Diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body diagnostic CT and MRI in the detection of spinal bone metastases associated with pheochromocytoma and paraganglioma

OBJECTIVE

To compare the diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body CT and MRI for the detection of pheochromocytoma/paraganglioma (PPGL)-related spinal bone metastases.

MATERIALS AND METHODS

Between 2014 and 2020, PPGL participants with spinal bone metastases prospectively underwent [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the cervical-thoracolumbar spine (MRIspine), contrast-enhanced MRI of the neck and thoraco-abdominopelvic regions (MRIWB), and contrast-enhanced CT of the neck and thoraco-abdominopelvic regions (CTWB). Per-patient and per-lesion detection rates were calculated. Counting of spinal bone metastases was limited to a maximum of one lesion per vertebrae. A composite of all functional and anatomic imaging served as an imaging comparator. The McNemar test compared detection rates between the scans. Two-sided p values were reported.

RESULTS

Forty-three consecutive participants (mean age, 41.7 ± 15.7 years; females, 22) with MRIspine were included who also underwent [68Ga]DOTATATE PET/CT (n = 43), [18F]FDG PET/CT (n = 43), MRIWB (n = 24), and CTWB (n = 33). Forty-one of 43 participants were positive for spinal bone metastases, with 382 lesions on the imaging comparator. [68Ga]DOTATATE PET/CT demonstrated a per-lesion detection rate of 377/382 (98.7%) which was superior compared to [18F]FDG (72.0%, 275/382, p < 0.001), MRIspine (80.6%, 308/382, p < 0.001), MRIWB (55.3%, 136/246, p < 0.001), and CTWB (44.8%, 132/295, p < 0.001). The per-patient detection rate of [68Ga]DOTATATE PET/CT was 41/41 (100%) which was higher compared to [18F]FDG PET/CT (90.2%, 37/41, p = 0.13), MRIspine (97.6%, 40/41, p = 1.00), MRIWB (95.7%, 22/23, p = 1.00), and CTWB (81.8%, 27/33, p = 0.03).

CONCLUSIONS

[68Ga]DOTATATE PET/CT should be the modality of choice in PPGL-related spinal bone metastases due to its superior detection rate.

CLINICAL RELEVANCE STATEMENT

In a prospective study of 43 pheochromocytoma/paraganglioma participants with spinal bone metastases, [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% (377/382), compared to [18F]FDG PET/CT (p < 0.001), MRI of the spine (p < 0.001), whole-body CT (p < 0.001), and whole-body MRI (p < 0.001).

KEY POINTS

• Data regarding head-to-head comparison between functional and anatomic imaging modalities to detect spinal bone metastases in pheochromocytoma/paraganglioma are limited. • [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% in the detection of spinal bone metastases associated with pheochromocytoma/paraganglioma compared to other imaging modalities: [18]F-FDG PET/CT, MRI of the spine, whole-body CT, and whole-body MRI. • [68Ga]DOTATATE PET/CT should be the modality of choice in the evaluation of spinal bone metastases associated with pheochromocytoma/paraganglioma.

Demonstration of a low loss, highly stable and re-useable edge coupler for high heralding efficiency and low g(2)(0) SOI correlated photon pair sources

We report a stable, low loss method for coupling light from silicon-on-insulator (SOI) photonic chips into optical fibers. The technique is realized using an on-chip tapered waveguide and a cleaved small core optical fiber. The on-chip taper is monolithic and does not require a patterned cladding, thus simplifying the chip fabrication process. The optical fiber segment is composed of a centimeter-long small core fiber (UHNA7) which is spliced to SMF-28 fiber with less than -0.1 dB loss. We observe an overall coupling loss of -0.64 dB with this design. The chip edge and fiber tip can be butt coupled without damaging the on-chip taper or fiber. Friction between the surfaces maintains alignment leading to an observation of ±0.1 dB coupling fluctuation during a ten-day continuous measurement without use of any adhesive. This technique minimizes the potential for generating Raman noise in the fiber, and has good stability compared to coupling strategies based on longer UHNA fibers or fragile lensed fibers. We also applied the edge coupler on a correlated photon pair source and observed a raw coincidence count rate of 1.21 million cps and raw heralding efficiency of 21.3%. We achieved an auto correlation function g H(2)(0) as low as 0.0004 at the low pump power regime.

Prevalence of lung cysts in adolescents and adults with a germline DICER1 pathogenic/likely pathogenic variant: a report from the National Institutes of Health and International Pleuropulmonary Blastoma/DICER1 Registry

BACKGROUND

Pleuropulmonary blastoma (PPB), the hallmark tumour associated with DICER1-related tumour predisposition, is characterised by an age-related progression from a cystic lesion (type I) to a high-grade sarcoma with mixed cystic and solid features (type II) or purely solid lesion (type III). Not all cystic PPBs progress; type Ir (regressed), hypothesised to represent regressed or non-progressed type I PPB, is an air-filled, cystic lesion lacking a primitive sarcomatous component. This study aims to evaluate the prevalence of non-progressed lung cysts detected by CT scan in adolescents and adults with germline DICER1 pathogenic/likely pathogenic (P/LP) variants.

METHODS

Individuals were enrolled in the National Cancer Institute Natural History of DICER1 Syndrome study, the International PPB/DICER1 Registry and/or the International Ovarian and Testicular Stromal Tumor Registry. Individuals with a germline DICER1 P/LP variant with first chest CT at 12 years of age or older were selected for this analysis.

RESULTS

In the combined databases, 110 individuals with a germline DICER1 P/LP variant who underwent first chest CT at or after the age of 12 were identified. Cystic lung lesions were identified in 38% (42/110) with a total of 72 cystic lesions detected. No demographic differences were noted between those with lung cysts and those without lung cysts. Five cysts were resected with four centrally reviewed as type Ir PPB.

CONCLUSION

Lung cysts are common in adolescents and adults with germline DICER1 variation. Further study is needed to understand the mechanism of non-progression or regression of lung cysts in childhood to guide judicious intervention.

Gastrointestinal and Hepatic Manifestations of Chronic Granulomatous Disease

Chronic granulomatous disease (CGD) is a rare inborn error of immunity, resulting from a defect in nicotinamide adenine dinucleotide phosphate oxidation and decreased production of phagocyte reactive oxygen species. The main clinical manifestations are recurrent infections and chronic inflammatory disorders. Current approaches to management include antimicrobial prophylaxis and control of inflammatory complications. Hematopoietic stem cell transplantation or gene therapy can provide definitive treatment. Gastrointestinal and hepatic manifestations are common in CGD and include structural changes, dysmotility, CGD-associated inflammatory bowel disease, liver abscesses, and noncirrhotic portal hypertension. The findings can be heterogeneous, and the management is complex in light of the underlying immune dysfunction. This review describes the various clinical findings and the latest studies in management of gastrointestinal and hepatic manifestations in CGD, as well as the management experience at the National Institutes of Health.

Shear wave elastography: How well does it perform in chronic hepatitis D virus infection?

