Pre-Treatment Trends in Child-Pugh Score as an Indicator of Post-Treatment Survival in Patients Receiving Liver SBRT for HCC

PURPOSE/OBJECTIVE(S)

We sought to understand the value of Child-Pugh (CP) score trends prior to undergoing stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma in patients with advanced cirrhosis, as an indicator of post-treatment morbidity and mortality. We hypothesize that an uptrend in CP score prior to RT increases risk of post-treatment cirrhosis progression, or death.

MATERIALS/METHODS

We retrospectively reviewed all patients who underwent definitive SBRT for HCC between 2014-2022 in our health system. Most patients were referred for treatment in the 2nd or 3rd line setting, allowing us to determine CP score at multiple points before SBRT. Response to treatment was evaluated with RECIST or mRECIST criteria. Acute treatment toxicities were assessed by CTCAE v5. OS was assessed using the Kaplan-Meier method, and differences between groups were evaluated using log-rank test.

RESULTS

A total of 61 patients were identified, 26 had an immediate pre-SBRT CP score of A5, 11 with A6, 10 with B7, 4 with B8, 4 with B9, 5 with C10, and 1 with C11. Median prescribed dose was 40Gy in 5fx. Median OS of all patients was 24 months. When stratified by CP category, median OS for CP A was not reached (NR) at time of analysis, CP B had a median OS of 14.8mo, and CP C with 1.9mo (p < 0.01). Local control rate at 6mo was 87.5%. 5 patients (8.3%) had CTCAE grade 2 acute toxicity. 10 patients had CP score progression of 2pts or more within 6mo after treatment, and 7 patients had a cause of death attributed to end stage liver disease. Median time interval between HCC diagnosis and start of RT was 338 days. In this time interval, patients with a CP score increase of 2 pts or more prior to starting RT had a median OS of 362 days, compared to NR for patients without increase (p = 0.02). When excluding the CP A group, patients with 2 pt increase had median OS of 362 days vs 445 days (p = 0.34). Again excluding the CP A group, patients with a 1 pt increase had median OS of 362 days vs NR (p = 0.23). Of 9 patients who had a pre-RT CP score increase of 2 pts or more, 7 experienced continued CP progression after treatment.

CONCLUSION

In this multi-institutional retrospective analysis, we found 24 patients with advanced CP B/C cirrhosis who underwent SBRT, none of whom received orthotopic liver transplant. While CP C patients did relatively poorly, we find that some patients with CP B cirrhosis may tolerate SBRT well with good oncologic effect. When taking pre-treatment CP score increase into consideration, we saw a trend but no statistical significance indicating that a pre-SBRT increase in CP score may be associated with worse OS after treatment among CP B/C patients. We conclude that there may be a subset of patients with advanced cirrhosis who, if well selected, are appropriate candidates for SBRT. We suggest a novel use of the CP score and pre-RT trends as an additional clinical tool to aid in decision making when selecting patients. We also suggest that patients with marked up-trending scores pre-treatment have a high likelihood of continued cirrhosis progression after treatment.

Brain charts for the human lifespan

Over the past few decades, neuroimaging has become a ubiquitous tool in basic research and clinical studies of the human brain. However, no reference standards currently exist to quantify individual differences in neuroimaging metrics over time, in contrast to growth charts for anthropometric traits such as height and weight1. Here we assemble an interactive open resource to benchmark brain morphology derived from any current or future sample of MRI data ( http://www.brainchart.io/ ). With the goal of basing these reference charts on the largest and most inclusive dataset available, acknowledging limitations due to known biases of MRI studies relative to the diversity of the global population, we aggregated 123,984 MRI scans, across more than 100 primary studies, from 101,457 human participants between 115 days post-conception to 100 years of age. MRI metrics were quantified by centile scores, relative to non-linear trajectories2 of brain structural changes, and rates of change, over the lifespan. Brain charts identified previously unreported neurodevelopmental milestones3, showed high stability of individuals across longitudinal assessments, and demonstrated robustness to technical and methodological differences between primary studies. Centile scores showed increased heritability compared with non-centiled MRI phenotypes, and provided a standardized measure of atypical brain structure that revealed patterns of neuroanatomical variation across neurological and psychiatric disorders. In summary, brain charts are an essential step towards robust quantification of individual variation benchmarked to normative trajectories in multiple, commonly used neuroimaging phenotypes.

Profiling of Circulating Free DNA Using Targeted and Genome-wide Sequencing in Patients with SCLC

INTRODUCTION

SCLC accounts for approximately 250,000 deaths worldwide each year. Acquisition of adequate tumor biopsy samples is challenging, and liquid biopsies present an alternative option for patient stratification and response monitoring.

METHODS

We applied whole genome next-generation sequencing to circulating free DNA (cfDNA) from 39 patients with limited-stage (LS) SCLC and 30 patients with extensive-stage SCLC to establish genome-wide copy number aberrations and also performed targeted mutation analysis of 110 SCLC associated genes. Quantitative metrics were calculated for copy number aberrations, including percent genome amplified (PGA [the percentage of genomic regions amplified]), Z-score (a measure of standard deviation), and Moran's I (a measure of spatial autocorrelation). In addition CellSearch, an epitope-dependent enrichment platform, was used to enumerate circulating tumor cells (CTCs) from a parallel blood sample.

