breast tissue, keratin materials) than in clinical matrices of controls. Cadmium does not appear to affect BC density. In contrast, Cd has been found to have a detrimental effect on sex hormones, disrupting the balance of estrogen and androgen. We found that studies looking at dietary Cd intake and BC risk generally (without measuring urine or blood Cd) do not support the association between dietary Cd intake and BC risk. In notable contrast, studies looking at dietary Cd intake and BC risk by measuring Cd in urine or blood generally support this association. The effect of airborne Cd on BC risk was weak, but in favor of specific histological forms, primarily ER-/PR- invasive tubular breast carcinomas. Regardless of the intake route of Cd into the body, it can be concluded that Cd has a harmful effect on breast health. However, well-designed longitudinal, mechanistic, meta-analytic, and other studies are urgently needed to confirm the exact role of environmental Cd in breast carcinogenesis.

Association between triglyceride-glucose related indicators, genetic risk, and incident breast cancer among postmenopausal women in UK Biobank

BACKGROUND

The potential links between triglyceride-glucose (TyG) related indicators and breast cancer incidence after menopause have been less well studied, and the joint associations between genetic risk, TyG related indicators, and breast cancer are unknown.

METHODS

Simple surrogate indicators of insulin resistance including TyG, TyG-waist circumference (TyG-WC), TyG-waist to height ratio (TyG-WHtR), TyG-waist to hip ratio (TyG-WHR), TyG-body mass index (TyG-BMI). Genetic susceptibility in breast cancer was estimated by categorizing polygenic risk scores (PRS). For estimating the associations, we used Cox proportional hazards regression modeling. Correlation shapes were evaluated using restricted cubic splines (RCS). Mediation analyses for assessing the role of sex hormone-binding globulin (SHBG), C-reactive protein (CRP), testosterone, and glycosylated hemoglobin (HbA1c) in mediating the associations were conducted.

RESULTS

The study included 83,873 UK biobank participants who were followed for a median of 13.8 years, with 3,561 new cases of postmenopausal breast cancer. Genetic risk and TyG related indicators were monotonically related to breast cancer, with additive but not multiplicative interactions between them. The highest quartiles of TyG, TyG-WC, TyG-WHtR, TyG-WHR, and TyG-BMI were significantly associated with increased breast cancer risk with hazard ratio (95% confidence interval) were 1.12 (1.01-1.25), 1.35 (1.23-1.49), 1.16 (1.05-1.28), 1.22(1.12-1.33), and 1.31 (1.19-1.44), respectively. TyG-WC was nonlinearly linked to breast cancer (P for nonlinear = 0.006). Individuals with high genetic risk and high TyG related indicators exhibited a substantially elevated breast cancer risk by 4- to 5-fold compared with reference group. The associations were mainly mediated by SHBG, CRP, and testosterone, with mediation proportions ranging from 10.24% to 68.29%.

CONCLUSIONS

TyG related factors are linked to incident postmenopausal breast cancer, and the combined effects with genetic risk significantly optimize risk stratification. High levels of TyG related indicators may amplify the influence of genetic factors on postmenopausal breast cancer.

TRIAL REGISTRATION

Not applicable.

Constructing shared genetic architecture between bioavailable testosterone and luminal A breast cancer in female

BACKGROUND

Observational studies have showed a strong association between bioavailable testosterone (BT) and breast cancer. However, the role of genetic factors in their comorbidity remains unknown.

METHODS

Using large genome-wide association study (GWAS) data, we employed linkage disequilibrium score regression (LDSC) to identify the breast cancer subtype most genetically correlated with BT. We then constructed the shared genetic architecture between BT and this subtype by: (1) applied Heritability Estimation from Summary Statistics for local genetic correlations and stratified-LDSC for partitioned heritability; (2) performed a cross-trait GWAS meta-analysis to find novel single-nucleotide polymorphism (SNP) and validated through colocalization; (3) conducted both cross-tissue and single-tissue transcriptome-wide association studies (TWAS) and validated the candidate genes through Mendelian randomization (MR); (4) investigated SNP-heritability enrichment at the gene set, tissue, and cell levels using Multi-marker Analysis of GenoMic Annotation.

RESULTS

Luminal A breast cancer (Luminal ABC) was selected as it is a common subtype of breast cancer and demonstrates a superior genetic correlation with BT. We identified strong local correlations in 132 distinct genomic regions and confirmed shared SNPs including rs1432679 and rs7175852. TWAS highlighted two pleiotropic genes, MICALL1 and TRIOBP, with TRIOBP validated by MR. We also found six shared pathways and luminal cells in mammary gland pregnancy shared between BT and Luminal ABC. For tissue-specific enrichment, BT was mainly found in the liver and adrenal gland, whereas Luminal ABC was found in the minor salivary gland.

CONCLUSIONS

This study sheds light on the genetic architecture of BT and Luminal ABC and suggests new avenues for research and therapy.

Hormone-associated dietary patterns and premenopausal breast cancer risk

PURPOSE

Circulating levels of sex steroid hormones have previously been associated with premenopausal breast cancer risk. Few studies have considered the association between dietary patterns and premenopausal hormone levels. Our objective was to derive dietary patterns associated with premenopausal hormone levels and investigate the association between pattern scores and premenopausal breast cancer risk.

METHODS

Using reduced rank regression among a subset of participants from the Nurses' Health Study II (NHSII) (n = 8,962), we identified dietary patterns correlated with premenopausal levels of five sex steroid hormones measured in the follicular and luteal phases. Then, in the full NHSII cohort (n = 90,341), we used Cox proportional hazards models to calculate hazard ratios (HRs) for breast cancer risk associated with each dietary pattern score.

RESULTS

Dietary patterns were identified for luteal estradiol, luteal free estradiol, follicular estrone, luteal estrone, and free testosterone. However, these patterns explained a low percent variation in individual hormone levels, ranging from 2.5-4.1%. During 24 years of follow-up, 1,956 premenopausal breast cancer cases were ascertained. Dietary patterns associated with luteal free estradiol (HR for fifth versus first quintile = 1.29; 95% CI = 1.11-1.49; Ptrend < 0.01) and follicular estrone (HR for fifth versus first quintile = 1.28; 95% CI = 1.10-1.49; Ptrend < 0.01) were positively associated with premenopausal breast cancer risk.

CONCLUSION

Our findings indicate that while some dietary factors may marginally influence premenopausal hormone levels, the relation between sex steroid hormones and premenopausal breast cancer risk is likely not driven by diet. Future studies should consider other mechanisms through which diet may impact breast cancer risk, including inflammatory processes.