Hepatitis delta virus (HDV) infection is associated with accelerated progression of liver disease to cirrhosis. Shear wave elastography (SWE) is a non-invasive evaluation method of liver fibrosis. Its performance in accurately characterizing HDV fibrosis compared to other noninvasive markers remains unknown. We assessed the performance of SWE in patients with chronic HDV, Hepatitis B (HBV) and Hepatitis C (HCV) infection. Cirrhosis was determined by histology or clinical data. Area under receiver operator characteristics (AUROC) was used to assess diagnostic performance in identifying cirrhosis by SWE in comparison with Fibroscan® (VCTE) and serologic tests of fibrosis. 158 patients with chronic hepatitis (HDV:44%, HBV: 46% and HCV: 29%) were evaluated. Cirrhosis was diagnosed in 28 (17.7%) patients. Mean noninvasive fibrosis measurements for the HBV/HCV and HDV groups, respectively, were as follows: APRI: 0.73 ± 1.08 and 1.3 ± 1.38; FIB-4: 1.90 ± 2.24 and 2.33 ± 2.24; VCTE: 8.9 ± 6.7 kPa vs 10.4 ± 5.3 kPa; SWE: 1.5 ± 0.2 m/s and 1.6 ± 0.2 m/s. The performance of SWE in detecting HDV-induced cirrhosis (AUROC 0.84, 95% CI 0.71-0.97) was slightly lower than in HBV/HCV induced disease (AUROC 0.88, 95% CI 0.81-0.96). For HDV patients, the performance of SWE was comparable to VCTE and slightly better than APRI and FIB-4 especially in APRI and FIB-4 indeterminate zones. The overall less accurate performance of noninvasive markers in HDV in comparison with HBV and HCV may be a result of significant hepatic inflammation in HDV.

Fracture Risk in Pediatric Patients With MEN2B

CONTEXT

The skeletal phenotype of patients with MEN2B has been described but fracture risk in these patients has not yet been evaluated.

OBJECTIVE

This work aims to better delineate fracture risk in patients with multiple endocrine neoplasia type 2B (MEN2B).

METHODS

This case series with chart review was conducted at the National Institutes of Health, Pediatric Oncology Branch. A total of 48 patients with MEN2B were identified, with an age range of 5 to 36 years, median of 19; 24 of 48 (50%) patients were female. Medical records, demographic information, available imaging, and laboratory results were reviewed. History up to age 19 was included in the statistical analyses.

RESULTS

Of the 48 patients with MEN2B, 20 patients experienced at least one fracture. The majority (n = 18) experienced their first fracture at or before age 19. The observed frequency of fracture occurrence throughout childhood (0-19 years) was 38%, with very little difference between males and females. This frequency is higher than the 9.47 to 36.1 fractures per 1000 persons per year that has been reported in healthy pediatric cohorts in the United States. Less common sites of fracture including vertebral compression fracture and pelvic fractures were observed in patients with MEN2B.

CONCLUSION

In this group of patients with MEN2B, there was an increased overall risk of fracture compared to general pediatric cohorts in the United States. Less common sites of fracture were also observed. This suggests a possible effect of an activating RET mutation on bone physiology and warrants further investigation.

CTIM-09. ENRICHED TCR/BCR VDJ REARRANGEMENTS CORRELATE WITH MRI AND SURVIVAL OUTCOMES IN PATIENTS WITH RECURRENT HIGH-GRADE GLIOMA TREATED WITH CAN-3110

BACKGROUND

CAN-3110 (rQNestin34.5v2) is an HSV-1 oncolytic viral immunotherapy with one copy of the inflammatory ICP34.5 gene under transcriptional control of the Nestin glioma-specific promoter. We completed a phase 1 sequential dose-escalation trial of CAN-3110 in recurrent high-grade glioma (rHGG).

METHODS

CAN-3110 was injected intratumorally starting at 1x106 plaque forming units (pfu) and dose- escalated by half log up to 1x1010 pfu in biopsy confirmed rHGG. An expansion cohort of 12 patients was then accrued at 1x109 pfus. Blood and post-injection rHGG were collected.

RESULTS

41 rHGG patients were treated (42 separate interventions): median age 56 years (range 27-74); 21 females, 20 males; median baseline KPS 90 (range 70-100). CAN-3110 administration was well-tolerated with no dose limiting toxicities. Median overall survival (mOS) was 11.9 months. Histologic and molecular analyses showed significantly increased T cell infiltration in post treatment samples with elevated T cell and/or B cell receptor (TCR/BCR) transcripts which correlated with patient survival (HR 0.26 for patients with elevated TCR/BCR rearrangements as compared to patients with low). Volumetric analyses of MRI suggest a trend between reduction in the relative change in tumor growth, TCR/BCRs enrichment and survival in CAN-3110 treated patients.

CLINICAL IMPLICATIONS

Administration of CAN-3110 into rHGG was well tolerated. OS of CAN-3110 treated subjects compare favorably to historical controls. The association of increased TCR/BCR transcripts with survival suggests that CAN-3110 induces T cell responses against rHGG, supporting further clinical development of CAN-3110 viral immunotherapy.

The deep space quantum link: prospective fundamental physics experiments using long-baseline quantum optics

The National Aeronautics and Space Administration's Deep Space Quantum Link mission concept enables a unique set of science experiments by establishing robust quantum optical links across extremely long baselines. Potential mission configurations include establishing a quantum link between the Lunar Gateway moon-orbiting space station and nodes on or near the Earth. This publication summarizes the principal experimental goals of the Deep Space Quantum Link. These goals, identified through a multi-year design study conducted by the authors, include long-range teleportation, tests of gravitational coupling to quantum states, and advanced tests of quantum nonlocality.

68Ga-DOTATATE Avid Metastatic Vertebral Renal Cell Carcinoma in the Setting of von Hippel-Lindau Syndrome

Although rare, a metastatic renal cell carcinoma could present with 68Ga-DOTATATE avidity. A 66-year-old man with von Hippel-Lindau syndrome (VHL) presented with 68Ga-DOTATATE uptake in the pancreatic head, splenic hilar region, and multiple osseous sites, including the right lateral portion of the T9 vertebrae. Biopsy of the T9 lesion confirmed metastatic renal cell carcinoma. Various VHL-associated cancers may display 68Ga-DOTATATE avidity, which can change and guide clinical decisions for the patient.

Boosting topological zero modes using elastomer waveguide arrays

We employ the Su-Schrieffer-Heeger model in elastic polymer waveguide arrays to design and realize traveling topologically protected modes. The observed delocalization of the optical field for superluminal defect velocities agrees well with theoretical descriptions. We apply mechanical strain to modulate the lattices' coupling coefficient. This work demonstrates a novel, to the best of our knowledge, platform for rapid prototyping of topological photonic devices and establishes strain-tuning as a viable design parameter for topological waveguide arrays.

