Fresh Frozen Tissue Samples Research Articles

Glutathione Peroxidase (GPx) and Superoxide Dismutase (SOD) in Oropharyngeal Cancer Associated with EBV and HPV Coinfection.

Recent reports have pointed to the link between persistent inflammation, oxidative stress, and carcinogenesis; however most of the studies concerning the role of viruses in head and neck cancer (HNC) are focused mainly on one type of virus. Our present study aimed to study the relationship between Epstein–Barr virus/human papilloma virus (EBV/HPV) coinfection and glutathione peroxidase (GPx) and superoxide dismutase (SOD) level in oropharyngeal cancer. Fresh-frozen tumor tissue samples were collected from 128 patients with oropharyngeal cancer infected with EBV or HPV or with EBV/HPV coinfection. After DNA extraction, EBV and HPV DNA was detected using a polymerase chain reaction (PCR) assay. GPx and SOD activity was determined in homogenates of cancer tissue using diagnostic kits produced by Randox Laboratories. Both GPx and SOD activity was statistically lower in patients with EBV/HPV coinfection than in a single EBV or HPV infection. Analysis of GPx and SOD activity in relation to histological grading and tumor, node (TN) classification revealed that in poorly-differentiated tumors, the level of antioxidant enzymes was lower compared with well-differentiated lesions and in cases with greater tumor dimensions and lymph-node involvement, both GPx and SOD activity was decreased. Further studies are necessary to clarify the influence of interplay between EBV, HPV, and oxidative stress on malignant transformation of upper aerodigestive tract epithelial cells.

Nuclei Isolation from Fresh Frozen Brain Tumors for Single-Nucleus RNA-seq and ATAC-seq.

Adult diffuse gliomas exhibit inter- and intra-tumor heterogeneity. Until recently, the majority of large-scale molecular profiling efforts have focused on bulk approaches that led to the molecular classification of brain tumors. Over the last five years, single cell sequencing approaches have highlighted several important features of gliomas. The majority of these studies have utilized fresh brain tumor specimens to isolate single cells using flow cytometry or antibody-based separation methods. Moving forward, the use of fresh-frozen tissue samples from biobanks will provide greater flexibility to single cell applications. Furthermore, as the single-cell field advances, the next challenge will be to generate multi-omics data from either a single cell or the same sample preparation to better unravel tumor complexity. Therefore, simple and flexible protocols that allow data generation for various methods such as single-nucleus RNA sequencing (snRNA-seq) and single nucleus Assay for Transposase-Accessible Chromatin with high-throughput sequencing (snATAC-seq) will be important for the field. Recent advances in the single cell field coupled with accessible microfluidic instruments such as the 10x genomics platform have facilitated single cell applications in research laboratories. To study brain tumor heterogeneity, we developed an enhanced protocol for the isolation of single nuclei from fresh frozen gliomas. This protocol merges existing single cell protocols and combines a homogenization step followed by filtration and buffer mediated gradient centrifugation. The resulting samples are pure single nuclei suspensions that can be used to generate single nucleus gene expression and chromatin accessibility data from the same nuclei preparation.

Abstract 4276: Target enrichment to enable RNA-sequencing on FFPE samples: Application to a patient selection biomarkers in colorectal cancer

Abstract In proof of concept clinical studies, selecting for patients that are the most likely to respond to a given therapy will increase the chance of demonstrating clinical benefit for a new investigational agent. Archived Formalin-Fixed, Paraffin-Embedded (FFPE) tissue taken at the time of first biopsy and cancer diagnosis are a ready source of material for such patient selection assays; however if the selection assay is RNA-based sequencing based assay, FFPE tumor tissues are typically refractory to standard methods. Here we describe Target Enrichment, an RNA-sequencing technique that enabled analysis of FFPE tumor tissue. The Target Enrichment technique provides the necessary, high quality gene expression data required for identifying the mesenchymal subtype of CRC. In this experiment, RNA was extracted from a set of 192 histologically characterized, archived colorectal cancer (CRC) FFPE tumor tissues with sufficient representation of all Consensus Molecular Subtypes of CRC. A major issue with FFPE tissue is that nucleic acids are not well preserved in the fixation process. The RNA extraction method was carefully optimized in advance toward improving yield and integrity of the total RNA. In order to accommodate the low FFPE RNA integrity, we used Target Enrichment, a technique derived from whole-exome sequencing that isolates and amplifies library fragments corresponding to only the transcribed regions of interest. After testing several protocols, we established a Target Enrichment technique to remove low-quality library fragments that would otherwise interfere and impair sequencing quality. This method allowed us to generate high-quality sequencing data for samples that proved challenging using traditional RNA-seq methods. Fresh-frozen tissue samples were used as a benchmark and our Target Enrichment technique showed comparable performance across multiple sequencing quality metrics including mapping rate, expression profiling efficiency, number of genes detected, also the pass rate. Furthermore, data generated using our Target Enrichment technique aligned with the known frequencies of the Consensus Molecular Subtypes of CRC. Overall, our Target Enrichment technique provides a protocol for generating high quality RNA-seq libraries from highly degraded FFPE RNA. Citation Format: Maximilian Rogers-Grazado, Joachim Theilhaber, Jack Pollard, Alexei Protopopov. Target enrichment to enable RNA-sequencing on FFPE samples: Application to a patient selection biomarkers in colorectal cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4276.