Multilayer analysis of ethnically diverse blood and urine biomarkers for breast cancer risk and prognosis

Breast cancer (BC) is one of the most common malignancies among women globally, characterized by complex pathogenesis involving various biomarkers present in blood and urine. To enhance understanding of the genetic associations between biomarkers and BC via multidimensional, cross ethnic investigations. Based on GWAS data of 35 blood and urine biomarkers from European populations, we adopted multiple analysis strategies including univariable Mendelian randomization (MR) analysis, reverse MR analysis, sensitivity analysis and multivariate MR to identify potential biomarkers associated with BC risk and survival. Our initial analysis included 122,977 BC and 105,974 controls of European ancestry. Building upon these findings, we conducted cross ethnic validation by applying the same analyses to East Asian populations using data from the IEU GWAS database, which included 5,552 BC and 89,731 controls. This step allowed us to investigate the universality and heterogeneity of our identified biomarkers across different ancestries. Subsequently, utilizing clinical laboratory detection data from multiple regions in China, we performed differential analyses and survival assessments on these potential biomarkers to evaluate their clinical relevance and utility. Notably, we leveraged Luzhou's clinical data to integrate HDL-C with conventional tumor markers (CEA, CA125, CA153) into a machine learning model, comparing its diagnostic efficacy against tumor marker combination. Our study validated associations of ALP, HDL-C, TG, SHBG, and IGF-1 with BC risk, reinforcing the reliability of these findings. Moreover, notable interethnic disparities emerged in the association between HDL-C and BC risk, where in HDL-C demonstrates a contrasting role: acting as a genetic protective agent against BC and suggesting promise as an auxiliary diagnostic marker in East Asian populations, yet inversely, it serves as a genetic dangerous predictor in European populations. Analyzing BC subtypes, we identified associations of HDL-C, TG, SHBG, and CRP with ER+BC, while ER-BC showed associations with GLU, urinary creatinine and microalbuminuria, underscoring subtype-specific genetic characteristics critical for personalized prevention and treatment strategies. Overall, this comprehensive study, by traversing the intricate landscape of genetic associations across ethnic boundaries and employing advanced analytical methodologies, not only uncovers the complex interplay between key biomarkers and BC susceptibility but also highlights the significance of ethnic-specific differences in the role of HDL-C. By enhancing the diagnostic power of a tailored biomarker panel through machine learning, this study contributes to the advancement of precision medicine in BC, offering strategies tailored to the unique genetic profiles and biomarker patterns across diverse populations.

Hereditary Breast Cancer: Comprehensive Risk Assessment and Prevention Strategies

Women carrying pathogenic/likely pathogenic (P/LP) variants in moderate- or high-penetrance genes have an increased risk of developing breast cancer. However, most P/LP variants associated with breast cancer risk show incomplete penetrance. Age, gender, family history, polygenic risk, lifestyle, reproductive, hormonal, and environmental factors can affect the expressivity and penetrance of the disease. However, there are gaps in translating how individual genomic variation affects phenotypic presentation. The expansion of criteria for genetic testing and the increasing utilization of comprehensive genetic panels may enhance the identification of individuals carrying P/LP variants linked to hereditary breast cancer. Individualized risk assessment could facilitate the implementation of personalized risk-reduction strategies for these individuals. Preventive interventions encompass lifestyle modifications, chemoprevention, enhanced surveillance through breast imaging, and risk-reducing surgeries. This review addresses the current literature's inconsistencies and limitations, particularly regarding risk factors and the intensity of preventive strategies for women with P/LP variants in moderate- and high-penetrance genes. In addition, it synthesizes the latest evidence on risk assessment and primary and secondary prevention in women at high risk of breast cancer.

Role of a Whole Plant Foods Diet in Breast Cancer Prevention and Survival

Breast cancer (BC) is one of the leading causes of death and morbidity among women worldwide. Epidemiologic evidence shows that the risk of BC and other chronic diseases decreases as the proportion of whole plant foods increases, while the proportion of animal foods (fish, meat, poultry, eggs, seafood, and dairy products) and non-whole plant foods (e.g., refined grains, added sugars, French fries) in the diet decreases. Whole plant foods include fruits, vegetables, roots, tubers, whole grains, legumes, nuts, and seeds from which no edible part has been removed and to which no non-whole food been added. A whole plant foods diet lowers insulin resistance, inflammation, excess body fat, cholesterol, and insulin-like growth factor 1 and sex hormone bioavailability; it also increases estrogen excretion, induces favorable changes in the gut microbiota, and may also favorably affect mammary microbiota composition and decrease the risk of early menarche, all contributing to reduced BC incidence, recurrence, and mortality. This review explores the connection between a whole plant foods diet and BC risk and mortality as well as the potential mechanisms involved. Additionally, this diet is compared with other dietary approaches recommended for BC. A whole plant foods diet seems the optimal dietary pattern for BC and overall disease prevention as it exclusively consists of whole plant foods which, based on existing evidence, lead to the best health outcomes.

Investigation of the relationship between breast cancer and clinical symptoms of polycystic ovarian syndrome: a case-control study

BACKGROUND

Breast cancer is the most commonly diagnosed cancer among women worldwide, and it is associated with significant number of metabolic and reproductive risk factors. Despite the overlap between hormonal and metabolic factors involved in the development of PCOS and many known risk factors for breast cancer, the relationship between PCOS and breast cancer, the most common type of cancer among women, remains unknown. This study was conducted with the aim of determining the relationship between breast cancer and clinical symptoms of PCOS.

METHODS

This case-control study was conducted on 285 women with breast cancer and 285 healthy women referred to three centers in Tehran in 2023. Both the case and control groups were matched in terms of age and body mass index. The data collection tool in this study was a researcher-made data registration form, that was completed in person by qualified individuals. A history of PCOS was identified according to the Rotterdam criteria. Women aged 15-49 years who were able to read and write were included in the study. The case group had a history of breast cancer, while the control group did not. Participants who did not consent to having their data use in the analysis were excluded. Data was analyzed using an independent t-test, a chi-square test and a logistic regression model.

RESULTS

The mean age of the participants in the case group was 43.05 ± 4.92 years and that of the control group was 42.78 ± 5.06 years. The two groups showed a statistically significant difference in terms of PCOS history (p < 0.001). After adjusting for confounding variables, the logistic regression model showed that women with PCOS had a significantly higher chance of developing breast cancer (0R: 3.677, 95%CI: 1.529-8.840, P = 0.004). Among PCOS symptoms, women with a history of hirsutism had a higher chance of developing breast cancer (OR: 2.188, 95% CI: 1.014-4.720, P = 0.046).

CONCLUSION

The findings of the present study suggest that PCOS is a risk factor for breast cancer. Well-designed further studies are highly recommended to determine the role of PCOS in predicting breast cancer.

The implications of hormone treatment for cancer risk, screening and treatment in transgender individuals

There is evidence that gender-affirming hormone treatment (GAHT) for transgender individuals modulates their risk for specific malignancies including breast and prostate cancer, and meningiomas. However, there is insufficient data to make precise risk estimates accounting for age and inherited cancer risk. As such, screening recommendations remain broad. Even less evidence exists for best practice in the management of active or historical cancers in the transgender population. Guidance is therefore mainly extrapolated from cisgender populations but with considerations of the significant benefits of GAHT in the face of any hormonal risk. Clinical experience, the multidisciplinary team and shared decision making with the patient are vital in providing person-centred care, while further research is acquired.

Breast and cervical cancer in transgender men: literature review and a case report

Transgender individuals exhibit a higher prevalence of cancer-related risk factors, such as substance abuse and sexually transmitted infections. These factors, coupled with suboptimal adherence to cancer screening recommendations, may lead to a higher incidence of cancers, such as breast and cervical cancer, and contribute to delayed diagnoses in transgender patients. Herein, we report a unique case of a transgender man with a history of alcohol and drug abuse, undergoing gender-affirming exogenous testosterone therapy, who developed synchronous locally advanced breast cancer and human papilloma virus (HPV)-related cervical cancer. He underwent concurrent chemoradiation for cervical cancer and surgery followed by endocrine therapy for breast cancer. The treatments were suboptimals due to patient's comorbidities, among them liver cirrhosis leading to an early death. Additionally, we have conducted a review of existing literature, including case reports, clinical studies, and review articles investigating the role of potential risk factors specifically related to breast and cervical tumors in transgender men. Gender-affirming testosterone therapy is common among transgender men to induce gender affirmation, but its link to breast cancer risk remains ambiguous, with studies being limited and sometimes contradictory. Conversely, HPV is a well-established cause of up to 99% of cervical cancers. Despite persistent risk for cervical cancer in transgender men who retain their cervix, several studies indicate notable disparities in screening adherence, due to personal and structural barriers. Moreover, alcohol and drug use disorders, commonly encountered in transgender population, may negatively influence the adherence to screening programs. Current cancer screening guidelines for this population are somewhat unclear, and specific programs based on more robust data are urgently required along with further tailored studies.