Performances of Functional and Anatomic Imaging Modalities in Succinate Dehydrogenase A-Related Metastatic Pheochromocytoma and Paraganglioma

Simple Summary

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine cancers which carry the risk of metastatic disease. Pathogenic variants in the succinate dehydrogenase subunit A gene (SDHA) have been shown to cause metastatic disease, occurring in various regions of the body. Imaging is an early and vital step in the diagnosis and clinical care of these patients. The study here identifies which imaging modality among positron emission tomography (PET), computed tomography (CT), and magnetic resonance imaging (MRI) performs better in localizing metastatic PPGL lesions related to SDHA. The study identified that ⁶⁸Ga-DOTATATE PET/CT performed best at overall lesion detection; however, ¹⁸F-FDG PET/CT performed better in certain anatomic regions of the body. A combined approach with ⁶⁸Ga-DOTATATE and ¹⁸F-FDG would optimize care and guide clinicians in selecting the appropriate interventions and therapies.

Abstract

The study identifies the importance of positron emission tomographic (PET) and anatomic imaging modalities and their individual performances in detecting succinate dehydrogenase A (SDHA)-related metastatic pheochromocytoma and paraganglioma (PPGL). The detection rates of PET modalities—⁶⁸Ga-DOTATATE, ¹⁸F-FDG, and ¹⁸F-FDOPA—along with the combination of computed tomography (CT) and magnetic resonance imaging (MRI) are compared in a cohort of 11 patients with metastatic PPGL in the setting of a germline SDHA mutation. The imaging detection performances were evaluated at three levels: overall lesions, anatomic regions, and a patient-by-patient basis. ⁶⁸Ga-DOTATATE PET demonstrated a lesion-based detection rate of 88.6% [95% confidence interval (CI), 84.3–92.5%], while ¹⁸F-FDG, ¹⁸F-FDOPA, and CT/MRI showed detection rates of 82.9% (CI, 78.0–87.1%), 39.8% (CI, 30.2–50.2%), and 58.2% (CI, 52.0–64.1%), respectively. The study found that ⁶⁸Ga-DOTATATE best detects lesions in a subset of patients with SDHA-related metastatic PPGL. However, ¹⁸F-FDG did detect more lesions in the liver, mediastinum, and abdomen/pelvis anatomic regions, showing the importance of a combined approach using both PET modalities in evaluating SDHA-related PPGL.

Fine-grained all-fiber nonlocal dispersion compensation in the telecommunications O-band

Nonlocal dispersion compensation between broadband nondegenerate photon pairs propagated over fiber corresponding to the ITU-T G.652D telecommunications standard was studied extensively via fine-grained measurements of the temporal correlation between them. We demonstrated near-ideal levels of nonlocal dispersion compensation by adjusting the propagation distance of the photon pairs to preserve photon timing correlations close to the effective instrument resolution of our detection apparatus (41.0±0.1ps). Experimental data indicates that this degree of compensation can be achieved with relatively large fiber increments (1km), compatible with real-world deployment. Ultimately, photon timing correlations were preserved down to 51ps±21ps over two multi-segmented 10km spans of deployed metropolitan fiber.

Testicular Sertoli cell tumour and potentially testicular Leydig cell tumour are features of DICER1 syndrome

DICER1 syndrome is a rare paediatric autosomal dominant inherited disorder predisposing to various benign and malignant tumours. It is caused by a germline pathogenic variant in DICER1, and the second hit for tumour development is usually a missense hotspot pathogenic variant in the DICER1 ribonuclease IIIb domain. While DICER1 predisposing variants account for about 60% of ovarian Sertoli-Leydig cell tumours, no DICER1-related testicular stromal tumours have been described. Here we report the first two cases of testicular stromal tumours in children carrying a DICER1 germline pathogenic variant: a case of Sertoli cell tumour and a case of Leydig cell tumour diagnosed at 2 and 12 years of age, respectively. A somatic DICER1 hotspot pathogenic variant was detected in the Sertoli cell tumour. This report extends the spectrum of DICER1-related tumours to include testicular Sertoli cell tumour and potentially testicular Leydig cell tumour. Diagnosis of a testicular Sertoli cell tumour should prompt DICER1 genetic testing so that patients with a DICER1 germline pathogenic variant can benefit from established surveillance guidelines. DICER1 genetic evaluation may be considered for testicular Leydig cell tumour. Our findings suggest that miRNA dysregulation underlies the aetiology of some testicular stromal tumours.

Fibre polarisation state compensation in entanglement-based quantum key distribution

Quantum key distribution (QKD) using polarisation encoding can be hard to implement over deployed telecom fibres because the routing geometry and the birefringence of the fibre link can alter the polarisation states of the propagating photons. These alterations cause a basis mismatch, leading to an increased quantum bit error rate (QBER). In this work we demonstrate a technique for a dynamically compensating fibre-induced state alteration in a QKD system. This compensation scheme includes a feedback loop that minimizes the QBER using a stochastic optimization algorithm. The effectiveness of this technique is implemented and verified in a polarisation entanglement QKD system over a deployed telecom fibre.

Imaging of Pheochromocytoma and Paraganglioma

Imaging plays a critical role in the management of pheochromocytomas and paragangliomas and often guides treatment. The discovery of susceptibility genes associated with these tumors has led to better understanding of clinical and imaging phenotypes. Functional imaging is of prime importance because of its sensitivity and specificity in subtypes of pheochromocytoma and paraganglioma. Several radiopharmaceuticals have been developed to target specific receptors and metabolic processes seen in pheochromocytomas and paragangliomas, including ¹³¹I/¹²³I-metaiodobenzylguanidine, 6-¹⁸F-fluoro-l-3,4-dihydroxyphenylalanine, ¹⁸F-FDG, and ⁶⁸Ga-DOTA-somatostatin analogs. Two of these have consequently been adapted for therapy. This educational review focuses on the current imaging approaches used in pheochromocytomas and paragangliomas, which vary among clinical and genotypic presentations.

A Long Noncoding RNA, GAS5 Can Be a Biomarker for Docetaxel Response in Castration Resistant Prostate Cancer

While functional studies of long noncoding RNAs (lncRNAs) have mostly focused on how they influence disease diagnosis and prognosis, the pharmacogenomic relevance of lncRNAs remains largely unknown. Here, we test the hypothesis that the expression of a lncRNA, grow arrest-specific 5 (GAS5) can be a biomarker for docetaxel response in castration resistant prostate cancer (CRPC) using both prostate cancer (PCa) cell lines and CRPC patient datasets. Our results suggest that lower GAS5 expression is associated with docetaxel resistance in both PCa cell lines and CRPC patients. Further experiments also suggest that GAS5 is downregulated in docetaxel resistant CRPC cell lines, which reinforces its potential as a biomarker for docetaxel response. To examine the underlying biological mechanisms, we transiently knockdown GAS5 expression in PCa cell lines and then subject the cells to docetaxel treatment overtime. We did not observe a decrease in docetaxel induced growth inhibition or apoptosis in the siRNA treated cells. The findings suggest that there is no direct causal relationship between change in GAS5 expression and docetaxel response. Subsequently, we explored the indirect regulation among GAS5, ATP binding cassette subfamily B member 1 (ABCB1), and docetaxel sensitivity. We showed that transient knockdown GAS5 did not lead to significant changes in ABCB1 expression. Therefore, we rule out the hypothesis that GAS5 directly down regulate ABCB1 that lead to docetaxel sensitivity. In conclusion, our work suggests that GAS5 can serve as a predictive biomarker for docetaxel response in CRPC; however, the exact mechanism behind the observed correlation remain to be elucidated.