RESULTS

Genome-wide and targeted cfDNA sequencing data identified tumor-related changes in 94% of patients with LS SCLC and 100% of patients with extensive-stage SCLC. Parallel analysis of CTCs based on at least 1 CTC/7.5 mL of blood increased tumor detection frequencies to 95% for LS SCLC. Both CTC counts and cfDNA readouts correlated with disease stage and overall survival.

CONCLUSIONS

We demonstrate that a simple cfDNA genome-wide copy number approach provides an effective means of monitoring patients through treatment and show that targeted cfDNA sequencing identifies potential therapeutic targets in more than 50% of patients. We are now incorporating this approach into additional studies and trials of targeted therapies.

Thermally stratified flow of Jeffrey fluid with homogeneous-heterogeneous reactions and non-Fourier heat flux model

This article investigates the mixed convective flow of Jeffrey fluid near the axisymmetric stagnation point over an inclined permeable stretching cylinder. Analysis subjected to Cattaneo-Christov heat flux, thermal stratification and homogeneous-heterogeneous reactions are accounted. Suitable transformations are employed to obtain nonlinear ordinary differential system. Non-dimensional system is computed by Homotopy technique. Graphs and tables are constructed to analyze the influence of different flow parameters on temperature, concentration and velocity fields. The interpretation of skin friction coefficient is deliberated. It is noticed from obtained results that temperature is a decreasing function of thermal stratification parameter. Reverse behaviour of concentration is witnessed for higher estimations of homogeneous and heterogeneous parameters. Numerical results are compared with previous published results and found to be in good agreement for special casesof the emerging parameters.

Analysis of circulating cell-free DNA identifies KRAS copy number gain and mutation as a novel prognostic marker in Pancreatic cancer

Serial biopsy of pancreatic ductal adenocarcinoma (PDAC), to chart tumour evolution presents a significant challenge. We examined the utility of circulating free DNA (cfDNA) as a minimally invasive approach across a cohort of 55 treatment-naïve patients with PDAC; 31 with metastatic and 24 with locally advanced disease. Somatic mutations in cfDNA were detected using next generation sequencing in 15/24 (62.5%) and 27/31 (87%) of patients with locally advanced and metastatic disease, respectively. Copy number changes were detected in cfDNA of 10 patients of whom 7 exhibited gain of chromosome 12p harbouring KRAS as well as a canonical KRAS codon 12 mutation. In multivariable Cox Regression analysis, we show for the first time that patients with KRAS copy number gain and KRAS mutation have significantly worse outcomes, suggesting that this may be linked to PDAC progression. The simple cfDNA assay we describe will enable determination of the presence of KRAS copy number gain and KRAS mutations in larger studies and clinical trials.

In silico error correction improves cfDNA mutation calling

MOTIVATION

Circulating-free DNA (cfDNA) profiling by sequencing is an important minimally invasive protocol for monitoring the mutation profile of solid tumours in cancer patients. Since the concentration of available cfDNA is limited, sample library generation relies on multiple rounds of PCR amplification, during which the accumulation of errors results in reduced sensitivity and lower accuracy.

RESULTS

We present PCR Error Correction (PEC), an algorithm to identify and correct errors in short read sequencing data. It exploits the redundancy that arises from multiple rounds of PCR amplification. PEC is particularly well suited to applications such as single-cell sequencing and circulating tumour DNA (ctDNA) analysis, in which many cycles of PCR are used to generate sufficient DNA for sequencing from small amounts of starting material. When applied to ctDNA analysis, PEC significantly improves mutation calling accuracy, achieving similar levels of performance to more complex strategies that require additional protocol steps and access to calibration DNA datasets.

AVAILABILITY AND IMPLEMENTATION

PEC is available under the GPL-v3 Open Source licence, and is freely available from: https://github.com/CRUKMI-ComputationalBiology/PCR_Error_Correction.git.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Entropy generation and activation energy mechanism in nonlinear radiative flow of Sisko nanofluid: rotating disk

The theme of the present communication is to explore the novel analysis of entropy generation optimization, binary chemical reaction and activation energy for nonlinear convective flow of Sisko model on a radially stretchable rotating disk in the presence of a uniform vertical magnetic field. Nonlinear mixed convection, nonlinear thermal radiation, MHD, viscous dissipation, Joule heating and non-uniform heat generation/absorption are also considered. Nanofluid model includes significant slip mechanism of Brownian motion and thermophoresis. Apposite transformations are endorsed to get the nonlinear coupled ODEs system. The resultant system of ordinary differential equations is endeavoured for series solutions through homotopic technique. Total entropy generation is inspected through numerous emerging flow variables. Comparative study is made for temperature, velocity, heat transfer rate, Bejan number, entropy generation and mass transfer Nusselt number by considering shear thickening and thinning fluids. Finally, a comparison is specified with the previous existing results.

