Genetic polymorphism at Val80 (rs700518) of the CYP19A1 gene is associated with aromatase inhibitor associated bone loss in women with ER + breast cancer

Machine learning predicts the risk of osteoporosis in patients with breast cancer and healthy women

OBJECTIVE

In this study, we investigated the effects of endocrine therapy and related drugs on the body composition and bone metabolism of patients with breast cancer. Additionally, using body composition-related indicators in machine learning algorithms, the risks of osteoporosis in patients with breast cancer and healthy women were predicted.

METHODS

We enrolled postmenopausal patients with breast cancer who were hospitalized in a tertiary hospital and postmenopausal women undergoing health checkups in our hospital between 2019 and 2021. The basic information, body composition, bone density-related indicators, and bone metabolism-related indicators of all the study subjects were recorded. Machine learning models were constructed using cross-validation.

RESULTS

Compared with a healthy population, the body composition of patients with breast cancer was low in bone mass, protein, body fat percentage, muscle, and basal metabolism, whereas total water, intracellular fluid, extracellular fluid, and waist-to-hip ratio were high. In patients with breast cancer, the bone mineral density (BMD), Z value, and T value were low and the proportion of bone loss and osteoporosis was high. BMD in patients with breast cancer was negatively correlated with age, endocrine therapy status, duration of medication, and duration of menopause, and it was positively correlated with body mass index (BMI) and basal metabolism. The parameters including body composition, age, hormone receptor status, and medication type were used for developing the machine learning model to predict osteoporosis risk in patients with breast cancer and healthy populations. The model showed a high accuracy in predicting osteoporosis, reflecting the predictive value of the model.

CONCLUSIONS

Patients with breast cancer may have changed body composition and BMD. Compared with the healthy population, the main indicators of osteoporosis in patients with breast cancer were reduced nonadipose tissue, increased risk of edema, altered fat distribution, and reduced BMD. In addition to age, duration of treatment, and duration of menopause, body composition-related indicators such as BMI and basal metabolism may be considerably associated with BMD of patients with breast cancer, suggesting that BMD status can be monitored in clinical practice by focusing on changes in the aforementioned indexes, which may provide a way to prevent preclinical osteoporosis.

Genetic Variants Associated with Acne Vulgaris

Acne vulgaris (AV) ranks among the common chronic inflammatory disorders that impact the sebaceous components of hair follicles. Acne vulgaris is characterised by cardinal manifestations such as the presence of pimples, nodules, pustules, and cysts, which have the potential to lead to the development of acne scarring and pigmentation. The phenomenon is influenced by polygenic inheritance or can be ascribed to the interplay between multiple genes and environmental factors. In recent years, some researchers have found that some genes (such as IL, TNF, RETN, CYP family, MMPs and TIMPs genes et al) are associated with acne vulgaris and may affect the progression and prognosis of the disease. The number of reviews addressing acne-associated genetic variants, however, is limited. In that case, we have compiled a list of prevalent genes associated with acne in recent times. This helps us understand acne's genetic basis and lets us step in early for people prone to severe acne, lowering the chance of acne scars.

Influence of the Osteogenomic Profile in Response to Alendronate Therapy in Postmenopausal Women with Osteoporosis: A Retrospective Cohort Study

BACKGROUND

Postmenopausal osteoporosis is a multifactorial disease. Genetic factors play an essential role in contributing to bone mineral density (BMD) variability, which ranges from 60 to 85%. Alendronate is used as the first line of pharmacological treatment for osteoporosis; however, some patients do not respond adequately to therapy with alendronate.

AIM

The aim of this work was to investigate the influence of combinations of potential risk alleles (genetic profiles) associated with response to anti-osteoporotic treatment in postmenopausal women with primary osteoporosis.

METHODS

A total of 82 postmenopausal women with primary osteoporosis receiving alendronate (70 mg administered orally per week) for one year were observed. The bone mineral density (BMD; g/cm2) of the femoral neck and lumbar spine was measured. According to BMD change, patients were divided into two groups: responders and non-responders to alendronate therapy. Polymorphic variants in CYP19, ESR1, IL-6, PTHR1, TGFβ, OPG and RANKL genes were determined and profiles were generated from the combination of risk alleles.

RESULTS

A total of 56 subjects were responders to alendronate and 26 subjects were non-responders. Carriers of the G-C-G-C profile (constructed from rs700518, rs1800795, rs2073618 and rs3102735) were predisposed to response to alendronate treatment (p = 0.001).

CONCLUSIONS

Our findings highlight the importance of the identified profiles for the pharmacogenetics of alendronate therapy in osteoporosis.

Breast cancer pharmacogenetics: a systematic review

Breast cancer was declared the most prevalent type of cancer in 2020. Among other factors, treatment response can be affected by genetic polymorphisms - which is the focus of pharmacogenetics - and ethnicity is also a contributing factor in this context. Relevant genes in disease treatment pathways were selected to evaluate treatment response from the pharmacogenetic perspective; polymorphism frequencies and ethnic and continental representation across the available literature were also assessed through a systematic review. The identified associations and gaps have been described in this study with the purpose that, in the future, treatments can be personalized and thus be more effective, safer, and accessible to all.

Association of the CYP19A1 rs700518 Polymorphism with Selected Markers of Bone Metabolism in Women with Hyperandrogenism

Hyperandrogenism is the most common endocrine disorder in women, characterized by an imbalance of normal estrogen and androgen levels in the blood. Androgens play an important role in the female body because they influence bone mineral density (BMD), body mass composition, muscle mass, mental state, and the regulation of sexual function. The reduced activity of aromatase, due to mutations in the CYP19A1 gene, reduces the estrogen pool in favor of androgens. Clinically, aromatase deficiency causes hyperandrogenism in women. Therefore, the aim of the study was to assess the effect of the CYP19A1 gene polymorphism on selected markers of bone metabolism and hormonal parameters in women with hyperandrogenism. The study group was comprised of 80 young women with hyperandrogenism who underwent measurements of bone mineral density (BMD), and determination of hormonal and metabolic parameters. Enzyme immunoassays were used to measure leptin, total sRANKL (free and bound RANKL), osteoprotegerin, and total 25-OH Vitamin D. An analysis of the CYP19A1 gene polymorphisms was performed using the real-time PCR method. The GG genotype of the CYP19A1 rs700518 polymorphism turned out to be associated with: FEI (Free Estradiol Index), SHGB concentration, estradiol concentration, and insulin concentration determined in the glucose tolerance test 60’ compared to AG and AA genotypes. Patients with the AG genotype had a higher ratio of android to gynoid fat and a greater content of visceral adipose tissue. Higher visceral tissue content may reduce BMD. In conclusion, the study showed that the CYP19A1 rs700518 polymorphism may be associated with the distribution of adipose tissue in young women with hyperandrogenism. These results suggest that patients with the AG genotype may develop osteoporosis.

