Oestradiol measurement during fulvestrant treatment for breast cancer

A method to detect fulvestrant interference in estradiol in breast cancer patients

Background

Fulvestrant resembles estradiol in its structure. Reports have been published concerning fulvestrant measured as estradiol by the immunoassays. This may induce falsely elevated estradiol results and wrongly impact medical decisions. Our aim was to confirm the interference of fulvestrant on estradiol concentration and test a method to identify the false results.

Methods

Four serum samples with low estradiol levels were spiked with fulvestrant at various concentrations. Estradiol was then measured directly on serum (Dir), after a 1:5 dilution (Dil), and a ratio Dil/Dir was estimated. On the second part of the study, estradiol results (Dir, Dil and ratio Dil/Dir) from 14 women treated with fulvestrant were analysed, as well as from 14 patients not under this treatment.

Results

The addition of exogenous fulvestrant to the serum samples induced a gradual rise on estradiol concentration with a mean ratio for the Dil/Dir samples of 2.1 ± 0.4 (range 1.7-2.9). Patients on fulvestrant treatment experienced a mean ratio for the Dil/Dir estradiol sample of 2.4 ± 0.4 (range 1.6-3.0). In the control group, a mean estradiol ratio Dil/Dir of 1.1 ± 0.1 was observed (range 0.8-1.3). No correlation between the number of days after fulvestrant injection and estradiol result (r = 0.531) was observed.

Conclusion

Our study confirmed the interference of fulvestrant in the estradiol measurement by immunoassay. When fulvestrant was present, the estradiol ratio for Dil/Dir sample was about 2. In the control group, the ratio was around 1. The estradiol Dil/Dir ratio is a simple tool which can be used to identify fulvestrant false immunoassay estradiol results.

Falsely Elevated Estradiol Results in a 62-Year-Old Male Patient

Falsely increased estradiol levels can lead to unnecessary tests and therapeutic interventions. Here, we present a case of a 62-year-old man with falsely elevated estradiol, which led to subsequent follow-up testing and prescriptions. Alternative immunoassay testing, in conjunction with Scantibodies' blocking reagents, polyethylene glycol precipitation, and liquid chromatography-tandem mass spectrometry confirmation demonstrated that the falsely elevated estradiol was due to the presence of macro-estradiol. This report emphasizes the importance of recognizing analytical interferences in immunoassays to appropriately manage subsequent testing and patient care.

Considering hormone-sensitive cancers as a single disease in the UK biobank reveals shared aetiology

Hormone-related cancers, including cancers of the breast, prostate, ovaries, uterine, and thyroid, globally contribute to the majority of cancer incidence. We hypothesize that hormone-sensitive cancers share common genetic risk factors that have rarely been investigated by previous genomic studies of site-specific cancers. Here, we show that considering hormone-sensitive cancers as a single disease in the UK Biobank reveals shared genetic aetiology. We observe that a significant proportion of variance in disease liability is explained by the genome-wide single nucleotide polymorphisms (SNPs), i.e., SNP-based heritability on the liability scale is estimated as 10.06% (SE 0.70%). Moreover, we find 55 genome-wide significant SNPs for the disease, using a genome-wide association study. Pair-wise analysis also estimates positive genetic correlations between some pairs of hormone-sensitive cancers although they are not statistically significant. Our finding suggests that heritable genetic factors may be a key driver in the mechanism of carcinogenesis shared by hormone-sensitive cancers.

Falsely elevated serum estradiol in woman of reproductive age led to unnecessary intervention and delayed fertility opportunity: a case report and literature review

BACKGROUND

The optimal management of patients in reproductive endocrinology relies on the accuracy and validity of sex hormone assays. Endogenous or exogenous substances can compete with the analyte. This competition can result in interfering errors and falsely indicate elevated serum levels. Obvious interference in estradiol assays appears to occur rarely. Consequently, clinicians who are not familiar with the potential of interference could be misled. In addition to unnecessary investigations and interventions and severe mental stress, falsely elevated estradiol results can result in missed or delayed fertility opportunities.

