From Formalin-fixed Paraffin-embedded Tissue Research Articles

Panfungal Polymerase Chain Reaction for Identification of Fungal Pathogens in Formalin-Fixed Animal Tissues

Identification of fungal organisms often poses a problem for pathologists because the histomorphology of some fungal organisms is not specific, fresh tissues may not be available, and isolation and identification in culture may take a long time. The purpose of this study was to validate the use of panfungal polymerase chain reaction (PCR) to identify fungal organisms from formalin-fixed paraffin-embedded (FFPE) tissues. Formalin-fixed paraffin-embedded curls were tested from 128 blocks containing canine, feline, equine, and bovine tissues with cutaneous, nasal, pulmonary, and systemic fungal infections, identified by the presence of fungi in histologic sections. Quantitative scoring of histologic sections identified rare (11.9%), occasional (17.5%), moderate (17.5%), or abundant (53.1%) fungal organisms. DNA was isolated from FFPE tissues and PCR was performed targeting the internal transcribed spacer 2 (ITS-2) region, a segment of noncoding DNA found in all eukaryotes. Polymerase chain reaction products were sequenced and identified at ≥97% identity match using the Basic Local Alignment Search Tool and the NCBI database of ITS sequences. Of the 128 blocks, 117 (91.4%) yielded PCR products and high-quality sequences were derived from 89 (69.5%). Sequence and histologic identifications matched in 79 blocks (61.7%). This assay was capable of providing genus- and species-level identification when histopathology could not and, thus, is a beneficial complementary tool for diagnosis of fungal diseases.

Molecular glycopathology by capillary electrophoresis: Analysis of the N-glycome of formalin-fixed paraffin-embedded mouse tissue samples.

Capillary electrophoresis with laser-induced fluorescence (CE-LIF) detection was used to analyze endoglycosidase released and fluorophore-labeled N-glycans from formalin-fixed paraffin-embedded (FFPE) mouse tissue samples of lung, brain, heart, spleen, liver, kidney and intestine. The FFPE samples were first deparaffinized followed by solubilization and glycoprotein retrieval. PNGase F mediated release of the N-linked oligosaccharides was followed by labeling with aminopyrene trisulfonate. After CE-LIF glycoprofiling of the FFPE mouse tissues, the N-glycan pool of the lung specimen was subject to further investigation by exoglycosidase array based carbohydrate sequencing. Structural assignment of the oligosaccharides was accomplished by the help of the GUcal software and the associated database, based on the mobility shifts after treatments with the corresponding exoglycosidase reaction mixtures. Sixteen major N-linked carbohydrate structures were sequenced from the mouse lung FFPE tissue glycome and identified, as high mannose (3) neutral biantennary (3) sialylated monoantennary (1) and sialylated bianennary (9) oligosaccharides. Two of these latter ones also possessed alpha(1-3) linked galactose residues.

P3.02a-010 Evaluation of Aberrant ALK Expression in Lung Cancer by RT-PCR and Comparison with FISH and Immunohistochemistry: Topic: ALK Biomarkers

In advanced lung cancer patients the gold standard for detecting ALK gene rearrangements is fluorescence in situ hybridization (FISH), and ALK protein expression can be also evaluated by immunohistochemistry (IHC). A single analysis performed alone may not detect all the ALK-positive cases and some patients with discordant FISH and IHC respond to tyrosine kinase inhibitors (TKIs). In this study we evaluated ALK aberrant expression in lung cancer patients by a reverse-transcription (RT)-PCR, to investigate its clinical utility and its concordance with FISH and IHC. ALK aberrant expression was retrospectively investigated on RNA from formalin-fixed paraffin-embedded tissue (FFPEt) of 24 advanced lung adenocarcinoma patients, previously evaluated by FISH and IHC. We used a one-step Scorpion RT-PCR that allowed in a single reaction either the mRNA reverse transcription and the cDNA amplification for ALK kinase-domain, normally not expressed, and a control gene, to assess RNA quality. Results are reported in Table 1. Despite the instability of mRNA from FFPEt, only 2 samples resulted inadequate for RT-PCR. RT-PCR was in disagreement with both FISH and IHC in one case, which is likely to be a RT-PCR false positive. RT-PCR did not detect ALK aberrant expression in a FISH positive case, which was negative also by IHC; unfortunately, this patient died after a cycle of pemetrexed therapy, before undergoing a second line TKI treatment. The presence of ALK rearrangements does not necessarily imply increased protein levels, because of the complex transcriptional and post-transcriptional regulations, so further analysis at RNA levels may clarify discrepancy between FISH and IHC allowing a better stratification of patients who could benefit from TKIs. Therefore, according to our results the RT-PCR evaluating ALK aberrant expression regardless of the fusion partners should be considered for introduction into routine ALK testing in lung cancer.