Androgen receptor: Structure, signaling, function and potential drug discovery biomarker in different breast cancer subtypes

The Androgen Receptor (AR) is emerging as an important factor in the pathogenesis of breast cancer (BC), which is the most common malignancy worldwide. >70 % of AR expression in primary and metastatic breast tumors has been observed which suggests that AR may be a new marker and a potential therapeutic target among AR-positive BC patients. Biological insight into AR-positive breast cancer reveals that AR may cross-talk with several vital signaling pathways, including key molecules and receptors. Downstream signaling of AR might also affect many clinically important pathways that are emerging as clinical targets in BC. AR exhibits different behaviors depending on the breast cancer molecular subtype. Preliminary clinical research using AR-targeted drugs, which have already been FDA-approved for prostate cancer (PC), has given promising results for AR-positive breast cancer patients. However, since AR positivity's prognostic and predictive value remains uncertain, it is difficult to identify and stratify patients who would benefit from AR-targeted therapies alone. Thus, the need of the hour is to target the androgen receptor as a monotherapy or in combination with other conventional therapies which has proven to be an effective clinical strategy for the treatment of prostate cancer patients, and these therapeutic strategies are increasingly being investigated in breast cancer. Therefore, in this manuscript, we review the role of AR in various cellular processes that promote tumorigenesis and aggressiveness, in different subtypes of breast cancer, as well as discuss ongoing efforts to target AR for the more effective treatment and prevention of breast cancer.

Sex-steroid hormones and risk of postmenopausal estrogen receptor-positive breast cancer: a case-cohort analysis

PURPOSE

Sex-steroid hormones are associated with postmenopausal breast cancer but potential confounding from other biological pathways is rarely considered. We estimated risk ratios for sex-steroid hormone biomarkers in relation to postmenopausal estrogen receptor (ER)-positive breast cancer, while accounting for biomarkers from insulin/insulin-like growth factor-signaling and inflammatory pathways.

METHODS

This analysis included 1208 women from a case-cohort study of postmenopausal breast cancer within the Melbourne Collaborative Cohort Study. Weighted Poisson regression with a robust variance estimator was used to estimate risk ratios (RRs) and 95% confidence intervals (CIs) of postmenopausal ER-positive breast cancer, per doubling plasma concentration of progesterone, estrogens, androgens, and sex-hormone binding globulin (SHBG). Analyses included sociodemographic and lifestyle confounders, and other biomarkers identified as potential confounders.

RESULTS

Increased risks of postmenopausal ER-positive breast cancer were observed per doubling plasma concentration of progesterone (RR: 1.22, 95% CI 1.03 to 1.44), androstenedione (RR 1.20, 95% CI 0.99 to 1.45), dehydroepiandrosterone (RR: 1.15, 95% CI 1.00 to 1.34), total testosterone (RR: 1.11, 95% CI 0.96 to 1.29), free testosterone (RR: 1.12, 95% CI 0.98 to 1.28), estrone (RR 1.21, 95% CI 0.99 to 1.48), total estradiol (RR 1.19, 95% CI 1.02 to 1.39) and free estradiol (RR 1.22, 95% CI 1.05 to 1.41). A possible decreased risk was observed for SHBG (RR 0.83, 95% CI 0.66 to 1.05).

CONCLUSION

Progesterone, estrogens and androgens likely increase postmenopausal ER-positive breast cancer risk, whereas SHBG may decrease risk. These findings strengthen the causal evidence surrounding the sex-hormone-driven nature of postmenopausal breast cancer.

The chronic alcohol consumption influences the gonadal axis in men: Results from a meta-analysis

BACKGROUND

Low testosterone concentrations affect 2-13% of adult males, with a direct association between reduction in testosterone (T) concentrations and cardiovascular events. Lifestyle habits have been linked to visceral fat accumulation and endocrine disorders like secondary hypogonadism. Alcohol intake has also been a topic of debate, with studies showing a detrimental effect on sperm production and underlying mechanisms. This meta-analysis aims to comprehensively evaluate the effect of alcohol consumption on T serum concentrations in adult men.

METHODS

The literature search included only controlled clinical trials comparing men who drink alcohol to men who do not, or who assumed placebo or nonalcoholic beverages. The primary outcome was the comparison of total testosterone serum concentrations between the study and control groups. The publications were examined for publication bias using Egger's test.

RESULTS

Twenty-one studies were included in the analysis for a total of 30 trials that examined the effects of alcohol consumption on testosterone level in 10,199 subjects. The meta-analysis showed that alcohol consumption overall is related to significant reduction in circulating concentrations of total testosterone (mean difference [MD] = -4.02; 95% CI -6.30, -1.73), free T (MD = -0.17; 95% CI -0.23, -0.12), sex hormone binding globulin (SHBG) (MD = -1.94; 95% CI -3.37, -0.48), an increase in estradiol (E2) (MD = 7.65; 95% CI 1.06, 14.23) and neutral effect on luteinizing hormone (LH) (MD = -0.15; 95% CI -0.36, 0.06), independently by age, body mass index (BMI), E2, and LH serum concentrations and alcohol intake. However, these results are evident only in healthy men exposed to chronic alcohol consumption and not in those with a recognized diagnosis of alcohol use disorder or after acute alcohol intake.

CONCLUSION

This study suggests how chronic alcohol consumption may inhibit the gonadal axis in healthy men, although the exact pathophysiological mechanisms connecting alcohol exposure and steroidogenesis are still not completely clarified.

Testosterone therapy in females is not associated with increased cardiovascular or breast cancer risk: a claims database analysis

BACKGROUND

Testosterone therapy (TTh) has been shown to improve libido in women with sexual dysfunction, but its utilization has been limited due to concern for cardiovascular events and past studies reporting highly variable results.

AIM

To assess the association of TTh in women with major adverse cardiac events (MACEs), including heart attack, stroke, or death, using a large database.

METHODS

The TriNetX Diamond Network was queried from 2009 to 2022. Our study cohort included adult females with ≥3 systemic testosterone prescriptions within a year. Our control cohort excluded females with any testosterone prescriptions, polycystic ovary syndrome, or androgen excess. Both cohorts excluded females with prior heart failure, unstable angina, intersex surgery (female to male), personal history of sex reassignment, or gender identity disorders. Propensity matching between the cohorts was performed. A subanalysis by age was conducted (18-55 and >55 years).

OUTCOMES

We evaluated the association of TTh to the following: MACE, upper or lower emboli or deep vein thrombosis (DVT), pulmonary embolism (PE), breast neoplasm, and hirsutism within 3 years of TTh.

RESULTS

When compared with propensity-matched controls, adult females with TTh had a lower risk of MACE (risk ratio [RR], 0.64; 95% CI, 0.51-0.81), DVT (RR, 0.61; 95% CI, 0.42-0.90), PE (RR, 0.48; 95% CI, 0.28-0.82), and malignant breast neoplasm (RR, 0.48; 95% CI, 0.37-0.62). Similarly, females aged 18 to 55 years with TTh had a lower risk of MACE (RR, 0.49; 95% CI, 0.28-0.85) and DVT (RR, 0.48; 95% CI, 0.25-0.93) and a similar risk of malignant breast neoplasm (RR, 0.62; 95% CI, 0.34-1.12). Females aged ≥56 years with TTh had a similar risk of MACE (RR, 0.84; 95% CI, 0.64-1.10), DVT (RR, 0.82; 95% CI, 0.50-1.36), and PE (RR, 0.52; 95% CI, 0.26-1.05) and a significantly lower risk of malignant breast neoplasm (RR, 0.51; 95% CI, 0.38-0.68). Risk of hirsutism was consistently higher in those with TTh as compared with propensity-matched controls.