Oncogene or tumor suppressor? Long noncoding RNAs role in patient's prognosis varies depending on disease type

Functional studies of long noncoding RNAs (lncRNAs) are often performed in the context of only a single cancer type. However, the tissue-specific expression patterns of lncRNAs raise the question of whether lncRNA associations identified in one cancer type are relevant to other cancer types. Here, we examine the relationships between the expression levels of 50 cancer-related lncRNAs and survival data from 24 types of cancer in The Cancer Genome Atlas (TCGA) with the goal of identifying prognosis related lncRNAs. Our results suggest that high expression levels of certain lncRNAs are consistently associated with worse/better survival in a number of cancers, while other lncRNAs have different prognostic roles in different types of cancer. Our analysis also identifies 20 novel unadjusted associations that have not been reported before. In addition, in low-grade glioma (LGG), prognostic-related lncRNAs are identified after conditioning on known clinical biomarker and common therapy, revealing that 2 lncRNAs, FOXP4-AS1, and NEAT1, are associated with temozolomide response-a standard-of-care in LGG. Pathway analysis suggests NF-kB/STAT3 signaling pathway enrichment in LGG patients with high NEAT1 expression and DNA repair/myc gene set enrichment in LGG patients with high expression of FOXP4-AS1. Our work demonstrates the context dependency of lncRNAs across cancer types and highlights a number of lncRNAs as potential novel cancer prognosis markers.

Entangled photon-pair sources based on three-wave mixing in bulk crystals

Entangled photon pairs are a critical resource in quantum communication protocols ranging from quantum key distribution to teleportation. The current workhorse technique for producing photon pairs is via spontaneous parametric down conversion (SPDC) in bulk nonlinear crystals. The increased prominence of quantum networks has led to a growing interest in deployable high performance entangled photon-pair sources. This manuscript provides a review of the state-of-the-art bulk-optics-based SPDC sources with continuous wave pump and discusses some of the main considerations when building for deployment.

Facilitating Drug Discovery in Breast Cancer by Virtually Screening Patients Using In Vitro Drug Response Modeling

(1) Background: Drug imputation methods often aim to translate in vitro drug response to in vivo drug efficacy predictions. While commonly used in retrospective analyses, our aim is to investigate the use of drug prediction methods for the generation of novel drug discovery hypotheses. Triple-negative breast cancer (TNBC) is a severe clinical challenge in need of new therapies. (2) Methods: We used an established machine learning approach to build models of drug response based on cell line transcriptome data, which we then applied to patient tumor data to obtain predicted sensitivity scores for hundreds of drugs in over 1000 breast cancer patients. We then examined the relationships between predicted drug response and patient clinical features. (3) Results: Our analysis recapitulated several suspected vulnerabilities in TNBC and identified a number of compounds-of-interest. AZD-1775, a Wee1 inhibitor, was predicted to have preferential activity in TNBC (p < 2.2 × 10-16) and its efficacy was highly associated with TP53 mutations (p = 1.2 × 10-46). We validated these findings using independent cell line screening data and pathway analysis. Additionally, co-administration of AZD-1775 with standard-of-care paclitaxel was able to inhibit tumor growth (p < 0.05) and increase survival (p < 0.01) in a xenograft mouse model of TNBC. (4) Conclusions: Overall, this study provides a framework to turn any cancer transcriptomic dataset into a dataset for drug discovery. Using this framework, one can quickly generate meaningful drug discovery hypotheses for a cancer population of interest.

Computationally predicting clinical drug combination efficacy with cancer cell line screens and independent drug action

Evidence has recently emerged that many clinical cancer drug combinations may derive their efficacy from independent drug action (IDA), where patients only receive benefit from the single most effective drug in a drug combination. Here we present IDACombo, an IDA based method to predict the efficacy of drug combinations using monotherapy data from high-throughput cancer cell line screens. We show that IDACombo predictions closely agree with measured drug combination efficacies both in vitro (Pearson's correlation = 0.93 when comparing predicted efficacies to measured efficacies for >5000 combinations) and in a systematically selected set of clinical trials (accuracy > 84% for predicting statistically significant improvements in patient outcomes for 26 first line therapy trials). Finally, we demonstrate how IDACombo can be used to systematically prioritize combinations for development in specific cancer settings, providing a framework for quickly translating existing monotherapy cell line data into clinically meaningful predictions of drug combination efficacy.

Lack of pathogenic germline DICER1 variants in males with testicular germ-cell tumors

BACKGROUND

Several studies have reported conflicting evidence on the inclusion of testicular germ cell tumors (TGCT) in the DICER1 tumor-predisposition phenotype. We evaluated the relationship between DICER1 and TGCT by reviewing scrotal ultrasounds of males with pathogenic germline variants in DICER1 and queried exome data from TGCT-affected men for DICER1 variants.

METHODOLOGY

Fifty-four male DICER1-carriers and family controls (n=41) enrolled in the National Cancer Institute (NCI) DICER1 Natural History Study were offered scrotal ultrasounds. These studies were examined by a single radiologist for abnormalities. In parallel, DICER1 variants from two large exome-sequenced TGCT cohorts were extracted. We used previously published AMG-AMP criteria to characterize rare DICER1 variants.

RESULTS

There was no observed difference in frequency of testicular cystic structures in DICER1-carriers versus controls. DICER1 variation was not associated with TGCT in the NCI DICER1-carriers. In 1,264 exome-sequenced men with TGCT, none harbored ClinVar- or InterVar-determined pathogenic or likely pathogenic variants in DICER1. Three DICER1 variants of uncertain significance (one case and two controls) were predicted "damaging" based on a priori criteria.

CONCLUSION

Using two complementary approaches, we found no evidence of an association between pathogenic DICER1 variants and TGCT.

Pulmonary Function in Patients With Multiple Endocrine Neoplasia 2B

CONTEXT

Multiple endocrine neoplasia type 2B (MEN2B) is a rare cancer predisposition syndrome resulting from an autosomal-dominant germline mutation of the RET proto-oncogene. No prior studies have investigated pulmonary function in patients with MEN2B.

OBJECTIVE

This study characterized the pulmonary function of patients with MEN2B.

DESIGN

This is a retrospective analysis of pulmonary function tests (PFTs) and chest imaging of patients enrolled in the Natural History Study of Children and Adults with MEN2A or MEN2B at the National Institutes of Health.