Biomonitoring DNA Adducts of Cooked Meat Carcinogens in Human Prostate by Nano Liquid Chromatography-High Resolution Tandem Mass Spectrometry: Identification of 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine DNA Adduct.

Epidemiologic studies have reported an association between frequent consumption of well-done cooked meats and prostate cancer risk. However, unambiguous physiochemical markers of DNA damage from carcinogens derived from cooked meats, such as DNA adducts, have not been identified in human samples to support this paradigm. We have developed a highly sensitive nano-LC-Orbitrap MS n method to measure DNA adducts of several carcinogens originating from well-done cooked meats, tobacco smoke, and environmental pollution, including 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-9H-pyrido[2,3-b]indole (AαC), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), benzo[a]pyrene (B[a]P), and 4-aminobiphenyl (4-ABP). The limit of quantification (LOQ) of the major deoxyguanosine (dG) adducts of these carcinogens ranged between 1.3 and 2.2 adducts per 10 9 nucleotides per 2.5 μg of DNA assayed. The DNA adduct of PhIP, N-(deoxyguanosin-8-yl)-PhIP (dG-C8-PhIP) was identified in 11 out of 35 patients, at levels ranging from 2 to 120 adducts per 10 9 nucleotides. The dG-C8 adducts of AαC and MeIQx, and the B[a]P adduct, 10-(deoxyguanosin-N 2 -yl)-7,8,9-trihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene (dG-N 2 -B[a]PDE) were not detected in any specimen, whereas N-(deoxyguanosin-8-yl)-4-ABP (dG-C8-4-ABP) was identified in one subject (30 adducts per 10 9 nucleotides). PhIP-DNA adducts also were recovered quantitatively from formalin fixed paraffin embedded (FFPE) tissues, signifying FFPE tissues can serve as biospecimens for carcinogen DNA adduct biomarker research. Our biomarker data provide support to the epidemiological observations implicating PhIP, one of the most mass-abundant heterocyclic aromatic amines formed in well-done cooked meats, as a DNA-damaging agent that may contribute to the etiology of prostate cancer.

Deciphering tumor heterogeneity from FFPE tissues: Its promise and challenges

ABSTRACTAn impediment to the understanding of cancer is the heterogeneous nature of cell populations within a tumor microenvironment. We reported a method to query protein signaling in single epithelial cells from formalin-fixed paraffin-embedded (FFPE) colorectal cancer tissues. Here, we discuss the feasibility and limitations of this approach for investigating signaling state heterogeneity.

Nucleic acid extraction from formalin-fixed paraffin-embedded cancer cell line samples: a trade off between quantity and quality?

BackgroundAdvanced genomic techniques such as Next-Generation-Sequencing (NGS) and gene expression profiling, including NanoString, are vital for the development of personalised medicines, as they enable molecular disease classification. This has become increasingly important in the treatment of cancer, aiding patient selection. However, it requires efficient nucleic acid extraction often from formalin-fixed paraffin-embedded tissue (FFPE).MethodsHere we provide a comparison of several commercially available manual and automated methods for DNA and/or RNA extraction from FFPE cancer cell line samples from Qiagen, life Technologies and Promega. Differing extraction geometric mean yields were evaluated across each of the kits tested, assessing dual DNA/RNA extraction vs. specialised single extraction, manual silica column based extraction techniques vs. automated magnetic bead based methods along with a comparison of subsequent nucleic acid purity methods, providing a full evaluation of nucleic acids isolated.ResultsOut of the four RNA extraction kits evaluated the RNeasy FFPE kit, from Qiagen, gave superior geometric mean yields, whilst the Maxwell 16 automated method, from Promega, yielded the highest quality RNA by quantitative real time RT-PCR. Of the DNA extraction kits evaluated the PicoPure DNA kit, from Life Technologies, isolated 2–14× more DNA. A miniaturised qPCR assay was developed for DNA quantification and quality assessment.ConclusionsCareful consideration of an extraction kit is necessary dependent on quality or quantity of material required. Here we provide a flow diagram on the factors to consider when choosing an extraction kit as well as how to accurately quantify and QC the extracted material.Electronic supplementary materialThe online version of this article (doi:10.1186/s12907-016-0039-3) contains supplementary material, which is available to authorized users.