CLINICAL IMPLICATIONS

Our results contribute to safety data on TTh, a therapy for sexual dysfunction in women.

STRENGTHS AND LIMITATIONS

The TriNetX Diamond Network allows for significant generalizability but has insufficient information for some factors.

CONCLUSIONS

We found a decreased risk of MACE among women with TTh as compared with matched controls and a similar risk of MACE in postmenopausal women while demonstrating a similar or significantly lower risk of breast cancer on age-based subanalysis.

Variation Analysis in Premenopausal and Postmenopausal Breast Cancer Cases

Menopausal status affects the prognoses and consequences of breast cancer. Therefore, this retrospective study aimed to reveal the molecular variation profile differences in breast cancer patients according to their menopausal status, with the hypothesis that the molecular variation profiles will be different at premenopausal and postmenopausal ages. Breast cancer patients (n = 254) who underwent molecular subtyping and QIAseq Human Breast Cancer NGS Panel screening between 2018 and 2022 were evaluated retrospectively. Their menopausal status was defined by age, and those aged 50 years and above were considered postmenopausal. Of the subjects, 58.66% (n = 149) were premenopausal and 41.34% (n = 105) were postmenopausal. The mean age at the time of diagnosis for all patients was 49.31 ± 11.19 years, with respective values of 42.11 ± 5.51 and 59.54 ± 9.01 years for the premenopausal and postmenopausal groups, respectively (p = 0.000). Among premenopausal patients, the percentages of patients in BCa subtypes (luminal A, luminal B-HER2(-), luminal B-HER2(+), HER2 positive, and triple-negative) were determined to be 34.90%, 8.05%, 26.17%, 10.74%, and 20.13%, respectively, while in the postmenopausal group, these values were 39.05%, 16.19%, 24.76%, 6.67%, and 13.33%, respectively (p > 0.05). Considering menopausal status, the distribution of hormone receptors in premenopausal patients was ER(+)/PgR(+) 63.76%, ER(-)/PgR(-) 23.49%, ER(+)/PgR(-) 10.74%, and ER(-)/PgR(+) 2.01%, respectively, while in postmenopausal women, this distribution was observed to be 74.29%, 23.81%, 1.90% and 0.00% in the same order (p = 0.008). The most frequently mutated gene was TP53 in 130 patients (51.18%), followed by PIK3CA in 85 patients (33.46%), BRCA2 and NF1 in 56 patients (22.05%), PTEN in 54 patients (21.26%), and ATR and CHEK2 in 53 patients (20.87%). TP53, PIK3CA, NF1, BRCA2, PTEN, and CHEK2 mutations were more frequently observed in premenopausal patients, while TP53, PIK3CA, BRCA2, BRCA1, and ATR mutations in postmenopausal patients. These findings contribute to a deeper understanding of the underlying causes of breast cancer with respect to menopausal status. This study is the first from Turkey that reflects the molecular subtyping and somatic mutation profiles of breast cancer patients according to menopausal status.

Obesity-Dependent Association of the rs10454142 PPP1R21 with Breast Cancer

The purpose of this work was to find a link between the breast cancer (BC)-risk effects of sex hormone-binding globulin (SHBG)-associated polymorphisms and obesity. The study was conducted on a sample of 1498 women (358 BC; 1140 controls) who, depending on the presence/absence of obesity, were divided into two groups: obese (119 BC; 253 controls) and non-obese (239 BC; 887 controls). Genotyping of nine SHBG-associated single nucleotide polymorphisms (SNP)-rs17496332 PRMT6, rs780093 GCKR, rs10454142 PPP1R21, rs3779195 BAIAP2L1, rs440837 ZBTB10, rs7910927 JMJD1C, rs4149056 SLCO1B1, rs8023580 NR2F2, and rs12150660 SHBG-was executed, and the BC-risk impact of these loci was analyzed by logistic regression separately in each group of obese/non-obese women. We found that the BC-risk effect correlated by GWAS with the SHBG-level polymorphism rs10454142 PPP1R21 depends on the presence/absence of obesity. The SHBG-lowering allele C rs10454142 PPP1R21 has a risk value for BC in obese women (allelic model: CvsT, OR = 1.52, 95%CI = 1.10-2.11, and pperm = 0.013; additive model: CCvsTCvsTT, OR = 1.71, 95%CI = 1.15-2.62, and pperm = 0.011; dominant model: CC + TCvsTT, OR = 1.95, 95%CI = 1.13-3.37, and pperm = 0.017) and is not associated with the disease in women without obesity. SNP rs10454142 PPP1R21 and 10 proxy SNPs have adipose-specific regulatory effects (epigenetic modifications of promoters/enhancers, DNA interaction with 51 transcription factors, eQTL/sQTL effects on five genes (PPP1R21, RP11-460M2.1, GTF2A1L, STON1-GTF2A1L, and STON1), etc.), can be "likely cancer driver" SNPs, and are involved in cancer-significant pathways. In conclusion, our study detected an obesity-dependent association of the rs10454142 PPP1R21 with BC in women.

Characteristics of systemic testosterone therapy for female hypoactive sexual desire disorder-a claims database analysis

BACKGROUND

Testosterone therapy (TTh) is recommended for postmenopausal women with hypoactive sexual desire disorder (HSDD); however, there remain insufficient data to support use of TTh in premenopausal women with sexual dysfunction.

AIM

In this study, we used a large national database to evaluate prescribing trends of TTh for women with HSDD.

METHODS

We conducted a cohort analysis of information from electronic health records acquired from the data network TriNetX Diamond. The study cohort consisted of women 18-70 years of age with a diagnosis of HSDD. We analyzed trends of testosterone prescriptions, routes of testosterone administration, and coadministration of testosterone with estrogen.

OUTCOMES

Despite an increase in rates of testosterone prescriptions for HSDD, there remains a high degree of variability in the duration of treatment, route of administration, and coadministration of estrogen with significant underprescription of testosterone.

RESULTS

Our query of the TriNetX database led to the identification of 33 418 women diagnosed with HSDD at a mean age of 44.2 ± 10.8 years, among whom 850 (2.54%) women received a testosterone prescription. The testosterone prescriptions were highly variable with regard to duration and route of administration and coadministration with estrogen. For all patients until 2015, the prevalence of testosterone prescriptions for HSDD showed a positive quadratic relation was observed. Since 2015 a linear increase in prevalence was observed, with the highest rate of increase for patients aged 41-55 years.

CLINICAL IMPLICATIONS

The findings of this study reveal a significant need for further research investigating the optimal use of TTh to enhance the sexual health of women with HSDD, and further studies on the long-term effects of testosterone use must be undertaken to ensure that patients have access to safe and effective treatment.

STRENGTHS AND LIMITATIONS

Limitations to this study include patient de-identification and lack of availability of testosterone dosage data. However, this study also has many strengths, including being the first, to our knowledge, to characterize the prescribing trends of testosterone for women with HSDD.

CONCLUSION

Testosterone therapy should be considered as a potential therapy for premenopausal female patients with HSDD. Further studies on the long-term effects of testosterone use must be undertaken to address disparities in the management of HSDD and to ensure patients can access treatment.