RESULTS

Thirty-six patients with MEN2B (18 males, 18 females) were selected based on the availability of PFTs; 27 patients underwent at least 2 PFTs and imaging studies. Diffusion abnormalities were observed in 94% (33/35) of the patients, with 63% (22/35) having moderate to severe defects. A declining trend in diffusion capacity was seen over time, with an estimated slope of -2.9% per year (P = 0.0001). Restrictive and obstructive abnormalities were observed in 57% (20/35) and 39% (14/36), respectively. Computed tomography imaging revealed pulmonary thin-walled cavities (lung cysts) in 28% (9/32) of patients and metastatic lung disease in 34% (11/32) of patients; patients with metastatic lung lesions also tended to have thin-walled cavities (P = 0.035).

CONCLUSIONS

This study characterized pulmonary function within a MEN2B cohort. Diffusion, restrictive, and obstructive abnormalities were evident, and lung cysts were present in 28% of patients. Further research is required to determine the mechanism of the atypical pulmonary features observed in this cohort.

Abstract 13: Clinical trial outcomes for cancer drug combinations can be predicted using cancer cell line monotherapy screens and a model of independent drug action

Drug combinations are a cornerstone of cancer therapy; however, the vast number of possible drug combinations makes it infeasible to experimentally evaluate all of these possibilities when identifying new therapies. For example, testing all possible 4-drug combinations for 200 compounds in 100 cell lines would require more than 6 billion experiments. To solve this problem, efforts have been made to develop computational models capable of accurately predicting drug combination efficacy without the need to experimentally test all of them. While these models have traditionally aimed to predict drug synergy, recent evidence has emerged suggesting that many cancer drug combinations may derive their efficacy from independent drug action (IDA), where patients only receive benefit from the single most effective drug in a drug combination. In light of these findings, we developed IDACombo, a computational method that uses IDA to predict the efficacy of drug combinations based on monotherapy data from high-throughput cancer cell line drug screens. We have demonstrated that IDACombo predictions closely agree with measured drug combination efficacies both in vitro (Pearson’s correlation = 0.94 when comparing predicted efficacies to measured efficacies for &gt;5,000 combinations) and in a systematically selected set of clinical trials (accuracy &gt;88% for predicting progression-free survival/time to progression or overall survival benefit in 26 first-line therapy trials). This work provides a framework for translating monotherapy cell line screening data into clinically meaningful efficacy predictions for hundreds of thousands of 2-drug combinations and millions of combinations of 3 or more drugs.

Citation Format: Alexander Ling, R. Stephanie Huang. Clinical trial outcomes for cancer drug combinations can be predicted using cancer cell line monotherapy screens and a model of independent drug action [abstract]. In: Proceedings of the AACR Special Conference on Advancing Precision Medicine Drug Development: Incorporation of Real-World Data and Other Novel Strategies; Jan 9-12, 2020; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(12_Suppl_1):Abstract nr 13.

18F-FDG PET Assessment of Malignant Pleural Mesothelioma: Total Lesion Volume and Total Lesion Glycolysis-The Central Role of Volume

Cancer survival is related to tumor volume. ¹⁸F-FDG PET measurement of tumor volume holds promise but is not yet a clinical tool. Measurements come in 2 forms: the first is total lesion volume (TLV) based on the number of voxels in the tumor, and the second is total lesion glycolysis (TLG), which is the TLV multiplied by the average SUL (i.e., SUV normalized for lean mass) of the tumor (SUL_average). In this study, we measured tumor volume in patients with malignant pleural mesothelioma (MPM). Methods: A threshold-based program in Interactive Data Language was developed to measure tumor volume in ¹⁸F-FDG PET images. Nineteen patients with MPM were studied before and after 2 cycles (6 wk) of chemoimmunotherapy. Measurements included TLV, TLG, the sum of the SULs in the tumor (SUL_total, a measure of total ¹⁸F-FDG uptake), and SUL_average Results: Baseline TLV ranged from 11 to 2,610 cm³ TLG ranged from 32 to 8,552 cm³ g/mL and correlated strongly with TLV. Although tumor volumes ranged over 3 orders of magnitude, SUL_average stayed within a narrow range of 2.4-5.3 units. Thus, TLV was the major component of TLG, whereas SUL_average was a minor component and was essentially constant. Further evaluation of SUL_average showed that in this cohort its 2 components, SUL_total and TLV, changed in parallel and were strongly correlated (r = 0.99, P < 0.01). Thus, whether the tumors were large or small, ¹⁸F-FDG uptake as measured by SUL_total was proportional to the TLV. Conclusion: TLG equals TLV multiplied by SUL_average, essentially TLV multiplied by a constant. Thus TLG, commonly considered a measure of metabolic activity in tumors, is also in this cohort a measure of tumor volume. The constancy of SUL_average is due to the fact that ¹⁸F-FDG uptake is proportional to tumor volume. Thus, in this study, ¹⁸F-FDG uptake was also a measure of volume.

Role of 68Ga-DOTATATE PET/CT in a Case of SDHB-Related Pterygopalatine Fossa Paraganglioma Successfully Controlled with Octreotide

We describe an unusual case of a 42-year-old female with an unresectable succinate dehydrogenase subunit B (SDHB)-related pterygopalatine fossa paraganglioma. She underwent somatostatin receptor imaging with ⁶⁸Ga-DOTA(0)-Tyr(3)-octreotate (⁶⁸Ga-DOTATATE) positron emission tomography/computed tomography (PET/CT), which showed uptake in the above mentioned tumor. Hence, the patient was started on octreotide, a cold somatostatin analog, and responded with tumor stabilization and improvement of clinical symptoms for 36 months since initiation of octreotide therapy. This case demonstrates the role of ⁶⁸Ga-DOTATATE PET/CT in diagnostic localization and its subsequent role in treatment using cold somatostatin analog as a potential choice of therapy in the management of paraganglioma in an unusual location with limited therapeutic options.

Enhancing SPDC brightness using elliptical pump shapes

We report on the use of elliptical pump spatial modes to increase the observed brightness of spontaneous parametric downconversion in critically phase-matched crystals. Simulations qualitatively predict this improvement, which depends on the eccentricity and orientation of the pump ellipse. We experimentally confirm a factor of two improvement in brightness when compared to the traditional circular-symmetric pump spatial modes. These results support previous theoretical work that proposes the use of elliptical pump modes to enhance the performance of parametric processes in anisotropic materials.

Abstract 5097: Clinical trial outcomes for drug combination therapies can be predicted by modeling independent action using cancer cell line screens

Background:

In many cancer settings, it is evident that combination drug therapies show increased efficacy compared to monotherapies. However, the development of new combination therapies is slowed by the fact that it is infeasible to experimentally evaluate the vast number of possible drug combinations. In an effort to overcome this problem, we developed a computational method which uses monotherapy screening data in cell lines to estimate the efficacy of combinations of two or more chemotherapy drugs. When validated against published phase 3 clinical cancer trial results, our method is capable of predicting clinical trial success or failure with a high degree of sensitivity and specificity.