Extraction of miRNAs from Formalin-Fixed Paraffin-Embedded (FFPE) Tissues.

miRNAs are small non-coding RNAs that regulate gene expression and are involved in numerous diseases ranging from osteoporosis, cardiovascular disease, and numerous cancer indications. Most of the clinical material that is accessible for study is archival FFPE blocks. Due to the harsh nature of fixation and embedding procedures involved in preserving clinical material, these samples are heavily fragmented and chemically cross-linked by formalin. miRNAs, due to their small size and increased stability, are easier to retrieve and study in these precious tissues. Therefore, miRNAs have become useful tools in the diagnosis, prognosis, and prediction of diseases. Due to their increased importance, isolation of miRNAs from FFPE material is extremely clinically relevant. Here, we describe the best method for miRNA extraction from FFPE tissue blocks and determine the Qiagen miRNeasy FFPE kit to be the best kit for this task.

CpG Methylation Analysis of HPV16 in Laser Capture Microdissected Archival Tissue and Whole Tissue Sections from High Grade Anal Squamous Intraepithelial Lesions: A Potential Disease Biomarker.

Incidence and mortality rates of anal cancer are increasing globally. More than 90% of anal squamous cell carcinomas (ASCC) are associated with human papillomavirus (HPV). Studies on HPV-related anogenital lesions have shown that patterns of methylation of viral and cellular DNA targets could potentially be developed as disease biomarkers. Lesion-specific DNA isolated from formalin-fixed paraffin-embedded (FFPE) tissues from existing or prospective patient cohorts may constitute a valuable resource for methylation analysis. However, low concentrations of DNA make these samples technically challenging to analyse using existing methods. We therefore set out to develop a sensitive and reproducible nested PCR-pyrosequencing based method to accurately quantify methylation at 10 CpG sites within the E2BS1, E2BS2,3,4 and Sp1 binding sites in the viral upstream regulatory region of HPV16 genome. Methylation analyses using primary and nested PCR-pyrosequencing on 52 FFPE tissue [26 paired whole tissue sections (WTS) and laser capture microdissected (LCM) tissues] from patients with anal squamous intraepithelial lesions was performed. Using nested PCR, methylation results were obtained for the E2BS1, E2BS2,3,4 and Sp1 binding sites in 86.4% of the WTS and 81.8% of the LCM samples. Methylation patterns were strongly correlated within median values of matched pairs of WTS and LCM sections, but overall methylation was higher in LCM samples at different CpG sites. High grade lesions showed low methylation levels in the E2BS1 and E2BS2 regions, with increased methylation detected in the E2BS,3,4/Sp1 regions, showing the highest methylation at CpG site 37. The method developed is highly sensitive in samples with low amounts of DNA and demonstrated to be suitable for archival samples. Our data shows a possible role of specific methylation in the HPV16 URR for detection of HSIL.

Abstract 1836: Global gene expression profiles from bladder tumor FFPE samples

Abstract Cancer is a disease characterized by uncontrolled cell growth and proliferation. Recent advances in molecular medicine and cancer biology have changed the way clinicians evaluate and consider treatment. Selected tumor biomarkers have been utilized as targets for drug therapy leading to better more effective treatment. Gene expression profiling has been used for identifying new biomarkers for tumor classification and driving decision making for better patient outcome in different tumor types. DNA microarrays have become a key method to acquire a comparative snapshot of the gene expression profile from test samples in a high throughput manner. Quantitative PCR and newer sequencing techniques are popular alternatives offering highly accurate gene expression measurements, but with limitations due to cost, complex instrumentation and analysis needs. RNA extracted from formalin fixed paraffin embedded tissue (FFPE) creates considerable additional challenges in acquiring accurate gene expression measurements due to the highly fragmented and compromised integrity of FFPE RNA due to the fixation process. To address the challenges of current sequencing based methods and take advantage of the simplicity of analysis that comes with using technologies such as microarrays; we have tested the Ion AmpliSeq™ Transcriptome Human Gene Expression Kit using RNA isolated from bladder tumor FFPE specimens. This targeted RNA sequencing approach allows profiling the global mRNA expression of human RNA in a highly multiplexed fashion using the Ion AmpliSeq™ technology. 10ng of total RNA extracted from FFPE tissue was reverse transcribed followed by automated library preparation on the Ion Chef™ system using the new Ion AmpliSeq™ Kit for Chef and the Ion AmpliSeq™ Transcriptome Human Gene Expression Panel. Eight pooled libraries were then sequenced on the Ion S5™XL System with Ion 540™ Chip. Libraries were also prepared with well characterized control RNAs, Universal Human Reference RNA (UHR) and First Choice Human Brain Reference RNA (HBR) using both the manual and automated library generation protocol for validation and comparison studies. The results show detection of more genes than popular microarray platforms with comparable differential gene expression measurements to quantitative PCR (r = 0.96) and RNA-Seq methods (r = 0.94). Gene expression values correlated with R>0.99 for all technical replicates and R>0.95 between manual and automated library preparation methods using well characterized samples. The Ion AmpliSeq™ Transcriptome Human Gene Expression Kit is a simple method to measure global gene expression profiles from human RNA samples in a timely, cost effective, and high throughput manner resulting in sensitive and accurate gene expression measurements. The new S5™XL System combined with automated library and template preparation on the Ion Chef™ system enable a simple RNA to gene expression data workflow requiring only 45 minutes of hands on time from 10ng of FFPE RNA. Citation Format: Varun Bagai, Jeoffrey Schageman, Kelli Bramlett, David J. McConkey, Woonyoung Choi. Global gene expression profiles from bladder tumor FFPE samples. [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 1836.

