Horiba has recently announced the publication of scientific studies which demonstrate the excellent performance of its new HELO high throughput fully automated hematology platform on body fluid and pathological samples. Horiba’s Yumizen® H2500 and H1500 automated hematology analysers within the HELO platform deliver enhanced precision for complete blood counts and white blood cell (WBC) differential testing, with body fluid analysis included as standard. This improves diagnosis, minimizes unnecessary manual microscopy slide reviewing and enhances laboratory workflow, as highlighted by two recent scientific evaluation studies.
The first study was undertaken by Nantes University Hospital (CHU de Nantes) focusing on the need for automated analysis of biological fluids for robust and reliable results reporting. Hematological analysis of body fluids (BF) can provide clinicians with valuable diagnostic information as it can indicate a number of serious medical conditions. Manual microscopy has traditionally been used to determine total and differentiated WBC in BFs, however, results can be affected by inter-operator variability and take time to undertake. By using an automated method of analysis of WBC in a body fluid smear, this can improve turnaround times and accuracy.
To ensure the robustness and reliability of automated BF analysis in routine laboratory workflows, the evaluation study was undertaken on the performance of the automated body fluid analysis cycle on the Yumizen H2500. The study included 98 samples from cerebro-spinal, pleural, ascitic, pericardic and bronchoalveolar liquid (BAL) fluids which were used for comparative leukocyte and erythrocyte counts, as well as differential. This confirmed the good analytical performance of Yumizen analyser in comparison with conventional microscopic count, as well as a reference analyser.
The second study explored the flagging efficiency of the new analyser. Pathological samples, coming from patients with altered hematopoiesis, often trigger a WBC-Diff flag; this is due to poor cell separation and requires a manual slide review (MSR) by microscopy to confirm the WBC differential. Laboratory workload would be optimized if MSR could be reduced without compromising patient care. Therefore, the study undertaken by the Institut Bergonié Comprehensive Cancer Centre compared the flagging performance in the WBC differential of the Yumizen H1500/H2500 to a routine analyser. This included patients with pathology or treatment affecting hematopoiesis, such as those undergoing chemotherapy or with onco-hematologic disorders.
The study on 228 pathological samples (100 from patients on chemotherapy for solid tumours and 128 from patients with malignant blood disease) demonstrated an improvement in the WBC-diff analysis and reliability of the Yumizen H1500/2500 analyser compared to a routine analyser. It delivered better precision and specificity, due to improved cell separation, and a significant decrease (-21%) in unnecessary morphology reviewing by microscopy, thus saving significant time in the laboratory.
Commenting on the successful outcome of the studies, Mandy Campbell, Horiba Medical said, “These evaluation studies undertaken by recognized authorities in hematological analysis, demonstrate the excellent performance of our new Yumizen H1500/H2500 automated hematology analysers with both body fluid and pathological samples. Body fluid analysis is available as standard on these analysers which have been shown to enhance diagnoses and lower film review rates to improve laboratory workflow.” www.horiba.com/medical

by Prof. Godfrey Grech, Dr Stefan Jellbauer and Dr Hilary Graham
Understanding the molecular characteristics of tumour heterogeneity and the dynamics of progression of disease requires the simultaneous measurement of multiple biomarkers. Of interest, in colorectal cancer, clinical decisions are taken on the basis of staging and grade of the tumour, resulting in highly variable clinical outcomes. Molecular classification using sensitive and precise multiplex assays is required. In this article we shall explain the use of innovative methodologies using signal amplification and bead-based technologies as a solution to this unmet clinical need.
Introduction
Cancer is the leading cause of death globally, accounting for 9.6-million deaths in 2018, with 70% of cancer-related mortality occurring in low- and middle-income countries. In 2017, only 26% of low-income countries provided evidence of full diagnostic services in the public sector, contributing to late-stage presentation [1]. There are various aspects that negatively affect the survival rate of patients, including but not limited to:
(a) highly variable clinical outcome mainly due to lack of molecular classification;
(b) treatment of advanced stage of the disease mainly due to lack of, or reluctance to, screening programmes, resulting in treatment of symptomatic disease that is already in advanced stage;
(c) heterogeneity of the tumours that are undetected using representative biopsies of the tumour at primary diagnostics; and
(d) lack of surveillance of patients to detect early progression of disease and metastasis, mainly due to clinically inaccessible tumour tissue and the need of sensitive technologies to measure early metastatic events.