Abstract 4266: Proteomics for precision oncology: Profiling the proteome of matching tumor and adjacent normal tissue using data-independent acquisition

Abstract Precision oncology requires a deep understanding of the molecular mechanism in cancer biology. The predominant approach today focuses on genome structure and gene expression data, which have become available with the rise of next-gen sequencing technology. On a phenotypic level, however, protein expression and activation are arguably more directly related to cellular function. The availability of combined genome and proteome level data from the same tumor is therefore expected to provide a much more complete picture of a tumor in a particular state. Until recently, proteomics technology could not match the scale of next-gen sequencing and consequently, precision medicine research has almost exclusively been based on gene-level data. Here we show the first truly large-scale data set for protein expression and protein phosphorylation for a large collection of biospecimens derived from the IndivuType cohort of Indivumed, Germany. Matching fresh-frozen tumor and adjacent normal tissue samples from thousands of patients including various cancer entities were obtained from Indivumed's network of partner hospitals Enabled by the novel data-independent acquisition (DIA) workflow, a mass spectrometric method that obtains peptide fragmentation data in a highly parallelized way with high reproducibility and sensitivity, more than 7,000 proteins in the whole proteome (WP) and 20,000 phospho-peptides in the phospho-proteome (PP) workflow were analyzed. Sample processing from 5 mg of tissue per sample was performed on 96-well plates with the help of a liquid handling robot. Phospho-peptide enrichment was carried out using a Kingfisher Flex device and MagReSyn Ti-IMAC magnetic beads (ReSyn Biosciences). Data-independent acquisition (DIA) LC-MS/MS was performed on multiple platforms consisting of a Thermo Scientific Q Exactive HF-X mass spectrometer coupled to a Waters M-Class LC. Chromatography was operating at 5 µL/min, and separation was achieved using 45 min (WP) and 60 min (PP) gradients. With a throughput of 850 WP and 650 PP samples per month, thousands of samples were analyzed to date. The resulting proteome data is integrated into Indivumed's IndivuType multi-omics database, supporting the identification and validation of new molecular cancer drug targets and biomarkers. Citation Format: Jakob Vowinckel, Karel Novy, Thomas Corwin, Tobias Treiber, Roland Bruderer, Lukas Reiter, Eike von Leitner, Oliver Rinner, Claudia Escher. Proteomics for precision oncology: Profiling the proteome of matching tumor and adjacent normal tissue using data-independent acquisition [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4266.

RET, NTRK, ALK, BRAF, and MET Fusions in a Large Cohort of Pediatric Papillary Thyroid Carcinomas.

