Accuracy and interrater reliability for the diagnosis of Barrett's neoplasia among users of a novel, portable high-resolution microendoscope

The high-resolution microendoscope (HRME) is a novel imaging modality that may be useful in the surveillance of Barrett's esophagus in low-resource or community-based settings. In order to assess accuracy and interrater reliability of microendoscopists in identifying Barrett's-associated neoplasia using HRME images, we recruited 20 gastroenterologists with no microendoscopic experience and three expert microendoscopists in a large academic hospital in New York City to interpret HRME images. They prospectively reviewed 40 HRME images from 28 consecutive patients undergoing surveillance for metaplasia and low-grade dysplasia and/or evaluation for high-grade dysplasia or cancer. Images were reviewed in a blinded fashion, after a 4-minute training with 11 representative images. All imaged sites were biopsied and interpreted by an expert pathologist. Sensitivity of all endoscopists for identification of high-grade dysplasia or cancer was 0.90 (95% confidence interval [CI]: 0.88-0.92) and specificity was 0.82 (95% CI: 0.79-0.85). Positive and negative predictive values were 0.72 (95% CI: 0.68-0.77) and 0.94 (95% CI: 0.92-0.96), respectively. No significant differences in accuracy were observed between experts and novices (0.90 vs. 0.84). The kappa statistic for all raters was 0.56 (95% CI: 0.54-0.58), and the difference between groups was not significant (0.64 vs. 0.55). These data suggest that gastroenterologists can diagnose Barrett's-related neoplasia on HRME images with high sensitivity and specificity, without the aid of prior microendoscopy experience.

Thyroid hormone modulates food intake and glycemia via ghrelin secretion in Zucker fatty rats

Hyperthyroidism is known to increase food intake and central administration of thyroid hormone shows acute orexigenic effects in rodents. We investigated whether T3 influences appetite and glucose homeostasis by modulating circulating ghrelin, an important orexigenic hormone, in Zucker fatty rats. The acute anorectic effects of T3 and ghrelin mimetic MK-0677 were studied in rats trained for fasting induced food intake. The serum concentration of T3, ghrelin, glucose, triglycerides, and liver glycogen were estimated. The involvement of sympathetic nervous system was evaluated by conducting similar experiments in vagotomized rats. T3 increased food intake and glucose in rats over 4 h, with increase in serum T3 and decrease in liver glycogen. T3 treatment was associated with increase in serum ghrelin. An additive effect on appetite and glucose was observed when T3 (oral) was administered with central (intracerebroventricular) administration of a ghrelin mimetic, MK-0677. Ghrelin antagonist, compound 8a, antagonized the hyperglycemic and hyperphagic effects of T3. In vagotomized rats, T3 did not show increase in appetite as well as glucose. Serum ghrelin levels were unchanged in these animals after T3 treatment. However, T3 showed increase in serum triglyceride levels indicating its peripheral lipolytic effect, in vagotomized as well as sham treated animals. To conclude, acute orexigenic and hyperglycemic effects of T3 are associated with ghrelin secretion and activity. This effect seems to be mediated via vagus nerves, and is independent of glucoregulatory hormones.

Abstract P1-02-05: Identification of HER-2/neu amplification using amplicon based benchtop next generation sequencing

Introduction

Aplicon based next generation sequencing (NGS) assays have the potential to incorporate simultaneous assessment of somatic mutations and copy number variation into a single platform. Although not specifically designed for this purpose, we noted numerous examples of apparent HER-2/neu gene amplification in analyzing results from our mutation profiling 46-gene cancer NGS panel (Life Technologies, South San Francisco, CA).

Material and Methods

Existing amplicon coverage data from the TorrentSuite 2.0 (Life Technologies) pipeline was accessed and used to generate a HER-2/neu coverage proportion (ratio between all HER-2/neu amplicon reads and all other amplicon reads). This ratio was calculated for 170 unique cases of breast carcinoma. A total of 4 cases were eliminated from analysis due to indeterminate IHC/FISH results. Using a total of 166 cases, we performed ROC curve analysis to determine the sensitivity and specificity of NGS based HER-2/neu amplification compared to that of traditional IHC and FISH testing (MedCalc v8.0).