Colorectal cancer (CRC) represents the second most common cause of cancer-related deaths, with tumour metastasis accounting for the majority of cases. To date, treatment decisions in CRC are based on cancer stage and tumour location, resulting in highly variable clinical outcomes. Only recently, a system of consensus molecular subtype (CMS) was proposed based on gene expression profiling of primary CRC samples [2]. Organoid cultures derived from CRC samples were used in various studies to adapt the CMS signature (CMS1–CMS4) to preclinical models, to study heterogeneity and measure response to therapies. Of interest, the epidermal growth factor receptor (EGFR) and receptor tyrosine-protein kinase erbB-2 (HER2) inhibitors were selective and have a strong inhibitory activity on CMS2, indicating that subtyping provides information on potential first-line treatment [3]. In CRC, copy number variations are associated with the adenoma-to-carcinoma progression, metastatic potential and therapy resistance [4]. Our recent studies using primary and matched metastatic tissue showed that TOP2A (encoding DNA topoisomerase II alpha) and CDX2 (encoding caudal type homeobox 2) gene amplifications are associated with disease progression and metastasis to specific secondary sites. Hence, introducing robust and clinically-friendly molecular assays to enable measurement of multiple biomarkers to assess matched resected material and tumour-derived cells or cell vesicles in blood during therapy and beyond, has become a necessity to overcome this deadly toll. In addition, to support diagnostics in remote countries, the assays should allow measurement in low input, low quality tissue material.
To enable precise future diagnosis and patient classification and surveillance, we developed innovative methodologies (Innoplex assays) measuring expression of multiple marker panels representing the primary tumour heterogeneity and the dynamic changes associated with disease progression. We optimized these Molecular Diagnostics Sensitive and precise multiplex assays enable accurate classification and surveillance of tumours April/May 2020 21 | methodologies for multiplex digitalized readout using various sample sources ranging from archival formalin-fixed paraffinembedded (FFPE) tissues and characterization of gene amplifications in blood-derived exosomes. In this article we summarize the Innoplex assays based on the xMAP Luminex Technology and the Invitrogen QuantiGene™ Plex Assay, the research outputs from the University of Malta in terms of the biomarker panels and the commercialization of the assays through Omnigene Medical Technologies Ltd.
Molecular profiling technology and workflow
The Innoplex multiplex assays are based on two components, namely (a) the integration of the Invitrogen QuantiGene™ Plex Assay (Thermo Fisher Scientific) and the xMAP Luminex technology enabling multiplexing of the technique, and (b) the novel panel of biomarkers developed by the Laboratory of Molecular Oncology at the University of Malta, headed by Professor Godfrey Grech. The technologies and the research output provides the versatility of the assays. To date a breast cancer molecular classification panel and a CRC metastatic panel were developed and are currently being optimized for the clinical workflow by Omnigene Medical Technologies Ltd through the miniaturization and automation of the RNA-bead plex assay.
The Innoplex RNA-bead plex assays use the Quantigene branched- DNA technology that runs on the Luminex xMAP technology. Specific probes are conjugated to paramagnetic microspheres (beads) that are internally infused with specific portions of red and infrared fluorophores, used by the Luminex optics (first laser/ detector) to identify the specific beads known to harbour specific probes. The Quantigene branched-DNA technology builds a molecular scaffold on the specifically bound probe-target complex to amplify the signal that is read by a second laser/LED [5].
The workflow of the assay can be divided into a pre-analytical phase involving the lysis/homogenization of the tissue or cells, and the analytical phase that involves hybridization, pre-amplification and signal amplification with a total hands-on time of 2|h. This is comparable to the time required to prepare a 5-plex quantitative real-time (qRT)-PCR reaction. Increased multiplexing within a reaction will result in an increase in hands-on time for qRT-PCR, while the same 2|h are retained for the Innoplex assays. As shown by Scerri et al. [5], qRT-PCR 40-plex reactions will require 9|h to prepare as compared to the bead-based assay which retains a 2|h workflow. Hence, the bead-based assays have the advantage for high-throughput analysis in multiplex format.
Performance and applications
We have shown in previous studies, using breast cancer patient material, that gene expression can be measured using our RNA-based multiplex assays in FFPE patient archival material that was of low quality and low input [6]. Using a 22-plex assay, inter-run regression analysis using RNA extracted from cell lines performed well with an r2>0.99 in our hands. These assays were also evaluated by other groups using snap-frozen and FFPE tissues derived from patient and xenograft samples. In comparison with the reference methods, the bead-based multiplex assays outperformed the qRT-PCR when using FFPE-tissue-derived RNA, giving reliability coefficients of 99.3–100% as compared to 82.4–95% for qPCR results, indicating a lower assay variance [5].