Utility of ctDNA to support patient selection for early phase clinical trials: the TARGET study

Next-generation sequencing (NGS) of circulating tumor DNA (ctDNA) supports blood-based genomic profiling but is not yet routinely implemented in the setting of a phase I trials clinic. TARGET is a molecular profiling program with the primary aim to match patients with a broad range of advanced cancers to early phase clinical trials on the basis of analysis of both somatic mutations and copy number alterations (CNA) across a 641 cancer-associated-gene panel in a single ctDNA assay. For the first 100 TARGET patients, ctDNA data showed good concordance with matched tumor and results were turned round within a clinically acceptable timeframe for Molecular Tumor Board (MTB) review. When a 2.5% variant allele frequency (VAF) threshold was applied, actionable mutations were identified in 41 of 100 patients, and 11 of these patients received a matched therapy. These data support the application of ctDNA in this early phase trial setting where broad genomic profiling of contemporaneous tumor material enhances patient stratification to novel therapies and provides a practical template for bringing routinely applied blood-based analyses to the clinic.

Abstract 5602: Detection of circulating cell-free tumor DNA (ctDNA) in patients with small cell lung cancer (SCLC)

Introduction: Tumor genomes can be reconstructed from the molecular information obtained from circulating cell-free DNA (cfDNA) and circulating tumor cells (CTCs) obtained from the peripheral blood of patients with cancer. The analysis of cfDNA and CTCs is a minimally invasive approach and represents a powerful research tool, with potential as a companion diagnostic for both patient stratification and monitoring. Here, we use cfDNA next-generation sequencing (NGS) analysis to assess and compare ctDNA profiles in patients with SCLC.

Methods: Whole genome sequencing (WGS) libraries were prepared from cfDNA isolated from the pre-treatment peripheral blood samples from 69 patients and 32 cancer-free controls. Libraries were subjected to WGS to establish genome wide copy number aberrations (CNA) as well as targeted mutation analysis of 110 SCLC associated genes. Quantitative metrics were calculated from CNA such as Percent Genome Altered (PGA; percentage of genomic regions altered), Z-score (measure of standard deviation) and Moran's I (measure of spatial autocorrelation). In addition CellSearch®, an epitope dependent enrichment platform was used to enumerate CTCs from a parallel blood sample.

Results: An examination of CNA patterns revealed SCLC associated changes such as losses on chromosomes 3p, 5q and 17p and gains on chromosome 3q and 5p as well as amplification of MYC in 21/69 (30%) and SOX2 in 36/69 (52%) as well losses on FHIT in 40/69 (58%), RASSFI in 38/69(55%) and RB1 in 24/69 (35%) patients. A combination of three CNA metrics enabled detection of tumor associated changes in 58/64 (84%) patients, with Moran's I emerging as the most sensitive CNA metric for detecting ctDNA. Targeted NGS detected tumor associated mutations in 60/64 (94%) with TP53 mutations detected in 50 patients (83% of patients with any detectable ctDNA). Somatic mutations and CNA were detected in both limited stage SCLC (LS-SCLC, confined to 1 hemithorax) and extensive stage (ES-SCLC, with distant metastases) with statistically significant differences seen for CNA metrics and variant allele frequencies of mutations consistent with higher levels of ctDNA in ES-SCLC. However, no significant differences between ES and LS were observed in the mutation patterns with respect to DNA damage repair, RAS and PI3K and transcriptional regulation pathways between the two stages of SCLC. There was considerable overlap between the detection of ctDNA and CTC counts, with cfDNA NGS readouts detecting tumor related changes in 96% of patients and CTCs were detected only in 76% of patients.

Conclusion: We have established sensitive methods for detecting ctDNA in cfDNA and combined with CTC enumeration we have an effective liquid biopsy for 98% of patients (96% in LS and 100% in ES) in this cohort. Future work will involve utilising this optimised NGS approach in an independent cohort of patients to correlate cfDNA metrics with clinical outcome.

Citation Format: Sumitra Mohan, Victoria Foy, Hui Sun Leong, Pietà G. Schofield, Mahmood Ayub, Nigel K. Smith, Sudhakar Sahoo, Chang Sik-Kim, Lynsey Priest, Mathew Carter, Hedley T. Carr, Crispin Miller, Corinne Finn-Faivre, Fiona Blackhall, Dominic G. Rothwell, Caroline Dive, Gerard Brady. Detection of circulating cell-free tumor DNA (ctDNA) in patients with small cell lung cancer (SCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5602.

Genetic differentiation of regional populations of the widespread Asiatic toad (Bufo gargarizans), as revealed by development of novel microsatellite markers

Dispersal is a key component of a species’ life history, by influencing population persistence, genetic structure, adaptation and maintenance of genetic diversity. The Asiatic toad (Bufo gargarizans) is a widespread species in east Asia. However, we still have no knowledge of what kind of geographical scale equates to genetic differentiation within B. gargarizans. In this study, the population genetics of B. gargarizans was studied at five localities, with the Yangtze River running through the sampling area, in order to detect the level of genetic differentiation and the natural barriers to the species’ dispersal on a small geographic scale, by means of the development and use of novel microsatellite loci. These markers revealed a relatively high level of genetic diversity. Distinct genetic structure among populations in B. gargarizans was observed, as described by genetic distance, AMOVA, PCA and Geneland results. A weak but significant positive correlation between genetic distance and geographical distance. The combination of these findings suggests that the Yangtze River and geographic distance may act as effective barriers for B. gargarizans. These results serve as benchmark data for understanding the impacts of dispersal barriers and continued landscape research on B. gargarizans.

twoddpcr: an R/Bioconductor package and Shiny app for Droplet Digital PCR analysis

