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

Musculoskeletal symptoms associated with aromatase inhibitors in the treatment of early breast cancer: A scoping review of risk factors and outcomes

PURPOSE

Aromatase inhibitor-associated musculoskeletal symptoms (AIMSS) are the most common adverse effects experienced by breast cancer patients. This scoping review aimed to systematically synthesize the predictors/risk factors and outcomes of AIMSS in patients with early-stage breast cancer.

METHODS

A systematic search was conducted in PubMed, Web of Science, EMBASE, CINAHL, and the China National Knowledge Internet (CNKI) from inception to December 2024 following the scoping review framework proposed by Arksey and O'Malley (2005).

RESULTS

A total of 5,008 studies were identified, and 98 were included in this review. The risk factors for AIMSS included psychosocial and demographic factors (e.g., age, BMI, menstrual status, and anxiety), clinical factors (e.g., history of chemotherapy, preexisting pain, and musculoskeletal diseases) and gene polymorphisms (e.g., ESR1, OPG, RANKL, TCL1A, and CYP19A1). The outcomes of AIMSS encompassed physical, psychological, behavioral, and survival-related impacts.

CONCLUSION

This scoping review synthesized the available evidence on predictors, risk factors, and outcomes of AIMSS, providing a foundation for developing risk prediction models and enhancing symptom management strategies.

Pharmacogenetics of Toxicities Related to Endocrine Treatment in Breast Cancer: A Systematic Review and Meta-analysis

BACKGROUND/AIM

Endocrine therapy is the standard treatment for hormone receptor-positive (HR+) breast cancer (BC). Yet, it is accompanied by treatment-related toxicities, leading to poor treatment adherence, high relapse, and low rates of survival. While pharmacogenomic variants have the potential to guide personalized treatment, their predictive value is inconsistent across published studies.

MATERIALS AND METHODS

To systematically assess the literature's current landscape of pharmacogenomics of endocrine therapy-related adverse drug effects, systematic searches in MEDLINE, Embase, Cochrane CENTRAL, Google Scholar and PharmGKB databases were conducted.

RESULTS

We identified 87 articles. Substantial heterogeneity and variability in pharmacogenomic effects were evident across studies, with many using data from the same cohorts and predominantly focusing on the Caucasian population and postmenopausal women. Meta-analyses revealed Factor V Leiden mutation as a predictor of thromboembolic events in tamoxifen-treated women (p<0.0001). Meta-analyses also found that rs7984870 and rs2234693 were associated with musculoskeletal toxicities in postmenopausal women receiving aromatase inhibitors (p<0.0001 and p<0.0001, respectively).

CONCLUSION

Overall, the current body of evidence regarding the potential role of pharmacogenomics in endocrine therapy-related toxicity in BC remains largely inconclusive. Key concerns include the heterogeneity in toxicity definitions, lack of consideration for genotype-treatment interactions, and the failure to account for multiple testing. The review underscores the necessity for larger and well-designed studies, particularly with the inclusion of premenopausal women and non-Caucasian populations.

Genome-wide association study of aromatase inhibitor discontinuation due to musculoskeletal symptoms

OBJECTIVE

Aromatase inhibitors (AIs) are commonly used to treat hormone receptor positive (HR +) breast cancer. AI-induced musculoskeletal syndrome (AIMSS) is a common toxicity that causes AI treatment discontinuation. The objective of this genome-wide association study (GWAS) was to identify genetic variants associated with discontinuation of AI therapy due to AIMSS and attempt to replicate previously reported associations.

METHODS

In the Exemestane and Letrozole Pharmacogenetics (ELPh) study, postmenopausal patients with HR + non-metastatic breast cancer were randomized to letrozole or exemestane. Genome-wide genotyping of germline DNA was conducted followed by imputation. Each imputed variant was tested for association with time-to-treatment discontinuation due to AIMSS using a Cox proportional hazards model assuming additive genetic effects and adjusting for age, baseline pain score, prior taxane treatment, and AI arm. Secondary analyses were conducted within each AI arm and analyses of candidate variants previously reported to be associated with AIMSS risk.

