Identification, Measurement, and Assessment of the Clinical Utility of Human Pancreatic Polypeptide by Liquid Chromatography-Tandem Mass Spectrometry

Human pancreatic polypeptide (HPP) is a 36 amino acid peptide hormone that plays a role in the bidirectional communication between the digestive system and the brain. HPP measurements are used to assess vagal nerve function following sham feeding and to detect gastroenteropancreatic-neuroendocrine tumors. These tests have historically been conducted by radioimmunoassays, but liquid chromatography-tandem mass spectrometry (LC-MS/MS) has several advantages such as improved specificity and elimination of radioactive molecules. Here, we present our LC-MS/MS method. Initially, samples were immunopurified and subjected to LC-high resolution accurate mass tandem mass spectrometry (HRAM-MS/MS) to identify circulating forms of the peptide in human plasma. We identified 23 forms of HPP, including several glycosylated forms. The most abundant peptides then were used for targeted LC-MS/MS measurements. LC-MS/MS performance for precision, accuracy, linearity, recovery, limit of detection, and carryover met our acceptance criteria based on CLIA regulations. Additionally, we observed the expected physiological rise in HPP in response to sham feeding. Our results indicate that HPP measurement by LC-MS/MS produces clinically equivalent results to our established immunoassay when several peptides are monitored, making it a suitable replacement. The measurement of peptide fragments, including modified species, might have additional clinical value.

Machine Learning-Based Fragment Selection Improves the Performance of Qualitative PRM Assays

Targeted mass spectrometry-based platforms have become a valuable tool for the sensitive and specific detection of protein biomarkers in clinical and research settings. Traditionally, developing a targeted assay for peptide quantification has involved manually preselecting several fragment ions and establishing a limit of detection (LOD) and a lower limit of quantitation (LLOQ) for confident detection of the target. Established thresholds such as LOD and LLOQ, however, inherently sacrifice sensitivity to afford specificity. Here, we demonstrate that machine learning can be applied to qualitative PRM assays to discriminate positive from negative samples more effectively than a traditional approach utilizing conventional methods. To demonstrate the utility of this method, we trained an ensemble machine learning model using 282 SARS-CoV-2 positive and 994 SARS-CoV-2 negative nasopharyngeal swabs (NP swab) analyzed using a targeted PRM method. This model was then validated using an independent set of 200 positive and 150 negative samples and achieved a sensitivity of 92% relative to results obtained by RT-PCR, which was superior to a traditional approach that resulted in 86.5% sensitivity when analyzing the same data. These results demonstrate that machine learning can be applied to qualitative PRM assays and results in superior performance relative to traditional methods.

Comparison of anti-peptide and anti-protein antibody-based purification techniques for detection of SARS-CoV-2 by targeted LC-MS/MS

The COVID-19 pandemic has necessitated exploration of alternative testing methods for detection of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) to ensure clinical laboratories can continue to provide critical testing results. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is established in many clinical laboratories due its high specificity and sensitivity, making it a logical alternative methodology. However, matching the sensitivity of quantitative reverse transcription-polymerase chain reaction (qRT-PCR) remains challenging, which forced utilization of antibody-based enrichment prior to targeted LC-MS/MS analysis. When utilizing antibody purification techniques, investigators must decide whether to enrich the target protein or peptides, but there are few studies comparing the two approaches to assist in this decision-making process. In this work, we present a comparison of intact protein and peptide antibody-based purification for LC-MS/MS based detection of SARS-CoV-2. We have found that protein purification yields more intense LC-MS/MS signals, but is also less specific, yielding higher noise and more background when compared to peptide purification techniques. Therefore, when using traditional data analysis techniques, the enrichment technique that provides superior sensitivity varies for individual peptides and no definitive overall conclusion can be made. These observations are corroborated when using a novel machine learning approach to determine positive/negative test results, which yielded superior sensitivity when using protein purification, but better specificity and area under the ROC curve when performing peptide purification.

Targeted Detection of SARS-CoV-2 Nucleocapsid Sequence Variants by Mass Spectrometric Analysis of Tryptic Peptides

COVID-19 vaccines are becoming more widely available, but accurate and rapid testing remains a crucial tool for slowing the spread of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus. Although the quantitative reverse transcription-polymerase chain reaction (qRT-PCR) remains the most prevalent testing methodology, numerous tests have been developed that are predicated on detection of the SARS-CoV-2 nucleocapsid protein, including liquid chromatography-tandem mass spectrometry (LC-MS/MS) and immunoassay-based approaches. The continuing emergence of SARS-CoV-2 variants has complicated these approaches, as both qRT-PCR and antigen detection methods can be prone to missing viral variants. In this study, we describe several COVID-19 cases where we were unable to detect the expected peptide targets from clinical nasopharyngeal swabs. Whole genome sequencing revealed that single nucleotide polymorphisms in the gene encoding the viral nucleocapsid protein led to sequence variants that were not monitored in the targeted assay. Minor modifications to the LC-MS/MS method ensured detection of the variants of the target peptide. Additional nucleocapsid variants could be detected by performing the bottom-up proteomic analysis of whole viral genome-sequenced samples. This study demonstrates the importance of considering variants of SARS-CoV-2 in the assay design and highlights the flexibility of mass spectrometry-based approaches to detect variants as they evolve.

A SISCAPA-based approach for detection of SARS-CoV-2 viral antigens from clinical samples

SARS-CoV-2, a novel human coronavirus, has created a global disease burden infecting > 100 million humans in just over a year. RT-PCR is currently the predominant method of diagnosing this viral infection although a variety of tests to detect viral antigens have also been developed. In this study, we adopted a SISCAPA-based enrichment approach using anti-peptide antibodies generated against peptides from the nucleocapsid protein of SARS-CoV-2. We developed a targeted workflow in which nasopharyngeal swab samples were digested followed by enrichment of viral peptides using the anti-peptide antibodies and targeted parallel reaction monitoring (PRM) analysis using a high-resolution mass spectrometer. This workflow was applied to 41 RT-PCR-confirmed clinical SARS-CoV-2 positive nasopharyngeal swab samples and 30 negative samples. The workflow employed was highly specific as none of the target peptides were detected in negative samples. Further, the detected peptides showed a positive correlation with the viral loads as measured by RT-PCR Ct values. The SISCAPA-based platform described in the current study can serve as an alternative method for SARS-CoV-2 viral detection and can also be applied for detecting other microbial pathogens directly from clinical samples.

A mass spectrometry-based targeted assay for detection of SARS-CoV-2 antigen from clinical specimens

Background

The COVID-19 pandemic caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) has overwhelmed health systems worldwide and highlighted limitations of diagnostic testing. Several types of diagnostic tests including RT-PCR-based assays and antigen detection by lateral flow assays, each with their own strengths and weaknesses, have been developed and deployed in a short time.

Methods

Here, we describe an immunoaffinity purification approach followed a by high resolution mass spectrometry-based targeted qualitative assay capable of detecting SARS-CoV-2 viral antigen from nasopharyngeal swab samples. Based on our discovery experiments using purified virus, recombinant viral protein and nasopharyngeal swab samples from COVID-19 positive patients, nucleocapsid protein was selected as a target antigen. We then developed an automated antibody capture-based workflow coupled to targeted high-field asymmetric waveform ion mobility spectrometry (FAIMS) - parallel reaction monitoring (PRM) assay on an Orbitrap Exploris 480 mass spectrometer. An ensemble machine learning-based model for determining COVID-19 positive samples was developed using fragment ion intensities from the PRM data.

Findings

The optimized targeted assay, which was used to analyze 88 positive and 88 negative nasopharyngeal swab samples for validation, resulted in 98% (95% CI = 0.922–0.997) (86/88) sensitivity and 100% (95% CI = 0.958–1.000) (88/88) specificity using RT-PCR-based molecular testing as the reference method.

Interpretation

Our results demonstrate that direct detection of infectious agents from clinical samples by tandem mass spectrometry-based assays have potential to be deployed as diagnostic assays in clinical laboratories, which has hitherto been limited to analysis of pure microbial cultures.

Monozygotic twins discordant for congenital adrenal hyperplasia due to mosaicism

INTRODUCTION

Genotype-phenotype discordance occurs occasionally in congenital adrenal hyperplasia (CAH). Its causes are largely unknown. We describe a case of monochorionic, diamniotic twins with discordant clinical presentations of CAH, and show evidence for this being due to mosaicism resulting from a postzygotic full gene deletion of CYP21A2 prior to twinning.

CASE DESCRIPTION

A 7-day-old 36-week gestation female infant (Twin A) presented to the emergency department with elevated 17-hydroxyprogesterone (17-OHP). Her identical twin (Twin B) had normal 17-OHP on newborn screening. Both twins showed signs of virilization, more pronounced in Twin B. Molecular genetic testing of both twins and their parents showed a WT paternally-inherited CYP21A2 and a maternally-inherited copy containing the c.293-13C>G mutation. Both twins were also found to have a 5'-CYP21A1P/CYP21A2-3' hybrid (product of the common 30-kb deletion), derived from the deletion of the paternally-inherited CYP21A2. Neither mother nor father carried the deletion.