SUMMARY

Droplet Digital PCR (ddPCR) is a sensitive platform used to quantify specific nucleic acid molecules amplified by polymerase chain reactions. Its sensitivity makes it particularly useful for the detection of rare mutant molecules, such as those present in a sample of circulating free tumour DNA obtained from cancer patients. ddPCR works by partitioning a sample into individual droplets for which the majority contain only zero or one target molecule. Each droplet then becomes a reaction chamber for PCR, which through the use of fluorochrome labelled probes allows the target molecules to be detected by measuring the fluorescence intensity of each droplet. The technology supports two channels, allowing, for example, mutant and wild type molecules to be detected simultaneously in the same sample. As yet, no open source software is available for the automatic gating of two channel ddPCR experiments in the case where the droplets can be grouped into four clusters. Here, we present an open source R package 'twoddpcr', which uses Poisson statistics to estimate the number of molecules in such two channel ddPCR data. Using the Shiny framework, an accompanying graphical user interface (GUI) is also included for the package, allowing users to adjust parameters and see the results in real-time.

AVAILABILITY AND IMPLEMENTATION

twoddpcr is available from Bioconductor (3.5) at https://bioconductor.org/packages/twoddpcr/ . A Shiny-based GUI suitable for non-R users is available as a standalone application from within the package and also as a web application at http://shiny.cruk.manchester.ac.uk/twoddpcr/ .

CONTACT

ged.brady@cruk.manchester.ac.uk or crispin.miller@cruk.manchester.ac.uk.

PACKAGE MAINTAINER

anthony.chiu@cruk.manchester.ac.uk.

Distinct subclonal tumour responses to therapy revealed by circulating cell-free DNA

BACKGROUND

The application of precision medicine in oncology requires in-depth characterisation of a patient's tumours and the dynamics of their responses to treatment.

PATIENTS AND METHODS

We used next-generation sequencing of circulating cell-free DNA (cfDNA) to monitor the response of a KIT p.L576P-mutant metastatic vaginal mucosal melanoma to sequential targeted, immuno- and chemotherapy.

RESULTS

Despite a KIT mutation, the response to imatinib was mixed. Unfortunately, tumours were not accessible for molecular analysis. To study the mechanism underlying the mixed clinical response, we carried out whole-exome sequencing and targeted longitudinal analysis of cfDNA. This revealed two tumour subclones; one with a KIT mutation that responded to imatinib and a second KIT-wild-type subclone that did not respond to imatinib. Notably, the subclones also responded differently to immunotherapy. However, both subclones responded to carboplatin/paclitaxel, and although the KIT-wild-type subclone progressed after chemotherapy, it responded to subsequent re-administration of paclitaxel.

CONCLUSION

We show that cfDNA can reveal tumour evolution and subclonal responses to therapy even when biopsies are not available.

Abstract 3960: Combined circulating tumour cell (CTC) and circulating tumor DNA (ctDNA) analysis of blood from patients with pancreatic cancer

Background

The challenge to improve outcomes for patients diagnosed with advanced pancreatic cancer remains very real with only small improvements in median survival gained by the use of systemic chemotherapy and little improvement in 5-year survival over the past decades. The advent of next generation sequencing (NGS) of tumor nucleic acids has opened up the possibility of improving outcomes through personalized therapies selected on the basis of tumor genetics.

Whilst NGS biomarkers can be measured in tumor biopsies sampled shortly before and after treatment this is often not practical for ethical, logistical and simple lack of availability. To circumvent problems associated with tumor sampling we have developed and evaluated blood-borne nucleic acids biomarkers for patients diagnosed with advanced pancreatic cancer.

Approach

We developed a NGS circulating free DNA (cfDNA) analysis pipeline based on the generation of whole genome NGS libraries followed by sequencing of over 600 cancer-associated genes using Agilent SureSelect. Using whole blood collected with Streck cell free DNA blood collection tubes (cfDNA BCT) we optimised combined circulating tumor cell (CTC) enrichment and cfDNA isolation. Quantitative measurements of KRAS mutations using both NGS and droplet digital PCR (ddPCR) were used to compare the tumor component present in both CTCs and cfDNA. We evaluated the overall approach using External Quality Assessment (EQA) controls and over 50 advanced pancreatic cancer patient samples. For CTC analysis we also compared epitope dependent (CellSearch) and independent (Parsortix) enrichment.

Results

After applying our NGS pipeline to 5 EQA genomic controls we identified all 14 known mutations correctly indicating high sensitivity and specificity. Both ddPCR and NGS identified KRAS mutations in patient cfDNA with a higher success rate seen for ddPCR consistent with the higher sensitivity of this methodology. From the NGS output additional mutations were detected in samples which either harboured or lacked detectable KRAS mutations. Consistent with previous observations CellSearch CTCs were detected at low levels in around 20% of patients with a similar frequency seen in initial analysis of CTCs obtained by epitope independent enrichment (Parsortix). In general KRAS mutations were detected at a higher level in patient cfDNA compared to enriched CTCs although some patients showed detectable CTC KRAS mutations with no KRAS mutations detected in their cfDNA by either ddPCR or NGS. Ongoing analysis is aimed at establishing if the molecular observations correlate with clinical outcome.

Conclusion

Combined CTC enrichment and cfDNA isolation is readily achievable using a single Streck cfDNA BCT. Results indicate that combined CTC and cfDNA analysis is more sensitive than either approach alone.