RESULTS

Four hundred ELPh participants were included in the combined analysis. Two variants surpassed the genome-wide significance level in the primary analysis (p value < 5 × 10-8), an intronic variant (rs79048288) within CCDC148 (HR = 4.42, 95% CI: 2.67-7.33) and an intergenic variant (rs912571) upstream of PPP1R14C (HR = 0.30, 95% CI: 0.20-0.47). In the secondary analysis, rs74418677, which is known to be associated with expression of SUPT20H, was significantly associated with discontinuation of letrozole therapy due to AIMSS (HR = 5.91, 95% CI: 3.16-11.06). We were able to replicate associations for candidate variants previously reported to be associated with AIMSS in this cohort, but were not able to replicate associations for any other variants previously reported in other patient cohorts.

CONCLUSIONS

Our GWAS findings identify several candidate variants that may be associated with AIMSS risk from AI generally or letrozole specifically. Validation of these associations in independent cohorts is needed before translating these findings into clinical practice to improve treatment outcomes in patients with HR + breast cancer.

Synonymous Variants: Necessary Nuance in our Understanding of Cancer Drivers and Treatment Outcomes

Once called "silent mutations" and assumed to have no effect on protein structure and function, synonymous variants are now recognized to be drivers for some cancers. There have been significant advances in our understanding of the numerous mechanisms by which synonymous single nucleotide variants (sSNVs) can affect protein structure and function by affecting pre-mRNA splicing, mRNA expression, stability, folding, miRNA binding, translation kinetics, and co-translational folding. This review highlights the need for considering sSNVs in cancer biology to gain a better understanding of the genetic determinants of human cancers and to improve their diagnosis and treatment. We surveyed the literature for reports of sSNVs in cancer and found numerous studies on the consequences of sSNVs on gene function with supporting in vitro evidence. We also found reports of sSNVs that have statistically significant associations with specific cancer types but for which in vitro studies are lacking to support the reported associations. Additionally, we found reports of germline and somatic sSNVs that were observed in numerous clinical studies and for which in silico analysis predicts possible effects on gene function. We provide a review of these investigations and discuss necessary future studies to elucidate the mechanisms by which sSNVs disrupt protein function and are play a role in tumorigeneses, cancer progression, and treatment efficacy. As splicing dysregulation is one of the most well recognized mechanisms by which sSNVs impact protein function, we also include our own in silico analysis for predicting which sSNVs may disrupt pre-mRNA splicing.

Further Evidence That OPG rs2073618 Is Associated With Increased Risk of Musculoskeletal Symptoms in Patients Receiving Aromatase Inhibitors for Early Breast Cancer

Background

Aromatase inhibitors (AI) reduce recurrence and death in patients with early-stage hormone receptor-positive (HR +) breast cancer. Treatment-related toxicities, including AI-induced musculoskeletal symptoms (AIMSS), are common and may lead to early AI discontinuation. The objective of this study was to replicate previously reported associations for candidate germline genetic polymorphisms with AIMSS.

Methods

Women with stage 0-III HR + breast cancer initiating adjuvant AI were enrolled in a prospective clinic-based observational cohort. AIMSS were assessed by patient-reported outcomes (PRO) including the PROMIS pain interference and physical function measures plus the FACT-ES joint pain question at baseline and after 3 and 6 months. For the primary analysis, AIMSS were defined as ≥ 4-point increase in the pain interference T-score from baseline. Secondary AIMSS endpoints were defined as ≥ 4-point decrease in the physical function T-score from baseline and as ≥ 1-point increase on the FACT-ES joint pain question from baseline. The primary hypothesis was that TCL1A rs11849538 would be associated with AIMSS. Twelve other germline variants in CYP19A1, VDR, PIRC66, OPG, ESR1, CYP27B1, CYP17A1, and RANKL were also analyzed assuming a dominant genetic effect and prespecified direction of effect on AIMSS using univariate logistic regression with an unadjusted α = 0.05. Significant univariate associations in the expected direction were adjusted for age, race, body mass index (BMI), prior taxane, and the type of AI using multivariable logistic regression.

Results

A total of 143 participants with PRO and genetic data were included in this analysis, most of whom were treated with anastrozole (78%) or letrozole (20%). On primary analysis, participants carrying TCL1A rs11849538 were not more likely to develop AIMSS (odds ratio = 1.29, 95% confidence interval: 0.55-3.07, p = 0.56). In the statistically uncorrected secondary analysis, OPG rs2073618 was associated with AIMSS defined by worsening on the FACT-ES joint pain question (OR = 3.33, p = 0.004), and this association maintained significance after covariate adjustment (OR = 3.98, p = 0.003).