CONCLUSIONS

The genetic findings are consistent with mosaicism for two CYP21A2 cell lines in both twins. The first cell line is expected, based on parental results, while the second line is due to a postzygotic full gene deletion of the paternally-inherited WT CYP21A2. The resultant genotype, compound heterozygosity for c.293-13C>G and a CYP21A2 full gene deletion, is consistent with a salt-wasting CAH phenotype. Differential distribution of the second cell line between the twins is most likely the cause for their discrepant phenotypes. We believe this is the first report of somatic CYP21A2 mosaicism, and represents a novel cause for discrepant CAH phenotypes in monozygotic twins.

Adrenal Cortical Carcinoma Associated With Lynch Syndrome: A Case Report and Review of Literature

Objective

Adrenocortical carcinoma (ACC) is a rare malignancy with poor prognosis. ACC was reported in 3.2% patients with Lynch syndrome (LS), however no particular case-detection strategies have been recommended.

Participants

We report a case of a 65-year-old woman who was incidentally discovered with a large adrenal mass during work-up of postmenopausal uterine bleeding. She was recently diagnosed with MSH6 germline mutation after her sister presented with uterine carcinoma in the setting of LS.

Results

Whereas the patient was asymptomatic for overt hormonal excess, biochemical work-up confirmed glucocorticoid autonomy and androgen and estrogen excess. Urine steroid profiling was suggestive of ACC. Adrenalectomy confirmed an oncocytic ACC with focal extracapsular extension into the periadrenal adipose tissue with a Ki-67 of 15% and a peak mitotic count of 40/50 high-power fields.

Conclusion

ACC can be the only manifestation of LS. A best case-detection approach for ACC in the asymptomatic patient with LS is unclear, however urine steroid profiling could be considered.

Compound heterozygosity for a whole gene deletion and p.R124C mutation in CYP21A2 causing nonclassic congenital adrenal hyperplasia

We present a family with 2 members who received long-term steroid treatment for presumed classic congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, until molecular testing revealed nonclassic CAH, not necessarily requiring treatment. A 17-year-old male presented to our clinic on glucocorticoid and mineralocorticoid treatment for classic CAH. He was diagnosed at 4 years of age based on mild-moderate elevations of 17-hydroxyprogesterone (17-OHP) and adrenocorticotropic hormone (ACTH), but without evidence of precocious adrenarche/puberty. Due to his diagnosis, his clinically asymptomatic 3-year-old sister was tested and also found to have elevated ACTH and 17-OHP levels and was started on glucocorticoids for classic CAH. Family history revealed a healthy sibling who had no biochemical evidence of CAH and consanguineous healthy parents. We questioned the diagnosis of classic CAH and performed an ACTH1-24 stimulation test, which showed a level of 17-OHP in the borderline range between classic and nonclassic CAH. Molecular testing, using sequencing and multiplex ligation-dependent probe amplification analysis of CYP21A2, revealed that both affected siblings were compound heterozygotes for a whole-gene deletion and a, likely pathogenic (nonclassical), sequence variant, p.R124C. The asymptomatic father had the same genotype, while the mother showed one deleted copy and 2 active copies, making her an asymptomatic carrier. Our report demonstrates the importance of molecular testing in atypical cases of CAH, as well as the importance of both sequencing and deletion analysis. The results of molecular testing should be interpreted in clinical context, and treatment should be prescribed according to guidelines when available.

Methodology, Criteria, and Characterization of Patient-Matched Thyroid Cell Lines and Patient-Derived Tumor Xenografts

OBJECTIVE

To investigate the molecular underpinnings of thyroid cancer, preclinical cell line models are crucial; however, ∼40% of these have been proven to be either duplicates of existing thyroid lines or even nonthyroid-derived lines or are not derived from humans at all. Therefore, we set out to establish procedures and guidelines that should proactively avoid these problems, which facilitated the creation of criteria to make valid preclinical models for thyroid cancer research.

DESIGN

Based on our recommendations, we systematically characterized all new cell lines that we generated by a standardized approach that included (1) determination of human origin, (2) exclusion of lymphoma, (3) DNA fingerprinting and histological comparisons to establish linkage to presumed tissue of origin, (4) examining thyroid differentiation by screening two to three thyroid markers, (5) examination of biological behavior (growth rate, tumorigenicity), and (6) presence of common thyroid cancer genetic changes (TP53, BRAF, PTEN, PIK3CA, RAS, TERT promoter, RET/PTC, PAX8/PPARγ, NF1, and EIF1AX).

RESULTS

We established seven new thyroid cell lines (LAM136, EAM306, SDAR1, SDAR2, JEM493, THJ529, and THJ560) out of 294 primary culture attempts, and 10 patient-derived tumor xenografts (PDTXs; MC-Th-95, MC-Th-374, MC-Th-467, MC-Th-491, MC-Th-493, MC-Th-504, MC-Th-524, MC-Th-529, MC-Th-560, and MC-Th-562) out of 67 attempts. All were successfully validated by our protocols.

CONCLUSIONS

This standardized approach for cell line and PDTX characterization should prevent (or detect) future cross-contamination and ensure that only valid preclinical models are used for thyroid cancer research.

Genotype-Phenotype Correlation of Hereditary Erythrocytosis Mutations, a single center experience

Hereditary erythrocytosis is associated with high oxygen affinity hemoglobin variants (HOAs), 2,3-bisphosphoglycerate deficiency and abnormalities in EPOR and the oxygen-sensing pathway proteins PHD, HIF2α, and VHL. Our laboratory has 40 years of experience with hemoglobin disorder testing and we have characterized HOAs using varied protein and molecular techniques including functional assessment by p50 analysis. In addition, we have more recently commenced adding the assessment of clinically relevant regions of the VHL, BPGM, EPOR, EGLN1 (PHD2), and EPAS1 (HIF2A) genes in a more comprehensive hereditary erythrocytosis panel of tests. Review of our experience confirms a wide spectrum of alterations associated with erythrocytosis which we have correlated with phenotypic and clinical features. Through generic hemoglobinopathy testing we have identified 762 patients with 81 distinct HOA Hb variants (61 β, 20 α), including 12 that were first identified by our laboratory. Of the 1192 cases received for an evaluation specific for hereditary erythrocytosis, approximately 12% had reportable alterations: 85 pathogenic/likely pathogenic mutations and 58 variants of unknown significance. Many have not been previously reported. Correlation with clinical and phenotypic data supports an algorithmic approach to guide economical evaluation; although, testing is expanded if the suspected causes are negative or of uncertain significance. Clinical features are similar and range from asymptomatic to recurrent headaches, fatigue, restless legs, chest pain, exertional dyspnea and thrombotic episodes. Many patients were chronically phlebotomized with reported relief of symptoms. This article is protected by copyright. All rights reserved.

High-Resolution, Accurate-Mass (HRAM) Mass Spectrometry Urine Steroid Profiling in the Diagnosis of Adrenal Disorders

BACKGROUND

Steroid profiling is a promising diagnostic tool with adrenal tumors, Cushing syndrome (CS), and disorders of steroidogenesis. Our objective was to develop a multiple-steroid assay using liquid-chromatography, high-resolution, accurate-mass mass spectrometry (HRAM LC-MS) and to validate the assay in patients with various adrenal disorders.

METHODS

We collected 24-h urine samples from 114 controls and 71 patients with adrenal diseases. An HRAM LC-MS method was validated for quantitative analysis of 26 steroid metabolites in hydrolyzed urine samples. Differences in steroid excretion between patients were analyzed based on Z-score deviation from control reference intervals.

RESULTS

Limits of quantification were 20 ng/mL. Dilution linearity ranged from 80% to 120% with means of 93% to 110% for all but 2 analytes. Intraassay and interassay imprecision ranged from 3% to 18% for all but 1 analyte. Control women had lower excretion of androgen and glucocorticoid precursors/metabolites than men (P < 0.001), but no difference in mineralocorticoids was seen (P = 0.06). Androgens decreased with age in both sexes (P < 0.001). Compared with patients with adrenocortical adenoma (ACA), patients with adrenocortical carcinoma (ACC) had 11 steroids with increased Z scores, especially tetrahydro-11-deoxycortisol (14 vs 0.5, P < 0.001), pregnanetriol (7.5 vs −0.4, P = 0.001), and 5-pregnenetriol (5.4 vs −0.4, P = 0.01). Steroid profiling also demonstrated metabolite abnormalities consistent with enzymatic defects in congenital adrenal hyperplasia and differences in pituitary vs adrenal CS.