Citation Format: Ged Brady, Dominic Rothwell, Mahmood Ayub, Nigel Smith, Sumitra Mohan, Jakub Chudziak, Kyaw Aung, Richard Hubner, Crispin Miller, Alison Backen, Hui Sun Leong, Sakshi Gulati, Chang Sik Kim, Angela Lamarca, Mairéad McNamara, Juan Valle, Caroline Dive. Combined circulating tumour cell (CTC) and circulating tumor DNA (ctDNA) analysis of blood from patients with pancreatic cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3960.

Genetic profiling of tumours using both circulating free DNA and circulating tumour cells isolated from the same preserved whole blood sample

Molecular information obtained from cancer patients' blood is an emerging and powerful research tool with immense potential as a companion diagnostic for patient stratification and monitoring. Blood, which can be sampled routinely, provides a means of inferring the current genetic status of patients' tumours via analysis of circulating tumour cells (CTCs) or circulating tumour DNA (ctDNA). However, accurate assessment of both CTCs and ctDNA requires all blood cells to be maintained intact until samples are processed. This dictates for ctDNA analysis EDTA blood samples must be processed with 4 h of draw, severely limiting the use of ctDNA in multi-site trials. Here we describe a blood collection protocol that is amenable for analysis of both CTCs and ctDNA up to four days after blood collection. We demonstrate that yields of circulating free DNA (cfDNA) obtained from whole blood CellSave samples are equivalent to those obtained from conventional EDTA plasma processed within 4 h of blood draw. Targeted and genome-wide NGS revealed comparable DNA quality and resultant sequence information from cfDNA within CellSave and EDTA samples. We also demonstrate that CTCs and ctDNA can be isolated from the same patient blood sample, and give the same patterns of CNA enabling direct analysis of the genetic status of patients' tumours. In summary, our results demonstrate the utility of a simple approach that enabling robust molecular analysis of CTCs and cfDNA for genotype-directed therapies in multi-site clinical trials and represent a significant methodological improvement for clinical benefit.

Development of a circulating miRNA assay to monitor tumor burden: From mouse to man

Circulating miRNA stability suggests potential utility of miRNA based biomarkers to monitor tumor burden and/or progression, particularly in cancer types where serial biopsy is impractical. Assessment of miRNA specificity and sensitivity is challenging within the clinical setting. To address this, circulating miRNAs were examined in mice bearing human SCLC tumor xenografts and SCLC patient derived circulating tumor cell explant models (CDX). We identified 49 miRNAs using human TaqMan Low Density Arrays readily detectable in 10 μl tail vein plasma from mice carrying H526 SCLC xenografts that were low or undetectable in non-tumor bearing controls. Circulating miR-95 measured serially in mice bearing CDX was detected with tumor volumes as low as 10 mm(3) and faithfully reported subsequent tumor growth. Having established assay sensitivity in mouse models, we identified 26 miRNAs that were elevated in a stage dependent manner in a pilot study of plasma from SCLC patients (n = 16) compared to healthy controls (n = 11) that were also elevated in the mouse models. We selected a smaller panel of 10 previously reported miRNAs (miRs 95, 141, 200a, 200b, 200c, 210, 335#, 375, 429) that were consistently elevated in SCLC, some of which are reported to be elevated in other cancer types. Using a multiplex qPCR assay, elevated levels of miRNAs across the panel were also observed in a further 66 patients with non-small cell lung, colorectal or pancreatic cancers. The utility of this circulating miRNA panel as an early warning of tumor progression across several tumor types merits further evaluation in larger studies.

Clinical evaluation of a novel microfluidic device for epitope-independent enrichment of circulating tumour cells in patients with small cell lung cancer

Circulating tumour cells (CTCs) have potential utility as minimally-invasive biomarkers to aid cancer treatment decision making. However, many current CTC technologies enrich CTCs using specific surface epitopes that do not necessarily reflect CTC heterogeneity. Here we evaluated the epitope-independent Parsortix system which enriches CTCs based on size and rigidity using both healthy normal volunteer blood samples spiked with tumour cells and blood samples from patients with small cell lung cancer (SCLC). Blood samples were maintained unfractionated at room temperature for up to 4 days followed by plasma removal for circulating free DNA (cfDNA) isolation and direct application of the remaining cell component to the Parsortix system. For tumour cells expressing the EpCAM cell surface marker the numbers of spiked cells retained using the Parsortix system and by EpCAM-positive selection using CellSearch® were not significantly different, whereas only the Parsortix system showed strong enrichment of cells with undetectable EpCAM expression. In a pilot clinical study we banked both enriched CTCs as well as plasma from SCLC patient blood samples. Upon retrieval of the banked Parsortix cellular samples we could detect cytokeratin positive CTCs in all 12 SCLC patients tested. Interestingly, processing parallel samples from the same patients by EpCAM enrichment using CellSearch® revealed only 83% (10/12) with cytokeratin positive CTCs indicating the Parsortix system is enriching for EpCAM negative SCLC CTCs. Our combined results indicate the Parsortix system is a valuable tool for combined cfDNA isolation and CTC enrichment that enables CTC analysis to be extended beyond dependence on surface epitopes.