Conclusion

Carriers of OPG rs2073618 may be at increased risk of AIMSS. If confirmed in other cohorts, OPG genotyping can be used to identify individuals with HR + early breast cancer in whom alternate endocrine therapy or interventions to enhance symptom detection and implement strategies to reduce musculoskeletal symptoms may be needed.

The Prognostic Impact of Intratumoral Aryl Hydrocarbon Receptor in Primary Breast Cancer Depends on the Type of Endocrine Therapy: A Population-Based Cohort Study

The aryl hydrocarbon receptor (AhR) is a master regulator of multiple pathways involved in breast cancer, and influences the estrogen receptor alpha (ER) and aromatase/CYP19A1. The purpose of this study was to elucidate the interplay between intratumoral levels of AhR and aromatase, patient characteristics (including AhR and CYP19A1 genotypes), clinicopathological features, and prognosis in breast cancer patients receiving adjuvant treatments. A prospective cohort of 1116 patients with primary breast cancer in Sweden, included 2002-2012, was followed until June 30th 2019 (median 8.7 years). Tumor-specific AhR (n=920) and aromatase levels (n=816) were evaluated on tissue microarrays using immunohistochemistry. Associations between cytoplasmatic (AhRcyt) and nuclear (AhRnuc) AhR levels, intratumoral aromatase, clinicopathological features, and prognosis in different treatment groups were analyzed. Low AhRcyt levels (n=183) and positive intratumoral aromatase (n=69) were associated with estrogen receptor (ER)- status and more aggressive tumors. Genotypes were not associated with their respective protein levels. The functional AhR Arg554Lys GG genotype was associated with recurrence-free survival in switch-therapy (sequential tamoxifen/aromatase inhibitors (AI) or AI/tamoxifen) treated patients (HRadj 0.42; 95% CI 0.22-0.83). High AhRcyt levels were associated with longer recurrence-free survival during the first 10 years of follow-up among tamoxifen-only treated patients (HRadj 0.40; 95% CI 0.23-0.71) compared to low AhRcyt levels, whereas an almost inverse association was seen in patients with switch-therapy (P interaction=0.023). Intratumoral aromatase had little prognostic impact. These findings warrant confirmation in an independent cohort, preferably in a randomized clinical trial comparing different endocrine regimens. They might also guide the selection of breast cancer patients for clinical trials with selective AhR modulators.

CYP19A1 rs10046 Pharmacogenetics in Postmenopausal Breast Cancer Patients Treated with Aromatase Inhibitors: One-year Follow-up

BACKGROUND

Significant individual variation in bone loss associated with aromatase inhibitors (AIs) emphasizes the importance of identifying postmenopausal breast cancer patients at high risk for this adverse effect. The study explores the clinical relevance of genetic variation in the Cytochrome P450 19A1 (CYP19A1) gene in a subset of South African patients during the first year of taking AIs for estrogen receptor (ER)-positive breast cancer.

METHODS

The study population consisted of ER-positive breast cancer patients on AIs, followed in real-life clinical practice. Body mass index was measured and bone mineral density (BMD) was determined at baseline and at month 12. CYP19A1 genotyping was performed using real-time polymerase chain reaction analysis of rs10046, extended to Sanger sequencing and whole exome sequencing in 10 patients with more than 5% bone loss at month 12 at the lumbar spine.

RESULTS

After 12 months of AI treatment, 72 patients had completed BMD and were successfully genotyped. Ten patients (14%) experienced more than 5% bone loss at the lumbar spine over the study period. Genotyping for CYP19A1 rs10046 revealed that patients with two copies of the A-allele were 10.79 times more likely to have an ordinal category change of having an increased percentage of bone loss or no increase at the lumbar spine, compared to patients with the GA or GG genotypes (CI of 1.771- 65.830, p=0.01). None of the 34 patients without lumbar spine bone loss at month 12 were homozygous for the functional CYP19A1 polymorphism. At the total hip region, patients with the AA genotype were 7. 37 times more likely to have an ordinal category change of having an increased percentage of bone loss or no increase (CI of 1.101- 49.336, p=0.04).