Results

The NGS based HER-2/neu coverage proportions in the 166 cases showed a clearly non-normal distribution with an outlier cluster of cases with an elevated NGS HER-2/neu ratio (6 cases with ratios >0.045). The distribution of NGS based HER-2/neu ratios for the entire population ranged from 0.01 to a maximum of 0.34. ROC curve analysis of NGS HER-2/neu proportions compared to IHC/FISH data showed a maximal sensitivity of 75.0% and specificity of 100% at an NGS ratio cut off of ≥0.045.

In the 166 cases, 6 showed a HER-2/neu coverage proportion of > 0.045 (range 0.045-0.34). Utilizing the 0.045 NGS ratio cut off value, the population frequency of cases positive for HER2 expression was 3.4%. Of the 160 samples with NGS coverage proportion < 0.045, only two cases were positive by IHC/FISH testing.

The correlation between NGS HER-2/neu coverage proportion and IHC/FISH testing was highly significant (Spearman rank correlation r = 0.67, p < 0.0001 CI: 0.58-0.75).

Conclusions

Even utilizing a limited somatic cancer panel that includes less than 200 amplicons in 46 genes, clinically significant HER-2/neu amplification can be readily identified. This is the first study to describe the functional utility of HER-2/neu amplification detection using a NGS based amplicon assay. This study shows that in addition to mutation analysis, amplification data can be simultaneously obtained, which has striking implications for potential clinical utility and HER-2/neu amplification detection outside of traditional IHC and HER2 testing modalities. Furthermore, utilizing this assay as a primary screening modality could limit the additional expense of multiple single gene testing.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-02-05.

Abstract P2-12-09: Developing clinical sequencing assays at Einstein-Montefiore

The Department of Genetics in collaboration with a group of Montefiore's clinicians initiated the development of clinical sequencing tests with the final goal to incrementally build clinical sequencing assays to improve clinical care in the Bronx. The use of next generation sequencing is particularly relevant for cancer biology since the heterogeneity of cancer requires deep sequencing and high read depth, which prior to recent advances in technology was expensive and labor intensive.

We designed a custom gene panel for target sequencing using the Illumina HiSeq 2500 consisting of 650 genes for multiple disorders and diseases, including various cancers, in addition to rare and complex mendelian disorders. We sequenced 17 samples, including a tumor-normal breast cancer pair, where we identified a novel, pathogenic stop variant in the highly mutated TP53 tumor suppressor gene. In addition to our custom target panel, we sequenced this sample pair on two additional cancer panels (AmpliSeq Cancer Hotspot and the Comprehensive Cancer Panel using the Ion Torrent Technology) and performed Whole Exome Sequencing (WES) to ensure the sensitivity and specificity of our custom panel. This variant was detected on all platforms.

We found targeted capture high-throughput sequencing to be a cost effective, time sensitive and efficient approach in detecting pathogenic variants to aid diagnosis of individuals affected by cancer or mendelian disorders. We are currently receiving samples to sequence and plan to expand our program to various groups within the Einstein-Montefiore community. Using a personalized medicine approach we expect to detect biomarkers and prospective targets to develop an accurate and effective treatment plan for these individuals.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-12-09.

The novel CXCR4 antagonist POL5551 mobilizes hematopoietic stem and progenitor cells with greater efficiency than Plerixafor

Mobilized blood has supplanted bone marrow (BM) as the primary source of hematopoietic stem cells for autologous and allogeneic stem cell transplantation. Pharmacologically enforced egress of hematopoietic stem cells from BM, or mobilization, has been achieved by directly or indirectly targeting the CXCL12/CXCR4 axis. Shortcomings of the standard mobilizing agent, granulocyte colony-stimulating factor (G-CSF), administered alone or in combination with the only approved CXCR4 antagonist, Plerixafor, continue to fuel the quest for new mobilizing agents. Using Protein Epitope Mimetics technology, a novel peptidic CXCR4 antagonist, POL5551, was developed. In vitro data presented herein indicate high affinity to and specificity for CXCR4. POL5551 exhibited rapid mobilization kinetics and unprecedented efficiency in C57BL/6 mice, exceeding that of Plerixafor and at higher doses also of G-CSF. POL5551-mobilized stem cells demonstrated adequate transplantation properties. In contrast to G-CSF, POL5551 did not induce major morphological changes in the BM of mice. Moreover, we provide evidence of direct POL5551 binding to hematopoietic stem and progenitor cells (HSPCs) in vivo, strengthening the hypothesis that CXCR4 antagonists mediate mobilization by direct targeting of HSPCs. In summary, POL5551 is a potent mobilizing agent for HSPCs in mice with promising therapeutic potential if these data can be corroborated in humans.