Background: Pediatric papillary thyroid carcinoma (PTC) is a rare malignancy, but with increasing incidence. Pediatric PTCs have distinct clinical and pathological features and even the molecular profile differs from adult PTCs. Somatic point mutations in pediatric PTCs have been previously described and studied, but complex information about fusion genes is lacking. The aim of this study was to identify different fusion genes in a large cohort of pediatric PTCs and to correlate them with clinical and pathological data of patients. Methods: The cohort consisted of 93 pediatric PTC patients (6-20 years old). DNA and RNA were extracted from fresh frozen tissue samples, followed by DNA and RNA-targeted next-generation sequencing analyses. Fusion gene-positive samples were verified by real-time polymerase chain reaction. Results: A genetic alteration was found in 72/93 (77.4%) pediatric PTC cases. In 52/93 (55.9%) pediatric PTC patients, a fusion gene was detected. Twenty different types of RET, NTRK3, ALK, NTRK1, BRAF, and MET fusions were found, of which five novel, TPR/RET, IKBKG/RET, BBIP1/RET, OPTN/BRAF, and EML4/MET, rearrangements were identified and a CUL1/BRAF rearrangement that has not been previously described in thyroid cancer. Fusion gene-positive PTCs were significantly associated with the mixture of classical and follicular variants of PTC, extrathyroidal extension, higher T classification, lymph node and distant metastases, chronic lymphocytic thyroiditis, and frequent occurrence of psammoma bodies compared with fusion gene-negative PTCs. Fusion-positive patients also received more doses of radioiodine therapy. The most common fusion genes were the RET fusions, followed by NTRK3 fusions. RET fusions were associated with more frequent lymph node and distant metastases and psammoma bodies, and NTRK3 fusions were associated with the follicular variant of PTC. Conclusions: Fusion genes were the most common genetic alterations in pediatric PTCs. Fusion gene-positive PTCs were associated with more aggressive disease than fusion gene-negative PTCs.

Data independent acquisition-mass spectrometry (DIA-MS)-based comprehensive profiling of bone metastatic cancers revealed molecular fingerprints to assist clinical classifications for bone metastasis of unknown primary (BMUP).

BackgroundBone metastasis is the third most common metastatic cancers worldwide. It is a group of highly heterogeneous diseases with various potential cancer primaries. Among them, one third was diagnosed as bone metastasis of unknown primary (BMUP) due to lack of indication for the primary tumor even after comprehensive examinations. Thus, the prognosis of BMUP is often very poor since the treatment was largely empirical and untargeted. To assist identification of the primary tumor, a series of molecular markers including traditional tissue-specific histochemistry as well as gene and mRNA markers were developed with moderate to good sensitivity and specificity.MethodsIn this paper, we carried out a comprehensive expression profiling for fresh-frozen tissue samples of bone metastasis from lung, prostate and liver cancers using high resolution, data-independent-acquisition mass spectrometry (DIA-MS). The proteome variation was analyzed and protein classifiers were prioritized.ResultsOver 6,000 proteins were quantified from 18 samples, which, to the best of our knowledge, was never achieved before. Further statistical analysis and bioinformatics data mining revealed 4 significant proteins (RFIP1, CK15, ESYT2, and MAL2) with excellent discriminating capabilities with AUCs higher than 0.8.ConclusionsThe comprehensive proteome map of bone metastases will complement available genomic and transcriptomic data. Newly discovered protein classifiers will expand current diagnostic arsenal for tissue of origin studies in BMUP. Furthermore, the proteome map generated in this study by DIA-MS allows future data re-mining as our knowledge advances to assist investigation of bone metastasis and progression of tumors as well as the development of diagnostic tools and prognosis management for BMUPs.

Accelerated Lysis and Proteolytic Digestion of Biopsy-Level Fresh-Frozen and FFPE Tissue Samples Using Pressure Cycling Technology.

Pressure cycling technology (PCT)-assisted tissue lysis and digestion have facilitated reproducible and high-throughput proteomic studies of both fresh-frozen (FF) and formalin-fixed paraffin-embedded (FFPE) tissue of biopsy scale for biomarker discovery. Here, we present an improved PCT method accelerating the conventional procedures by about two-fold without sacrificing peptide yield, digestion efficiency, peptide, and protein identification. The time required for processing 16 tissue samples from tissues to peptides is reduced from about 6 to about 3 h. We analyzed peptides prepared from FFPE hepatocellular carcinoma (HCC) tissue samples by the accelerated PCT method using multiple MS acquisition methods, including short-gradient SWATH-MS, PulseDIA-MS, and 10-plex TMT-based shotgun MS. The data showed that up to 8541 protein groups could be reliably quantified from the thus prepared peptide samples. We applied the accelerated sample preparation method to 25 pairs (tumorous and matched benign) of HCC samples followed by a single-shot, 15 min gradient SWATH-MS analysis. An average of 18 453 peptides from 2822 proteins were quantified in at least 20% samples in this cohort, while 1817 proteins were quantified in at least 50% samples. The data not only identified the previously known dysregulated proteins such as MCM7, MAPRE1, and SSRP1 but also discovered promising novel protein markers, including DRAP1 and PRMT5. In summary, we present an accelerated PCT protocol that effectively doubles the throughput of PCT-assisted sample preparation of biopsy-level FF and FFPE samples without compromising protein digestion efficiency, peptide yield, and protein identification.