CONCLUSION

Homozygosity for the CYP19A1 rs10046 A-allele may provide information, in addition to clinical and biochemical factors that may be considered in risk stratification to optimize bone health in postmenopausal breast cancer women on AIs. Further investigation is required to place the clinical effect observed for a single CYP19A1 gene variant in a genomic context.

Polymorphisms of T- cell leukemia 1A gene loci are not related to the development of adjuvant letrozole-induced adverse events in breast cancer

Letrozole, an aromatase inhibitor (AI), is the first-line adjuvant drug for treating hormone receptor-positive (HR+) breast cancer in postmenopausal women. However, harmful adverse events (AEs) and significant differences in drug response among individuals remain a significant problem in clinical application. Current evidence suggests that the observed individual variation in the treatment outcomes of AI is conferred by genetic variants. Hence, in this study, we examined the association of TCL1A gene polymorphisms with letrozole-induced AEs. The study subjects were postmenopausal HR+ breast cancer patients who were receiving adjuvant letrozole. Genomic DNA was isolated by a routine standard phenol-chloroform method. In total, 198 South Indian patients were genotyped for four single nucleotide polymorphisms (SNPs) in the TCL1A gene loci by the TaqMan allelic discrimination assay using the RT-PCR system. We used the odds ratio and 95% confidence interval to assess the genetic association. Musculoskeletal (MS) AEs and vasomotor symptoms (VMSs) are the most common side effects observed in the study cohort. Among 198 patients, 81 experienced musculoskeletal toxicity, reporting MS-AEs, 57 had VMSs, and 33 of them had both. The most frequently identified polymorphic variants in the patient series were rs11849538 (G), with an allele frequency of about 27.3%, followed by rs7158782-G (27.3%), rs7159713-G (25.8%), and rs2369049-G (22.5%). The genetic association analysis indicated no significant difference in the proportion of TCL1A gene variants between patients with and without AEs on either MS-AEs or VMSs. Though we observed high LD in all patient groups, the inferred haplotypes displayed a non-significant association with letrozole-induced specific AEs. However, the SNP functionality analysis by RegulomeDB provided a 2b rank score for rs7158782, suggesting a potential biological function. Our findings suggest that TCL1A gene polymorphisms may not play any role in the prediction of letrozole-induced AEs in South Indian HR+ breast cancer patients.

Recent advances in the personalized treatment of estrogen receptor-positive breast cancer with tamoxifen: a focus on pharmacogenomics

Introduction: Tamoxifen is still an important drug in hormone-dependent breast cancer therapy. Personalization of its clinical use beyond hormone receptor positivity could improve the substantial variability of the treatment response.Areas covered: The overview of the current evidence for the treatment personalization using therapeutic drug monitoring, or using genetic biomarkers including CYP2D6 is provided. Although many studies focused on the PK aspects or the impact of CYP2D6 variability the translation into clinical routine is not clearly defined due to the inconsistent clinical outcome data.Expert opinion: We believe that at least the main candidate factors, i.e. CYP2D6 polymorphism, CYP2D6 inhibition, endoxifen serum levels may become important predictors of clinical relevance for tamoxifen treatment personalization in the future. To achieve this aim, however, further research should take into consideration more precise characterization of the disease, epigenetic factors and also utilize an appropriately powered multifactorial approach instead of a single gene evaluating studies.

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.

Clinical and genetic risk factors for aromatase inhibitor-associated arthralgia in breast cancer survivors

BACKGROUND

Arthralgia is a common and debilitating toxicity of aromatase inhibitors (AI) that leads to premature drug discontinuation. We sought to evaluate the clinical and genetic risk factors associated with AI-associated arthralgia (AIAA).

METHODS

We performed a cross-sectional study among postmenopausal women with stage 0-III breast cancer who were prescribed a third-generation AI for adjuvant therapy. The primary outcome was patient-reported AIAA occurrence. We extracted and assayed germline DNA for single nucleotide polymorphisms (SNPs) of genes implicated in estrogen and inflammation pathways. Multivariable logistic regression models examined the association between demographic, clinical, and genetic factors and AIAA. Analyses were restricted to White participants.