Methods and Results:

We processed existing high-throughput in vitro drug screening datasets (i.e. GDSC and CTRPv2) to obtain fitted dose response curves for more than 600,000 drug-cell line pairs, including data for 695 unique compounds and 1347 unique cell lines. We then used this dataset to develop a method of estimating the efficacy of combinations of two or more drugs. While previous efforts to predict drug combination efficacy have largely focused on dose-agnostic estimates of drug synergy, we modeled dose-dependent estimates of independent drug action, where each patient treated with a drug combination only derives benefit from the single drug in the combination to which they are most sensitive. For method validation, we systematically searched clinicaltrials.gov to identify completed, phase 3 cancer clinical trials that evaluated drug combinations for which we could estimate efficacy and which had at least 50 patients per trial arm. Of the &gt;9,000 clinical trials considered, 37 trials (11 successful and 26 unsuccessful) met our inclusion criteria.

Using clinically determined plasma concentrations for each drug, we then predicted relative efficacy for each of the experimental drug combinations versus the control group therapies in these trials. These predictions were clustered into two groups (predicted high benefit vs low benefit) using k-means clustering, and these clusters were compared to whether or not the clinical trials were considered a success by the original study investigators. Our method correctly classified 84% of the trials, with a sensitivity of 73% and a specificity of 88%. Furthermore, efficacy predictions for combinations containing erlotinib were dependent on EGFR mutation status, suggesting that this method may be useful for identifying molecular subtypes which are sensitive to a given combination therapy.

Conclusion:

Clinically meaningful predictions of drug combination efficacy can be generated from single-agent, in vitro drug screens under the assumption of independent drug action. This enables efficacy predictions to be made for &gt;150,000 2-drug combinations and millions of 3- and 4-drug combinations using the existing GDSC and CTRPv2 datasets.

Citation Format: Alexander Ling, R. Stephanie Huang. Clinical trial outcomes for drug combination therapies can be predicted by modeling independent action using cancer cell line screens [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5097.

Manipulation and measurement of quantum states with liquid crystal devices

We present the use of liquid crystal retarders (LCR) as phase control elements in optical quantum technologies. We show that an entangled photon pair state can be actively controlled using an LCR without introducing state mixing or polarization drifts. Similarly, we demonstrate that the entanglement quality can be conveniently analyzed using liquid crystal polarization retarders.

Satellite Quantum Communications When Man-in-the-Middle Attacks Are Excluded

An application of quantum communications is the transmission of qubits to create shared symmetric encryption keys in a process called quantum key distribution (QKD). Contrary to public-private key encryption, symmetric encryption is considered safe from (quantum) computing attacks, i.e. it provides forward security and is thus attractive for secure communications. In this paper we argue that for free-space quantum communications, especially with satellites, if one assumes that man-in-the-middle attacks can be detected by classical channel monitoring techniques, simplified quantum communications protocols and hardware systems can be implemented that offer improved key rates. We term these protocols photon key distribution (PKD) to differentiate them from the standard QKD protocols. We identify three types of photon sources and calculate asymptotic secret key rates for PKD protocols and compare them to their QKD counterparts. PKD protocols use only one measurement basis which we show roughly doubles the key rates. Furthermore, with the relaxed security assumptions one can establish keys at very high losses, in contrast to QKD where at the same losses privacy amplification would make key generation impossible.

Clinical, Diagnostic, and Treatment Characteristics of SDHA-Related Metastatic Pheochromocytoma and Paraganglioma

Background: Pheochromocytoma and paraganglioma (PHEO/PGL) are rare neuroendocrine tumors which may cause potentially life-threatening complications, with about a third of cases found to harbor specific gene mutations. Thus, early diagnosis, treatment, and meticulous monitoring are of utmost importance. Because of low incidence of succinate dehydrogenase complex subunit A (SDHA)-related metastatic PHEO/PGL, currently there exists insufficient clinical information, especially with regards to its diagnostic and treatment characteristics.

Methods: Ten patients with SDHA-related metastatic PHEO/PGL were followed-up prospectively and/or retrospectively between January 2010–July 2018. They underwent biochemical tests (n = 10), ¹²³I-MIBG (n = 9) scintigraphy, and multiple whole-body positron emission tomography/computed tomography (PET/CT) scans with ⁶⁸Ga-DOTATATE (n = 10), ¹⁸F-FDG (n = 10), and ¹⁸F-FDOPA (n = 6).

Results: Our findings suggest that these tumors can occur early and at extra-adrenal locations, behave aggressively, and have a tendency to develop metastatic disease within a short period of time. None of our patients had a family history of PHEO/PGL, making them appear sporadic. Nine out of 10 patients showed abnormal PHEO/PGL-specific biochemical markers with predominantly noradrenergic and/or dopaminergic phenotype, suggesting their utility in diagnosing and monitoring the disease. Per patient detection rates of ⁶⁸Ga-DOTATATE (n = 10/10), ¹⁸F-FDG (n = 10/10), ¹⁸F-FDOPA (n = 5/6) PET/CT, and ¹²³I-MIBG (n = 7/9) scintigraphy were 100, 100, 83.33, and 77.77%, respectively. Five out of 7 ¹²³I-MIBG positive patients had minimal ¹²³I-MIBG avidity or detected very few lesions compared to widespread metastatic disease on ¹⁸F-FDG PET/CT, implying that diagnosis and treatment with ^123/131I-MIBG is not a good option. ⁶⁸Ga-DOTATATE PET/CT was found to be superior or equal to ¹⁸F-FDG PET/CT in 7 out of 10 patients and hence, is recommended for evaluation and follow-up of these patients. All 7 out of 7 patients who received conventional therapies (chemotherapy, somatostatin analog therapy, radiation therapy, ¹³¹I-MIBG, peptide receptor radionuclide therapy) in addition to surgery showed disease progression.

Conclusion: In our cohort of patients, SDHA-related metastatic PHEO/PGL followed a disease-course similar to that of SDHB-related metastatic PHEO/PGL, showing highly aggressive behavior, similar imaging and biochemical phenotypes, and suboptimal response to conventional therapies. Therefore, we recommend careful surveillance of the affected patients and a search for effective therapies.

Gallbladder Paraganglioma Associated with SDHD Mutation: a Potential Pitfall on 18F-FDOPA PET Imaging

A 36-year-old male patient initially presented with hypertension, tinnitus, bilateral carotid masses, a right jugular foramen, and a periaortic arch mass with an elevated plasma dopamine level but an otherwise normal biochemical profile. On surveillance MRI 4 years after initial presentation, he was found to have a 2.2-cm T2 hyperintense lesion with arterial enhancement adjacent to the gallbladder, which demonstrated avidity on ⁶⁸Ga-DOTATATE PET/CT and retrospectively on ¹⁸F-FDOPA PET/CT but was non-avid on ¹⁸F-FDG PET/CT. Biochemical work-up including plasma catecholamines, metanephrines, and chromogranin A levels were found to be within normal limits. This lesion was surgically resected and was confirmed to be a paraganglioma (PGL) originating from the gallbladder wall on histopathology. Pheochromocytoma (PHEO) and PGL are rare tumors of the autonomic nervous system. Succinate dehydrogenase subunit D (SDHD) pathogenic variants of the succinate dehydrogenase complex are usually involved in parasympathetic, extra-adrenal, multifocal head, and neck PGLs. We report an unusual location of PGL in the gallbladder associated with SDHD mutation which could present as a potential pitfall on ¹⁸F-FDOPA PET/CT as its normal excretion occurs through biliary system and gallbladder. This case highlights the superiority of ⁶⁸Ga-DOTATATE in comparison to ¹⁸F-FDOPA and ¹⁸F-FDG in the detection of SDHD-related parasympathetic PGL. ClinicalTrials.gov Identifier: NCT00004847.