CONCLUSIONS

Our HRAM LC-MS assay successfully quantifies 26 steroids in urine. The statistically significant differences in steroid production of ACC vs ACA, adrenal vs pituitary CS, and in congenital adrenal hyperplasia should allow for improved diagnosis of patients with these diseases.

Primary Renal Paragangliomas and Renal Neoplasia Associated with Pheochromocytoma/Paraganglioma: Analysis of von Hippel-Lindau (VHL), Succinate Dehydrogenase (SDHX) and Transmembrane Protein 127 (TMEM127)

Alterations of von Hippel-Lindau (VHL), succinate dehydrogenase (SDHX), and TMEM127 have been associated with the development of pheochromocytomas (PCs) and paragangliomas (PGLs) and are also associated with the development of renal neoplasms. This study involved 2 primary renal PGL and 12 cases of PC/PGL with associated renal neoplasia with a mean follow up of 74 months. Germline VHL and SDHX mutation status was obtained from the medical record. Immunohistochemistry for SDHB and mutation analysis for TMEM127 was performed, in addition to analysis of The Cancer Genome Atlas datasets for SDHX and TMEM127 mutated renal cell carcinomas (RCCs). The spectrum of renal neoplasia included clear cell and tubulocystic and papillary RCC, as well as a case of multiple papillary adenomas. Three patients had metastatic PC/PGL and three patients had VHL syndrome. Previously unreported TMEM127 alterations were identified in two patients, both without evidence of VHL syndrome or SDH-deficiency, and were classified as variants of uncertain significance. Primary renal PGL and neoplasia was associated with about 2% of 710 cases of PC/PGL. These were diagnosed concurrently or on average 27 months prior to the PC/PGL, and most were low-grade, low-stage clear cell RCCs. Up to half of patients with PC/PGL and renal neoplasia had VHL syndrome, SDH deficiency, or alterations in TMEM127. One (of three) case of metastatic PC/PGL had SDHB mutation and loss of SDHB by immunohistochemistry. The other two cases had retained SDHB expression.

Fatal Catecholamine-Induced Cardiotoxicity Associated with Pheochromocytoma: Report of a Postpartum Case and Review of the Literature

Pheochromocytomas and paragangliomas are catecholamine-secreting tumors characterized by excessive adrenergic stimulation. Common manifestations include hypertension, headache, sweating, and palpitations; however, rare life-threatening conditions have also been reported and include cardiovascular shock, myocardial infarction, arrhythmias, and cardiomyopathy. We report a case of a previously healthy 31-year-old postpartum female presenting with headache who died suddenly in an emergency room. Autopsy revealed a pheochromocytoma of the right adrenal with significantly elevated metanephrine concentrations and acute "myocarditis." Sudden excessive catecholamine release can cause cardiovascular complications and be rapidly fatal without significant elevation of blood pressure. Awareness of this association by the medical examiner/coroner is vital in order to properly classify the death and apprise relatives of the potential utility of genetic screening.

Monocyte HLA-DR expression and neutrophil CD64 expression as biomarkers of infection in critically ill neonates and infants

BACKGROUND

Reduced monocyte HLA-DR expression and increased neutrophil CD64 expression have been proposed as biomarkers of infection.

METHODS

From 2009-2011, blood samples from neonatal intensive care unit (NICU) and pediatric intensive care unit (ICU) patients <1 y of age were collected at enrollment and during subsequent evaluation for suspected infection, if it occurred. Samples were analyzed for monocyte HLA-DR and neutrophil CD64 expression levels by flow cytometry.

RESULTS

Forty-seven infants had study samples collected at enrollment; 26 infants had study samples collected at the time of a suspected infection. At enrollment, there was an inverse relationship between neutrophil CD64 expression and age (P ≤ 0.047). At the time of suspected infection, infants with an infection demonstrated a lower percentage of HLA-DR+ monocytes (P = 0.02, area under the curve (AUC) 0.78), higher percentage of CD64+ neutrophils (P = 0.009, AUC 0.81), and higher neutrophil CD64 expression levels (P = 0.04, AUC 0.75).

CONCLUSION

Monocyte HLA-DR and neutrophil CD64 expression in critically ill infants are related to age and infection.

Altered Calcium and Vitamin D Homeostasis in First-Time Calcium Kidney Stone-Formers

Background

Elevated serum 1,25-dihydroxyvitamin D (1,25(OH)₂D) concentrations have been reported among cohorts of recurrent calcium (Ca) kidney stone-formers and implicated in the pathogenesis of hypercalciuria. Variations in Ca and vitamin D metabolism, and excretion of urinary solutes among first-time male and female Ca stone-formers in the community, however, have not been defined.

Methods

In a 4-year community-based study we measured serum Ca, phosphorus (P), 25-hydroxyvitamin D (25(OH)D), 1,25(OH)₂D, 24,25-dihydroxyvitamin D (24,25(OH)₂D), parathyroid hormone (PTH), and fibroblast growth factor-23 (FGF-23) concentrations in first-time Ca stone-formers and age- and gender frequency-matched controls.

Results

Serum Ca and 1,25(OH)₂D were increased in Ca stone-formers compared to controls (P = 0.01 and P = 0.001). Stone-formers had a lower serum 24,25(OH)₂D/25(OH)D ratio compared to controls (P = 0.008). Serum PTH and FGF-23 concentrations were similar in the groups. Urine Ca excretion was similar in the two groups (P = 0.82). In controls, positive associations between serum 25(OH)D and 24,25(OH)₂D, FGF-23 and fractional phosphate excretion, and negative associations between serum Ca and PTH, and FGF-23 and 1,25(OH)₂D were observed. In SF associations between FGF-23 and fractional phosphate excretion, and FGF-23 and 1,25(OH)₂D, were not observed. 1,25(OH)₂D concentrations associated more weakly with FGF-23 in SF compared with C (P <0.05).

Conclusions

Quantitative differences in serum Ca and 1,25(OH)₂D and reductions in 24-hydroxylation of vitamin D metabolites are present in first-time SF and might contribute to first-time stone risk.

Abstract 1458: Characterization of novel thyroid PDX models and their response to combination therapies

Patient derived xenografts (PDX) mouse models for many types of cancer have demonstrated therapeutic responses similar to those seen in patients. Thus, resected patient tumor tissue directly implanted into immune compromised mice followed by therapy and tumor growth analysis is thought to be the closest preclinical model to predict patient therapeutic responses. To date, few models are available for the different histotypes of thyroid cancer derived from follicular thyrocytes; these include papillary, follicular, Hurthle cell, squamous and anaplastic thyroid carcinoma. We have developed eight PDX models in athymic nude mice representing all of these subtypes. The models have been extensively characterized for mutational status (i.e. BRAF, telomerase, RAS, PTEN, TP53, RB, etc) as well as validation by short tandem repeat (STR) analysis to match that of the originating patient tumor tissue. Squamous and anaplastic thyroid cancers are rare tumor types with no FDA approved therapies. Each model demonstrated their own unique responses to radiation, cytotoxic or molecular targeted therapies such as doxorubicin, sorafenib (tyrosine kinase inhibitor), cisplatin, paclitaxel, sunitinib (tyrosine kinase inhibitor), erlotinib (EGFR inhibitor), trametinib (MEK inhibitor) and vemurafenib (BRAF inhibitor). We expect that these models may provide useful in vivo models for thyroid cancer research as well as models for therapeutic guidance based upon histotype, mutational status and response to therapies.

Citation Format: Laura A. Marlow, Adam C. Mathias, Louis K. Dawson, William F. Durham, Kenneth A. Meshaw, Robert J. Mullin, Daniel L. Small, Aidan J. Synnott, Dragana Milosevic, Brian C. Netzel, Stefan K. Grebe, Kevin Wu, Robert C. Smallridge, John A. Copland. Characterization of novel thyroid PDX models and their response to combination therapies. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1458. doi:10.1158/1538-7445.AM2015-1458

Evidence for gonadotrophin secretory and steroidogenic abnormalities in brothers of women with polycystic ovary syndrome

STUDY QUESTION

Are there abnormalities in gonadotrophin secretion, adrenal steroidogenesis and/or testicular steroidogenesis in brothers of women with polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

Brothers of women with PCOS have increased gonadotrophin responses to gonadotrophin releasing hormone (GnRH) agonist stimulation and alterations in adrenal and gonadal steroidogenesis.

WHAT IS KNOWN ALREADY

PCOS is a complex genetic disease. Male as well as female first-degree relatives have reproductive features of the syndrome. We previously reported that brothers of affected women have elevated circulating dehydroepiandrosterone sulfate levels.

STUDY DESIGN, SIZE, DURATION

This was a case-control study performed in 29 non-Hispanic white brothers of 22 women with PCOS and 18 control men.