Pharmacogenetics of Breast Cancer Treatments: A Sub-Saharan Africa Perspective

Breast cancer is the most frequent cause of cancer death in low- and middle-income countries, in particular among sub-Saharan African women, where response to available anticancer treatment therapy is often limited by the recurrent breast tumours and metastasis, ultimately resulting in decreased overall survival rate. This can also be attributed to African genomes that contain more variation than those from other parts of the world. The purpose of this review is to summarize published evidence on pharmacogenetic and pharmacokinetic aspects related to specific available treatments and the known genetic variabilities associated with metabolism and/or transport of breast cancer drugs, and treatment outcomes when possible. The emphasis is on the African genetic variation and focuses on the genes with the highest strength of evidence, with a close look on CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4/5, CYP19A1, UGT1A4, UGT2B7, UGT2B15, SLC22A16, SLC38A7, FcγR, DPYD, ABCB1, and SULT1A1, which are the genes known to play major roles in the metabolism and/or elimination of the respective anti-breast cancer drugs given to the patients. The genetic variability of their metabolism could be associated with different metabolic phenotypes that may cause reduced patients’ adherence because of toxicity or sub-therapeutic doses. Finally, this knowledge enhances possible personalized treatment approaches, with the possibility of improving survival outcomes in patients with breast cancer.

Aromatase and CDK4/6 Inhibitor-Induced Musculoskeletal Symptoms: A Systematic Review

BACKGROUND

Treatment with aromatase inhibitors (AIs) is fundamental in women with hormone receptor-positive breast cancer in the adjuvant as well as the metastatic setting. Even though it is considered to be a well-tolerated therapy, aromatase inhibitor-associated musculoskeletal syndrome (AIMSS) is the most common adverse event encountered by breast cancer patients. CDK4/6 inhibitors have emerged as a new treatment strategy in metastatic hormone receptor-positive breast cancer. However, the impact of CDK4/6 inhibitors on musculoskeletal symptoms caused by AIs is not well-defined.

OBJECTIVES

This systematic review aims to identify the frequency of joint symptoms induced by treatment with AIs and CDK4/6 inhibitors in the metastatic setting.

SEARCH STRATEGY

Eligible articles were identified by a search of existing literature for the period 2005/01/01-2021/01/01; The algorithm consisted of a predefined combination of the following keywords "breast", "cancer", "aromatase inhibitors", "CDK4/6", "phase III".

SELECTION CRITERIA

This study was performed in accordance with PRISMA guidelines. All randomized controlled Phase III trials (RCTs) evaluating the administration of third-generation aromatase inhibitors (AIs) and CDK4/6 inhibitors in postmenopausal women in the metastatic setting were considered eligible for this review.

DATA COLLECTION

Overall, 16 randomized control trials (RCTs) were retrieved, of which nine studies explored the administration of AIs in the metastatic setting and seven studies investigated the combination of CDK4/6 inhibitors and AIs. Arthralgia was reported in 1-47% of patients treated with AIs and 5.8-33.3% of patients treated with CDK4/6 inhibitors. Myalgias occurred in 2-23.7% of patients receiving AIs compared with 4.8-11.9% of patients treated with CDK4/6 inhibitors. The incidence of back pain was 7-32.9% vs. 2.9-8.5% in postmenopausal women with metastatic disease treated with AIs and CDK4/6 inhibitors, respectively. Bone pain was reported in 7-32.9% of postmenopausal women treated with AIs and 2.9-8.5% of women treated with CDK4/6 inhibitors.

CONCLUSIONS

AI treatment-induced musculoskeletal syndrome is an adverse event affecting over one-third (20-47%) of postmenopausal patients treated with AIs that often leads to treatment discontinuation. Data from RCTs provide evidence that the incidence of musculoskeletal symptoms is relatively decreased upon CDK4/6 inhibitor administration. CDK4/6 inhibitors may provide a protective role against AIMSS development.

Aromatase Inhibitor-Associated Musculoskeletal Syndrome: Understanding Mechanisms and Management

Aromatase inhibitors (AIs) are a key component in the chemoprevention and treatment of hormone receptor-positive (HR+) breast cancer. While the addition of AI therapy has improved cancer-related outcomes in the management of HR+ breast cancer, AIs are associated with musculoskeletal adverse effects known as the aromatase inhibitor-associated musculoskeletal syndrome (AIMSS) that limit its tolerability and use. AIMSS is mainly comprised of AI-associated bone loss and arthralgias that affect up to half of women on AI therapy and detrimentally impact patient quality of life and treatment adherence. The pathophysiology of AIMSS is not fully understood though has been proposed to be related to estrogen deprivation within the musculoskeletal and nervous systems. This review aims to characterize the prevalence, risk factors, and clinical features of AIMSS, and explore the syndrome's underlying mechanisms and management strategies.

Challenges in Preventing Bone Loss Induced by Aromatase Inhibitors

CONTEXT

Aromatase inhibitors have become a mainstay in the adjuvant treatment regimen in postmenopausal women with hormone receptor-positive breast cancer. While many of these patients have an excellent long-term prognosis, adverse effects on bone represent an emerging complication of aromatase inhibitor treatment, resulting in substantial bone loss and fragility fractures. Treatment approaches to prevent aromatase inhibitor-induced bone loss typically consist of an antiresorptive approach with bisphosphonates or the RANKL antibody denosumab. However, different guidelines vary with respect to treatment thresholds, duration, and dosing. The choice of antiresorptive regime is further complicated by comorbidities and potential disease-modifying effects of individual agents.

OBJECTIVE

This review summarizes the evidence of how aromatase inhibitors affect bone health and provides an update of clinical approaches to preserve bone strength in affected women. (J Clin Endocrinol Metab XX: 0-0, 2020).