Structural renal abnormalities in the DICER1 syndrome: a family-based cohort study

BACKGROUND

The DICER1 syndrome is a tumor-predisposition disorder caused by germline pathogenic variation in DICER1 and is associated with cystic nephroma and other renal neoplasms. Dicer1 mouse and rare human DICER1 syndrome case reports describe structural kidney and collecting system anomalies. We investigated renal function and the frequency of structural abnormalities of the kidney and collecting system in individuals with germline loss-of-function variants in DICER1.

METHODS

In this family-based cohort study, prospectively ascertained germline DICER1-mutation carriers (DICER1-carriers) and unaffected family controls were evaluated at the National Institutes of Health Clinical Center with renal ultrasound and comprehensive laboratory testing. Two radiologists reviewed the imaging studies from all participants for structural abnormalities, cysts, and tumors.

RESULTS

Eighty-nine DICER1-carriers and 61 family controls were studied. Renal cysts were detected in 1/33 DICER1-carrier children without history of cystic nephroma. Similar proportions of adult DICER1-carriers (8/48; 17%) and controls (11/50; 22%) had ultrasound-detected renal cysts (P = 0.504). 8/89 (9%) DICER1-carriers harbored ultrasound-detected structural abnormalities of varying severity within the collecting system or kidney, nephrolithiasis, or nephrocalcinosis. None of the family controls (0/61) had similar findings on ultrasound (P = 0.02). No meaningful differences in renal laboratory values between DICER1-carriers and unaffected family controls were observed.

CONCLUSIONS

Our report is the first to systematically characterize renal function and anatomy in a large prospective cohort of DICER1-carriers and DICER1-negative family controls. DICER1-carriers may be at increased risk of structural anomalies of the kidney or collecting system. The role for DICER1 in renal morphogenesis merits additional investigation.

More than fishing for a cure: The promises and pitfalls of high throughput cancer cell line screens

High-throughput screens in cancer cell lines (CCLs) have been used for decades to help researchers identify compounds with the potential to improve the treatment of cancer and, more recently, to identify genomic susceptibilities in cancer via genome-wide shRNA and CRISPR/Cas9 screens. Additionally, rich genomic and transcriptomic data of these CCLs has allowed researchers to pair this screening data with biological features, enabling efforts to identify biomarkers of treatment response and gene dependencies. In this paper, we review the major CCL screening efforts and the large datasets these screens have made available. We also assess the CCL screens collectively and include a resource with harmonized CCL and compound identifiers to facilitate comparisons across screens. The CCLs in these screens were found to represent a wide range of cancer types, with a strong correlation between the representation of a cancer type and its associated mortality. Patient ages and gender distributions of CCLs were generally as expected, with some notable exceptions of female underrepresentation in certain disease types. Also, ethnicity information, while largely incomplete, suggests that African American and Hispanic patients may be severely underrepresented in these screens. Nearly all genes were targeted in the genetic perturbations screens, but the compounds used for the drug screens target less than half of known cancer drivers, likely reflecting known limitations in our drug design capabilities. Finally, we discuss recent developments in the field and the promise they hold for enabling future screens to overcome previous limitations and lead to new breakthroughs in cancer treatment.

Characterization of the hepatosplenic and portal venous findings in patients with Proteus syndrome

Proteus syndrome (PS) is a rare disorder caused by a mosaic AKT1 variant that comprises patchy overgrowth of tissues derived from all three germinal layers affecting multiple viscera. We sought to delineate the extent of hepatoportal manifestations in patients with PS. We identified patients with PS who had abdominal imaging from 1989 to 2015 in a natural history study. Imaging was characterized for evidence of focal findings in the liver, spleen, and portal vasculature and for organomegaly. Relevant clinical and laboratory data were compared among those with or without organomegaly. Abdominal imaging was available on 38 patients including 20 who had serial studies. Nine patients had focal hepatic lesions including vascular malformations (VMs). Focal splenic abnormalities were noted in seven patients. Patients without cutaneous VMs did not have visceral VMs. Nine patients had splenomegaly, 12 had portal vein dilation, and 4 had hepatomegaly. There was a weak correlation of portal vein dilation to spleen height ratio (r² = 0.18, p < .05). On laboratory evaluation, hepatic function was normal but there was thrombocytopenia in those with splenomegaly; platelet counts were 179 ± 87K/μL compared to those with normal spleen size at 253 ± 57K/μL (p < .05). Overall, focal hepatosplenic abnormalities occurred in 11 of 38 (29%) patients with PS. Splenomegaly and portal venous dilation were both found in 8 of 38 (21%) patients; however, other than relative thrombocytopenia, there was no evidence of portal hypertension. Although the AKT1-E17K somatic variant is a suspected oncogene, there were no malignant lesions identified in this study.

Long-term use of continuous subcutaneous hydrocortisone infusion therapy in patients with congenital adrenal hyperplasia

BACKGROUND

In a phase 2 short-term (6 months) study of patients with congenital adrenal hyperplasia (CAH), continuous subcutaneous hydrocortisone infusion (CSHI) was found to be a safe, effective and well-tolerated method of replacing cortisol with improved disease and patient-related outcomes.

OBJECTIVE

To evaluate the safety and efficacy of long-term CSHI.

DESIGN

Single-centre, open-label, phase 2 extension study.

PATIENTS

Five adults with classic CAH.

MEASUREMENTS

Biomarkers of disease control, metabolic indices and health-related quality-of-life (HRQoL) estimates.

RESULTS

Six of eight patients chose to continue on long-term CSHI therapy. Compared to baseline, eighteen months of CSHI resulted in decreased (P = 0.043) 0700-hour ACTH, 17-hydroxyprogesterone, androstenedione and progesterone; increased whole-body lean mass (P = 0.024); and improved HRQoL, especially symptoms of adrenal insufficiency (P = 0.003). Findings at six and eighteen months did not differ, and improvements achieved in androgen control, lean body mass and HRQoL after 6 months of CSHI were maintained at eighteen months. The hydrocortisone dose appeared to decrease with time [6 vs 18 months: 38.3 ± 8.8 vs 33.6 ± 12.2 mg/day (P = 0.062)], especially in women receiving oral contraceptives. Reduction of testicular adrenal rest and adrenal size observed at 6 months remained stable. In one patient, an adrenal adenoma continually decreased over time. Subjective improvement in hirsutism was reported.