Abstract 3638: A rapid, multiplexed, and highly accurate next-generation sequencing RAS Panel for FFPE colorectal samples reporting on the absence or presence of low frequency somatic variants

Abstract Introduction: Next generation sequencing (NGS) is a highly sensitive method for detecting somatic mutations. Mutations in NRAS and KRAS may affect up to 50% of patients with colorectal cancer (CRC). Recent data suggest the clinical benefit of panitumumab is restricted to patients who have no tumor mutations in RAS, defined as codons 12, 13, 59, 61, 117 and 146 of KRAS and NRAS genes. An Extended RAS panel* targets these codons as a single multiplex assay. A dual strand approach distinguishes true mutations from artifacts commonly found in DNA from Formalin Fixed Paraffin Embedded (FFPE) tissue. Analytical performance of this panel was characterized. Methods: FFPE tissue was examined for tumor content and area. DNA was extracted from FFPE tissue, cell lines and plasmids. The DNA quality and quantity were simultaneously determined through a quantitative PCR measurement of amplifiability. TruSeq Custom Amplicon technology targeting each strand of DNA was used to construct NGS libraries. Sequencing was performed on the MiSeqDx, and the Illumina Somatic Variant Caller was used to call somatic variants. Results: The dual-strand amplicon approach results in high accuracy by eliminating false positives observed on one strand of DNA typical of an FFPE artifact, by requiring every variant to be detected on both strands. We evaluated performance on 500 FFPE CRC samples processed with the Extended RAS panel. Concordance against Qiagen TheraScreen and Sanger Sequencing results was evaluated. The somatic variant caller yields a specificity of 0.98 and sensitivity of 0.72 for variants in the 5%-10% range, and a specificity of 0.96 and sensitivity of 0.98, overall, where we take the alternate methods as truth. Cumulative FFPE tissue area influences performance of the RAS panel. FFPE of a range of tissue area were tested using 1, 3, 5, and 8 sections per sample. 80mm2 minimum (240mm2 recommended) cumulative tissue area using 5uM slices was optimal for performance and accuracy. DNA quantity and quality also influence test accuracy and sensitivity. A study with 40 FFPE specimens assayed over multiple operators and sequencers produced average coverage of 32,000 reads per target per sample, and over 93% alignable reads per sample. Reproducibility of mutations detected over multiple operators and instruments was 100%. The Extended RAS Panel demonstrates robust performance across many sources of variation, including FFPE DNA extraction method, DNA storage time, recommended DNA input range, qPCR/PCR thermocyclers with little to no impact on sample pass rate and agreement with Sanger sequencing. We also demonstrate detection of 56 distinct mutations in a single run. Conclusion: This multiplex assay achieves high accuracy for detection of somatic mutations from DNA extracted from FFPE colorectal tissue samples. *In development For Research Use Only. Not for use in diagnostic procedures. Citation Format: Tamsen Dunn, Anita Iyer, Margaret Porter, Robert Haigis, Shannon Smith, Desiree Lee, Nitin Udar. A rapid, multiplexed, and highly accurate next-generation sequencing RAS Panel for FFPE colorectal samples reporting on the absence or presence of low frequency somatic variants. [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 3638.