RESULTS

Among 1049 White participants, 543 (52%) reported AIAA. In multivariable analyses, women who had a college education [Adjusted Odds Ratio (AOR) 1.49, 95% Confidence Interval (CI) 1.00-2.20], had a more recent transition into menopause (<10 years) (5-10 years AOR 1.55, 95% CI 1.09-2.22; <5 years AOR 1.78, 95% CI 1.18-2.67), were within one year of starting AIs (AOR 1.61, 95% CI 1.08-2.40), and those who received chemotherapy (AOR 1.38, 95% CI 1.02-1.88) were significantly more likely to report AIAA. Additionally, SNP rs11648233 (HSD17B2) was significantly associated with higher odds of AIAA (AOR 2.21, 95% CI 1.55-3.16).

CONCLUSIONS

Time since menopause and start of AIs, prior chemotherapy, and SNP rs11648233 within the HSD17B2 gene in the estrogen pathway were significantly associated with patient-reported AIAA. These findings suggest that clinical and genetic factors involved in estrogen withdrawal increase the risk of AIAA in postmenopausal breast cancer survivors.

A New Genetic Risk Score to Predict the Outcome of Locally Advanced or Metastatic Breast Cancer Patients Treated With First-Line Exemestane: Results From a Prospective Study

INTRODUCTION

Approximately 50% of locally advanced or metastatic breast cancer (MBC) patients treated with first-line exemestane do not show objective response and currently there are no reliable biomarkers to predict the outcome of patients using this therapy. The constitutive genetic background might be responsible for differences in the outcome of exemestane-treated patients. We designed a prospective study to investigate the role of germ line polymorphisms as biomarkers of survival.

PATIENTS AND METHODS

Three hundred two locally advanced or MBC patients treated with first-line exemestane were genotyped for 74 germ line polymorphisms in 39 candidate genes involved in drug activity, hormone balance, DNA replication and repair, and cell signaling pathways. Associations with progression-free survival (PFS) and overall survival (OS) were tested with multivariate Cox regression. Bootstrap resampling was used as an internal assessment of results reproducibility.

RESULTS

Cytochrome P450 19A1-rs10046TC/CC, solute carrier organic anion transporter 1B1-rs4149056TT, adenosine triphosphate binding cassette subfamily G member 2-rs2046134GG, fibroblast growth factor receptor-4-rs351855TT, and X-ray repair cross complementing 3-rs861539TT were significantly associated with PFS and then combined into a risk score (0-1, 2, 3, or 4-6 risk points). Patients with the highest risk score (4-6 risk points) compared with ones with the lowest score (0-1 risk points) had a median PFS of 10 months versus 26.3 months (adjusted hazard ratio [AdjHR], 3.12 [95% confidence interval (CI), 2.18-4.48]; P < .001) and a median OS of 38.9 months versus 63.0 months (AdjHR, 2.41 [95% CI, 1.22-4.79], P = .012), respectively.

CONCLUSION

In this study we defined a score including 5 polymorphisms to stratify patients for PFS and OS. This score, if validated, might be translated to personalize locally advanced or MBC patient treatment and management.

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.

Personalizing aromatase inhibitor therapy in patients with breast cancer

BACKGROUND

Aromatase inhibitors are the mainstay of therapy for patients with hormone receptor-positive breast cancer in both adjuvant and metastatic settings. Their use in clinical practice has been challenged by significant inter-individual variability in response and tolerability. Hence, the purpose of this paper is to provide a succinct review of the literature on the genetic factors contributing to this variability.

DESIGN

A systematic search in PUBMED was conducted to identify studies that investigated the association between germline polymorphisms and disposition, clinical response and toxicities of aromatase inhibitors, as well as those evaluating the implications of mutations in ESR1 on clinical response.

RESULTS

Polymorphisms in genes coding for phase I and phase II enzymes (pharmacokinetic genes) significantly modulated exposure to aromatase inhibitors; however, there is a paucity of data linking interindividual variability in drug exposure to clinical response. Furthermore, pharmacogenetic studies interrogating relationship between polymorphisms in CYP19A1 (the target site of aromatase inhibitors, i.e. a pharmacodynamic gene) and response yielded conflicting results. Acquired mutations in ESR1 receptors have been identified as the underlying mechanism of resistance to aromatase inhibitors, and likely predict drug response. Although some pharmacogenetic studies have implicated polymorphisms in CYP19A1 and ESR1 with drug-related side effects, the putative role of these genes in predicting toxicity warrants further validation.