Aromatase Inhibitors-Induced Musculoskeletal Disorders: Current Knowledge on Clinical and Molecular Aspects

Aromatase inhibitors (AIs) have radically changed the prognosis of hormone receptor positive breast cancer (BC) in post-menopausal women, and are a mainstay of the adjuvant therapy for BC after surgery in place of, or following, Tamoxifen. However, AIs aren't side effect-free; frequent adverse events involve the musculoskeletal system, in the form of bone loss, AI-associated arthralgia (AIA) syndrome and autoimmune rheumatic diseases. In this narrative review, we reported the main clinical features of these three detrimental conditions, their influence on therapy adherence, the possible underlying molecular mechanisms and the available pharmacological and non-pharmacological treatments. The best-known form is the AIs-induced osteoporosis, whose molecular pathway and therapeutic possibilities were extensively investigated in the last decade. AIA syndrome is a high prevalent joint pain disorder which often determines a premature discontinuation of the therapy. Several points still need to be clarified, as a universally accepted diagnostic definition, the pathogenetic mechanisms and satisfactory management strategies. The association of AIs therapy with autoimmune diseases is of the utmost interest. The related literature has been recently expanded, but many issues remain to be explored, the first being the molecular mechanisms.

Management of osteoporosis in women with breast cancer

The screening, prevention and treatment of osteoporosis are similar in women with or without breast cancer. Breast cancer treatments, such as aromatase inhibitors, chemotherapy-induced ovarian failure and gonadotropin-releasing hormone antagonists all decrease estrogen levels, which in turn causes net bone resorption and bone loss. Bone loss over time will be of sufficient magnitude to cause some women to experience fractures. Thus, osteoporosis is an equation; the peak bone mass achieved by age 30 years minus the age-related and menopausal bone loss. Women should have their bone density measured by dual x-ray absorptiometry scans every 2 years. As clinically indicated, women should receive anti-osteoporosis drugs such as zoledronic acid, denosumab or oral bisphosphonates.

Association of CYP19A1 gene variations with adjuvant letrozole-induced adverse events in South Indian postmenopausal breast cancer cohort expressing hormone-receptor positivity

PURPOSE

Musculoskeletal adverse events (MS-AEs) and vasomotor symptoms (VMSs) are the major side-effects of newer generation non-steroidal aromatase inhibitor (AI), letrozole. Single-nucleotide polymorphisms (SNPs) in CYP19A1 gene coding for the enzyme aromatase are related to AI treatment-associated adverse drug reactions. Therefore, we aimed to determine whether SNPs in the CYP19A1 gene are associated with adjuvant letrozole-induced 'specific' AEs in postmenopausal hormone receptor-positive (HR+) breast cancer patients.

METHODS

Genomic DNA was isolated from 198 HR+ breast cancer patients by the phenol-chloroform method, and eleven SNPs in the CYP19A1 gene were genotyped by TaqMan genotyping assays on the qRT-PCR system. Toxicity was assessed according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0, and the data were analyzed using SPSS v19.0 and Haploview v4.2 statistical software.

RESULTS

Subjects carrying the genetic variants of CYP19A1 gene SNP rs700519 had significantly higher odds (OR 2.33; 95% CI [1.29-4.20], P = 0.0057) of MS-AEs under dominant statistical effect. The frequency of the two distinct haplotypes that include the variant allele 'T' at rs700519 locus, H5-GCTATCTGGCG (P = 0.042) and H11-GCTATTGCACG (P = 0.013) were significantly higher in patients with musculoskeletal toxicity than in those without MS-AEs and thus predisposing to MS-AEs. Similarly, H6-GCCAGCTGGCG (P = 0.037) haplotype exhibited higher frequencies in patients presented with VMSs. However, no such association was observed between CYP19A1 genotypes and VMSs.

CONCLUSIONS

To the best of our knowledge, this is the first study assessing the impact of CYP19A1 genetic variations with adjuvant letrozole treatment-associated AEs in Indian women. Genetic variations in the CYP19A1 gene is associated with letrozole-induced AEs and warrants further investigation in larger cohorts to validate this finding.

Association of CYP gene polymorphisms with breast cancer risk and prognostic factors in the Jordanian population

Background

Single nucleotide polymorphisms (SNPs) in several CYP genes have been associated with altered breast cancer (BC) risk in different populations. Despite this, there is a dearth of information on the roles of these SNPs in Jordanian BC patients. Therefore, this study aims to determine if there is any single nucleotide polymorphism (SNP) within CYP19A1, CYP2C19, CYP2C9, CYP1B1, CYP3A4, and CYP1A2 genes associated with BC in the Jordanian population. In addition, this work investigates the association between selected BC prognostic factors and variants of the aforementioned CYP candidate genes.

Methods

Blood samples were withdrawn from 221 BC patients and 218 healthy volunteers recruited from the Jordanian population. Genomic DNA was withdrawn and, after quantification and quality control, was genotyped using the Sequenom MassARRAY® system (iPLEX GOLD). Statistical analysis was then carried out to assess allelic and genotypic frequencies as well as genetic association between cases and controls.

Results

The CYP19A1 SNP rs7176005 (p < 0.0045) and the CYP1A2 SNP rs762551 (p = 0.004) were significantly associated with BC risk. However, no such association was found for the screened SNPs of the CYP2C9, CYP1B1, CYP2C19 and CYP3A4 genes. Regarding the prognostic factors of BC, several of the screened SNPs were associated with different pathological and clinical features.

Conclusions

Certain CYP genes, particularly CYP19A1 and CYP1A2, were associated with BC risk and development in the Jordanian population.

Bone and body composition response to testosterone therapy vary according to polymorphisms in the CYP19A1 gene

PURPOSE

To evaluate the influence of single nucleotide polymorphisms (SNPs) of CYP19A1 on the response and susceptibility to side effects from testosterone therapy. This is a prospective, single-arm study of men with low-morning serum testosterone (<10.68 nmol/l) administered testosterone cypionate 200 mg intramuscularly every 2 weeks for 18 months.

METHODS

We measured areal bone mineral density (aBMD) and body composition by dual energy X-ray absorptiometry, tibial volumetric BMD and geometry by peripheral quantitative computer tomography, bone turnover markers by enzyme-linked immunosorbent assay, testosterone, and estradiol by liquid-chromatography/mass-spectroscopy, genotyping by microarray, CYP19A1 expression by quantitative polymerase chain reaction, hematocrit and prostate-specific antigen (PSA).