Sex-Hormone-Binding Globulin Gene Polymorphisms and Breast Cancer Risk in Caucasian Women of Russia

In our work, the associations of GWAS (genome-wide associative studies) impact for sex-hormone-binding globulin (SHBG)-level SNPs with the risk of breast cancer (BC) in the cohort of Caucasian women of Russia were assessed. The work was performed on a sample of 1498 women (358 BC patients and 1140 control (non BC) subjects). SHBG correlated in previously GWAS nine polymorphisms such as rs780093 GCKR, rs17496332 PRMT6, rs3779195 BAIAP2L1, rs10454142 PPP1R21, rs7910927 JMJD1C, rs4149056 SLCO1B1, rs440837 ZBTB10, rs12150660 SHBG, and rs8023580 NR2F2 have been genotyped. BC risk effects of allelic and non-allelic SHBG-linked gene SNPs interactions were detected by regression analysis. The risk genetic factor for BC developing is an SHBG-lowering allele variant C rs10454142 PPP1R21 ([additive genetic model] OR = 1.31; 95%CI = 1.08-1.65; pperm = 0.024; power = 85.26%), which determines 0.32% of the cancer variance. Eight of the nine studied SHBG-related SNPs have been involved in cancer susceptibility as part of nine different non-allelic gene interaction models, the greatest contribution to which is made by rs10454142 PPP1R21 (included in all nine models, 100%) and four more SNPs-rs7910927 JMJD1C (five models, 55.56%), rs17496332 PRMT6 (four models, 44.44%), rs780093 GCKR (four models, 44.44%), and rs440837 ZBTB10 (four models, 44.44%). For SHBG-related loci, pronounced functionality in the organism (including breast, liver, fibroblasts, etc.) was predicted in silico, having a direct relationship through many pathways with cancer pathophysiology. In conclusion, our results demonstrated the involvement of SHBG-correlated genes polymorphisms in BC risk in Caucasian women in Russia.

Low levels of sex hormone-binding globulin predict an increased breast cancer risk and its underlying molecular mechanisms

Sex hormone-binding globulin (SHBG) is a serum glycoprotein exhibiting the unique feature of binding sex steroids with high affinity and specificity. Over the past few decades, there have been significant breakthroughs in our understanding of the function and regulation of SHBG. The biological role of SHBG has expanded from being considered a simple sex hormone transporter to being associated with several complex physiological and pathological changes in a variety of target tissues. Many factors can affect the plasma SHBG levels, with fluctuations in circulating levels affecting the development of various diseases, such as increasing the risk of developing breast cancer. This article reviews the clinical significance of changes in circulating SHBG levels in the development of breast cancer and the possible influence of these levels on endocrine drug resistance in hormone receptor-positive breast cancer. Higher levels of plasma SHBG significantly reduce the risk of estrogen receptor-positive breast cancer, especially in postmenopausal women. Moreover, the molecular mechanisms by which SHBG affects breast cancer risk are also summarized in detail. Finally, transcriptomics and proteomics data revealed that SHBG expression in breast tissue can effectively distinguish breast cancer from normal tissue. Additionally, the association between SHBG expression levels and various classical tumor-related pathways was investigated.

Hematological and biochemical markers influencing breast cancer risk and mortality: Prospective cohort study in the UK Biobank by multi-state models

BACKGROUND

Breast cancer is the most common cancer and the leading cause of cancer-related death among women. However, evidence concerning hematological and biochemical markers influencing the natural history of breast cancer from in situ breast cancer to mortality is limited.

METHODS

In the UK Biobank cohort, 260,079 women were enrolled during 2006-2010 and were followed up until 2019 to test the 59 hematological and biochemical markers associated with breast cancer risk and mortality. The strengths of these associations were evaluated using the multivariable Cox regression models. To understand the natural history of breast cancer, multi-state survival models were further applied to examine the effects of biomarkers on transitions between different states of breast cancer.

RESULTS

Eleven biomarkers were found to be significantly associated with the risk of invasive breast cancer, including mainly inflammatory-related biomarkers and endogenous hormones, while serum testosterone was also associated with the risk of in-situ breast cancer. Among them, C-reactive protein (CRP) was more likely to be associated with invasive breast cancer and its transition to death from breast cancer (HR for the highest quartile = 1.46, 95 % CI = 1.07-1.97), while testosterone and insulin-like growth factor-1 (IGF-1) were more likely to impact the early state of breast cancer development (Testosterone: HR for the highest quartile = 1.31, 95 % CI = 1.12-1.53; IGF-1: HR for the highest quartile = 1.17, 95 % CI = 1.00-1.38).

CONCLUSION

Serum CRP, testosterone, and IGF-1 have different impacts on the transitions of different breast cancer states, confirming the role of chronic inflammation and endogenous hormones in breast cancer progression. This study further highlights the need of closer surveillance for these biomarkers during the breast cancer development course.

Prospective study design and data analysis in UK Biobank

Population-based prospective studies, such as UK Biobank, are valuable for generating and testing hypotheses about the potential causes of human disease. We describe how UK Biobank's study design, data access policies, and approaches to statistical analysis can help to minimize error and improve the interpretability of research findings, with implications for other population-based prospective studies being established worldwide.

Immunomodulatory effects of exercise in cancer prevention and adjuvant therapy: a narrative review

Successful application of cancer immunotherapy has rekindled hope in cancer patients. However, a number of patients are unresponsive to immunotherapy and related treatments. This unresponsiveness in cancer patients toward different treatment regimens can be mainly attributed to severe immune dysfunction in such patients. Several reports indicate that physical exercise can significantly lead to improved cancer patient outcomes. Since exercise gets immense response from the immune system, it can be utilized to improve immune function. Leukocytes with enhanced functions are substantially mobilized into the circulation by a single bout of intense physical exercise. Chronic physical exercise results in greater muscle endurance and strength and improved cardiorespiratory function. This exercise regime is also useful in improving T-cell abundance and reducing dysfunctional T cells. The current available data strongly justify for future clinical trials to investigate physical exercise use as an adjuvant in cancer therapy; however, optimal parameters using exercise for a defined outcome are yet to be established. The components of the immune system associate with almost every tumorigenesis step. The inter-relationship between inflammation, cancer, and innate immunity has recently gained acceptance; however, the underlying cellular and molecular mechanisms behind this relationship are yet to be solved. Several studies suggest physical exercise-mediated induction of immune cells to elicit anti-tumorigenic effects. This indicates the potential of exercising in modulating the behavior of immune cells to inhibit tumor progression. However, further mechanistic details behind physical exercise-driven immunomodulation and anticancer effects have to be determined. This review aims to summarize and discuss the association between physical exercise and immune function modulation and the potential of exercise as an adjuvant therapy in cancer prevention and treatment.

Effect of baseline oestradiol serum concentration on the efficacy of anastrozole for preventing breast cancer in postmenopausal women at high risk: a case-control study of the IBIS-II prevention trial

BACKGROUND

An increased risk of breast cancer is associated with high serum concentrations of oestradiol and testosterone in postmenopausal women, but little is known about how these hormones affect response to endocrine therapy for breast cancer prevention or treatment. We aimed to assess the effects of serum oestradiol and testosterone concentrations on the efficacy of the aromatase inhibitor anastrozole for the prevention of breast cancer in postmenopausal women at high risk.