One main advantage of the Innoplex assays is the direct measurement of gene expression on lysed/homogenized tissues and cells, providing a simplified workflow without RNA extraction, cDNA synthesis and target amplification. In addition, due to its chemistry and use of beads, gene expression can be measured in a multiplex format (up to 80 genes) using low input and low quality material. This enables the use of the assay in remote laboratories, and as detailed below for stained microdissected material and to measure multiple markers in low abundance material, such as blood-derived circulating tumours cells.
Comparison of gene expression data from homogenized and lysed patient tissue derived from either unstained or hematoxylin and eosin (H&E)-stained sections shows a high correlation (r2>0.98). This provides an advantage when studying heterogeneous tumours that are microdissected from H&E stained slides. In fact, using this methodology, an estrogen-receptor-positive tumour was analysed and one of the tumour foci had a more advanced tumour expressing the mesenchymal marker, FN1 (fibronectin). This was only possible by running a 40-plex assay on minimal input material (microdissected from 20|μm section) representing markers for molecular classification, epithelial to mesenchymal transition, and proliferation markers [7]. A recent audit on breast cancer diagnosis, indicates clearly that heterogeneous cases characterized using the bead-based multiplex assays on resection tumour samples are not represented in matched biopsies used for patient diagnosis. In fact, only 3.5% of 97 intra-tumour heterogeneous cases were detected in a cohort of 570 patients at diagnosis. The advantage of the digitalized result of the Innoplex assays is to avoid increasing the workload of pathologists when resected samples are re-analysed to characterize multiple sites within a tumour.
Multiplexing provides both sensitivity and versatility in biomarker validation and was instrumental in our hands to measure gene amplifications in cancer-derived exosomes (tumour-derived vesicles in blood) using plasma from CRC patients. Of interest, these methods have been optimized using cancer cell lines to measure RNA transcripts in cells at low abundance, mimicking the isolation of circulating tumour cells from blood [5]. In this study we show that measurement of transcripts of EPCAM (encoding epithelial cell adhesion molecule), KRT19 (encoding keratin, type I cytoskeletal 19), ERBB2 (encoding HER2) and FN1 maintain a linear signal down to 15 cells or less. In addition, the simple workflow with direct measurement using lysed cells enables this assay to be translated more efficiently to the clinical setting. Absolute quantification of transcripts presents alternative endpoint methods to the Invitrogen QuantiGene™ Plex Assay. Droplet digital PCR (dPCR) and Nanostring’s nCounter® technology are precise and sensitive methods. Multiplexing in dPCR is limiting and RNA studies are hindered by reverse transcription inefficiency. The nCounter® technology requires multiple target enrichment (PCR-based pre-amplification) to measure low input RNA, which introduces amplification bias and risk for false positive results.
Summary
In conclusion, the innovative multiplex assays indicate a shift from reactive medicine (treating patients based on average risks) towards predictive, precise and personalized treatment that takes into account heterogeneity of primary tumour, progression of tumour during therapy and the metastatic surveillance of the individual patient. The versatility of the method allows the development of various assays to support different applications (Figs|1 & 2). Our first innovative methods were developed for the molecular classification of luminal and basal breast cancer and to predict sensitivity to specific therapy in triple-negative breast cancer subtype [8]. As discussed above, the multiplex assays have a wide range of possible applications in the diagnosis of tumours and surveillance of tumours during therapy. The main advantages of these methods include:
(a) implementation of high-throughput analysis which has a positive impact on remote testing and implementation of such assays in patient surveillance and clinical trials;
(b) the digitalized result excludes subjectivity and equivocal interpretation, which are common events in image-based measurements, and also eliminates the need for highly specialized facilities and human resources;
(c) accurate and precise detection of multiple targets in one assay, minimizing the use of precious patient samples; and
(d) enables the measurement of gene expression in heterogeneous tumours and low input / low quality patient material. The method is streamlined with the current pathology laboratory practices resulting in a workflow that is cost-effective and with minimal turnaround time.
The authors
Godfrey Grech*1,2 PhD, Stefan Jelbauer3 PhD, Hilary Graham4 PhD
1 Department of Pathology, Faculty of Medicine & Surgery, University of Malta
2 Scientific Division, Omnigene Medical Technologies Ltd, Malta
3 Thermo Fisher Scientific, Carlsbad, CA 92008, United States
4 Licensed Technologies Group, Luminex Corporation, Austin, Texas

*Corresponding author
E-mail: godfrey.grech@um.edu.mt