PARTICIPANTS/MATERIALS, SETTING, METHODS

PCOS brothers and control men were of comparable age, weight and ethnicity. Adrenocorticotrophic hormone (ACTH) and GnRH agonist stimulation tests were performed. Gonadotrophin responses to GnRH agonist as well as changes in precursor-product steroid pairs (delta, Δ) across steroidogenic pathways in response to ACTH and GnRH agonist were examined.

MAIN RESULTS AND THE ROLE OF CHANCE

Basal total (T) levels did not differ, but dehydroepiandrosterone (DHEA) levels (0.13 ± 0.08 brothers versus 0.22 ± 0.09 controls, nmol/l, P = 0.03) were lower in brothers compared with control men. ACTH-stimulated Δ17-hydroxypregnenolone (17Preg)/Δ17-hydroxyprogesterone (17Prog) (7.8 ± 24.2 brothers versus 18.9 ± 21.3 controls, P = 0.04) and ΔDHEA/Δandrostenedione (AD) (0.10 ± 0.05 brothers versus 0.14 ± 0.08 controls, P = 0.04) were lower in brothers than in the controls. GnRH agonist-stimulated Δ17Prog/ΔAD (0.28 ± 8.47 brothers versus 4.79 ± 10.28 controls, P = 0.003) was decreased and luteinizing hormone (38.6 ± 20.6 brothers versus 26.0 ± 9.8 controls, IU/l, P = 0.02), follicle-stimulating hormone (10.2 ± 7.5 brothers versus 4.8 ± 4.1 controls, IU/l P = 0.002), AD (1.7 ± 1.4 brothers versus 0.9 ± 1.5 controls, nmol/l, P = 0.02) and ΔAD/ΔT (0.16 ± 0.14 brothers versus 0.08 ± 0.12 controls, P = 0.005) responses were increased in brothers compared with controls.

LIMITATIONS, REASONS FOR CAUTION

The modest sample size may have limited our ability to observe other possible differences in steroidogenesis between PCOS brothers and control men.

WIDER IMPLICATIONS OF THE FINDINGS

Decreased ACTH-stimulated Δ17Preg/Δ17Prog and ΔDHEA/ΔAD responses suggested increased adrenal 3β-hydroxysteroid dehydrogenase activity in the brothers. Decreased Δ17Prog/ΔAD and increased ΔAD/ΔT responses to GnRH agonist stimulation suggested increased gonadal 17,20-lyase and decreased gonadal 17β-hydroxysteroid dehydrogenase activity in the brothers. Increased LH and FSH responses to GnRH agonist stimulation suggested neuroendocrine alterations in the regulation of gonadotrophin secretion similar to those in their proband sisters. These changes in PCOS brothers may reflect the impact of PCOS susceptibility genes and/or programming effects of the intrauterine environment.

STUDY FUNDING/COMPETING INTERESTS

This research was supported by P50 HD044405 (A.D.), K12 HD055884 (L.C.T.), U54 HD034449 (A.D., R.S.L.) from the National Institute of Child Health and Development. Some hormone assays were performed at the University of Virginia Center for Research in Reproduction Ligand Assay and Analysis Core that is supported by U54 HD28934 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Partial support for some of the clinical studies was provided by UL1 RR025741 and UL1 TR000150 (Northwestern University Clinical and Translational Sciences Institute) from the National Center for Research Resources, National Institutes of Health, which is now the National Center for Advancing Translational Sciences. The authors have no conflict of interest to declare.

Abstract LB-111: Neuronal Pentraxin 2: a novel tumor-specific molecular target that mediates clear cell renal cell carcinoma malignancy

Introduction: Renal cell carcinoma (RCC) is the most common malignancy of the kidney, responsible for 13,000 deaths in the United States annually. Patients who present with the clear cell (ccRCC) variant of this disease demonstrate a worse prognosis as compared to other subtypes. Due to its asymptomatic nature, patients often do not demonstrate signs of illness until the disease has progressed to an advanced stage. It is estimated that 30% of patients present with metastatic disease at initial diagnosis, and 20-30% of patients with localized cases treated surgically relapse with metastatic disease likely due to the presence of undetectable micrometastases. The treatment for metastatic disease is limited due to its profound resistance against chemotherapy, radiation, and current FDA approved targeted therapies. Despite advances in treatment strategies for patients with metastatic RCC, there remains a need for identification of tumor-specific therapeutic targets. Additionally, elucidation of key signatures which contribute to the development of metastatic disease is paramount. Our group has identified secreted neuronal pentraxin 2 (NPTX2) as a novel oncogenic factor that is highly overexpressed specifically in ccRCC at all stages of disease, and facilitates tumor cell invasion through its interaction with the ionotropic glutamate receptor 4 subunit (GluR4). Methods: NPTX2 expression was evaluated by Affymetrix gene array and immunohistochemistry analysis of patient tumor tissue compared to matched normal samples. Nextbio meta-analysis was used to evaluate NPTX2 expression patterns among RCC subtypes and disease staging. Lentiviral mediated knock-down of NPTX2 and GluR4 was performed in representative ccRCC cell lines and resulting changes in proliferation, viability, morphology, and invasion were evaluated. NPTX2-GluR4 interactions were evaluated via immunoprecipitation, immunofluorescence, and intracellular calcium assays. Results: NPTX2 mRNA and protein is consistently elevated in the clear cell variant of RCC at all stages of disease, and is important for tumor cell viability. We correlate NPTX2 expression with an invasive phenotype, and demonstrate that over-expression of NPTX2 in tumor cells leads to actin cytoskeletal remodeling and increased invasion. We identify GluR4 as a mediator for NPTX2 activity which leads to increased intracellular calcium influx in tumor cells. Conclusions: NPTX2 is a tumor-specific factor that is consistently over-expressed in ccRCC. We further identify GluR4 as a downstream mediator of NPTX2 activity, whereby it modulates intracellular calcium levels, actin cytoskeletal remodeling, and tumor cell invasion. Inhibition of NPTX2 or GluR4 expression via shRNA leads to decreased tumor cell proliferation and invasion, and induces programed cell death. We propose NPTX2 as a new candidate for targeted therapy not previously described in cancer, whose inhibition may demonstrate a clinical benefit in patients suffering from metastatic ccRCC.

Citation Format: Christina A. von Roemeling, Derek C. Radisky, Laura A. Marlow, Simon J. Cooper, Stefan K. Grebe, Panagiotis Z. Anastasiadis, Han W. Tun, John A. Copland. Neuronal Pentraxin 2: a novel tumor-specific molecular target that mediates clear cell renal cell carcinoma malignancy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-111. doi:10.1158/1538-7445.AM2014-LB-111

Neuronal pentraxin 2 supports clear cell renal cell carcinoma by activating the AMPA-selective glutamate receptor-4

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancer and has the highest propensity to manifest as metastatic disease. Recent characterizations of the genetic signature of ccRCC have revealed several factors correlated with tumor cell migration and invasion; however, the specific events driving malignancy are not well defined. Furthermore, there remains a lack of targeted therapies that result in long-term, sustainable response in patients with metastatic disease. We show here that neuronal pentraxin 2 (NPTX2) is overexpressed specifically in ccRCC primary tumors and metastases, and that it contributes to tumor cell viability and promotes cell migration through its interaction with the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluR4. We propose NPTX2 as a novel molecular target for therapy for patients with ccRCC diagnosed with or at risk of developing metastatic disease.

Development and characterization of a differentiated thyroid cancer cell line resistant to VEGFR-targeted kinase inhibitors

BACKGROUND

Vascular endothelial growth factor-targeted kinase inhibitors have emerged as highly promising therapies for radioiodine-refractory metastatic differentiated thyroid cancer. Unfortunately, drug resistance uniformly develops, limiting their therapeutic efficacies and thereby constituting a major clinical problem.

APPROACH AND METHODS

To study acquired drug resistance and elucidate underlying mechanisms in this setting, BHP2-7 human differentiated thyroid cancer cells were subjected to prolonged continuous in vitro selection with 18 μM pazopanib, a clinically relevant concentration; acquisition of pazopanib resistance was serially assessed, with the resulting resistant cells thereafter subcloned and characterized to assess potential mechanisms of acquired pazopanib resistance.

RESULTS

Stable 2- to 4-fold in vitro pazopanib resistance emerged in response to pazopanib selection associated with similar in vitro growth characteristics but with markedly more aggressive in vivo xenograft growth. Selected cells were cross-resistant to sunitinib and to a lesser extent sorafenib but not to MAPK kinase (MEK1/2) inhibition by GSK1120212. Genotyping demonstrated acquisition of a novel activating KRAS codon 13 GGC to GTT (glycine to valine) mutation, consistent with the observed resistance to upstream vascular endothelial growth factor receptor inhibition yet sensitivity to downstream MAPK kinase (MEK1/2) inhibition.