Deciphering tissue‐based proteome signatures revealed novel subtyping and prognostic markers for thymic epithelial tumors

Thymic epithelial tumors (TETs) belong to a group of tumors that rarely occur, but have unresolved mechanisms and heterogeneous clinical behaviors. Current care of TET patients demands biomarkers of high sensitivity and specificity for accurate histological classification and prognosis management. In this study, 134 fresh‐frozen tissue samples (84 tumor, 40 tumor adjacent, and 10 normal thymus) were recruited to generate a quantitative and systematic view of proteomic landscape of TETs. Among them, 90 samples were analyzed by data‐independent acquisition mass spectrometry (DIA‐MS) leading to discovery of novel classifying molecules among different TET subtypes. The correlation between clinical outcome and the identified molecules was probed, and the prioritized proteins of interest were further validated on the remaining samples (n = 44) via parallel reaction monitoring (PRM) as well as immunohistochemical and confocal imaging analysis. In particular, two proteins, the cellular mRNA deadenylase CCR4 (carbon catabolite repressor 4)‐NOT (negative on TATA) complex subunit 2/9 (CNOT2/9) and the serine hydroxymethyltransferase that catalyzes the reversible interconversions of serine and glycine (SHMT1), were found at dramatic low levels in the thymic epithelia of more malignant subtype, thymic squamous cell carcinoma (TSCC). Interestingly, the mRNA levels of these two genes were shown to be closely correlated with prognosis of the TET patients. These results extended the existing human tissue proteome atlas and allowed us to identify several new protein classifiers for TET subtyping. Newly identified subtyping and prognosis markers, CNOT2/9 and SHMT1, will expand current diagnostic arsenal in terms of higher specificity and prognostic insights for TET diagnosis and management.

MPC-08 CLINICOPATHOLOGICAL ANALYSIS OF 12P GAIN IN INTRACRANIAL GERM CELL TUMORS

BACKGROUNDGain of short arm of chromosome 12 (12p) is commonly observed in testicular germ cell tumors (tGCTs). 12p gain is also frequently seen in intracranial GCTs (iGCTs). However, little is known about the clinical significance of 12p gain in iGCTs.MATERIALS AND METHODSWe have collected over 200 fresh frozen tissue samples of iGCTs through the Intracranial Germ Cell Tumor Genome Analysis Consortium in Japan. Firstly, we analyzed DNA methylation status in 83 iGCTs, 3 seminomas and 6 normal control samples using Infinium Human Methylation 450K BeadChip array (Illumina, CA). Idat files were processed using R (Version 3.5.3) and minfi package (1.30.0) to generate copy number variations. Compared with average genome-wide copy number level, 12p gain was determined. Then, 58 iGCTs with clinicopathological information were analyzed for progression-free survival (PFS) and overall survival (OS). Those tumors that consist of only either germinoma and/or mature teratoma components were classified as Favorable Histology (FH) and all the others that contains malignant histological components were classified as Unfavorable Histology (UFH).RESULT12p gain was observed in 100% (3/3) of seminoma, 13.6% (3/22) of germinoma, 16.7% (1/6) of mature teratoma, 25% (1/4) of immature teratoma, 55% (11/20) of mixed germ cell tumor, 100% (4/4) of yolk sac tumor, 100% (1/1) of embryonal carcinoma, and 100% (1/1) of choriocarcinoma. In total, 44.6% (37/83) of iGCT showed 12p gain. Regarding histological classification, the 12p gain rate in UFH (72%, 18/25) was significantly higher than that in FH (12.1%, 4/33, P<0.01). Both PFS and OS were significantly worse in iGCTs with 12p gain (PFS: P=0.027, OS: P=0.0012). DISCUSSION12p gain can be a molecular marker to predict prognosis and histological malignancy in iGCTs.