METHODS

In this case-control study we used data from the IBIS-II prevention trial, a randomised, controlled, double-blind trial in postmenopausal women aged 40-70 years at high risk of breast cancer, conducted in 153 breast cancer treatment centres across 18 countries. In the trial, women were randomly assigned (1:1) to receive anastrozole (1 mg/day, orally) or placebo daily for 5 years. In this pre-planned case-control study, the primary analysis was the effect of the baseline oestradiol to sex hormone binding globulin (SHBG) ratio (oestradiol-SHBG ratio) on the development of all breast cancers, including ductal carcinoma in situ (the primary endpoint in the trial). Cases were participants in whom breast cancer was reported after trial entry and until the cutoff on Oct 22, 2019, and who had valid blood samples and no use of hormone replacement therapy within 3 months of trial entry or during the trial. For each case, two controls without breast cancer were selected at random, matched on treatment group, age (within 2 years), and follow-up time (at least that of the matching case). For each treatment group, we applied a multinominal logistic regression likelihood-ratio trend test to assess what change in the proportion of cases was associated with a one-quartile change in hormone ratio. Controls were used only to determine quartile cutoffs. Profile likelihood 95% CIs were used to indicate the precision of estimates. A secondary analysis also investigated the effect of the baseline testosterone-SHBG ratio on breast cancer development. We also assessed relative benefit of anastrozole versus placebo (calculated as 1 - the ratio of breast cancer cases in the anastrozole group to cases in the placebo group). The trial was registered with ISRCTN (number ISRCTN31488319) and completed recruitment on Jan 31, 2012, but long-term follow-up is ongoing.

FINDINGS

3864 women were recruited into the trial between Feb 2, 2003, and Jan 31, 2012, and randomly assigned to receive anastrozole (n=1920) or placebo (n=1944). Median follow-up time was 131 months (IQR 106-156), during which 85 (4·4%) cases of breast cancer in the anastrozole group and 165 (8·5%) in the placebo group were identified. No data on gender, race, or ethnicity were collected. After exclusions, the case-control study included 212 participants from the anastrozole group (72 cases, 140 controls) and 416 from the placebo group (142 cases, 274 controls). A trend of increasing breast cancer risk with increasing oestradiol-SHBG ratio was found in the placebo group (trend per quartile 1·25 [95% CI 1·08 to 1·45], p=0·0033), but not in the anastrozole group (1·06 [0·86 to 1·30], p=0·60). A weaker effect was seen for the testosterone-SHBG ratio in the placebo group (trend 1·21 [1·05 to 1·41], p=0·011), but again not in the anastrozole group (trend 1·18 [0·96 to 1·46], p=0·11). A relative benefit of anastrozole was seen in quartile 2 (0·55 [95% CI 0·13 to 0·78]), quartile 3 (0·54 [0·22 to 0·74], and quartile 4 (0·56 [0·23 to 0·76]) of oestradiol-SHBG ratio, but not in quartile 1 (0·18 [-0·60 to 0·59]).

INTERPRETATION

These results suggest that serum hormones should be measured more routinely and integrated into risk management decisions. Measuring serum hormone concentrations is inexpensive and might help clinicians differentiate which women will benefit most from an aromatase inhibitor.

FUNDING

Cancer Research UK, National Health and Medical Research Council (Australia), Breast Cancer Research Foundation, and DaCosta Fund.

Sex-steroid hormones and risk of postmenopausal estrogen receptor-positive breast cancer: a case-cohort analysis

Purpose

Sex-steroid hormones are associated with postmenopausal breast cancer but potential confounding from other biological pathways is rarely considered. We estimated risk ratios for sex-steroid hormone biomarkers in relation to postmenopausal estrogen receptor (ER)-positive breast cancer, while accounting for biomarkers from insulin/insulin-like growth factor-signaling and inflammatory pathways.

Methods

This analysis included 1,208 women from a case-cohort study of postmenopausal breast cancer within the Melbourne Collaborative Cohort Study. Weighted Poisson regression with a robust variance estimator was used to estimate risk ratios (RRs) and 95% confidence intervals (CIs) of postmenopausal ER-positive breast cancer, per doubling plasma concentration of progesterone, estrogens, androgens, and sex hormone binding globulin (SHBG). Analyses included sociodemographic and lifestyle confounders, and other biomarkers identified as potential confounders.

Results

Increased risks of postmenopausal ER-positive breast cancer were observed per doubling plasma concentration of progesterone (RR: 1.22, 95% CI: 1.03 to 1.44), androstenedione (RR: 1.20, 95% CI: 0.99 to 1.45), dehydroepiandrosterone (RR: 1.15, 95% CI: 1.00 to 1.34), total testosterone (RR: 1.11, 95% CI: 0.96 to 1.29), free testosterone (RR: 1.12, 95% CI: 0.98 to 1.28), estrone (RR: 1.21, 95% CI: 0.99 to 1.48), total estradiol (RR: 1.19, 95% CI: 1.02 to 1.39) and free estradiol (RR: 1.22, 95% CI: 1.05 to 1.41). A possible decreased risk was observed for SHBG (RR: 0.83, 95% CI: 0.66 to 1.05).

Conclusion

Progesterone, estrogens and androgens likely increase postmenopausal ER-positive breast cancer risk, whereas SHBG may decrease risk. These findings strengthen the causal evidence surrounding the sex hormone-driven nature of postmenopausal breast cancer.

Exploring regression dilution bias using repeat measurements of 2858 variables in ≤49 000 UK Biobank participants

BACKGROUND

Measurement error in exposures and confounders can bias exposure-outcome associations but is rarely considered. We aimed to assess random measurement error of all continuous variables in UK Biobank and explore approaches to mitigate its impact on exposure-outcome associations.

METHODS

Random measurement error was assessed using intraclass correlation coefficients (ICCs) for all continuous variables with repeat measures. Regression calibration was used to correct for random error in exposures and confounders, using the associations of red blood cell distribution width (RDW), C-reactive protein (CRP) and 25-hydroxyvitamin D [25(OH)D] with mortality as illustrative examples.

RESULTS

The 2858 continuous variables with repeat measures varied in sample size from 109 to 49 121. They fell into three groups: (i) baseline visit [529 variables; median (interquartile range) ICC = 0.64 (0.57, 0.83)]; (ii) online diet by 24-h recall [22 variables; 0.35 (0.30, 0.40)] and (iii) imaging measures [2307 variables; 0.85 (0.73, 0.94)]. Highest ICCs were for anthropometric and medical history measures, and lowest for dietary and heart magnetic resonance imaging.The ICCs (95% confidence interval) for RDW, CRP and 25(OH)D were 0.52 (0.51, 0.53), 0.29 (0.27, 0.30) and 0.55 (0.54, 0.56), respectively. Higher RDW and levels of CRP were associated with higher risk of all-cause mortality, and higher concentration of 25(OH)D with lower risk. After correction for random measurement error in the main exposure, the associations all strengthened. Confounder correction did not influence estimates.

CONCLUSIONS

Random measurement error varies widely and is often non-negligible. For UK Biobank we provide relevant statistics and adaptable code to help other researchers explore and correct for this.

Putative causal inference for the relationship between obesity and sex hormones in males: a bidirectional Mendelian randomization study

Background

Obesity is a chronic disease with a high prevalence rate and is an established risk factor for human health. Body mass index (BMI) is a common and primary indicator used in assessing obesity. This work aims to investigate the putative causal relationship among BMI, sex hormone-binding globulin (SHBG), bioavailable testosterone (BioT), and estradiol levels.

Materials and Methods

We conducted a bidirectional Mendelian randomization study, using single-nucleotide polymorphisms (SNPs) strongly associated with BMI, SHBG, BioT, and estradiol as instrumental variables. All SNPs were identified from the genome-wide association study (GWAS) summary data of large sample studies recruiting more than 150,000 European adult male individuals. The inverse-variance-weighted (IVW) approach was used as a primary algorithm for putative causal estimation.