CASE

A 28-year-old female with pregnancy demand was diagnosed with polycystic ovary syndrome, Hashimoto's thyroiditis and subclinical hypothyroidism. She was found to have persistently elevated levels of serum estradiol in the early follicular phase (between 527 and 642 pg/mL). Screening workup was performed for nearly 11 months to find the causes. Serum tumor biomarkers were normal. Abdominal and pelvic computed tomography were negative for adrenal or adnexal masses. A left mesosalpinx cyst and benign pathological results were achieved by laparoscopic surgery. Hormonal substances and dietary supplements were absent, as determined by dietary records. Ultrasound confirmed follicles could grow slowly and eventually ovulate. Falsely elevated estradiol levels were suspected due to the discrepancy among high estradiol levels, follicle growth and normal gonadotropin levels. Immunological interference by heterophile antibody was finally verified by two competitive chemiluminescent immunoassay platforms (estradiol levels in the early follicle phase: 619 pg/mL, Siemens ADVIA CENTAUR and 60 pg/mL, Beckman, DxI 800). Successful clinical pregnancy was eventually achieved by combining induced ovulation, ultrasound monitoring and intercourse guidance.

CONCLUSIONS

Analytical interference and laboratory error should be suspicious at first when the clinical characteristics contradict the laboratory results of serum hormones. Measuring serum estradiol with another immunoassay platform is an easy and non-time-consuming method to exclude the heterophile interfering.

Fulvestrant May Falsely Increase 17β-Estradiol Levels in Immunoassays: A Case Report of a 57-Year-Old Postmenopausal Patient With Recurrent Estrogen Receptor-Positive Breast Cancer

The prognosis for female patients with locoregionally recurrent breast cancer has improved with the concurrent local and systemic treatment under multiple disciplinary teams. Radiotherapy is a valuable local treatment measure for unresectable locoregional recurrent breast cancer; however, reirradiation in previously irradiated areas is still a matter of debate. Antihormonal therapy achieves an overall survival benefit for most of these patients with estrogen receptor-positive (ER+) breast cancer in both adjuvant and metastatic settings. Fulvestrant is an ER antagonist and selective ER downregulator widely used in antihormonal therapy, especially in recurrent postmenopausal ER+ breast cancers. However, fulvestrant closely resembles 17β-estradiol in its molecular structure which may result in false increases in serum 17β-estradiol levels in commercially available immunoassays leading to incorrect medical decisions. Herein, we report a case of a 57-year-old postmenopausal patient with recurrent ER+ breast cancer treated with concurrent fulvestrant and reirradiation. There was a good clinical response, and the combination treatment was well tolerable. During the quarterly follow-up, we monitored a gradual increase of the serum 17β-estradiol level in immunoassays, unexpectedly, because the patient underwent natural menopause 8 years ago. To rule out the suspected fulvestrant cross-reactivity with 17β-estradiol in immunoassay, the patient’s serum 17β-estradiol levels were subsequently tested with the more sensitive and specific liquid chromatography-mass spectrometry (LC-MS) method, which confirmed 17β-estradiol levels at the postmenopausal level. Concomitant fulvestrant with reirradiation seems to be a safe and effective therapy for locoregionally recurrent ER+ breast cancer. However, a falsely increased 17β-estradiol may result from cross-reactivity between 17β-estradiol and its molecular analog compounds, for example, fulvestrant. Therefore, it is important for the clinicians with the knowledge of this interaction to prevent unnecessary erroneous interpretation of results and avoid wrong medical decisions.

Six Main Contributing Factors to High Levels of Mycotoxin Contamination in African Foods

Africa is one of the regions with high mycotoxin contamination of foods and continues to record high incidences of liver cancers globally. The agricultural sector of most African countries depends largely on climate variables for crop production. Production of mycotoxins is climate-sensitive. Most stakeholders in the food production chain in Africa are not aware of the health and economic effects of consuming contaminated foods. The aim of this review is to evaluate the main factors and their degree of contribution to the high levels of mycotoxins in African foods. Thus, knowledge of the contributions of different factors responsible for high levels of these toxins will be a good starting point for the effective mitigation of mycotoxins in Africa. Google Scholar was used to conduct a systemic search. Six factors were found to be linked to high levels of mycotoxins in African foods, in varying degrees. Climate change remains the main driving factor in the production of mycotoxins. The other factors are partly man-made and can be manipulated to become a more profitable or less climate-sensitive response. Awareness of the existence of these mycotoxins and their economic as well as health consequences remains paramount. The degree of management of these factors regarding mycotoxins varies from one region of the world to another.