Multimodal Mass Spectrometry Imaging of N-Glycans and Proteins from the Same Tissue Section

On-tissue digestion matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) can be used to record spatially correlated molecular information from formalin-fixed, paraffin-embedded (FFPE) tissue sections. In this work, we present the in situ multimodal analysis of N-linked glycans and proteins from the same FFPE tissue section. The robustness and applicability of the method are demonstrated for several tumors, including epithelial and mesenchymal tumor types. Major analytical aspects, such as lateral diffusion of the analyte molecules and differences in measurement sensitivity due to the additional sample preparation methods, have been investigated for both N-glycans and proteolytic peptides. By combining the MSI approach with extract analysis, we were also able to assess which mass spectral peaks generated by MALDI-MSI could be assigned to unique N-glycan and peptide identities.

Assessment of PAXgene Fixation on Preservation of Morphology and Nucleic Acids in Microdissected Retina Tissue

ABSTRACTAim: To compare the effect of the two fixatives on tissue morphology and utility to obtain good quality nucleic acids for molecular analysis from micro-dissected retinal samples.Methods: Enucleated specimens from New Zealand white rabbits were fixed in formalin or PAXgene fixative according to standard protocols, and then processed and embedded in paraffin for sectioning. Sections were stained with hematoxylin and eosin to assess the structural integrity of retina. Retinal tissue on slides was micro-dissected. DNA/RNA were extracted and assessed for preservation of the quality and quantity of the retinal tissue.Results: The retinal morphology was well preserved with both PAXgene and formalin fixation. The RNA yield obtained using both fixation methods was similar, but RNA from PAXgene fixed paraffin embedded (PFPE) samples had better purity than that from formalin fixed paraffin embedded (FFPE) samples. There was a twofold greater yield of DNA in PFPE compared to FFPE samples but with similar purity. Quantitative reverse transcription PCR analyses showed that the mean cycle threshold values for beta-actin, beta-microglobin, Opsin 1-sw, Rhodopsin, and 18S RNA of the PFPE group were significantly lower than those of the FFPE group (p < 0.01). Greater than 10-fold greater levels of gene expression were detected in PFPE relative to FFPE for the above genes.Conclusion: PAXgene fixed tissue retinal morphology is comparable to FFPE tissue. PAXgene may be a good alternative to formalin, providing good tissue morphology and ability to isolate high quality nucleic acids from micro-dissected paraffin embedded retinal samples.

The paraffin-embedded RNA metric (PERM) for RNA isolated from formalin-fixed, paraffin-embedded tissue.

RNA isolated from formalin-fixed, paraffin-embedded (FFPE) tissue is commonly evaluated in both investigative and diagnostic pathology. However, the quality of the data is directly impacted by RNA quality. The RNA integrity number (RIN), an algorithm based on a combination of electrophoretic features, is widely applied to RNA isolated from paraffin-embedded tissue, but it is a poor indicator of the quality of that RNA. Here we describe the novel paraffin-embedded RNA metric (PERM) for quantifying the quality of RNA from FFPE tissue. The PERM is based on a formula that approximates a weighted area-under-the-curve analysis of an electropherogram of the extracted RNA. Using biochemically degraded RNAs prepared from experimentally fixed mouse kidney specimens, we demonstrate that PERM values correlate with mRNA transcript measurements determined using the QuantiGene system. Furthermore, PERM values correlate with real-time PCR data. Our results demonstrate that the PERM can be used to qualify RNA for different end-point studies and may be a valuable tool for molecular studies using RNA extracted from FFPE tissue.

PD11-09 MOLECULAR TUMOR GRADING OF NON MUSCLE INVASIVE BLADDER CANCER BASED ON WHOLE TRANSCRIPTOME ANALYSIS

PD11-09 MOLECULAR TUMOR GRADING OF NON MUSCLE INVASIVE BLADDER CANCER BASED ON WHOLE TRANSCRIPTOME ANALYSIS

Abstract P3-07-47: Comprehensive profiling of metaplastic breast carcinoma reveals frequent over-expression of PD-L1