Abstract A176: RET inhibition: Development of novel compounds and a personalized medicine strategy in lung adenocarcinoma

Background:RET is a receptor tyrosine kinase (RTK) and forms part of a macromolecular receptor complex containing dimerised RET receptor, two co-receptors and a bound ligand. Signalling networks downstream of RET play an important role in regulating cell survival, differentiation, proliferation, migration and chemotaxis. Activating mutations in RET (e.g. C634W and M918T) are known drivers in medullary thyroid carcinomas (MTC). More recently, oncogenic RET fusions (e.g. CCDC6-RET and KIF5B-RET) have been identified in 1-2% of lung adenocarcinoma patients. We are currently developing novel, selective inhibitors of RET, and at the same time, investigating a number of biomarker approaches for the stratification of RET fusion-positive lung cancer patients who might benefit from such therapy.

Methods: We have undertaken collaborative studies using established techniques including immunohistochemistry (IHC) and FISH (DNA break apart and RNA). In addition, we have investigated hybrid capture DNA sequencing of both biopsy material and circulating tumour DNA in the blood. Here we, compare and contrast the benefits of each biomarker assay evaluated and consider how these approaches could be translated for use in Phase I clinical trials at The Christie.

Conclusion: Our data supports the successful implementation of predictive biomarkers to identify patients who might benefit from treatment with selective RET inhibitors.

Acknowledgements:This work was funded by Cancer Research UK (Grant numbers C480/A1141 and C5759/A17098).

Citation Format: Mandy Watson, Helen Small, Phil Chapman, Gemma Hopkins, Habiba Begum, Ian D. Waddell, Garry Ashton, Caron Abbey, Jade Harris, Mahmood Ayub, Sumitra Mohan, Dominic Rothwell, Ged Brady, Caroline Dive, Allan Jordan, Donald Ogilvie. RET inhibition: Development of novel compounds and a personalized medicine strategy in lung adenocarcinoma. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A176.

Peristaltic flow of Williamson fluid in a convected walls channel with Soret and Dufour effects

Peristaltic flow of magnetohydrodynamic (MHD) Williamson fluid in a symmetric channel is addressed. Modeling is given with Soret and Dufour effects. Channel walls have compliant properties. Analysis has been carried out through long wavelength and low Reynolds number approach. The obtained series solutions for small Weissenberg number are developed. Impact of variables reflecting the salient features of wall properties, Biot numbers and Soret and Dufour on the velocity, temperature and concentration has been point out. Trapping phenomenon is also analyzed.

Evaluation and validation of a robust single cell RNA-amplification protocol through transcriptional profiling of enriched lung cancer initiating cells

BACKGROUND

Although profiling of RNA in single cells has broadened our understanding of development, cancer biology and mechanisms of disease dissemination, it requires the development of reliable and flexible methods. Here we demonstrate that the EpiStem RNA-Amp™ methodology reproducibly generates microgram amounts of cDNA suitable for RNA-Seq, RT-qPCR arrays and Microarray analysis.

RESULTS

Initial experiments compared amplified cDNA generated by three commercial RNA-Amplification protocols (Miltenyi μMACS™ SuperAmp™, NuGEN Ovation® One-Direct System and EpiStem RNA-Amp™) applied to single cell equivalent levels of RNA (25-50 pg) using Affymetrix arrays. The EpiStem RNA-Amp™ kit exhibited the highest sensitivity and was therefore chosen for further testing. A comparison of Affymetrix array data from RNA-Amp™ cDNA generated from single MCF7 and MCF10A cells to reference controls of unamplified cDNA revealed a high degree of concordance. To assess the flexibility of the amplification system single cell RNA-Amp™ cDNA was also analysed using RNA-Seq and high-density qPCR, and showed strong cross-platform correlations. To exemplify the approach we used the system to analyse RNA profiles of small populations of rare cancer initiating cells (CICs) derived from a NSCLC patient-derived xenograft. RNA-Seq analysis was able to identify transcriptional differences in distinct subsets of CIC, with one group potentially enriched for metastasis formation. Pathway analysis revealed that the distinct transcriptional signatures demonstrated in the CIC subpopulations were significantly correlated with published stem-cell and epithelial-mesenchymal transition signatures.

CONCLUSIONS

The combined results confirm the sensitivity and flexibility of the RNA-Amp™ method and demonstrate the suitability of the approach for identifying clinically relevant signatures in rare, biologically important cell populations.

Abstract 3060: Circulating tumor cells from small cell lung cancer patients are tumorigenic