RESULTS

We enrolled 105 men (40-74-years-old). SNPs rs1062033 and rs700518 were associated with significant differences in outcomes at 18 months. The GG genotype in rs1062033 had significant increase in whole body aBMD, but had significant decrease in tibial bone size compared to the CG and CC genotypes. Body composition analysis showed that the CC genotype of rs1062033, and the AA genotype of rs700518, had significant increase in total lean and appendicular lean mass compared to CG and GG, and AG and GG, respectively. The GG genotype of rs700518 had significant increase in PSA (GG = 105.8 ± 23.3% vs. AG + AA = 53.4 ± 11.3%, p = 0.046) while hematocrit changes were comparable among genotypes. CYP19A1 expression was highest in GG genotype in both SNPs.

CONCLUSIONS

For the first time, we demonstrated that CYP19A1 SNPs influence response to testosterone therapy in hypogonadal men, highlighting the importance of genetic profiling in therapeutics even for common clinical conditions.

Association between CYP19A<G rs700518 Polymorphism with Acne Vulgaris and its Severity: Influence on Sex Hormones Level

Acne vulgaris (AV) is a common skin disease that causes physical and psychological problems for the affected individual. In addition to systemic changes in hormone levels, overproduction of local steroids, especially androgens are associated with AV. Cytochrome (CYP) 19 is involved in the synthesis of estrogens. The aim of the present study was to investigate the influence of CYP19A <G rs700518 variants on sex hormones level and the risk of AV. In this case-control study, 181 patients with AV and 144 healthy individuals from Western Iran were investigated. The CYP19 variants were detected by PCR-RFLP method. The frequency of GG genotype in all patients (27.1%) was significantly higher than the controls (10.4%, P<0.001), which increased the relative risk of AV by 1.96 times. Also, the presence of this genotype was associated with 1.5-fold (P=0.005), 1.89-fold (P=0.011) and 3.33-fold (P=0.019) increased risk of mild, moderate and severe AV, respectively. A significantly higher serum level of estradiol was observed in women in the presence of AA genotype (107.3±72.1 pg/ml) in comparison with GG genotype (73.2±58.8 pg/ml) (P=0.009). Our study demonstrated that the GG genotype of CYP19 rs700518 polymorphism increased the risk of AV and the severity of the disease, and also was associated with lower levels of estradiol in females. Significantly decreased serum level of sex hormone-binding globulin in women with AV in comparison with healthy individuals could be related to increasing level of androgen that was observed in women with AV.

The Roles of Common Variation and Somatic Mutation in Cancer Pharmacogenomics

Cancer pharmacogenomics is the science concerned with understanding genetic alterations and its effects on the pharmacokinetics and pharmacodynamics of anti-cancer drugs, with the aim to provide cancer patients with the precise medication that will achieve a good response and cause low/no incidence of adverse events. Advances in biotechnology and bioinformatics have enabled genomic research to evolve from the evaluation of alterations at the single-gene level to studies on the whole-genome scale using large-scale genotyping and next generation sequencing techniques. International collaborative efforts have resulted in the construction of databases to curate the identified genetic alterations that are clinically significant, and these are currently utilized in clinical sequencing and liquid biopsy screening/monitoring. Furthermore, countless clinical studies have accumulated sufficient evidence to match cancer patients to therapies by utilizing the information of clinical-relevant alterations. In this review we summarize the importance of germline alterations that act as predictive biomarkers for drug-induced toxicity and drug response as well as somatic mutations in cancer cells that function as drug targets. The integration of genomics into the medical field has transformed the era of cancer therapy from one-size-fits-all to cancer precision medicine.

A comprehensive overview on osteoporosis and its risk factors

Osteoporosis is a bone disorder with remarkable changes in bone biologic material and consequent bone structural distraction, affecting millions of people around the world from different ethnic groups. Bone fragility is the worse outcome of the disease, which needs long term therapy and medical management, especially in the elderly. Many involved genes including environmental factors have been introduced as the disease risk factors so far, of which genes should be considered as effective early diagnosis biomarkers, especially for the individuals from high-risk families. In this review, a number of important criteria involved in osteoporosis are addressed and discussed.

Osteoporosis and musculoskeletal complications related to therapy of breast cancer

Aromatase inhibitors (AIs) are the treatment of choice for the majority of postmenopausal women with estrogen receptor (ER) positive breast cancers in early and advanced stage settings. One of most frequent side effects of AIs is bone loss that is of sufficient magnitude to increase risk of osteoporotic fractures. Osteoporosis is primarily a complex genetic disease with few modifiable risk factors. As the lifespan increases, and breast mortality decreases, more women with breast cancer will be at risk of osteoporotic fractures, or falls that result in fractures. The screening, prevention, and treatment of osteoporosis do not differ in women with or without breast cancer. Rather, breast cancer treatments, including AIs, chemotherapy-induced ovarian failure, and gonadotropin-releasing hormone (GnRH) agonists, all decrease estrogen, which causes net bone resorption, leading some women to experience fracture. Occurring in about fifty-percent of women, AI-induced arthralgia is one of the most common side effects, and causes of nonadherence and discontinuation. Registry studies show that nonadherence and discontinuation may contribute to higher breast cancer mortality. Thus, understanding the mechanisms, risk factors, and interventions to mitigate symptoms of AI-induced arthralgia is a high priority.

Cancer Treatment and Bone Health

Considerable advances in oncology over recent decades have led to improved survival, while raising concerns about long-term consequences of anticancer treatments. In patients with breast or prostate malignancies, bone health is a major issue due to the high risk of bone metastases and the frequent prolonged use of hormone therapies that alter physiological bone turnover, leading to increased fracture risk. Thus, the onset of cancer treatment-induced bone loss (CTIBL) should be considered by clinicians and recent guidelines should be routinely applied to these patients. In particular, baseline and periodic follow-up evaluations of bone health parameters enable the identification of patients at high risk of osteoporosis and fractures, which can be prevented by the use of bone-targeting agents (BTAs), calcium and vitamin D supplementation and modifications of lifestyle. This review will focus upon the pathophysiology of breast and prostate cancer treatment-induced bone loss and the most recent evidence about effective preventive and therapeutic strategies.