CONCLUSION

Genetic polymorphisms in pharmacokinetic and pharmacodynamic genes appear to influence aromatase inhibitor disposition, response and/or toxicity; however, prospective interventional studies are needed to understand the application of genomics to personalize aromatase inhibitor therapy in breast cancer patients.

Elevated Aromatase (CYP19A1) Expression Is Associated with a Poor Survival of Patients with Estrogen Receptor Positive Breast Cancer

Genetic variants in CYP19A1, the gene encoding aromatase, have been reported to be associated with circulating estrogen concentrations, a key risk factor for breast cancer. The mechanism underlying this association is still unclear; it has been suggested that some of these variants may alter the expression and/or activity of aromatase. Here we analyzed the expression of intra-tumoral CYP19A1 messenger RNA (mRNA) and the genotypes of rs10046, a well-characterized single nucleotide polymorphism in CYP19A1, in 138 breast cancer patients and 15 breast cancer cell lines. The genotype TT was detected in 36 patients and six cell lines, genotype CT in 55 patients and five cell lines, and genotype CC in 28 patients and four cell lines. We found no evidence for a significant association of CYP19A1 levels with rs10046 genotypes, although expression tended to be higher in tumors and cell lines with the homozygous risk genotype TT. We also found no evidence for a significant association of rs10046 genotypes with breast cancer prognosis. In contrast, high CYP19A1 expression was highly significantly associated with a poor overall, disease-free, and metastasis-free survival in estrogen receptor-positive but not negative breast cancer patients. Moreover, CYP19A1 mRNA was significantly elevated in postmenopausal patients and in patients older than 50 years, and a trend towards a positive correlation with ER status and ESR1 mRNA expression was observed. These findings highlight the key role of aromatase in estrogen receptor-positive breast cancer biology.

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.

"Just Wear Dark Underpants Mainly": Learning from Adolescents' and Young Adults' Experiences with Early Discontinuation of the Contraceptive Implant

STUDY OBJECTIVE

Long-acting reversible contraception, including the contraceptive implant, is recommended for teens and young women. However, some young women discontinue the implant early, and we seek to better understand their experiences.

DESIGN, SETTING, AND PARTICIPANTS

We conducted interviews with 16 young women ages 14 to 24 who presented for removal of the contraceptive implant within 6 months after placement at outpatient adolescent, family medicine, and obstetrics and gynecology clinics. We coded and analyzed transcripts to identify themes and develop a thematic framework.

INTERVENTIONS AND MAIN OUTCOME MEASURES

We explored decision-making regarding placement and removal of the implant, differences between anticipated and experienced side effects, and recommendations for counseling.

RESULTS

The participants reported experiencing significant side effects that led to removal, most often frequent or heavy bleeding or mood changes. These healthy young women were unprepared for these symptoms, despite remembering being told about possible side effects. Participants wanted more concrete examples of possible side effects, and personal stories of side effects experienced by others, rather than general terms such as irregular bleeding or mood changes. Few discussed problems with their providers; instead, they relied on the Internet or friends to help decide when to remove the implant. Nearly half of the participants did not start new contraception after removal, although they voiced a continued desire to avoid pregnancy.

CONCLUSION

We identified a need for more descriptive counseling about side effects experienced by individuals, and guidance on what to do about problems encountered after placement.

The Association of CYP19A1 Variation with Circulating Estradiol and Aromatase Inhibitor Outcome: Can CYP19A1 Variants Be Used to Predict Treatment Efficacy?