Small cell lung cancer (SCLC), is a highly aggressive and metastatic disease with a 5 year survival of 5%. SCLC represents 15-20% of all lung cancers and causes &gt;160,000 deaths a year. The majority of patients present with metastatic disease and consequently resections are rare, while biopsies are small and only for diagnostic purposes thus hampering the study of SCLC. However, circulating tumour cells (CTCs) are highly prevalent in SCLC patients and may represent an avenue for the better understanding this disease. Our aim was to determine whether CTCs isolated from SCLC patients were able to form tumours in immunocompromised mice. This was accomplished by erythrocyte and leukocyte depletion and implantation of the remaining cells. Of the 6 initial patients whose CTCs were implanted, 4 gave rise to tumours in less than 5 months. Immuno-histochemical analysis of the tumours revealed them to be human in nature and express markers consistent with SCLC. Whole exome sequencing demonstrated that the tumours had mutations (e.g. TP53 and RB1) and CNV (e.g. loss of 3p and 13q) commonly observed in SCLC samples. Furthermore, single cell analysis of CTCs isolated from the corresponding patient revealed that genetic abnormalities detected in the tumour were also present in the patients CTCs. This confirmed that the tumours (termed CDX for CTC derived explant), were indeed derived from CTCs. In all 4 successful cases, analysis of parallel blood samples by CellSearch demonstrated that the patients had more than 400 CTCs/7.5 ml blood. Two of these patients were initially sensitive to platinum/etoposide therapy, while 2 were refractory. The doubling times of CDX derived from refractory and sensitive patients were 7.2 and 5.0 days compared to 14.2 and 13.4 days, consistent with refractory SCLC being more aggressive than sensitive SCLC. We have been able to successfully passage, freeze and resurrect all the CDX models and aim to report whether the patient response to therapy is mirrored in their CDX. These data demonstrate that SCLC CTCs are tumorigenic and we are investigating whether the CTC derived tumours represent a faithful model of the clinical disease.

Citation Format: Christopher J. Morrow, Cassandra L. Hodgkinson, Yaoyong Li, Robert Metcalf, Dominic Rothwell, Francesca Trapani, Radoslaw Polanski, Debbie Burt, Kathryn Simpson, Karen Morris, Stuart Pepper, Daisuke Nonaka, Alastair Greystole, Paul Kelly, Matthew Krebs, Jenny Antonello, Mahmood Ayub, Suzanne Faulkner, Lynsey Priest, Louise Carter, Catriona Tate, Crispin J. Miller, Fiona Blackhall, Ged Brady, Caroline Dive. Circulating tumor cells from small cell lung cancer patients are tumorigenic. [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 3060. doi:10.1158/1538-7445.AM2014-3060

Tumorigenicity and genetic profiling of circulating tumor cells in small-cell lung cancer

Small-cell lung cancer (SCLC), an aggressive neuroendocrine tumor with early dissemination and dismal prognosis, accounts for 15-20% of lung cancer cases and ∼200,000 deaths each year. Most cases are inoperable, and biopsies to investigate SCLC biology are rarely obtainable. Circulating tumor cells (CTCs), which are prevalent in SCLC, present a readily accessible 'liquid biopsy'. Here we show that CTCs from patients with either chemosensitive or chemorefractory SCLC are tumorigenic in immune-compromised mice, and the resultant CTC-derived explants (CDXs) mirror the donor patient's response to platinum and etoposide chemotherapy. Genomic analysis of isolated CTCs revealed considerable similarity to the corresponding CDX. Most marked differences were observed between CDXs from patients with different clinical outcomes. These data demonstrate that CTC molecular analysis via serial blood sampling could facilitate delivery of personalized medicine for SCLC. CDXs are readily passaged, and these unique mouse models provide tractable systems for therapy testing and understanding drug resistance mechanisms.

Poverty and Inequality

Despite economic growth, a large number of Africans continue to live in poverty and experiences high levels of income and opportunity inequality. Not only does inequality dampen the poverty reduction impact of growth, lower the growth rate, hollow out the middle class, encourage corruption and rent seeking, increase crime and violence, and undermine social stability, but it also precludes sustained growth. Access to education, power supply, health services, and water and sanitation are critical to improve the lives of all Africans, especially girls and those in rural areas. In this area, public spending and government transfers can only go so far—the voice of Africa’s poorest citizens needs to be heard by policymakers. While maintaining central government oversights, appropriate steps should be taken to increase participation of the beneficiaries of public services.

Identification of a receptor for neuropeptide VGF and its role in neuropathic pain

VGF (nonacronymic) is a neuropeptide precursor that plays multiple roles in regulation of energy balance, reproduction, hippocampal synaptic plasticity, and pain. Data from a number of pain models showed significant up-regulation of VGF in sensory neurons. TLQP-21, one of the VGF-derived neuropeptides, has been shown to induce a hyperalgesic response when injected subcutaneously into the hind paw of mice. However, the precise role of VGF-derived neuropeptides in neuropathic pain and the molecular identity of the receptor for VGF-derived peptides are yet to be investigated. Here we identified gC1qR, the globular heads of the C1q receptor, as the receptor for TLQP-21 using chemical cross-linking combined with mass spectrometry analysis. TLQP-21 caused an increase in intracellular Ca²⁺ levels in rat macrophages and microglia. Inoculation of TLQP-21-stimulated macrophages into rat hind paw caused mechanical hypersensitivity. The increase in intracellular Ca²⁺ levels in macrophages was attenuated by either siRNA or neutralizing antibodies against gC1qR. Furthermore, application of the gC1qR-neutralizing antibody to rats with partial sciatic nerve ligation resulted in a delayed onset of nerve injury-associated mechanical hypersensitivity. These results indicate that gC1qR is the receptor for TLQP-21 and plays an important role in chronic pain through activation of macrophages. Because direct association between TLQP-21 and gC1qR is required for activation of macrophages and causes hypersensitivity, disrupting this interaction may be a useful new approach to develop novel analgesics.