Glucose-6-phosphate-mediated activation of liver glycogen synthase plays a key role in hepatic glycogen synthesis

The liver responds to an increase in blood glucose levels in the postprandial state by uptake of glucose and conversion to glycogen. Liver glycogen synthase (GYS2), a key enzyme in glycogen synthesis, is controlled by a complex interplay between the allosteric activator glucose-6-phosphate (G6P) and reversible phosphorylation through glycogen synthase kinase-3 and the glycogen-associated form of protein phosphatase 1. Here, we initially performed mutagenesis analysis and identified a key residue (Arg(582)) required for activation of GYS2 by G6P. We then used GYS2 Arg(582)Ala knockin (+/R582A) mice in which G6P-mediated GYS2 activation had been profoundly impaired (60-70%), while sparing regulation through reversible phosphorylation. R582A mutant-expressing hepatocytes showed significantly reduced glycogen synthesis with glucose and insulin or glucokinase activator, which resulted in channeling glucose/G6P toward glycolysis and lipid synthesis. GYS2(+/R582A) mice were modestly glucose intolerant and displayed significantly reduced glycogen accumulation with feeding or glucose load in vivo. These data show that G6P-mediated activation of GYS2 plays a key role in controlling glycogen synthesis and hepatic glucose-G6P flux control and thus whole-body glucose homeostasis.

Inosine triphosphatase deficiency helps predict anaemia, anaemia management and response in chronic hepatitis C therapy

Anaemia frequently complicates peginterferon/ribavirin therapy for chronic hepatitis C infection. Better prediction of anaemia, ribavirin dose reduction or erythropoietin (EPO) need, may enhance patient management. Inosine triphosphatase (ITPA) genetic variants are associated with ribavirin-induced anaemia and dose reduction; however, their impact in real-life clinic patient cohorts remains to be defined. We studied 193 clinic patients with chronic hepatitis C infection of mixed viral genotype (genotype 1/4 n = 123, genotype 2/3, n = 70) treated with peginterferon/ribavirin. Patients were genotyped for ITPA polymorphisms rs1127354 and rs7270101 using Taqman primers. Hardy-Weinberg equilibrium was present. Estimated ITPA deficiency was graded on severity (0-3, no deficiency/mild/moderate/severe, n = 126/40/24/3, respectively). Multivariable models tested the association with anaemia at 4 weeks of treatment [including decline in haemoglobin (g/dL); haemoglobin <10 g/dL and haemoglobin decline >3 g/dL]; ribavirin dose reduction and EPO use and explored sustained viral response (SVR) to peginterferon/ribavirin. More severe ITPA deficiency was associated with less reduction in haemoglobin level (P <0.001; R(2) = 0.34), less ribavirin dose reduction (OR 0.42; (95% CI = 0.23-0.77); P = 0.005) and less EPO use [OR 0.53; (0.30-0.94); P = 0.029]. ITPA deficiency was associated with SVR [OR: 1.70; (1.02-2.83); P = 0.041] independently of clinical covariates (adjusted R(2) = 0.31). In this clinical cohort, ITPA deficiency helped predict the risk of on-treatment anaemia, ribavirin dose reduction, need for EPO support and was associated with SVR. For patients on HCV regimens including peginterferon/ribavirin, testing for ITPA deficiency may have clinical utility.

Role of disrupted in schizophrenia 1 (DISC1) in stress-induced prefrontal cognitive dysfunction