Abstract Background: Metaplastic breast carcinoma (MBC) is a rare subtype of breast carcinoma less responsive to conventional chemotherapy relative to usual breast carcinomas (UBCs) such as ductal and lobular subtype. In molecular terms MBC usually clusters with triple negative breast cancer (TNBC), but MBCs portray a worse prognosis in comparison to TNBCs. Published studies investigating MBCs for specific biomarkers of therapy response are rare and limited by the methodological approaches. Methods: This study included 132 patients with 38 histologically confirmed MBCs and 94 UBCs. Amongst the 94 UBCSs, 44 were estrogen receptor positive, 33 were triple negative and 17 were HER2 positive. Direct sequencing analysis was performed on genomic DNA isolated from formalin-fixed paraffin-embedded tissue (FFPE) using the Illumina MiSeq Next Generation Sequencing platform (NGS). Immunohistochemistry for PD-L1 (SP142, Spring Bioscience), PD-1 (NAT105, Ventana) and EGFR (31G7, Life Technologies) was performed using automated procedures. Additionally, mutation analysis for EGFRvIII was performed on RNA extracted from FFPE tissue. Results: At the genomic level, numerous cases of MBC had multiple genomic alterations with the most frequent genetic mutation in TP53 gene (14/24), similar to the TNBC controls (17/33). BRCA1 mutations were detected in 2/10 cases. Potentially actionable mutations were rare and included PIK3CA gene. Importantly, PD-L1 expression on cancer cells was detected in significantly higher proportion of MBCs (37%) than in the UBC cohort (6%) or TNBC control (14%) (p=3.7x10-5 and p=0.03, respectively). PD-1 positive tumors infiltrating lymphocytes (TILS) varied greatly in MBC (0 to &amp;gt;50/mm2). Over-expression of EGFR was frequent in MBCs (62%); however no mutations in the gene including EGFRvIII were detected. Conclusion: Comprehensive profiling of a large cohort of this rare carcinoma highlighted predominance of TP53 mutations, wild type EGFR gene expression, a distinct increase in proportion of PD-L1 expression in carcinoma cells, and PD-1 expression in TILS. The latter properties can be exploited in clinical trials utilizing immune check point inhibitors. Citation Format: Gatalica Z, Joneja U, Ghazalpour A, Swensen J, Feldman R, Cai F, Chen W, Xiao N, Reddy S, Palazzo J. Comprehensive profiling of metaplastic breast carcinoma reveals frequent over-expression of PD-L1. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-47.

Molecular tumor grading of non muscle invasive bladder cancer based on whole transcriptome analysis.

467 Background: There is an unmet need for a comprehensive genomic characterization of non muscle invasive bladder cancer (NMIBC). NMIBC comprise over 70% of all bladder cancers at presentation. They have highly variable clinical behavior that is not always adequately predicted on the basis of their histological grade (2004 World Health Organization low and high grade, LG-HG). The discrepancy between phenotype and genotype is compounded further by interobserver variability in pathological grading. We have previously established methods for whole transcriptome RNAseq from formalin fixed paraffin embedded tissues (FFPE). Methods: Whole transcriptomic analysis of 110 NMI FFPE BC both LG and HG was performed incorporating messenger RNA expression, splice variants, gene fusion, and pathway perturbation. We used a discovery (n = 40) and a validation cohort (n = 70). These data were integrated and tested for correlation with both pathological grading and clinical outcomes. Grade Risk Index (GRI) score quantifying how closely a patient's transcriptome is related to a reference set of LG NMIBC samples was established. Conventional pathological grading was reviewed by 3 different expert uro-pathologists and interobserver variability calculated. Results: Unsupervised clustering of data from RNA sequencing uncovered classification of three robust - - nonoverlapping, prognostically significant subtypes of NMIBC with distinct GRIs and signatures. When applied by expert pathologists, interobserver variability in histological grading was observed in 17.5%. In the intermediate group (GRI 0.13 to 0.19), pathologists disagreed in 37.5% whether BC was LG or HG. HG NMIBC clustered with MIBC. LG NMIBC in the intermediate GRI group included either very bulky tumors or extremely rare metastatic LG BC (n = 4). HG disease was associated with a shift in BMP signaling and a germ stem cell-like phenotype. Multiple components of the centromere complex and APOBEC3B were upregulated in HG BC. FGFR3::TACC3 fusion events were observed in LG NMIBC only (11.5%). Conclusions: Whole transcriptomic sequencing data delineated three molecular classes of NMIBC.

The effect of deoxyribonucleic acid extraction methods from lymphoid tissue on the purity, content, and amplifying ability.