CONCLUSIONS

Selection of thyroid cancer cells with clinically utilized therapeutics can lead to acquired drug resistance and altered in vivo xenograft behavior that can recapitulate analogous drug resistance observed in patients. This approach has the potential to lead to insights into acquired treatment-related drug resistance in thyroid cancers that can be subjected to subsequent validation in serially collected patient samples and that has the potential to yield preemptive and responsive approaches to dealing with this important clinical problem.

Clinical applications of LC-MS sex steroid assays: evolution of methodologies in the 21st century

PURPOSE OF REVIEW

The purpose of this review is to summarize why and how liquid chromatography tandem mass spectrometry (LC-MS/MS) is increasingly replacing other methodologies for the measurement of sex steroids.

RECENT FINDINGS

Measurement of sex steroids, particularly testosterone and estradiol, is important for diagnosis or management of a host of conditions (e.g. disorders of puberty, hypogonadism, polycystic ovary syndrome, amenorrhea, and tumors of ovary, testes, breast and prostate). Historically, metabolites of testosterone and estradiol were measured as ketosteroids in urine using colorimetric assays that lacked sensitivity and specificity due to endogenous and exogenous interferences. Extracted competitive manual radio-immunoassays provided improved, but still imperfect, specificity, and offered increased sensitivity. As testing demand increased, they were displaced by automated immunoassays. These offered better throughput and precision, but suffered worse specificity problems. Moreover, agreement between different immunoassays has often been poor and they are all compromised by a limited dynamic measurement range. To overcome these problems, LC-MS/MS methods have been developed and validated for quantitation of sex steroids. These methods reduce interferences, provide better specificity, improve dynamic range, and reduce between-method bias.

SUMMARY

Endocrine Society and Urology Society guidelines have highlighted the limitations of the immunoassays for sex steroids and have provided convincing evidence that mass spectrometric methods are preferable for measurement of sex steroid hormones. In this review, we describe LC-MS/MS methods for measurement of testosterone and estradiol.

RNA sequencing identifies multiple fusion transcripts, differentially expressed genes, and reduced expression of immune function genes in BRAF (V600E) mutant vs BRAF wild-type papillary thyroid carcinoma

CONTEXT

The BRAF V600E mutation (BRAF-MUT) confers an aggressive phenotype in papillary thyroid carcinoma, but unidentified additional genomic abnormalities may be required for full phenotypic expression.

OBJECTIVE

RNA sequencing (RNA-Seq) was performed to identify genes differentially expressed between BRAF-MUT and BRAF wild-type (BRAF-WT) tumors and to correlate changes to patient clinical status.

DESIGN

BRAF-MUT and BRAF-WT tumors were identified in patients with T1N0 and T2-3N1 tumors evaluated in a referral medical center. Gene expression levels were determined (RNA-Seq) and fusion transcripts were detected. Multiplexed capture/detection and digital counting of mRNA transcripts (nCounter, NanoString Technologies) validated RNA-Seq data for immune system-related genes.

PATIENTS

BRAF-MUT patients included nine women, three men; nine were TNM stage I and three were stage III. Three (25%) had tumor infiltrating lymphocytes. BRAF-WT included five women, three men; all were stage I, and five (62.5%) had tumor infiltrating lymphocytes.

RESULTS

RNA-Seq identified 560 of 13 085 genes differentially expressed between BRAF-MUT and BRAF-WT tumors. Approximately 10% of these genes were related to MetaCore immune function pathways; 51 were underexpressed in BRAF-MUT tumors, whereas 4 (HLAG, CXCL14, TIMP1, IL1RAP) were overexpressed. The four most differentially overexpressed immune genes in BRAF-WT tumors (IL1B; CCL19; CCL21; CXCR4) correlated with lymphocyte infiltration. nCounter confirmed the RNA-Seq expression level data. Eleven different high-confidence fusion transcripts were detected (four interchromosomal; seven intrachromosomal) in 13 of 20 tumors. All in-frame fusions were validated by RT-PCR.

CONCLUSION

BRAF-MUT papillary thyroid cancers have reduced expression of immune/inflammatory response genes compared with BRAF-WT tumors and correlate with lymphocyte infiltration. In contrast, HLA-G and CXCL14 are overexpressed in BRAF-MUT tumors. Sixty-five percent of tumors had between one and three fusion transcripts. Functional studies will be required to determine the potential role of these newly identified genomic abnormalities in contributing to the aggressiveness of BRAF-MUT and BRAF-WT tumors.

Reexpression of tumor suppressor, sFRP1, leads to antitumor synergy of combined HDAC and methyltransferase inhibitors in chemoresistant cancers

Metastatic solid tumors are aggressive and mostly drug resistant, leading to few treatment options and poor prognosis as seen with clear cell renal cell carcinoma (ccRCC) and triple-negative breast cancer (TNBC). Therefore, the identification of new therapeutic regimes for the treatment of metastatic disease is desirable. ccRCC and TNBC cell lines were treated with the HDAC inhibitor romidepsin and the methyltransferase inhibitor decitabine, two epigenetic modifying drugs approved by the U.S. Food and Drug Administration for the treatment of various hematologic malignancies. Cell proliferation analysis, flow cytometry, quantitative PCR, and immunoblotting techniques were used to evaluate the antitumor synergy of this drug combination and identify the reexpression of epigenetically silenced tumor suppressor genes. Combinatorial treatment of metastatic TNBC and stage IV ccRCC cell lines with romidepsin/decitabine leads to synergistic inhibition of cell growth and induction of apoptosis above levels of individual drug treatments alone. Synergistic reexpression of the tumor suppressor gene secreted frizzled-related protein one (sFRP1) was observed in combinatorial drug-treated groups. Silencing sFRP1 (short hairpin RNA) before combinatorial drug treatment showed that sFRP1 mediates the growth inhibitory and apoptotic activity of combined romidepsin/decitabine. Furthermore, addition of recombinant sFRP1 to ccRCC or TNBC cells inhibits cell growth in a dose-dependent manner through the induction of apoptosis, identifying that epigenetic silencing of sFRP1 contributes to renal and breast cancer cell survival. Combinatorial treatment with romidepsin and decitabine in drug resistant tumors is a promising treatment strategy. Moreover, recombinant sFRP1 may be a novel therapeutic strategy for cancers with suppressed sFRP1 expression.

Analysis of circulating microRNA: preanalytical and analytical challenges

BACKGROUND

There is great interest in circulating microRNAs (miRNAs) as disease biomarkers. Translating promising miRNAs into validated clinical tests requires the characterization of many preanalytical and analytical parameters.

METHODS

miRNAs were extracted from serum and plasma samples of healthy volunteers, and miRNAs known to be present in serum and plasma (miR-15b, miR-16, miR-24, and miR-122) were amplified by reverse-transcription quantitative PCR. Stability and the effects of hemolysis were determined. Assay variation and its components, including the effect of adding control miRNA, were assessed by nested ANOVA.

RESULTS

miRNA concentrations were higher in plasma than in serum. Processing of plasma to remove subcellular/cellular components reduced miRNA concentrations to those of serum. The miRNAs analyzed were stable refrigerated or frozen for up to 72 h and were stable at room temperature for 24 h. Hemolysis increased the apparent concentration of 3 of the miRNAs. The total variability of replicate miRNA concentrations was <2.0-fold, with most of the variability attributable to the extraction process and interassay imprecision. Normalizing results to those of spiked exogenous control miRNAs did not improve this variability.

CONCLUSIONS

Detailed validation of the preanalytical steps affecting miRNA detection and quantification is critical when considering the use of individual miRNAs as clinical biomarkers. Unless these causes of imprecision are considered and mitigated, only miRNAs that are extremely up- or downregulated will be suitable as clinical biomarkers.

Catecholamine metabolomic and secretory phenotypes in phaeochromocytoma

Phaeochromocytomas and paragangliomas (PPGLs) are highly heterogeneous tumours with variable catecholamine biochemical phenotypes and diverse hereditary backgrounds. This analysis of 18 catecholamine-related plasma and urinary biomarkers in 365 patients with PPGLs and 846 subjects without PPGLs examined how catecholamine metabolomic profiles are impacted by hereditary background and relate to variable hormone secretion. Catecholamine secretion was assessed in a subgroup of 156 patients from whom tumour tissue was available for measurements of catecholamine contents. Among all analytes, the free catecholamine O-methylated metabolites measured in plasma showed the largest tumour-related increases relative to the reference group. Patients with tumours due to multiple endocrine neoplasia type 2 and neurofibromatosis type 1 (NF1) showed similar catecholamine metabolite and secretory profiles to patients with adrenaline-producing tumours and no evident hereditary background. Tumours from these three patient groups contained higher contents of catecholamines, but secreted the hormones at lower rates than tumours that did not contain appreciable adrenaline, the latter including PPGLs due to von Hippel-Lindau (VHL) and succinate dehydrogenase (SDH) gene mutations. Large increases of plasma dopamine and its metabolites additionally characterised patients with PPGLs due to the latter mutations, whereas patients with NF1 were characterised by large increases in plasma dihydroxyphenylglycol and dihydroxyphenylacetic acid, the deaminated metabolites of noradrenaline and dopamine. This analysis establishes the utility of comprehensive catecholamine metabolite profiling for characterising the distinct and highly diverse catecholamine metabolomic and secretory phenotypes among different groups of patients with PPGLs. The data further suggest developmental origins of PPGLs from different populations of chromaffin cell progenitors.