Identification of genomic deletions spanning the PCDH19 gene in two unrelated girls with intellectual disability and seizures

Recently, missense and truncating mutations in the gene PCDH19 have been reported to cause female-restricted epilepsy with mental retardation (EFMR). EFMR (MIM#300088) is an X-linked disorder characterized by early onset seizures and intellectual disability (ID). Interestingly, unlike typical X-linked mode of inheritance, the phenotype is restricted to females, and males are unaffected carriers. PCDH19 is highly expressed in brain, and the encoded protein belongs to the cadherin superfamily. Here we report two unrelated female patients with deletions spanning PCDH19 identified by copy number variation (CNV) analysis and validated by qPCR. In one, we have identified a 3 Mb interstitial deletion at Xq21.33-q22.1 which spans PCDH19, LOC442459 & TNMD. This patient had her first seizure at 8 months old, and also has ID and aggressive behavior. In another female patient we identified a de novo 603 kb heterozygous deletion in a female patient with fits (since 1 year of age), ID, hyperactivity and aggressive behavior. The deletion spans the entire PCDH19 gene (also TNMD, SRPX2, TSPAN6 and SYTL4). In conclusion, our results suggest that deletions at PCDH19 also cause EFMR.

Radiometric analysis of samples of domestic fish species and radiological implications

Radiometric analysis of samples of commonly sold fish species in Pakistan were carried out for the measurement of concentrations of naturally occurring and artificial radionuclides. For this purpose, a high resolution Ge detector was employed. Mean concentrations of (226)Ra, (228)Ra, and (40)K in fish samples were 1.3 +/- 0.3, 1.0 +/- 0.2, and 90 +/- 15 Bq kg, respectively, whereas concentration of (137)Cs was not detected. The annual effective dose due to ingestion of these radionuclides through fish diet was evaluated to be 2.3 microSv y(-1). This value of effective dose is found much below the average radiation dose of 0.29 mSv y(-1) received per capita worldwide through ingestion of natural radionuclides during the consumption of food assessed by the United Nations Scientific Committee on the Effects of Atomic Radiation. It is concluded that fish supplies in the markets from the domestic fish farms are free from radiological risks. These results may contribute to the national and regional data regarding radioactivity levels in domestic fish species.

Mutations in the P2RY5 gene underlie autosomal recessive hypotrichosis in 13 Pakistani families

BACKGROUND

Autosomal recessive hypotrichosis is a rare genetic irreversible hair loss characterized by sparse scalp hair, sparse to absent eyebrows and eyelashes, and sparse axillary and body hair. Affected male individuals have normal beard hair.

OBJECTIVES

To search for pathogenic mutations in the human P2RY5 gene in Pakistani families with autosomal recessive hereditary hypotrichosis.

METHODS

In the present report, 16 unrelated consanguineous Pakistani families having multiple affected individuals with autosomal recessive hypotrichosis were investigated. Linkage in these families was searched by genotyping microsatellite markers linked to autosomal recessive hypotrichosis loci LAH1, LAH2 and LAH3. Thirteen of the families showed linkage to the LAH3 locus on chromosome 13q14.11-q21.32. These families were then subjected to direct sequencing of the P2RY5 gene, which encodes a G protein-coupled receptor.

RESULTS

Sequence analysis of the P2RY5 gene revealed two novel missense mutations (c.742A>T; p.N248Y and c.830C>T; p.L277P) in three families. Five previously described mutations including three missense (c.188A>T; p.D63V, c.436G>A; p.G146R, c.562A>T; p.I188F), one insertion (c.69insCATG; p.24insHfsX52) and one complex deletion (c.172-175delAACT; 177delG; p.N58-L59delinsCfsX88) were detected in the other 10 families.

CONCLUSIONS

Mutations revealed in the present study extend the body of evidence implicating the P2RY5 gene in the pathogenesis of human hereditary hair loss.

A note on plane wave diffraction by a perfectly conducting strip in a homogeneous bi-isotropic medium

We studied the problem of diffraction of an electromagnetic plane wave by a perfectly conducting finite strip in a homogeneous bi-isotropic medium and obtained some improved results which were presented both mathematically and graphically. The problem was solved by using the Wiener-Hopf technique and Fourier transform. The scattered field in the far zone was determined by the method of steepest decent. The significance of present analysis was that it recovered the results when a strip was widened into a half plane.

Localization of a novel autosomal recessive hypotrichosis locus (LAH3) to chromosome 13q14.11-q21.32

Autosomal recessive hypotrichosis is a rare form of alopecia characterized by sparse hair on scalp, sparse to absent eyebrows and eyelashes, and sparse auxiliary and body hair. Previously, for this form of hypotrichosis, two loci LAH (localized hereditary hypotrichosis) and AH (autosomal recessive hereditary hypotrichosis) have been mapped on chromosome 18q12.1 and 3q27.2, respectively. In the study presented here, we report the localization of a third locus for autosomal recessive form of hypotrichosis in two large Pakistani families. The patients in the two families exhibited typical features of the hereditary hypotrichosis. Genome scan using polymorphic microsatellite markers mapped the gene on chromosome 13q14.11-q21.32. A maximum combined two-point logarithm of odds (LOD) score of 4.79 at theta= 0.0 was obtained for several markers. Multipoint linkage analysis resulted in a maximum LOD score of 5.9, which further supports the linkage. Haplotype analysis defined the linkage interval of 17.35 cM flanked by markers D13S325 and D13S1231 according to the Rutgers combined linkage-physical map. This region contains 24.41 Mb according to the build 36 of the human genome sequence-based physical map.