The relationship between the CYP19 alleles rs727479A/C, rs700518A/G, and rs700519C/T and pregnancy outcome after assisted reproductive technology in patients with polycystic ovary syndrome in a Chinese population: A population-based study

This study investigated the relationship between the CYP19 alleles, rs727479A/C, rs700518A/G, and rs700519C/T, and pregnancy outcome after assisted reproductive technology (ART) in patients with polycystic ovary syndrome (PCOS). Between January 2012 and September 2015, 293 PCOS patients undergoing ART were randomly selected for the study. According to pregnancy outcome after ART, the patients were assigned to pregnancy and non-pregnancy groups. CYP19 rs727479A/C, rs700518A/G and rs700519C/T genotypes were determined using the denaturing high-performance liquid chromatography (DHPLC) method. Haplotype frequencies of the CYP19 alleles rs727479A/C, rs700518A/G and rs700519C/T were estimated using the SHEsis platform. Logistic regression analysis was employed to analyze the factors influencing the pregnancy outcome after ART. The frequency of the AC + CC genotype of rs727479A/C was higher in the pregnancy group than in the non-pregnancy group. The frequency of the CT + TT genotype of rs700519A/G was also higher in the pregnancy group than in the non-pregnancy group. Haplotype analysis indicated that the AAC and AGT haplotypes both exhibited unfavorable influence on the pregnancy outcome after ART. The AAT and CGT haplotypes were favorable to the pregnancy outcome after ART. Logistic regression analysis suggested that the rs727479A/C AA genotype, the rs700519C/T CC genotype and body mass index (BMI) might exert unfavorable influence on the pregnancy outcome after ART for PCOS patients. These findings indicated that the CYP19 alleles rs727479A/C and rs700519C/T might be associated with the pregnancy outcome after ART in patients with PCOS.

Pharmacogenetics and aromatase inhibitor induced side effects in breast cancer patients

This paper reviews genetic variations mainly related to the onset of adverse events during aromatase inhibitors in early breast cancer. Genetic variability could occur at different steps. The analysis included studies that involved breast cancer patients, treated with an aromatase inhibitor, genotyped for CYP19A1 and/or CYP17A1 and/or CYP27B1 and/or TCLA1, and/or RANK/RANKL/OPG and/or ESR1/ESR2, and assessed for toxicity profile. Twenty-two articles were included for the analysis. Three studies evaluated outcomes and adverse events; 19 studies assessed only side effects. Functional variations may be useful in predicting the onset of toxicities. The identification of polymorphisms at increased risk of toxicity may enable patient management. However, more data are needed to be applied in the individualization of treatment in daily practice.

Germline genetic predictors of aromatase inhibitor concentrations, estrogen suppression and drug efficacy and toxicity in breast cancer patients

The third-generation aromatase inhibitors (AIs), anastrozole, letrozole and exemestane, are highly effective for the treatment of estrogen receptor-positive breast cancer in postmenopausal women. AIs inhibit the aromatase (CYP19A1)-mediated production of estrogens. Most patients taking AIs achieve undetectable blood estrogen concentrations resulting in drug efficacy with tolerable side effects. However, some patients have suboptimal outcomes, which may be due, in part, to inherited germline genetic variants. This review summarizes published germline genetic associations with AI treatment outcomes including systemic AI concentrations, estrogenic response to AIs, AI treatment efficacy and AI treatment toxicities. Significant associations are highlighted with commentary about prioritization for future validation to identify pharmacogenetic predictors of AI treatment outcomes that can be used to inform personalized treatment decisions in patients with estrogen receptor-positive breast cancer.

Impact of R264C and R264H polymorphisms in human aromatase function

The cytochrome P450 aromatase is involved in the last step of sex hormones biosynthesis by converting androgens into estrogens. The human enzyme is highly polymorphic and literature data correlate aromatase single nucleotide polymorphisms to the onset of pathologies such as breast cancer and neurodegenerative diseases. The aims of this study were i) to study the influence of the mutations R264C and R264H on the structure-function of the enzyme also upon phosphorylation by selected kinases and ii) to compare the activity of the variants to that of aromatase wild type in two different cell lines. Far-UV circular dichroism spectroscopy, thermal denaturation experiments and CO-binding assay showed that the two polymorphic variants are correctly folded. Steady-state kinetics experiments showed that rArom R264C and R264H exhibit a 1.5 and 3.4 folds lower catalytic efficiency, respectively, when compared to the wild type protein. Since R264 is part of the consensus motif of PKA and PKG1, phosphorylation experiments were performed to study the effect on aromatase function. Phosphorylation by PKA caused a decrease in activity by 36.2%, 49.3% and 27.9% in the wild type, R264C and R264H proteins respectively. Phosphorylation by PKG1 was also found to decrease the activity by 30.3%, 30.5% and 15.4% in the wild type, R264C and R264H proteins respectively. Experiments performed on the three full-length proteins expressed in human MCF-7 breast cancer cells and rat ST14A neuronal cells showed that, depending on the cell line used, the activity of the proteins is different, implicating different cellular mechanisms modulating aromatase activity. This work demonstrate that R264 polymorphism causes an intrinsic alteration of aromatase activity together with a different consensus for phosphorylation by different kinases, indicating that estrogen production can be different when such mutations are present. These findings are significant in understanding the onset and treatment of pathologies in which aromatase has been shown to be involved.

The rs4646 and rs12592697 Polymorphisms in CYP19A1 Are Associated with Disease Progression among Patients with Breast Cancer from Different Racial/Ethnic Backgrounds

Given the racial/ethnic disparities in breast cancer, we evaluated the association between CYP19A1 single nucleotide polymorphisms (SNPs) on disease progression in women with breast cancer from different racial/ethnic backgrounds. This is a cross-sectional analysis of data from 327 women with breast cancer in the Expanded Breast Cancer Registry program of the University of New Mexico. Stored DNA samples were analyzed for CYP19A1 SNPs using a custom designed microarray panel. Genotype-phenotype correlations were analyzed. Of the 384 SNPs, 2 were associated with clinically significant outcomes, the rs4646 and rs12592697. The T allele for the rs4646 was associated with advanced stage of the disease at the time of presentation (odds ratio [OR]:1.8, confidence intervals [CI]: 1.05–3.13, p < 0.05) and a more progressive disease (OR: 2.1 [CI: 1.1–4.0], p = 0.04). For the rs12592697, the variant T allele was more frequent in Hispanic women and associated with a more progressive disease (OR: 2.05 [CI: 1.0–4.0], p = 0.04). However, further analysis according to menopausal status showed that the association between these 2 SNPs with disease progression or the stage at diagnosis are confined only to postmenopausal women. The odds ratios of disease progression among postmenopausal women carrying the T allele for the rs4646 and rs12592697 are 3.05 (1.21, 7.74, p = 0.02) and 3.80 (1.24, 11.6, p = 0.02), respectively. Regardless, differences in disease progression among the different genotypes for both SNPs disappeared after adjustment for treatment. In summary, the rs4646 and the rs12592697 SNPs in CYP19A1 are associated with differences in disease progression in postmenopausal women. However, treatment appears to mitigate the differences in genetic risk.