Measurements of plasma methoxytyramine, normetanephrine, and metanephrine as discriminators of different hereditary forms of pheochromocytoma

BACKGROUND

Pheochromocytomas are rare catecholamine-producing tumors derived in more than 30% of cases from mutations in 9 tumor-susceptibility genes identified to date, including von Hippel-Lindau tumor suppressor (VHL); succinate dehydrogenase complex, subunit B, iron sulfur (Ip) (SDHB); and succinate dehydrogenase complex, subunit D, integral membrane protein (SDHD). Testing of multiple genes is often undertaken at considerable expense before a mutation is detected. This study assessed whether measurements of plasma metanephrine, normetanephrine, and methoxytyramine, the O-methylated metabolites of catecholamines, might help to distinguish different hereditary forms of the tumor.

METHODS

Plasma concentrations of O-methylated metabolites were measured by liquid chromatography with electrochemical detection in 173 patients with pheochromocytoma, including 38 with multiple endocrine neoplasia type 2 (MEN 2), 10 with neurofibromatosis type 1 (NF1), 66 with von Hippel-Lindau (VHL) syndrome, and 59 with mutations of SDHB or SDHD.

RESULTS

In contrast to patients with VHL, SDHB, and SDHD mutations, all patients with MEN 2 and NF1 presented with tumors characterized by increased plasma concentrations of metanephrine (indicating epinephrine production). VHL patients usually showed solitary increases in normetanephrine (indicating norepinephrine production), whereas additional or solitary increases in methoxytyramine (indicating dopamine production) characterized 70% of patients with SDHB and SDHD mutations. Patients with NF1 and MEN 2 could be discriminated from those with VHL, SDHB, and SDHD gene mutations in 99% of cases by the combination of normetanephrine and metanephrine. Measurements of plasma methoxytyramine discriminated patients with SDHB and SDHD mutations from those with VHL mutations in an additional 78% of cases.

CONCLUSIONS

The distinct patterns of plasma catecholamine O-methylated metabolites in patients with hereditary pheochromocytoma provide an easily used tool to guide cost-effective genotyping of underlying disease-causing mutations.

Accuracy of calculated free testosterone differs between equations and depends on gender and SHBG concentration

Serum free testosterone (fT) concentrations are often calculated, however different equations often yield discrepant results. This study explores the sources of this variability. We compared three established and two new equations that differed only by their testosterone association constants with isotope dilution equilibrium dialysis in two patient groups with different gender distributions. Equation components were examined to determine how they impacted correlation with isotope dilution equilibrium dialysis. Association constants derived for each patient group correlated best with isotope dilution equilibrium dialysis for that group and not the other set. Samples with the poorest correlation between isotope dilution equilibrium dialysis and calculated fT results had significantly higher SHBG concentrations. Regardless of equation, ≥ 25% of samples showed unacceptable deviation from isotope dilution equilibrium dialysis. Association constants and gender makeup and SHBG concentration of the patient groups used to establish an equation all significantly impact correlation with isotope dilution equilibrium dialysis. Application of many fT equations to wider populations will therefore frequently yield results that differ substantially from isotope dilution equilibrium dialysis.

Detailed molecular fingerprinting of four new anaplastic thyroid carcinoma cell lines and their use for verification of RhoB as a molecular therapeutic target

CONTEXT

Anaplastic thyroid carcinoma (ATC) is a highly aggressive carcinoma in need of therapeutic options. One critical component of drug discovery is the availability of well-characterized cell lines for identification of molecular mechanisms related to tumor biology and drug responsiveness. Up to 42% of human thyroid cancer cell lines are redundant or not of correct tissue origin, and a comprehensive analysis is currently nonexistent. Mechanistically, RhoB has been identified as a novel molecular target for ATC therapy.

OBJECTIVE

The aim was to develop four ATC cell lines detailing genetic, molecular, and phenotypic characteristics and to test five classes of drugs on the cell lines to determine whether they inhibited cell proliferation in a RhoB-dependent fashion.

DESIGN

Four cell lines were derived from ATC tumors. Short tandem DNA repeat and mutational status of the originating tumors and cell lines were performed along with molecular and phenotypic characterizations. Compounds were tested for growth inhibition and ability to up-regulate RhoB.

RESULTS

Cell line authenticity was confirmed by DNA short tandem repeat analysis. Each proved unique regarding expression of thyroid markers, oncogene status, amplified and deleted genes, and proliferative growth rates. FTI-277, GGTI-286, lovastatin, romidepsin, and UCN-01 up-regulated RhoB and inhibited cell proliferation in a dose-responsive fashion with only romidepsin and FTI-277 being RhoB dependent.

CONCLUSIONS

Molecular descriptions of thyroid lines were matched to the originating tumors, setting a new standard for cell line characterization. Furthermore, suppressed RhoB is implicated as a molecular target for therapy against ATC because five classes of drugs up-regulate RhoB and inhibit growth dose-responsively.

Infants of women with polycystic ovary syndrome have lower cord blood androstenedione and estradiol levels

CONTEXT

Prenatal androgen excess can cause a phenocopy of polycystic ovary syndrome (PCOS) in mammals. Retrospective studies have suggested that girls at risk for PCOS have low birth weight, and prospective studies have suggested an increased prevalence of small-for-gestational-age offspring in women with PCOS.

OBJECTIVE

The objective of the study was to determine whether infants of women with PCOS have reduced birth weight or increased intrauterine androgen levels.

DESIGN

This was a prospective case-control study.

PARTICIPANTS

Thirty-nine PCOS and 31 control women and their infants participated in the study.

MAIN OUTCOME MEASURES

Birth weight and mixed cord blood testosterone, androstenedione (A), dehydroepiandrosterone, 17-hydroxyprogesterone, estradiol (E2), and dihydrotestosterone levels were measured.

RESULTS

Mean birth weight did not differ, but there was a significant increase in the prevalence of large-for-gestational-age infants in the PCOS group. Cord blood E2 and A levels were lower (P < 0.05), but testosterone to E2 ratios did not differ in female PCOS compared with control offspring. There was no difference in E2 and A levels in the male PCOS and control offspring. There was no difference in 17-hydroxyprogesterone or other androgen levels in either male or female PCOS offspring compared with their respective control group.

CONCLUSION

Infants of women with PCOS were more likely to be large for gestational age. Female offspring of affected women have lower cord blood A levels; other cord blood androgen levels do not differ compared with female control offspring. Cord blood E2 levels are also significantly decreased in PCOS, without any difference in the testosterone to E2 ratio, suggesting decreased fetal or placental production of steroids.

Quantification of Serum 1–84 Parathyroid Hormone in Patients with Hyperparathyroidism by Immunocapture In Situ Digestion Liquid Chromatography–Tandem Mass Spectrometry

Background: Immunoassays specific for 1–84 parathyroid hormone (PTH) reportedly reflect the bioactivity of PTH; however, PTH immunoassays can be susceptible to interference by cross-reacting PTH fragments. In addition, these assays currently lack standardization. A methodology using immunocapture purification with liquid chromatography–tandem mass spectrometry (LC-MS/MS) detection, along with a stable isotope–labeled internal standard, may help address these issues.

Methods: We isolated 1–84 PTH from 1 mL serum by immunocapture on a 6.5-mm polystyrene bead. The immobilized PTH was digested in situ and analyzed by LC-MS/MS. For quantification, we used the selected reaction monitoring response from the N-terminal tryptic peptide 1–13 PTH (1SVSEIQLMHNLGK13).

Results: The linear range of the assay was 39.1–4560 ng/L, and the limit of detection and limit of quantification were 14.5 ng/L and 39.1 ng/L, respectively. The intraassay CVs ranged from 6% to 11%, and the interassay CVs ranged from 7% to 17%. Interference by PTH fragments 1–44 PTH, 7–84 PTH, 43–68 PTH, 52–84 PTH, 64–84 PTH, and PTH-related protein (PTHrP) was ≤1% to ≤0.001%. Method comparison of LC-MS/MS vs the Roche Cobas® immunoassay yielded Deming fit of LC-MS/MS = 1.01x immunoassay – 13.21. The mean bias by Bland–Altman plot was −9.4%.

Conclusions: In patients with hyperparathyroidism, the immunocapture in situ digestion LC-MS/MS method can provide accurate and precise PTH results compared with immunoassay.