Hormone Immunoassay Interference: A 2021 Update

Immunoassays are powerful qualitative and quantitative analytical techniques. Since the first description of an immunoassay method in 1959, advances have been made in assay designs and analytical characteristics, opening the door for their widespread implementation in clinical laboratories. Clinical endocrinology is closely linked to laboratory medicine because hormone quantification is important for the diagnosis, treatment, and prognosis of endocrine disorders. Several interferences in immunoassays have been identified through the years; although some are no longer encountered in daily practice, cross-reaction, heterophile antibodies, biotin, and anti-analyte antibodies still cause problems. Newer interferences are also emerging with the development of new therapies. The interfering substance may be exogenous (e.g., a drug or substance absorbed by the patient) or endogenous (e.g., antibodies produced by the patient), and the bias caused by interference can be positive or negative. The consequences of interference can be deleterious when clinicians consider erroneous results to establish a diagnosis, leading to unnecessary explorations or inappropriate treatments. Clinical laboratories and manufacturers continue to investigate methods for the detection, elimination, and prevention of interferences. However, no system is completely devoid of such incidents. In this review, we focus on the analytical interferences encountered in daily practice and possible solutions for their detection or elimination.

Sex Differences in Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) occurs in women more than men whereas survival in men is worse than in women. In recent years, much research has been carried out to understand these sex differences in PAH. This article discusses clinical and preclinical studies that have investigated the influences of sex, serotonin, obesity, estrogen, estrogen synthesis, and estrogen metabolism on bone morphogenetic protein receptor type II signaling, the pulmonary circulation and right ventricle in both heritable and idiopathic pulmonary hypertension.

Falsely elevated serum estradiol due to heterophile antibody interference: a case report

Falsely elevated estradiol is rare, may result from heterophile antibody interference, and can result in unnecessary investigation and intervention. We present the case of a 56-year-old female with falsely elevated estradiol levels inconsistent with her overall clinical picture, which ultimately led to an unnecessary surgical procedure. With the use of alternative analytical platforms and a heterophile antibody blocking agent, we determined the false elevation was due to heterophile antibody interference. Clinicians must suspect and investigate for laboratory error when the clinical picture contradicts laboratory results.

Estrogen Signaling and Portopulmonary Hypertension: The Pulmonary Vascular Complications of Liver Disease Study (PVCLD2)

BACKGROUND AND AIMS

Portopulmonary hypertension (POPH) was previously associated with a single-nucleotide polymorphism (SNP) rs7175922 in aromatase (cytochrome P450 family 19 subfamily A member 1 [CYP19A1]). We sought to determine whether genetic variants and metabolites in the estrogen signaling pathway are associated with POPH.

APPROACH AND RESULTS

We performed a multicenter case-control study. POPH patients had mean pulmonary artery pressure >25 mm Hg, pulmonary vascular resistance >240 dyn-sec/cm-5 , and pulmonary artery wedge pressure ≤15 mm Hg without another cause of pulmonary hypertension. Controls had advanced liver disease, right ventricular (RV) systolic pressure <40 mm Hg, and normal RV function by echocardiography. We genotyped three SNPs in CYP19A1 and CYP1B1 using TaqMan and imputed SNPs in estrogen receptor 1 using genome-wide markers. Estrogen metabolites were measured in blood and urine samples. There were 37 patients with POPH and 290 controls. Mean age was 57 years, and 36% were female. The risk allele A in rs7175922 (CYP19A1) was significantly associated with higher levels of estradiol (P = 0.02) and an increased risk of POPH (odds ratio [OR], 2.36; 95% confidence interval [CI], 1.12-4.91; P = 0.02) whereas other SNPs were not. Lower urinary 2-hydroxyestrogen/16-α-hydroxyestrone (OR per 1-ln decrease = 2.04; 95% CI, 1.16-3.57; P = 0.01), lower plasma levels of dehydroepiandrosterone-sulfate (OR per 1-ln decrease = 2.38; 95% CI, 1.56-3.85; P < 0.001), and higher plasma levels of 16-α-hydroxyestradiol (OR per 1-ln increase = 2.16; 95% CI, 1.61-2.98; P < 0.001) were associated with POPH.

CONCLUSIONS

Genetic variation in aromatase and changes in estrogen metabolites were associated with POPH.