Results

Genetically predicted elevated BMI was associated with decreased SHBG (IVW, β = -0.103, 95% confidence interval [CI] [-0.113 to -0.092], P = 1.50 × 10^-77) and BioT levels (IVW, β = -0.139, 95% CI [-0.165 to -0.113], P = 9.54 × 10^-26) and high estradiol levels (IVW, β = 0.014, 95% CI [0.009-0.019], P = 2.19 × 10^-7). Increased SHBG levels were causally associated with low BMI (IVW, β = -0.051, 95% CI [-0.098 to -0.005], P = 0.030) and BioT (IVW, β = -0.126, 95% CI [-0.175 to -0.077], P = 5.97 × 10^-7) and high estradiol levels (IVW, β = 0.046, 95% CI [0.035-0.056], P = 6.51 × 10^-17). Conversely, no evidence of an effect of estradiol imbalance on SHBG levels (IVW, β = 1.035, 95% CI [-0.854 to 2.926], P = 0.283) and BMI (IVW, β = 0.091, 95% CI [-0.094 to 0.276], P = 0.336) was obtained. However, increased BioT levels were causally associated with lower SHBG levels (IVW, β = -0.044, 95% CI [-0.061 to -0.026], P = 8.76 × 10^-7), not BMI (IVW, β = -0.006, 95% CI [-0.035 to 0.023], P = 0.679).

Conclusions

The findings support a network putative causal relationship among BMI, SHBG, BioT, and estradiol. SHBG, BioT, and estradiol may partly mediate the effect of obesity on male health. Reasonably modulating BioT and estradiol, especially SHBG, facilitated the attenuation of the harmful effects of obesity on male health.

Combining machine learning with Cox models to identify predictors for incident post-menopausal breast cancer in the UK Biobank

We aimed to identify potential novel predictors for breast cancer among post-menopausal women, with pre-specified interest in the role of polygenic risk scores (PRS) for risk prediction. We utilised an analysis pipeline where machine learning was used for feature selection, prior to risk prediction by classical statistical models. An "extreme gradient boosting" (XGBoost) machine with Shapley feature-importance measures were used for feature selection among [Formula: see text] 1.7 k features in 104,313 post-menopausal women from the UK Biobank. We constructed and compared the "augmented" Cox model (incorporating the two PRS, known and novel predictors) with a "baseline" Cox model (incorporating the two PRS and known predictors) for risk prediction. Both of the two PRS were significant in the augmented Cox model ([Formula: see text]). XGBoost identified 10 novel features, among which five showed significant associations with post-menopausal breast cancer: plasma urea (HR = 0.95, 95% CI 0.92-0.98, [Formula: see text]), plasma phosphate (HR = 0.68, 95% CI 0.53-0.88, [Formula: see text]), basal metabolic rate (HR = 1.17, 95% CI 1.11-1.24, [Formula: see text]), red blood cell count (HR = 1.21, 95% CI 1.08-1.35, [Formula: see text]), and creatinine in urine (HR = 1.05, 95% CI 1.01-1.09, [Formula: see text]). Risk discrimination was maintained in the augmented Cox model, yielding C-index 0.673 vs 0.667 (baseline Cox model) with the training data and 0.665 vs 0.664 with the test data. We identified blood/urine biomarkers as potential novel predictors for post-menopausal breast cancer. Our findings provide new insights to breast cancer risk. Future research should validate novel predictors, investigate using multiple PRS and more precise anthropometry measures for better breast cancer risk prediction.

Comparison of the clinical effectiveness of treatments for aromatase inhibitor-induced arthralgia in breast cancer patients: A systematic review with network meta-analysis

Aromatase inhibitor-induced arthralgia (AIA) contributes to poor adherence of aromatase inhibitor therapies in patients with breast cancer. A systematic review using network meta-analysis (NMA) was conducted to examine the clinical effectiveness of multiple therapies and rank probabilities for the management of AIA. Randomized controlled trials (RCTs) assessing treatments for AIA in postmenopausal women with stage 0-III hormone receptor-positive breast cancer were searched from inception to October 2021. The main NMA involved 1516 participants from 17 RCTs. Acupuncture was the highest ranked intervention to improve pain intensity followed by sham acupuncture, multicomponent herbal medicine, exercise, duloxetine, vitamin D, omega-3 fatty acids, physical therapy, testosterone, and inactive controls. Single natural products were inferior to controls. The current review provides new insights into the management of AIA in breast cancer survivors for increased survival and can be utilized to make evidence-based decisions regarding treatment.

Linking Physical Activity to Breast Cancer Risk via the Insulin/Insulin-like Growth Factor Signaling System, Part 2: The Effect of Insulin/Insulin-like Growth Factor Signaling on Breast Cancer Risk

Perturbation of the insulin/insulin-like growth factor (IGF) signaling system is often cited as a mechanism driving breast cancer risk. A systematic review identified prospective cohort studies and Mendelian randomization studies that examined the effects of insulin/IGF signaling (IGF, their binding proteins (IGFBP), and markers of insulin resistance] on breast cancer risk. Meta-analyses generated effect estimates; risk of bias was assessed and the Grading of Recommendations Assessment, Development and Evaluation system applied to evaluate the overall quality of the evidence. Four Mendelian randomization and 19 prospective cohort studies met our inclusion criteria. Meta-analysis of cohort studies confirmed that higher IGF-1 increased risk of breast cancer; this finding was supported by the Mendelian randomization studies. IGFBP-3 did not affect breast cancer. Meta analyses for connecting-peptide and fasting insulin showed small risk increases, but confidence intervals were wide and crossed the null. The quality of evidence obtained ranged from 'very low' to 'moderate'. There were insufficient studies to examine other markers of insulin/IGF signaling. These findings do not strongly support the biological plausibility of the second part of the physical activity-insulin/IGF signaling system-breast cancer pathway. Robust conclusions cannot be drawn due to the dearth of high quality studies. See related article by Swain et al., p. 2106.

A novel age-related gene expression signature associates with proliferation and disease progression in breast cancer

BACKGROUND AND OBJECTIVE

Breast cancer (BC) diagnosed at ages <40 years presents with more aggressive tumour phenotypes and poorer clinical outcome compared to older BC patients. Here, we explored transcriptional BC alterations to gain a better understanding of age-related tumour biology, also subtype-stratified.

METHODS

We studied publicly available global BC mRNA expression (n = 3999) and proteomics data (n = 113), exploring differentially expressed genes, enriched gene sets, and gene networks in the young compared to older patients.

RESULTS

We identified transcriptional patterns reflecting increased proliferation and oncogenic signalling in BC of the young, also in subtype-stratified analyses. Six up-regulated hub genes built a novel age-related score, significantly associated with aggressive clinicopathologic features. A high 6 Gene Proliferation Score (6GPS) demonstrated independent prognostic value when adjusted for traditional clinicopathologic variables and the molecular subtypes. The 6GPS significantly associated also with disease-specific survival within the luminal, lymph node-negative and Oncotype Dx intermediate subset.

CONCLUSIONS

We here demonstrate evidence of higher tumour cell proliferation in young BC patients, also when adjusting for molecular subtypes, and identified a novel age-based six-gene signature pointing to aggressive tumour features, tumour proliferation, and reduced survival-also in patient subsets with expected good prognosis.