Background:Nowadays, definitive diagnosis of numerous diseases is based on the genetic and molecular findings. Therefore, preparation of fundamental materials for these evaluations is necessary. Deoxyribonucleic acid (DNA) is the first material for the molecular pathology and genetic analysis, and better results need more pure DNA. Furthermore, higher concentration of achieved DNA causes better results and higher amplifying ability for subsequent steps. We aim to evaluate five DNA extraction methods to compare DNA intimacy including purity, concentration, and amplifying ability with each other.Materials and Methods:The lymphoid tissue DNA was extracted from formalin-fixed, paraffin embedded (FFPE) tissue through five different methods including phenol-chloroform as the reference method, DNA isolation kit (QIAamp DNA FFPE Tissue Kit, Qiagen, Germany), proteinase K and xylol extraction and heat alkaline plus mineral oil extraction as authorship innovative method. Finally, polymerase chain reaction (PCR) and real-time PCR method were assessed to compare each following method consider to DNA purity and its concentration.Results:Among five different applied methods, the highest mean of DNA purity was related to heat alkaline method. Moreover, the highest mean of DNA concentration was related to heat alkaline plus mineral oil. Furthermore, the best result in quantitative PCR was in proteinase K method that had the lowest cycle threshold averages among the other extraction methods.Conclusion:We concluded that our innovative method for DNA extraction (heat alkaline plus mineral oil) achieved high DNA purity and concentration.

Association of Gene Expression Profiling, Interim PET, EBV Status and PD-L1 Expression in Classical Hodgkin Lymphoma

IntroductionA challenge in the management of classical Hodgkin lymphoma (CHL) is selecting treatment which will maximise success while minimising treatment side effects. The international Response Adapted Therapy in Hodgkin Lymphoma (RATHL) trial (NCT00678327) demonstrated that treatment may be successfully adapted based on positron emission tomography (PET-CT) scan results after 2 cycles (PET2) of ABVD chemotherapy in advanced CHL. This approach however delays risk stratification meaning some patients may be over or under treated and therefore a baseline predictor is highly desirable. A gene expression-based model performed on RNA from formalin-fixed paraffin-embedded tissue (FFPET) biopsies on the Nanostring platform (Scott et al, J Clin Oncol 2013; 31:692-700) has been published. In addition Steidl et al used gene expression profiling (GEP) to correlate tumour-associated macrophages with survival in CHL (Steidl et al, NEJM 2010; 10:875-885). In order to explore whether GEP at baseline could be used in combination with PET2 results to predict outcome, these published gene signatures were explored on the DASL platform in a series of CHL cases and correlated with PET2 response. Recently, PD-1 ligand (PD-L1) on the cell surface of Reed-Sternberg cells (the hallmark cells of CHL) has been demonstrated to co-opt the PD-1 pathway allowing immune evasion (Green et al, Blood 2010;116:3268-77). Therefore this was also performed by immunohistochemistry (IHC) and GEP as well as assessment of EBV status.Methods50 patients with CHL were identified, with at least 2 years of follow up, diagnosed between 2008 and 2013. Deauville scores at PET2 were determined. IHC consistent with CHL, including: CD3, CD19, CD20, CD30, CD79, BOB-1, OCT-2, MUM1 and TARC was performed on 3mm FFPET lymph node sections, and reported by two independent observers. Latent Epstein-Barr virus (EBV) infection was determined by IHC for LMP-1 expression and in-situ hybridisation using fluorescein-labelled peptide nucleic acid probes (Dako, K5201). PD-L1 expression was determined by IHC using a rabbit monoclonal antibody (Cell Signaling Technology, E1L3N, #13684). Three to five 5mm sections of FFPET were used for RNA extraction using the Ambion RecoverAll™ kit standard protocol. GEP was quantified using Illumina's whole genome cDNA-mediated annealing, selection, extension, and ligation Assay (WG-DASL). 61 genes of interest were analysed for significance in the difference in gene expression between groups and included genes from the two recently reported GEP predictor tools in CHL (Steidl et al, 2010, Scott et al 2013) as well as PD-1 and PD-L1. The Mann-Whitney test was used to assess the significance in the difference between means (significant if p<0.05).ResultsA statistically significant difference in EBV status was found between PET negative (Deauville scores 1-3) and PET positive (Deauville scores 4-5) groups (Fisher's exact test: P-Value = 0.028). All patients who were EBV positive had a negative PET2 scan. GEP using WG-DASL revealed that only 2 genes of those reported in recent predictor models (Steidl et al 2010, Scott et al 2013) were expressed at significantly different levels between PET negative and PET positive patients (GLUL, RNF144B), both with increased expression in the PET2 positive group. There was no significant difference between PD-L1 expression and PET scores, CD274 gene expression and outcome. Assessment as to whether samples would cluster into groups according to PET positivity or PD-L1 expression status by unsupervised cluster analysis using four recently reported B cell lymphoma gene signatures (Monti et al, Blood 2005; 5:1851-61, Care et al, PloS one 2013; 2: e55895) was performed, but no significant grouping was found.ConclusionGEP on the DASL platform was not able to predict PET response. The original models were trained on outcome and therefore retraining of the GEP model based on PET response is likely to be required. EBV status was found to be predictive of PET response but this could not be correlated with other biomarkers to predict outcome. Although PD-1 and PD-L1 targeted therapy has shown exciting results in patients with CHL, PD-L1 IHC expression and CD274 gene expression, did not correlate with PET2 response or outcome. Baseline biomarkers capable of identifying patients likely to benefit from targeted treatment needs to be further investigated in proposed clinical trials. DisclosuresNo relevant conflicts of interest to declare.