After menopause, estradiol is primarily synthesized in peripheral tissues by the enzyme aromatase, encoded by CYP19A1. CYP19A1 variation associates with circulating estradiol in postmenopausal women and this variation is best represented by the intronic variant rs727479. This variation appears to have pleiotropic effects as it also associates with endometrial cancer risk. Indeed, estradiol plays an important role in the development of breast and endometrial cancer. Aromatase inhibitor (AI) drugs are used in the treatment of both diseases, however, response rates for AIs are low and there is currently no way to identify breast or endometrial cancer patients who are more likely to receive a clinical benefit. Multiple studies have proposed that genetic variation in CYP19A1 will have effects on AI efficacy: eight candidate variant studies of sample size greater than 50 describe associations between CYP19A1 variation and the outcome of patients treated with AIs. Nominally significant associations with patient outcome were reported for several variants, including rs727479. However, only an association between rs4646 and time to progression was replicated in an independent study. Moreover, rs4646 is also the only variant that has an association with patient outcome that passes a multiple testing threshold and this variant is in linkage disequilibrium with rs727479, supporting the hypothesis that associations with patient outcome may be driven through the effects on circulating estradiol. Despite this preliminary evidence, well phenotyped and comprehensively genotyped patient sets need to be studied before conclusions can be drawn about the effects of CYP19A1 variation on AI efficacy.

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.

CYP1A2--a novel genetic marker for early aromatase inhibitor response in the treatment of breast cancer patients

Background

Endocrine resistance is a major obstacle to optimal treatment effect in breast cancer. Some genetic markers have been proposed to predict response to aromatase inhibitors (AIs) but the data is insufficient. The aim of the study was to find new genetic treatment predictive markers of AIs.

Methods

The ongoing population-based BC-blood study in Lund, Sweden includes women with primary breast cancer. This paper is based on AI-treated patients with estrogen receptor positive tumors who underwent breast cancer surgery in 2002–2008. First, an exploratory analysis of 1931 SNPs in 227 genes involved in absorption, distribution, metabolism, and elimination of multiple medications, using DMET™ chips, was conducted in a subset of the cohort with last follow-up in December 31^st 2011 (13 cases, 11 controls). Second, selected SNPs from the first analysis were re-analyzed concerning risk for early breast cancer events in the extended cohort of 201 AI-treated with last follow-up in June 30^th 2014. Clinical data were obtained from medical records and population registries.

Results

Only CYP1A2 rs762551 C-allele was significantly associated with increased risk for early events in the 24 patients (P = 0.0007) and in the extended cohort, adjusted Hazard ratio (HR) 2.22 (95 % CI 1.03–4.80). However, the main prognostic impact was found within five years, adjusted HR 7.88 (95 % CI 2.13–29.19). The impact of the CYP1A2 rs762551 C-allele was modified by a functional polymorphism in the regulator gene AhR Arg554Lys (G > A). Compared to patients who were homozygous for the major allele in both genes (CYP1A2 A/A and AhR G/G), a 9-fold risk for early events was found in patients who had at least one minor allele in both genes, adjusted HR 8.95 (95 % CI 2.55–31.35), whereas patients with at least one minor allele in either but not both genes had a 3-fold risk for early events, adjusted HR 2.81 (95 % CI 1.07–7.33). The impact of CYP1A2 rs762551 C-allele was also modified by the CYP19A1 rs4646 C/C, adjusted HR 3.39 (95 % CI 1.60–7.16) for this combination. This association was strongest within the first five years, adjusted HR 10.42 (95 % CI 3.45–31.51).

Conclusion

CYP1A2 rs762551 was identified as a new potential predictive marker for early breast cancer events in AI-treated breast cancer patients. Moreover, combined genotypes of CYP1A2 rs762551 and CYP19A1 rs4646 or AhR Arg554Lys could further improve prediction of early AI-treatment response. If confirmed, these results may provide a way to more personalized medicine.

Predictive markers in elderly patients with estrogen receptor-positive breast cancer treated with aromatase inhibitors: an array-based pharmacogenetic study

So far, no reliable predictive clinicopathological markers of response to aromatase inhibitors (AIs) have been identified, and little is known regarding the role played by host genetics. To identify constitutive predictive markers, an array-based association study was performed in a cohort of 55 elderly hormone-dependent breast cancer (BC) patients treated with third-generation AIs. The array used in this study interrogates variants in 225 drug metabolism and disposition genes with documented functional significance. Six variants emerged as associated with response to AIs: three located in ABCG1, UGT2A1, SLCO3A1 with a good response, two in SLCO3A1 and one in ABCC4 with a poor response. Variants in the AI target CYP19A1 resulted associated with a favourable response only as haplotype; haplotypes with increased response association were also detected for ABCG1 and SLCO3A1. These results highlight the relevance of host genetics in the response to AIs and represent a first step toward precision medicine for elderly BC patients.