Recent genetic studies have linked mental illness to alterations in disrupted in schizophrenia 1 (DISC1), a multifunctional scaffolding protein that regulates cyclic adenosine monophosphate (cAMP) signaling via interactions with phosphodiesterase 4 (PDE4). High levels of cAMP during stress exposure impair function of the prefrontal cortex (PFC), a region gravely afflicted in mental illness. As stress can aggravate mental illness, genetic insults to DISC1 may worsen symptoms by increasing cAMP levels. The current study examined whether viral knockdown (KD) of the Disc1 gene in rat PFC increases susceptibility to stress-induced PFC dysfunction. Rats were trained in a spatial working memory task before receiving infusions of (a) an active viral construct that knocked down Disc1 in PFC (DISC1 KD group), (b) a 'scrambled' construct that had no effect on Disc1 (Scrambled group), or (c) an active construct that reduced DISC1 expression dorsal to PFC (Anatomical Control group). Data were compared with an unoperated Control group. Cognitive performance was assessed following mild restraint stress that had no effect on normal animals. DISC1 KD rats were impaired by 1  h restraint stress, whereas Scrambled, Control, and Anatomical Control groups were unaffected. Thus, knocking down Disc1 in PFC reduced the threshold for stress-induced cognitive dysfunction, possibly through disinhibited cAMP signaling at neuronal network synapses. These findings may explain why patients with DISC1 mutations may be especially vulnerable to the effects of stress.

Shielding effectiveness measurements and uncertainty estimation for textiles by a VNA-based free space transmission method

A free-space transmission method has been used for reliable shielding effectiveness measurement of the easily available textile materials. Textiles with three different yarn densities were studied for their shielding effectiveness with the help of a vector network analyzer and laboratory calibrated two X-band horn antennas. The expressions of uncertainty estimation have been derived in accordance with the present free-space measurement setup for the calculated SE values. The measurements have shown that an electromagnetic energy can be maximum shielded up to 16.24 dB with measurement uncertainty less than 0.21 dB in 8.2 to 12.4 GHz range by a 160.85 μm textile. Thus, a thin textile with a high density can have higher shielding and this property mainly depends on its intrinsic structure, frequency range and thickness. This study promises the potential applications of such materials as a very cost effective shielding material at microwave frequencies with some modifications.

Body mass index as a predictive factor of periodontal therapy outcomes

Body mass index (BMI) and obesity are associated with the prevalence, extent, and severity of periodontitis. This study investigated the predictive role of overweight/obesity on clinical response following non-surgical periodontal therapy in patients with severe periodontitis. Two hundred sixty adults received an intensive course of non-surgical periodontal therapy. Periodontal status at baseline and 2 months was based upon probing pocket depths (PPD), clinical attachment levels (CAL), and whole-mouth gingival bleeding (FMBS) as assessed by two calibrated examiners. Generalized estimating equations (GEE) were used to estimate the impact of BMI and overweight/obesity on periodontal treatment response while controlling for baseline status, age, smoking status (smoker or non-smoker), and full-mouth dental plaque score. BMI (continuous variable) and obesity (vs. normal weight) were associated with worse mean PPD (p < .005), percentage of PPD > 4 mm (p = .01), but not with FMBS (p > .05) or CAL (p > .05) at 2 months, independent of age, smoking status, or dental plaque levels. The magnitude of this association was similar to that of smoking, which was also linked to a worse clinical periodontal outcome (p < .01). BMI and obesity appear to be independent predictors of poor response following non-surgical periodontal therapy.

The Role of Bystander Effects in the Antitumor Activity of the Hypoxia-Activated Prodrug PR-104

Activation of prodrugs in tumors (e.g., by bioreduction in hypoxic zones) has the potential to generate active metabolites that can diffuse within the tumor microenvironment. Such “bystander effects” may offset spatial heterogeneity in prodrug activation but the relative importance of this effect is not understood. Here, we quantify the contribution of bystander effects to antitumor activity for the first time, by developing a spatially resolved pharmacokinetic/pharmacodynamic (SR-PK/PD) model for PR-104, a phosphate ester pre-prodrug that is converted systemically to the hypoxia-activated prodrug PR-104A. Using Green’s function methods we calculated concentrations of oxygen, PR-104A and its active metabolites, and resultant cell killing, at each point of a mapped three-dimensional tumor microregion. Model parameters were determined in vitro, using single cell suspensions to determine relationships between PR-104A metabolism and clonogenic cell killing, and multicellular layer (MCL) cultures to measure tissue diffusion coefficients. LC-MS/MS detection of active metabolites in the extracellular medium following exposure of anoxic single cell suspensions and MCLs to PR-104A confirmed that metabolites can diffuse out of cells and through a tissue-like environment. The SR-PK/PD model estimated that bystander effects contribute 30 and 50% of PR-104 activity in SiHa and HCT116 tumors, respectively. Testing the model by modulating PR-104A-activating reductases and hypoxia in tumor xenografts showed overall clonogenic killing broadly consistent with model predictions. Overall, our data suggest that bystander effects are important in PR-104 antitumor activity, although their reach may be limited by macroregional heterogeneity in hypoxia and reductase expression in tumors. The reported computational and experimental techniques are broadly applicable to all targeted anticancer prodrugs and could be used to identify strategies for rational prodrug optimization.