Pediatric brain natriuretic peptide concentrations vary with age and sex and appear to be modulated by testosterone

BACKGROUND

Natriuretic peptide concentrations in adults require age- and sex-specific reference intervals for optimal interpretation. Females have higher natriuretic peptide concentrations, and hypotheses suggest that estrogen may be responsible. This study sought to determine the influence of hormone modulation on N-terminal probrain natriuretic peptide (NT-proBNP) by using a pediatric cohort. Children/adolescents typically have rapid hormone changes during puberty, making them an ideal group to study.

METHODS

We selected 759 specimens (303 male, 456 female; ages 2 months to 18 years, mean 13 years) obtained from the Mayo Clinic Pediatric Residual Specimen Bank. We measured NT-proBNP, sex hormone-binding globulin (SHBG), estradiol, and testosterone by immunoassays or LC-MS/MS and calculated free testosterone. We performed univariate and multivariate analyses to investigate the significance of NT-proBNP with each hormone.

RESULTS

Reference values demonstrated a sex difference and sequential age differences in females. Univariate modeling of the hormones with NT-proBNP revealed an independent inverse association of NT-proBNP with testosterone, a direct association with SHBG, and no significant association with estradiol. Multivariate modeling confirmed a strong association of testosterone and SHBG with NT-proBNP. Correlation of hormones with NT-proBNP retained greater significance than either age or sex.

CONCLUSIONS

In pediatric patients, NT-proBNP is independently associated with both testosterone and SHBG hormone concentrations. Measurements of testosterone are inversely associated with NT-proBNP, and estrogens are marginally associated with NT-proBNP in males but not females, suggesting that androgens and not estrogens modulate sex differences notable in natriuretic peptides. Children and adolescents may require an objective assessment of hormones if optimal interpretation of natriuretic peptide concentrations is desired or the concentrations are confounded. .

Molecular diagnosis of a BRAF papillary thyroid carcinoma with multiple chromosome abnormalities and rare adrenal and hypothalamic metastases

OBJECTIVE

Molecular characterization of thyroid tumors is rarely applied to patient management. Our aim was to demonstrate the application of molecular and cell biology to patient care.

DESIGN

Clinical and molecular case study.

MAIN OUTCOMES

A 57-year-old man with papillary thyroid carcinoma presented with adrenal and several other presumed metastases, pulmonary nodules, and mediastinal lymphadenopathy. Bronchial carcinoma was entertained for the pulmonary lesions because of a tobacco history. Mediastinal lymph node biopsy was nondiagnostic. Cells from the biopsy were grown in tissue culture and characterized by immunocytochemical (ICC), allele-specific polymerase chain reaction (PCR), reverse transcription (RT)-PCR, DNA sequencing, and cytogenetics. A panel of agents were tested the cells for tumoricidal activity. The cells expressed thyroid-specific markers [thyroid-stimulating hormone receptor (TSH-R), thyroglobulin (TG), sodium iodide symporter (NIS)] and markers [thyroid transcription factor-1 (TTF-1), cytokeratin-7, epidermal growth factor receptor (EGF-R)] present in the primary tumor and adrenal metastasis. The BRAF V600E mutation was detected. The karyotype was 44-48,XY, + der(1) t(1;9)(p13;p13),add(9)(p13),-17,-18, + 0-3mar[cp20]. Lovastatin, gefitinib, paclitaxel, depsipeptide, and 17-AAG inhibited the growth of the cultured cells. Combinations of two or three drugs produced additive or synergistic effects depending upon the combination.

CONCLUSIONS

Unusual metastases may be associated with multiple molecular and cytogenetic abnormalities. Thus, molecular and cell-biological studies can allow otherwise difficult thyroid tumor diagnosis and may be used for targeted, individualized selection of potential treatments.

Quantitative, Highly Sensitive Liquid Chromatography–Tandem Mass Spectrometry Method for Detection of Synthetic Corticosteroids

Background: Measurements of serum or urine concentrations of synthetic glucocorticoids are useful for assessing suspected iatrogenic hypothalamic-pituitary-adrenal axis suppression and Cushing syndrome. We have developed a liquid chromatography–tandem mass spectrometry (LC-MS/MS) assay for the simultaneous quantitative analysis of beclomethasone dipropionate, betamethasone, budesonide, dexamethasone, fludrocortisone, flunisolide, fluorometholone, fluticasone propionate, megestrol acetate, methylprednisolone, prednisolone, prednisone, triamcinolone, and triamcinolone acetonide.

Methods: Stable isotopes of cortisol-9,11,12,12-d4 and triamcinolone-d1 acetonide-d6 were added as internal standards to calibrators, controls, and unknown samples. After acetonitrile precipitation, these samples were extracted with methylene chloride, and the extracts were washed and dried. Reconstituted extract (15 μL) was injected on a reversed-phase column and analyzed by LC-MS/MS in positive-ion mode. Assay precision, accuracy, linearity, and sample stability were determined by use of enriched samples. Clinical validation included analysis of 8 serum and 20 urine samples from patients with undetectable cortisol concentrations and analysis of different types of tablets.

Results: Functional assay sensitivity was as low as 0.6–1.6 nmol/L for all compounds except for triamcinolone (7.6 nmol/L). Interassay CVs were 3.0–20% for concentrations of 0.6–364 nmol/L for all analytes. Recoveries of all analytes (except triamcinolone in serum) were 82–138% at 19.2–693 nmol/L. All but one of the serum and urine samples from patients who were tested because of suppressed cortisol concentrations contained at least one synthetic steroid. Tablet analysis recovered 75% of the synthetic steroids in suspected drugs.

Conclusions: LC-MS/MS allows simultaneous quantitative detection of various synthetic steroids in serum, plasma, urine, and tablets. This provides a valuable tool for evaluating the clinical effects of topical and systemic synthetic corticosteroids.

Liquid chromatography-tandem mass spectrometry assay for simultaneous measurement of estradiol and estrone in human plasma

BACKGROUND

Estradiol (E2) and estrone (E1) measurements form an integral part of the assessment of female reproductive function and have expanding roles in other fields. However, many E1 and E2 immunoassays have limited functional sensitivity, suffer from cross-reactivity, and display poor intermethod agreement. To overcome these problems, we developed a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the simultaneous measurement of E1 and E2.

METHODS

After dansyl chloride derivatization, samples were separated by fast gradient chromatography and injected into a tandem mass spectrometer after formation of positive ions with atmospheric pressure chemical ionization. The limits of detection and quantification, recovery, linearity, precision, and reference intervals were determined, and performance was compared with several immunoassays.

RESULTS

Total run time per sample was 5 min. The multiple-reaction monitoring ion pairs were m/z 506/171 for 3-dansyl-estradiol and m/z 504/171 for 3-dansyl-estrone. The limits of detection for E1 and E2 were 12.9 pmol/L (3.5 ng/L) and 10.3 pmol/L (2.8 ng/L), respectively. Interassay imprecision (CV) was 4-20% (n = 20). The limits of quantification (functional sensitivities) for E1 and E2 were 44.1 pmol/L (11.9 ng/L) and 23.2 pmol/L (6.3 ng/L), respectively. The assay was linear to >2200 pmol/L ( approximately 600 ng/L) for each analyte. Recoveries were 93-108% for E1 and 100-110% for E2. No cross-reactivity was observed. Method comparison with several immunoassays revealed that the latter were inaccurate and prone to interferences at low E1 and E2 concentrations.

CONCLUSIONS

LC-MS/MS allows rapid, simultaneous, sensitive, and accurate quantification of E1 and E2 in human serum.

Evolving classification of renal cell neoplasia

The development of consensus classifications for renal epithelial neoplasia in 1996 and 1997 led to the recognition of renal adenoma, renal oncocytoma and metanephric adenoma/adenofibroma as benign tumors and conventional (clear cell) renal cell carcinoma (RCC), papillary RCC, chromophobe RCC and collecting duct carcinoma as malignant morphotypes. While the overwhelming majority of renal adenomas and metanephric adenomas are benign, malignant transformation of both types have been described and genetic predictors of malignant transformation are as yet unknown. The main groups of malignant renal tumors are associated with characteristic genetic changes; conventional RCC (-3p), papillary RCC (+7, +17, -Y), chromophobe RCC (hypodiploid). Recent studies have also shown focal loss of heterozygosity of 3p segments in papillary and chromophobe RCC, indicating that 3p mutations are not confined to the conventional RCC morphotype and suggesting the presence of an important tumor suppressor gene at this site. Sarcomatoid metaplasia may occur in any morphotype and this is associated with a poor prognosis. More recently additional varieties of conventional RCC (multilocular cystic RCC), collecting duct carcinoma (medullary renal carcinoma) and papillary RCC (Types 1 and 2), each showing a characteristic morphology, have been recognized.

Oral shark cartilage does not abolish carcinogenesis but delays tumor progression in a murine model

BACKGROUND

Shark cartilage and shark cartilage extracts have been reported to have anti-angiogenic and anti-neoplastic properties. This study reports the effects of oral administration of powdered shark cartilage on tumor progression in a murine renal tumor model.