The CYP19A1 rs3751592 variant confers susceptibility to Alzheimer disease in the Chinese Han population

BACKGROUND

The CYP19A1 enzyme (aromatase) encoded by the cytochrome P450 (CYP) 19A1 gene influences the final step in the biosynthesis of estrogen, which has been associated with Alzheimer disease (AD). It is possible that genetic polymorphisms in CYP19A1 could influence the risk of AD by altering the expression of CYP19A1. The ε4 allele of the apolipoprotein E (APOE) gene, which is the most significant known genetic risk factor for AD, may mask the effects of other loci.

METHODS

To assess the potential association of CYP19A1 gene polymorphisms with the risk of AD, we conducted a case-control study in a Chinese Han population by recruiting 463 cases, including 207 patients diagnosed with AD and 256 healthy people matched for sex and age.

RESULTS

In APOE ε4 carriers, the distributions of the G allele and the AG + GG genotype of CYP19A1 rs3751592 in patients differed significantly (P < 0.05) from those in healthy people. However, no difference was observed in the distribution of CYP19A1 rs1065778 between the patient and control populations, regardless of their APOE ε4 status.

CONCLUSION

The results demonstrated that the rs3751592 A/G polymorphism of the CYP19A1 gene was associated with the incidence of AD in a Chinese Han population, which suggests that CYP19A1 rs3751592 is a predisposing genetic factor for AD.

Structural and functional characterization of aromatase, estrogen receptor, and their genes in endocrine-responsive and -resistant breast cancer cells

Aromatase and estrogen receptor α (ER) are two key proteins for the proliferation of endocrine-responsive and -resistant breast cancers. Aromatase is an enzyme involved in the conversion of androgen (such as testosterone) to estrogen (such as 17β-estradiol). It is also a very effective therapeutic target for the treatment of endocrine-responsive breast cancer. Comparing endocrine-responsive and -resistant breast cancer, aromatase protein levels do not change significantly. Aromatase activity; however, can be increased via PI3K/Akt/IGFR signaling pathways in endocrine resistant cells. The activity of aromatase has been reported to be modulated by phosphorylation. The ER is an important steroid nuclear receptor in the proliferation of both endocrine-responsive and -resistant cells. Although the mutation or amplification of ER can cause endocrine resistance, it is not commonly found. Some point mutations and translocation events have been characterized and shown to promote estrogen-independent growth. Phosphorylation by cross-talk with growth factor pathways is one of the main mechanisms for ligand-independent activation of ER. Taken together, both ER and aromatase are important in ER-dependent breast cancer and the development of endocrine resistance.

The implications of genetic variation for the pharmacokinetics and pharmacodynamics of aromatase inhibitors

INTRODUCTION

Breast cancer is the most common female cancer and remains a serious public health concern worldwide. Third-generation aromatase inhibitors (AIs) are widely used in postmenopausal women with estrogen receptor positive breast cancer. However, there is marked interindividual variability in terms of the efficacy and incidence of adverse events following treatment with AIs. Pharmacogenetics has the potential to predict clinical outcomes based on patients' genetic information, paving the way towards personalized treatment.

AREAS COVERED

This article reviews pharmacogenetic studies of AIs, including pharmacokinetic and pharmacodynamic aspects, highlighting those studies where the efficacy and adverse events of AIs have been examined using both candidate gene and genome-wide approaches.

EXPERT OPINION

Pharmacogenetics is a promising approach to develop personalized medicine with AIs. However, the application of pharmacogenetics to predict therapeutic efficacy and adverse events in breast cancer patients is still far from implementation in routine clinical practice. Large, comprehensive, multicenter studies that simultaneously evaluate multiple genes and pathways, including rare variants, are warranted in order to produce reliable and informative results. The ultimate aim is to develop clinically-relevant guidelines for breast cancer therapy.

Genetic polymorphism at Val80 (rs700518) of the CYP19A1 gene is associated with body composition changes in women on aromatase inhibitors for ER (+) breast cancer

OBJECTIVE

Polymorphisms in the CYP19A1 (aromatase) gene influence disease-free survival and bone loss in patients taking aromatase inhibitors (AIs) for estrogen receptor-positive (ER+) breast cancers. Because AI use results in severe estrogen deficiency that may lead to changes in body composition, the aim of this study was to determine the effect of the rs700518 polymorphism in the CYP19A1 gene on the changes in body composition among postmenopausal women who were treated with AIs for ER+ breast cancer.

PATIENTS AND METHODS

This was a 1-year prospective study of changes in body composition in postmenopausal women who were initiated on third-generation AIs for ER+ breast cancer. Body composition was measured by dual-energy absorptiometry at 6 and 12 months, serum estradiol by radioimmunoassay, and genotyping by a TaqMan single-nucleotide polymorphism allelic discrimination assay.

RESULTS

Eighty-two women could provide at least one follow-up body composition measurement. Women with the GG genotype for the rs700518 (G/A at Val80) developed a significant increase in truncal fat mass index (P=0.03) and a significant decrease in fat-free mass index (P=0.01) at 12 months relative to patients carrying the A allele (GA/AA). There was no significant difference in the changes in estradiol levels among the genotypes.

CONCLUSION

Patients with the GG genotype for the rs700518 polymorphism in the CYP19A1 gene are at risk for significant loss of fat-free mass and increase in truncal fat with AI therapy. Whether there are associated metabolic abnormalities and whether changes would persist with long-term AI therapy need to be confirmed in a larger study with a longer duration of follow-up.

CYP19A1 Genetic Polymorphisms rs4646 and Osteoporosis in Patients Treated with Aromatase Inhibitor-Based Adjuvant Therapy

OBJECTIVE

Third-generation aromatase inhibitors (AI) are potent suppressors of aromatase activity. The aim of this study was to measure the incidence of adverse effects in breast cancer patients treated with AI-based adjuvant therapy and the relationship with the CYP19A1 genotypes.

MATERIALS AND METHODS

Forty-five postmenopausal breast cancer patients (46-85 yrs) in AI adjuvant treatment were genotyped for the rs4646 polymorphisms of CYP19A1 gene and three variations were identified. Toxicities were registered at each follow-up medical examination, and classified in accord with the Common Terminology Criteria for Adverse Events.