Commercially available kits for manual and automatic extraction of nucleic acids from formalin-fixed, paraffin-embedded (FFPE) tissues.

Formalin-fixed, paraffin-embedded (FFPE) tissues represent an invaluable source for diagnostic purposes when fresh clinical material is unavailable, and also for molecular and epidemiological studies. The recovery of nucleic acids from FFPE tissues is particularly challenging, and several in-house methods have been developed for this purpose over the last three decades. Recently, several commercial kits specifically developed for DNA and/or RNA extraction from FFPE tissues have been introduced to the market, but their inventory is not available in peer-reviewed literature. This article provides the first comprehensive inventory of commercial FFPE DNA/RNA extraction kits currently available on the market and describes their basic characteristics and features. A total of 69 commercial kits from 43 companies were identified. Thirty-five kits were developed specifically for DNA extraction, 22 for RNA extraction, and 12 for both DNA and RNA extraction. Only two commercial kits allow full automation of the entire nucleic acid extraction procedure. The tissue deparaffinization step is omitted in many protocols by melting paraffin directly in a tissue lysis buffer. Purification of the released nucleic acids is mainly based on silica or resin adsorption technology. A formalin reverse cross-linking step to increase the quality of extracted DNA and RNA is an intrinsic part of over half of the kits identified. It is hope that this comprehensive list of available commercial kits for extracting nucleic acids from FFPE will encourage researchers to strongly consider using them in diagnostic and research settings instead of old-fashioned, crude, and probably less effective in-house methods.

Gene fusion detection in formalin-fixed paraffin-embedded benign fibrous histiocytomas using fluorescence in situ hybridization and RNA sequencing

Benign fibrous histiocytomas (FH) can be subdivided into several morphological and clinical subgroups. Recently, gene fusions involving either one of two protein kinase C genes (PRKCB and PRKCD) or the ALK gene were described in FH. We here wanted to evaluate the frequency of PRKCB and PRKCD gene fusions in FH. Using interphase fluorescence in situ hybridization on sections from formalin-fixed paraffin-embedded (FFPE) tumors, 36 cases could be analyzed. PRKCB or PRKCD rearrangements were seen in five tumors: 1/7 regular, 0/3 aneurysmal, 0/6 cellular, 2/7 epithelioid, 0/1 atypical, 2/10 deep, and 0/2 metastatic lesions. We also evaluated the status of the ALK gene in selected cases, finding rearrangements in 3/7 epithelioid and 0/1 atypical lesions. To assess the gene fusion status of FH further, deep sequencing of RNA (RNA-Seq) was performed on FFPE tissue from eight cases with unknown gene fusion status, as well as on two FH and six soft tissue sarcomas with known gene fusions; of the latter eight positive controls, the expected fusion transcript was found in all but one, while 2/8 FH with unknown genetic status showed fusion transcripts, including a novel KIRREL/PRKCA chimera. Thus, also a third member of the PRKC family is involved in FH tumorigenesis. We conclude that gene fusions involving PRKC genes occur in several morphological (regular, cellular, aneurysmal, epithelioid) and clinical (cutaneous, deep) subsets of FH, but they seem to account for only a minority of the cases. In epithelioid lesions, however, rearrangements of PRKC or ALK were seen, as mutually exclusive events, in the majority (5/7) of cases. Finally, the study also shows that RNA-Seq is a promising tool for identifying gene fusions in FFPE tissues.