MATERIALS AND METHODS

Renal tumors were induced in CBA female mice by a single bolus of IV streptozotocin. 57 mice were fed shark cartilage and the numbers and rate of development of dysplastic convoluted tubules, papillary and solid renal epithelial tumors was compared with 57 control mice over an 88 week follow-up period.

RESULTS

In the shark cartilage fed group dysplasia was first observed after 23 weeks (control 19 weeks), papillary tumors after 24 weeks (control 23 weeks) and solid tumors after 55 weeks (control 19 weeks). There was no significant difference in the rate of development of dysplastic tubules between test and control animals. The development of papillary and solid tumors was significantly delayed in the test group.

CONCLUSIONS

In this tumor model oral shark cartilage delays, but does not abolish, tumor progression.

FHIT and TSG101 in thyroid tumours: aberrant transcripts reflect rare abnormal RNA processing events of uncertain pathogenetic or clinical significance

OBJECTIVE

The chromosomal regions containing the two putative tumour suppressors, fragile histidine triad gene (FHIT) and tumour suppressor gene 101 (TSG101), are deleted frequently in thyroid tumours. We therefore analysed FHIT and TSG101 transcripts in a group of advanced thyroid tumours to establish their role in thyroid tumorigenesis.

DESIGN

Retrospective analysis of FHIT and TSG101 mRNA transcripts and genomic DNA from cryo-preserved thyroid tumours. TP53, previously shown at the genomic level not to be mutated in this cohort of tumours, served as a control.

PATIENTS

We analysed nine follicular thyroid carcinomas (FTC), six papillary thyroid carcinomas and six follicular adenomas (FA) and histologically normal thyroid tissue from four of the FA patients.

MEASUREMENTS

Single stage and nested reverse transcription polymerase chain reaction (RT-PCR) products of FHIT, TSG101, and TP53 were analysed by agarose or polyacrylamide gel electrophoresis and sequenced. Genomic DNA was also analysed by polymerase chain reaction and sequencing (FHIT) or by Southern blotting (TSG101). Clinical data were correlated with the results of the mutation analysis.

RESULTS

Truncated FHIT transcripts were observed frequently alongside full length transcripts with nested RT-PCR, most often in FTC, while single stage RT-PCR revealed only normal length transcripts in all tumours. Similar results were obtained for TP53, while abnormal TSG101 transcripts were detectable by single stage RT-PCR. Sequence analysis of the truncated FHIT and TSG101 transcripts revealed mainly exon skipping and alternate RNA processing events. Only a single point mutation (of TSG101) was found. Southern blotting for the TSG101 gene, and PCR amplification and sequencing of the FHIT gene showed no evidence of genomic abnormalities in either case, and there was no evidence of splice site mutations in the FHIT gene, suggesting that the truncated transcripts result from altered RNA processing. There was no relationship between tumour stage, grade or survival and the presence of FHIT or TSG101 abnormalities.

CONCLUSIONS

Truncated FHIT and TSG101 transcripts in thyroid tumours reflect alternate mRNA splicing events, rather than genomic deletions. Such abnormal RNA processing seems to be common and widespread in thyroid neoplasms, as similar results were obtained by analysis of transcripts of TP53, which we had previously shown not to be mutated in these specimens. Although a pathogenetic role for these aberrant transcripts remains possible, no correlation was found with stage, histological grade or outcome in this small group of advanced thyroid malignancies. Relaxation of mRNA splice control appears to be a feature of follicular cell-derived thyroid neoplasms.

Sarcomatoid carcinoma of the prostate: progression from adenocarcinoma is associated with p53 over-expression

BACKGROUND

The pathogenesis of sarcomatoid metaplasia of prostatic adenocarcinoma is uncertain. The histologic features of sarcomatoid carcinoma arising in two patients with previously irradiated prostatic adenocarcinoma are reported and the relationship between prostatic adenocarcinoma and subsequent sarcomatoid carcinoma is investigated by immunohistochemical detection of epithelial and soft tissue tumor markers, and p53 protein.

METHODS AND RESULTS

Two patients, aged 72 and 67 years, underwent localized radiotherapy for prostatic adenocarcinoma and re-presented with sarcomatoid carcinoma 41 months and 60 months later, respectively. In both cases the tumor consisted of anaplastic spindle cells with occasional osteoclast-like giant cells. The initial tumors showed immunohistochemical staining typical of prostatic adenocarcinoma with absence of expression of p53 protein. The subsequent sarcomatoid carcinomas were positive for vimentin and negative for epithelial cell markers. In both cases serial biopsies showed a temporal increase in tumor expression of p53 protein.

CONCLUSIONS

The development of sarcomatoid carcinoma in prostatic adenocarcinoma is associated with progressive accumulation of p53. This is suggestive of increasing clonal dominance of dedifferentiated tumor cells carrying p53 mutations.

Acidic isoforms of chorionic gonadotrophin in European and Samoan women are associated with hyperemesis gravidarum and may be thyrotrophic

OBJECTIVE

There is conflicting evidence concerning the role of human chorionic gonadotrophin (hCG) in the aetiology of hyperemesis gravidarum (HG); particular isoforms of hCG may be the critical factor. Ethnic differences in HG prevalence and putative thyrotrophic effects of hCG may also relate to differences in hCG isoform profiles. To address these issues we examined the relationship of hCG isoforms to HG and thyroid function tests in two groups of women from ethnic backgrounds with significantly different HG prevalence rates.

PATIENTS AND DESIGN

We enrolled 10 European and 10 Samoan women with HG and an equally sized non-hyperemetic, gestational stage matched control group.

MEASUREMENTS

We administered a questionnaire, generated serum hCG charge-isoform profiles by chromatofocusing and measured the serum concentrations of total hCG, oestradiol (E2), thyrotrophin (TSH) and free thyroxine (FT4).

RESULTS

The mean serum total hCG levels were highest in the Samoan hyperemetics (176,268 IU/l), and overall higher in hyperemetics compared with controls (159,770 IU/l vs. 86,420 IU/l, P < 0.001). When compared with controls, hyperemetics displayed increased hCG concentrations in the more acidic half (pH < 4) of the chromatofocusing pH range (89,843 IU/l vs. 41,146 IU/l, P < 0.003). Serum E2 levels did not differ between the four groups, but correlated with the hCG concentration between pH 5.2 and 4.01. Mean serum TSH levels were significantly lower in hyperemetics than in controls (0.33 mIU/l vs. 1.19 mIU/l, P < 0.001) and correlated with the hCG concentration between pH 4.6 and 2.8, while serum FT4 correlated with the hCG concentration below pH 4.0.

CONCLUSIONS

Acidic isoforms of hCG may play a role in the aetiology of HG and gestational thyrotoxicosis. Minor ethnic differences in hCG isoform profiles were observed, but the relationship of acidic hCG isoforms to HG and serum thyroid hormone levels was largely independent of the patients' ethnicity. The mechanisms by which acidic isoforms might provoke nausea remain uncertain, but do not seem to involve E2, while the longer half-life of acidic hCG isoforms may result in increased in vivo TSH receptor cross-talk with resultant thyrotrophic effects.

Loss of heterozygosity at 3p14.2 in clear cell renal cell carcinoma is an early event and is highly localized to the FHIT gene locus

The VHL tumor suppressor gene (TSG) at 3p25-26 is strongly implicated in the pathogenesis of clear cell renal cell carcinoma (cRCC). In addition, 3p14.2 and 3p21 are suspected of harboring additional TSGs in cRCC, with FHIT being a candidate TSG at 3p14.2. We examined 87 microdissected, histologically well-defined cRCCs classified according to tumor-node-metastasis (TNM) stage (stage 1, 23 cases; stage 2, 14 cases; stage 3, 24 cases; stage 4, 26 cases) and Fuhrman grade (grade 1, 24 cases; grade 2, 19 cases; grade 3, 19 cases; grade 4, 8 cases; sarcomatoid cRCC, 17 cases) for loss of heterozygosity (LOH) at 3p14.2 and 3p25-26 using a series of precisely mapped microsatellite probes. We found that LOH at 3p14.2 exceeded LOH at 3p25-26 in frequency (69% versus 48.3%; P < 0.03) and was highly localized to markers within the FHIT gene locus (D3S1300 and D3S4260), with the majority of chromosomal breakpoints also mapping to this region. In addition, 3p14.2 LOH (P < 0.03), but not 3p25-26 LOH (P = nonsignificant), was associated with lower tumor grades (grades 1-3). These findings suggest that 3p14.2 genomic deletions may be among the earliest events in cRCC pathogenesis, preceding genomic deletions at the VHL locus. FHIT, or an as yet undiscovered TSG mapping to the D3S4103-D3S4260 interval, could be the molecular target of the 3p14.2 deletions.