RESULTS

Twenty-four (53.3%) patients presented the GG genotype; 19 (42.2%) the GT, and 2 (4.4%) the TT. The AI treatment was Anastrazole for 35 patients (77.8%) and Letrozole for the others (n=10; 22.2%). Osteoporosis was significantly associated with the GG genotype (p=0.001). Treatment discontinuation (TD) was observed in 6 cases (13.3%). The only parameter able to predict TD was the appearance of severe arthralgia/myalgia (Odds Ratio, OR=23.75; p=0.009), when adjusted for age and AI treatment.

CONCLUSION

Our results suggest that CYP19A1 polymorphic variants may influence susceptibility to develop AI-related side effects. Further prospective studies are needed to confirm the role of the aromatase gene (CYP19A1) polymorphisms in predicting adverse effects to AI-based therapy.

Associations between genetic variants and the effect of letrozole and exemestane on bone mass and bone turnover

Adjuvant therapy for hormone receptor (HR) positive postmenopausal breast cancer patients includes aromatase inhibitors (AI). While both the non-steroidal AI letrozole and the steroidal AI exemestane decrease serum estrogen concentrations, there is evidence that exemestane may be less detrimental to bone. We hypothesized that single nucleotide polymorphisms (SNP) predict effects of AIs on bone turnover. Early stage HR-positive breast cancer patients were enrolled in a randomized trial of exemestane versus letrozole. Effects of AI on bone mineral density (BMD) and bone turnover markers (BTM), and associations between SNPs in 24 candidate genes and changes in BMD or BTM were determined. Of the 503 enrolled patients, paired BMD data were available for 123 and 101 patients treated with letrozole and exemestane, respectively, and paired BTM data were available for 175 and 173 patients, respectively. The mean change in lumbar spine BMD was significantly greater for letrozole-treated (-3.2 %) compared to exemestane-treated patients (-1.0 %) (p = 0.0016). Urine N-telopeptide was significantly increased in patients treated with exemestane (p = 0.001) but not letrozole. Two SNPs (rs4870061 and rs9322335) in ESR1 and one SNP (rs10140457) in ESR2 were associated with decreased BMD in letrozole-treated patients. In the exemestane-treated patients, SNPs in ESR1 (Rs2813543) and CYP19A1 (Rs6493497) were associated with decreased bone density. Exemestane had a less negative impact on bone density compared to letrozole, and the effects of AI therapy on bone may be impacted by genetic variants in the ER pathway.

The influence of genetic polymorphisms on the efficacy and side effects of anastrozole in postmenopausal breast cancer patients

Breast cancer is a common cause of cancer mortality among women. Several genetic factors have been implicated in its development. Current treatment guidelines for estrogen receptor-positive breast cancer recommend that anastrozole [or any of the other two aromatase inhibitors (letrozole and exemestane)] is used as an alternative to tamoxifen or following several years of tamoxifen treatment. Nevertheless, this approach is still associated with many challenges, ranging from the recurrence of breast cancer to considerable interindividual variability in the tolerability of anastrozole, which may cause adverse effects, such as musculoskeletal symptoms, and lead to the withdrawal of many patients from treatment. Variabilities in the genes encoding the drug target (aromatase) or its metabolizing enzymes (CYP3A and UGT1A) contribute toward the interindividual variability in anastrozole's pharmacokinetics and/or pharmacodynamics. This paper reviews the role of genetic polymorphisms of CYP19A1, CYP3A4, and UGT1A4 in the responses of female hormone receptor-positive postmenopausal breast cancer patients to anastrozole. Many reviews in the literature have suggested that the study of functional polymorphisms and investigation of relevant genetic markers may provide valuable information in predicting responses to anastrozole in terms of its therapeutic and adverse effects. Nevertheless, more studies are required before the knowledge of its pharmacogenomics can be applied to the individualization of treatment to ensure that patients receive the maximum benefits. Therefore, future analyses, including but not limited to genome-wide association studies, are encouraged to address some of the gray areas in the pharmacogenomics of anastrozole therapy in postmenopausal breast cancer cases; this will help in providing guidance for future pharmacogenomics protocols when anastrozole is utilized in patients' management.

Cancer treatment-induced bone loss (CTIBL): pathogenesis and clinical implications

Osteopenia and osteoporosis are often long-term complications of anti-neoplastic treatments, defined as "cancer treatment-induced bone loss" (CTIBL). This pathological condition in oncologic patients results in a higher fracture risk than in the general population, and so has a significant negative impact on their quality of life. Hormone treatment is the main actor in this scenario, but not the only one. In fact, chemotherapies, radiotherapy and tyrosine kinase inhibitors may contribute to deregulate bone remodeling via different mechanisms. Thus, the identification of cancer patients at risk for CTIBL is essential for early diagnosis and appropriate intervention, that includes both lifestyle modifications and pharmacological approaches to prevent bone metabolism failure during anti-tumor treatments.

Influence of CYP19A1 polymorphisms on the treatment of breast cancer with aromatase inhibitors: a systematic review and meta-analysis

BACKGROUND

Many clinical trials have shown the efficacy of aromatase inhibitors (AIs) in the management of breast cancer (BC). There is growing evidence that CYP19A1 single-nucleotide polymorphisms (SNPs) are associated with clinical response (CR) and adverse effects (AEs) among BC patients treated with AIs. The aim of this study was to analyze the association between CYP19A1 polymorphisms and AI treatment in BC patients.

METHODS

A systematic review was performed in MEDLINE, EMBASE, and LILACS. A meta-analysis was conducted to compare the association between CYP19A1 variants and treatment response among BC patients.

RESULTS

A total of 12 studies were included in the final analysis. There was significant variation among the populations studied and the SNPs and outcomes investigated. A meta-analysis was only possible for the evaluation of SNP rs4646 vs. the wild-type variant with respect to time to progression (TTP) among metastatic BC patients treated with AI. TTP was significantly increased in patients with the rs4646 variant compared with the wild-type gene (hazard ratio (HR) = 0.51 [95 % confidence interval (CI), 0.33-0.78], P = 0.002). Seven studies analyzed the association between AEs with different polymorphisms of CYP19A1. Although there was a statistically significant association with musculoskeletal adverse events (rs934635, rs60271534, rs700518rs, and haplotype M_3_5) and with vasomotor symptoms (rs934635, rs1694189, rs7176005, and haplotype M_5_3) in individual studies, similar associations were not observed in further studies. No statistically significant association between musculoskeletal AEs and SNPs rs4646, rs10046, rs727479, and rs1062033 was found.