Serum hormone levels and normal breast histology among premenopausal women

PURPOSE

Breast terminal duct lobular units (TDLUs) are the main source of breast cancer (BC) precursors. Higher serum concentrations of hormones and growth factors have been linked to increased TDLU numbers and to elevated BC risk, with variable effects by menopausal status. We assessed associations of circulating factors with breast histology among premenopausal women using artificial intelligence (AI) and preliminarily tested whether parity modifies associations.

METHODS

Pathology AI analysis was performed on 316 digital images of H&E-stained sections of normal breast tissues from Komen Tissue Bank donors ages ≤ 45 years to assess 11 quantitative metrics. Associations of circulating factors with AI metrics were assessed using regression analyses, with inclusion of interaction terms to assess effect modification.

RESULTS

Higher prolactin levels were related to larger TDLU area (p < 0.001) and increased presence of adipose tissue proximate to TDLUs (p < 0.001), with less significant positive associations for acini counts (p = 0.012), dilated acini (p = 0.043), capillary area (p = 0.014), epithelial area (p = 0.007), and mononuclear cell counts (p = 0.017). Testosterone levels were associated with increased TDLU counts (p < 0.001), irrespective of parity, but associations differed by adipose tissue content. AI data for TDLU counts generally agreed with prior visual assessments.

CONCLUSION

Among premenopausal women, serum hormone levels linked to BC risk were also associated with quantitative features of normal breast tissue. These relationships were suggestively modified by parity status and tissue composition. We conclude that the microanatomic features of normal breast tissue may represent a marker of BC risk.

Understanding the role of sex hormones in cancer for the transgender community

Sex hormones are crucial for the body's development and function. Therefore, many transgender people seek hormone therapy as part of their transition. However, sex hormones modulate cancer risk. Studying sex hormones in cisgender and transgender populations will improve our knowledge of their biological role in cancer and reduce health disparities.

Risk of cancer in regular and low meat-eaters, fish-eaters, and vegetarians: a prospective analysis of UK Biobank participants

BACKGROUND

Following a vegetarian diet has become increasingly popular and some evidence suggests that being vegetarian may be associated with a lower risk of cancer overall. However, for specific cancer sites, the evidence is limited. Our aim was to assess the associations of vegetarian and non-vegetarian diets with risks of all cancer, colorectal cancer, postmenopausal breast cancer, and prostate cancer and to explore the role of potential mediators between these associations.

METHODS

We conducted a prospective analysis of 472,377 UK Biobank participants who were free from cancer at recruitment. Participants were categorised into regular meat-eaters (n = 247,571), low meat-eaters (n = 205,385), fish-eaters (n = 10,696), and vegetarians (n = 8685) based on dietary questions completed at recruitment. Multivariable-adjusted Cox regressions were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for all cancer incidence and separate cancer sites across diet groups.

RESULTS

After an average follow-up of 11.4 years, 54,961 incident cancers were identified, including 5882 colorectal, 7537 postmenopausal breast, and 9501 prostate cancers. Compared with regular meat-eaters, being a low meat-eater, fish-eater, or vegetarian were all associated with a lower risk of all cancer (HR: 0.98, 95% CI: 0.96-1.00; 0.90, 0.84-0.96; 0.86, 0.80-0.93, respectively). Being a low meat-eater was associated with a lower risk of colorectal cancer in comparison to regular meat-eaters (0.91, 0.86-0.96); however, there was heterogeneity in this association by sex (p = 0.007), with an inverse association across diet groups in men, but not in women. Vegetarian postmenopausal women had a lower risk of breast cancer (0.82, 0.68-0.99), which was attenuated and non-significant after adjusting for body mass index (BMI; 0.87, 0.72-1.05); in mediation analyses, BMI was found to possibly mediate the observed association. In men, being a fish-eater or a vegetarian was associated with a lower risk of prostate cancer (0.80, 0.65-0.99 and 0.69, 0.54-0.89, respectively).

CONCLUSION

The lower risk of colorectal cancer in low meat-eaters is consistent with previous evidence suggesting an adverse impact of meat intake. The lower risk of postmenopausal breast cancer in vegetarian women may be explained by their lower BMI. It is not clear whether the other differences observed for all cancers and for prostate cancer reflect any causal relationships or are due to other factors such as residual confounding or differences in cancer detection.

Energy homeostasis genes modify the association between serum concentrations of IGF-1 and IGFBP-3 and breast cancer risk

Breast cancer is a multifactorial disease in which the interplay among multiple risk factors remains unclear. Energy homeostasis genes play an important role in carcinogenesis and their interactions with the serum concentrations of IGF-1 and IGFBP-3 on the risk of breast cancer have not yet been investigated. The aim of this study was to assess the modifying effect of the genetic variation in some energy homeostasis genes on the association of serum concentrations of IGF-1 and IGFBP-3 with breast cancer risk. We analyzed 78 SNPs from 10 energy homeostasis genes in premenopausal women from the 4-Corner’s Breast Cancer Study (61 cases and 155 controls) and the Mexico Breast Cancer Study (204 cases and 282 controls). After data harmonization, 71 SNPs in HWE were included for interaction analysis. Two SNPs in two genes (MBOAT rs13272159 and NPY rs16131) showed an effect modification on the association between IGF-1 serum concentration and breast cancer risk (P_interaction < 0.05, adjusted P_interaction < 0.20). In addition, five SNPs in three genes (ADIPOQ rs182052, rs822391 and rs7649121, CARTPT rs3846659, and LEPR rs12059300) had an effect modification on the association between IGFBP-3 serum concentration and breast cancer risk (P_interaction < 0.05, adjusted P_interaction < 0.20). Our findings showed that variants of energy homeostasis genes modified the association between the IGF-1 or IGFBP-3 serum concentration and breast cancer risk in premenopausal women. These findings contribute to a better understanding of this multifactorial pathology.

Alcohol Intake and Endogenous Hormones in Pre- and Postmenopausal Women: Findings from the UK Biobank

BACKGROUND

Alcohol intake may influence breast cancer risk in women through hormonal changes, but the evidence to date is inconclusive. We investigated cross-sectional associations between habitual alcohol intake and serum concentrations of testosterone, sex hormone binding globulin (SHBG), insulin-like growth factor-1 (IGF-1), and estradiol (premenopausal women only) in UK Biobank.

METHODS

We included 30,557 premenopausal and 134,029 postmenopausal women aged between 40 and 69 years when recruited between 2006 and 2010. At their initial assessment visit, habitual alcohol intake was assessed using a touchscreen questionnaire, and serum hormone concentrations were assayed. Multivariable linear regression analysis was performed.

RESULTS

Per 10 g/day increment in alcohol intake, testosterone concentration was 3.9% [95% confidence intervals (CI): 3.3%-4.5%] higher in premenopausal women and 2.3% (1.8%-2.7%) higher in postmenopausal women (P heterogeneity < 0.0001); SHBG concentration was 0.7% (0.2%-1.1%) higher in premenopausal women and 2.4% (2.2%-2.6%) lower in postmenopausal women (P heterogeneity < 0.0001); and IGF-1 concentration was 1.9% (1.7%-2.1%) lower in premenopausal women and 0.8% (0.6%-0.9%) lower in postmenopausal women (P heterogeneity < 0.0001). In premenopausal women, there was no significant overall association of alcohol with estradiol but a positive association was observed in the early and mid-luteal phases: 1.9% (95% CI: 0.2%-3.6%) and 2.4% (95% CI: 0.7%-4.2%) higher, respectively.

CONCLUSIONS

This study confirms significant but modest associations between alcohol intake and hormones, with evidence of heterogeneity by menopausal status.

IMPACT

The findings facilitate better understanding of whether alcohol intake influences hormone concentrations, but further work is necessary to fully understand the mechanisms linking alcohol with cancer risk.