Renal disease masquerading as pyrexia of unknown origin

Pyrexia of unknown origin is a challenging clinical problem. Infections, malignancies, and connective tissue diseases form the major etiologies for this condition. We report a case of a 57-year-old diabetic male who presented with fever of unknown origin for several months. The course of investigations led to a kidney biopsy which clinched the cause of his fever as well as the underlying diagnosis. The light microscopy findings of expansile storiform fibrosis with a dense inflammatory infiltrate suggested the diagnosis which was confirmed by positive staining of Immunoglobulin G4, the dense lympho-plasmacytic infiltrate and elevated serum IgG4 concentrations. A course of steroids followed by mycophenolate mofetil as maintenance immunosuppression rendered the patient afebrile with improvement of renal function.

Endoscopic ultrasound-guided fine needle aspiration training: evaluation of a new porcine lymphadenopathy model for in vivo hands-on teaching and training, and review of the literature

BACKGROUND AND STUDY AIMS

Adequate training is required to achieve successful endoscopic ultrasound (EUS)-guided fine-needle aspiration (EUS-FNA). Of the variety of training models currently available, none offers verisimilitude to the tactile feel of puncturing a human lymph node. The aim of the current study was to evaluate a new porcine lymph node model for EUS-FNA training and to evaluate its impact on trainees' performance in patients compared with the literature of other models available.

METHODS

Two trainees each performed EUS-FNA of 96 lymph nodes in 18 animals with induced lymphadenopathy (mean 1.6 cm [range 0.9-3.5 cm]). Accuracy, speed, adequacy of sampling, and trainees' performance pre- and post-training were measured. Using a questionnaire, data were gathered regarding the effect of training and comfort level in patients. Results were compared with those in the literature.

RESULTS

Trainees progressed from hands-on assistance to occasional verbal guidance toward the end of animal training. There was good correlation between puncture time and number of EUS-FNA procedures performed in all but the subcarinal location (r = - 0.17). Comparison of trainee performance in patients before and after training showed a reduction in puncture time (P = 0.0014). Questionnaire analysis revealed increased confidence in echoendoscope- and needle-handling. Comparison with other published models supports these results.

CONCLUSION

Results from the literature and the current study showed that animal training improves trainee performance, confidence, and procedural comfort when returning to patient examinations. The new model produces a realistic response that is similar to EUS-FNA in patients; this experience provides a benefit to endoscopists in terms of improved performance in patients and could be considered for use in accreditation. Due to the small numbers of trainees, larger experiences are needed to confirm training efficacy.

Signal-dependent fra-2 regulation in skeletal muscle reserve and satellite cells

Activator protein-1 (AP-1) is a ubiquitous transcription factor that paradoxically also has some tissue-specific functions. In skeletal muscle cells, we document that the AP-1 subunit, Fra-2, is expressed in the resident stem cells (Pax7-positive satellite cells) and also in the analogous undifferentiated ‘reserve' cell population in myogenic cultures, but not in differentiated myofiber nuclei. Silencing of Fra-2 expression enhances the expression of differentiation markers such as muscle creatine kinase and myosin heavy chain, indicating a possible role of Fra-2 in undifferentiated myogenic progenitor cells. We observed that Fra-2 is a target of cytokine-mediated extracellular signal-regulated kinase-1/2 signaling in cultured muscle cells, and extensive mass spectrometry and mutational analysis identified S320 and T322 as regulators of Fra-2 protein stability. Interestingly, Fra-2 S320 phosphorylation occurs transiently in activated satellite cells and is extinguished in myogenin-positive differentiating cells. Thus, cytokine-mediated Fra-2 expression and stabilization is linked to regulation of myogenic progenitor cells having implications for the molecular regulation of adult muscle stem cells and skeletal muscle regeneration.