CONCLUSIONS

These findings suggest that the presence of the rs4646 variant may be a predictive factor of the benefit of AI treatment for BC. The effects of CYP19A1 polymorphisms on clinical outcomes were most often detected in individual studies, suggesting that longer-term studies will better clarify these associations. Additional studies are needed to clarify the predictive value of other SNPs and whether CYP19A1 genotyping should be used to guide AI treatment.

CYP19A1 polymorphisms and clinical outcomes in postmenopausal women with hormone receptor-positive breast cancer in the BIG 1-98 trial

To determine whether CYP19A1 polymorphisms are associated with abnormal activity of aromatase and with musculoskeletal and bone side effects of aromatase inhibitors. DNA was isolated from tumor specimens of 4861 postmenopausal women with hormone receptor-positive breast cancer enrolled in the BIG 1-98 trial to receive tamoxifen and/or letrozole for 5 years. Tumors were genotyped for six CYP19A1 polymorphisms using PCR-based methods. Associations with breast cancer-free interval (BCFI), distant recurrence-free interval (DRFI), musculoskeletal and bone adverse events (AEs) were assessed using Cox proportional hazards models. All statistical tests were two-sided. No association between the CYP19A1 genotypes and BCFI or DRFI was observed overall. A reduced risk of a breast cancer event for tamoxifen-treated patients with rs700518 variants was observed (BCFI CC/TC vs. TT: HR 0.53, 95 % CI 0.34-0.82, interaction P = 0.08), but not observed for letrozole-treated patients. There was an increased risk of musculoskeletal AEs for patients with rs700518 variants CC/TC versus TT (HR 1.22, 95 % CI 1.03-1.45, P = 0.02), regardless of treatment. Tamoxifen-treated patients with rs4646 variants had a reduced risk of bone AEs (AA/CA vs. CC: HR 0.76, 95 % CI 0.59-0.98), whereas an increase of minor allele (C) of rs10046 was associated with an increased risk of bone AEs (HR 1.28, 95 % CI 1.07-1.52). rs936308 variants were associated with a reduced risk of bone AEs in letrozole-treated patients (GG/GC vs. CC: HR 0.73, 95 % CI 0.54-0.99), different from in tamoxifen-treated patients (GG/GC vs. CC: HR 1.32, 95 % CI 0.92-1.90, interaction P = 0.01). CYP19A1 rs700518 variants showed associations with BCFI, DRFI, in tamoxifen treated patients and musculoskeletal AEs regardless of treatment. SNPs rs4646, rs10046, and rs936308 were associated with bone AEs.

Germline variants in the CYP19A1 gene are related to specific adverse events in aromatase inhibitor users: a substudy of Dutch patients in the TEAM trial

Musculoskeletal adverse events (MSAEs) and vasomotor symptoms (VMSs) are known side-effects of aromatase inhibitors, and may be related to genetic variations of the aromatase gene (CYP19A1). We investigated the relationship between these specific AEs and single nucleotide polymorphisms (SNPs) in the CYP19A1 gene in postmenopausal, hormone receptor-positive early breast cancer (BC) patients treated with adjuvant exemestane for 5 years. Dutch patients who were randomized to receive 5 years of exemestane in the Tamoxifen Exemestane Adjuvant Multinational (TEAM) trial were included. A tagging-SNP approach was performed, covering 80 % of variations of the CYP19A1 gene with 30 SNPs. Logistic regression analyses were used to assess the risk of reporting VMSs or MSAEs in relation to genotypes within selected SNPs. Of 737 included patients, 281 patients reported at least one MSAE (n = 210) or VMS (n = 163). Homozygous AA genotype of rs934635 was associated with a significantly higher odds of MSAEs (multivariate odds ratio (OR) 4.66, p = 0.008) and VMSs (multivariate OR 2.78, p = 0.044). Regarding both rs1694189 and rs7176005, the homozygous variant genotypes (TT) were associated with a higher odds of VMSs, but not MSAEs (OR 1.758, p = 0.025 and OR 6.361, p = 0.021, respectively). Our exploratory analysis demonstrated that some CYP19A1 gene variations may be associated with MSAEs and/or VMSs. Specifically, patients with the homozygous variant rs934635 genotype reported more MSAEs and VMSs. Although further confirmatory studies are warranted, genomic profiling can help identify patients at an increased risk of reporting these specific AEs, potentiating further personalized BC treatment.

Cancer-associated bone disease

Bone is commonly affected in cancer. Cancer-induced bone disease results from the primary disease, or from therapies against the primary condition, causing bone fragility. Bone-modifying agents, such as bisphosphonates and denosumab, are efficacious in preventing and delaying cancer-related bone disease. With evidence-based care pathways, guidelines assist physicians in clinical decision-making. Of the 57 million deaths in 2008 worldwide, almost two thirds were due to non-communicable diseases, led by cardiovascular diseases and cancers. Bone is a commonly affected organ in cancer, and although the incidence of metastatic bone disease is not well defined, it is estimated that around half of patients who die from cancer in the USA each year have bone involvement. Furthermore, cancer-induced bone disease can result from the primary disease itself, either due to circulating bone resorbing substances or metastatic bone disease, such as commonly occurs with breast, lung and prostate cancer, or from therapies administered to treat the primary condition thus causing bone loss and fractures. Treatment-induced osteoporosis may occur in the setting of glucocorticoid therapy or oestrogen deprivation therapy, chemotherapy-induced ovarian failure and androgen deprivation therapy. Tumour skeletal-related events include pathologic fractures, spinal cord compression, surgery and radiotherapy to bone and may or may not include hypercalcaemia of malignancy while skeletal complication refers to pain and other symptoms. Some evidence demonstrates the efficacy of various interventions including bone-modifying agents, such as bisphosphonates and denosumab, in preventing or delaying cancer-related bone disease. The latter includes treatment of patients with metastatic skeletal lesions in general, adjuvant treatment of breast and prostate cancer in particular, and the prevention of cancer-associated bone disease. This has led to the development of guidelines by several societies and working groups to assist physicians in clinical decision making, providing them with evidence-based care pathways to prevent skeletal-related events and bone loss. The goal of this paper is to put forth an IOF position paper addressing bone diseases and cancer and summarizing the position papers of other organizations.