CONCLUSIONS

Long-term use of CSHI is a safe and well-tolerated treatment option in a select set of adults with classic CAH. Improvements observed short term in disease control and subjective health status continued long term.

Achalasia in a Patient Undergoing Hematologic Stem Cell Transplant After Exposure to Tacrolimus

Calcineurin inhibitors (CNIs) are effective agents used for prevention of graft-vs-host disease after allogeneic hematopoietic stem cell transplant or for organ rejection in solid-organ transplant. However, CNIs have a wide range of adverse effects that may necessitate changing to another CNI or immunosuppressive agent. We report a case of acute myeloid leukemia in which achalasia developed after exposure to tacrolimus, as revealed by esophagram results. The patient's symptoms and signs were ameliorated after a change to cyclosporine. This case is the first in the literature to reveal achalasia associated with tacrolimus. Achalasia should be part of a differential diagnosis of upper gastrointestinal symptoms in patients undergoing transplant, and changing to another CNI may be a useful therapeutic intervention.

Impaired Bone Mineral Density in Pediatric Patients with Chronic Graft-versus-Host Disease

Pediatric allogeneic hematopoietic stem cell transplantation (AHSCT) recipients with chronic graft-versus-host disease (cGVHD) are at high risk for endocrinopathies, particularly impaired bone mineral density (BMD). However, rates of BMD impairment in pediatric AHSCT recipients with cGVHD have not been well documented. We report 33 patients with cGVHD who were referred to the National Institutes of Health (NIH) for the Natural History of Clinical and Biological Factors Determining Outcomes in Chronic Graft-versus-Host Disease Study (NCT 0092235) and underwent formal BMD assessment via dual-energy X-ray absorptiometry (DEXA). Not surprisingly, we found much higher rates of BMD impairment than previously reported for pediatric AHSCT recipients who were not stratified by the presence or absence of cGVHD. Most of these patients (73%) had a z-score ≤-2 in at least 1 anatomic site. Although we expected the rate to be higher than that observed for pediatric AHSCT recipients in studies that did not analyze patients with cGVHD separately, this rate is nonetheless extremely high. Furthermore, the overall rate of occult vertebral compression fractures (VCFs) in our cohort was 17%, and the rate was 23% in patients with at least 1 z-score of ≤-2. The rates of BMD impairment and VCF in our pediatric cohort were significantly higher than those seen in the adult AHSCT recipients who were concurrently enrolled on the same study at the NIH and had similar cGVHD severity. We found that older age at cGVHD diagnosis and a greater number of systemic therapies were associated with occult VCF. Moreover, the intensity of current immunosuppression negatively impacted lumbar spine and total hip BMD in this cohort. Our study, although limited by small patient numbers and lack of a control AHSCT recipient group without cGVHD, indicates that children with cGVHD are at a greater risk for BMD impairment than previously appreciated. Given the rising incidence of cGVHD in AHSCT recipients and our findings, we recommend that pre-AHSCT DEXA be incorporated into routine pediatric pretransplantation screening studies. A baseline DEXA study could facilitate longitudinal monitoring of BMD in children, who may be more susceptible than adults to the negative effects of AHSCT on BMD. In addition, given the high risk of BMD impairment in pediatric AHSCT recipients with cGVHD, such patients should undergo BMD evaluation upon developing cGVHD, with continued monitoring thereafter to allow intervention before progression of the BMD impairment to its severe manifestation, VCF.

Experimental entangled photon pair generation using crystals with parallel optical axes

We present an optical design where polarization-entangled photon pairs are generated within two β-Barium Borate crystals whose optical axes are parallel. This design increases the spatial mode overlap of the emitted photon pairs enhancing single mode collection without the need for additional spatial walk-off compensators. The observed photon pair rate is at least 65 000 pairs/s/mW with a quantum state fidelity of 99.53 ± 0.22% when pumped with an elliptical spatial profile.

18F-FDOPA PET/CT Imaging of MAX-Related Pheochromocytoma

CONTEXT

MYC-associated factor X (MAX) has been recently described as a new susceptibility pheochromocytoma (PHEO) gene with a total of ~40 reported cases. At present, no study has specifically described the functional imaging phenotype of MAX-related PHEO.

OBJECTIVE, PATIENTS, AND DESIGN

The objective of the present study was to present our experience with contrast-enhanced computed tomography (CT) and 18F-fluorodihydroxyphenylalanine (18F-FDOPA) positron emission tomography (PET)/CT in six consecutive patients (four at the initial diagnosis and two at the follow-up evaluation) with rare, but clinically important, MAX-related PHEOs. In five patients, 18F-FDOPA was also compared with other radiopharmaceutical agents.

RESULTS

The patients had five different mutations in the MAX gene that caused disruption of Max/Myc interaction and/or abolished interaction with DNA based on in silico analyses. All but one patient developed bilateral PHEOs during their lifetime. In all cases, 18F-FDOPA PET/CT accurately visualized PHEOs that were often multiple within the same gland or bilaterally and detected more adrenal and extra-adrenal lesions than did CT (per-lesion sensitivity, 90.9% vs 52.4% for CT/magnetic resonance imaging). The two PHEOs missed on 18F-FDOPA PET/CT were <1 cm, corresponding to nodular adrenomedullary hyperplasia. 68Ga-DOTA,Tyr3-octreotate PET/CT detected fewer lesions than did 18F-FDOPA PET/CT in one of three patients, and 18F-fluorodeoxyglucose PET/CT was only faintly positive in two of four patients with underestimation of extra-adrenal lesions in one patient.

CONCLUSIONS

MAX-related PHEOs exhibit a marked 18F-FDOPA uptake, a finding that illustrates the common well-differentiated chromaffin pattern of PHEOs associated with activation of kinase signaling pathways. 18F-FDOPA PET/CT should be considered as the first-line functional imaging modality for diagnostic or follow-up evaluations for these patients.

Breakdown flash at telecom wavelengths in InGaAs avalanche photodiodes

Quantum key distribution (QKD) at telecom wavelengths (1260 - 1625 nm) has the potential for fast deployment due to existing optical fibre infrastructure and mature telecom technologies. At these wavelengths, Indium Gallium Arsenide (InGaAs) avalanche photodiode (APD) based detectors are the preferred choice for photon detection. Similar to their Silicon counterparts used at shorter wavelengths, they exhibit fluorescence from recombination of electron-hole pairs generated in the avalanche breakdown process. This fluorescence may open side channels for attacks on QKD systems. Here, we characterize the breakdown fluorescence from two commercial InGaAs single photon counting modules, and find a spectral distribution between 1000 nm and 1600 nm. We also show that by spectral filtering, this side channel can be efficiently suppressed.

Tracking capacitance of liquid crystal devices to improve polarization rotation accuracy

We report a capacitance tracking method for achieving arbitrary polarization rotation from nematic liquid crystals. By locking to the unique capacitance associated with the molecular orientation, any polarization rotation can be achieved with improved accuracy over a wide temperature range. A modified relaxation oscillator circuit that can simultaneously determine the capacitance and drive the rotator is presented.