Effect of seasonal variation in ambient temperature on RNA quality of breast cancer tissue in a remote biobank setting

Studies involving oncology especially diagnosis, prognosis and therapeutic monitoring are increasingly relying on molecular analyses. These analyses require high quality biomolecules to get accurate and precise results and this requires among others, monitoring for pre-analytical variables. The purpose of our study was to validate the SOPs of the newly established Egyptian National Cancer Institute (ENCI) biobank. We used a panel of 91 fresh frozen breast cancer tissue samples and their matched normal tissues and have investigated the overall quality (integrity and yield) of RNA extracted from fresh frozen breast tumor tissues and matched normal breast tissues. We investigated the effect of several factors including seasonal temperature variation, cold ischemia time, transportation method, and RNA extraction method. The RNA yield and quality were significantly increased with tumor samples collected in winter, transported on wet ice and using an automated RNA extraction platform. No significant effect was observed due to increased cold ischemia time >30 min. The effect of delay in time to cryopreservation on RNA degradation in fresh tissue samples may vary according to the type of tissue, temperature during tissue collection and transportation, and the use of stabilizing agents as RNA later.

In-Depth Characterization of Mass Spectrometry-Based Proteomic Profiles Revealed Novel Signature Proteins Associated with Liver Metastatic Colorectal Cancers.

Liver metastasis is the most common form of metastatic colorectal cancers during the course of the disease. The global change in protein abundance in liver metastatic colorectal cancers and its role in metastasis establishment have not been comprehensively analyzed. In the present study, fresh-frozen tissue samples including normal colon/localized/liver metastatic CRCs from each recruited patient were analyzed by quantitative proteomics using a multiplexed TMT labeling strategy. Around 5000 protein groups were quantified from all samples. The proteomic profile of localized/metastatic CRCs varied greatly from that of normal colon tissues; differential proteins were mainly from extracellular regions and participate in immune activities, which is crucial for the chronic inflammation signaling pathways in the tumor microenvironment. Further statistical analysis revealed 47 proteins exhibiting statistical significance between localized and metastatic CRCs, of which FILI1P1 and PLG were identified for the first time in proteomic data, which were highly associated with liver metastasis in CRCs.

88P - The Sidra LUMC advanced colon cancer NGS cohort

BackgroundIt is now clear that the immune system has a substantial effect on the progression of colon cancer. Typically, an immune response defined by a polarized Th1 phenotype, characterized by expression of CXCR3/CCR5 chemokine-receptor ligands, activation of interferon stimulated genes and production of cytotoxic molecules by effector immune cells, has been associated with immune-mediated tumor rejection. We have previously introduced a gene signature, called Immunology Constant of Rejection (ICR), that reflects these immune components. This signature was able to differentiate quite well the patients with an active immune environment and improved survival vs those who did not display this phenotype. This phenomenon although expected based on other immune infiltration studies could not be observed in the TCGA colon cancer cohort, likely due to the per protocol exclusion of samples with low purity. To gain more insight in the underlying mechanism of cancer tissue rejection by the immune system, we build an extensive data repository from high quality colon cancer samples unbiased for tumor purity. MethodsRNA and DNA were isolated from fresh frozen tissue samples of a cohort of 366 colon cancer patients collected over the last decade at the University of Leiden, Netherlands. Tissue sections flanking the corresponding samples were hematoxylin and eosin stained. RNA-seq (HiSeq4000) data was obtained using HISAT2 alignment and quantile normalization of the GC corrected raw counts. Whole Exome Sequencing (>100X) for our cohort for normal and cancer tissue respectively. T-cell repertoire profiling of 150 tumors was achieved using Adaptive immunoSEQ. Tumor immune phenotype classification was done using unsupervised consensus clustering based on the expression of ICR genes. ResultsOur preliminary data supports a positive impact of ICR gene expression in our colon cancer cohort: patients in ICR High cluster had a significantly improved survival compared to other clusters. ConclusionsThis newly generated immune centric NGS dataset, generated in Qatar, will is used to elucidate the genetic determinants of immune phenotype in colon cancer and the relationship of the immune phenotype, the tumors genetics the TCR diversity. Legal entity responsible for the studySidra Medicine. FundingQatar National Research Fund. DisclosureAll authors have declared no conflicts of interest.

The importance of inducible nitric oxide synthase and nitrotyrosine as prognostic markers for oral squamous cell carcinoma.

The prognosis of human cancer depends on the deregulations of many molecular patterns. In recent years, a great interest in the intracellular signaling mechanisms related to nitric oxide (NO)-induced carcinogenesis has appeared, as one of the most preeminent prognostic markers for many types of neoplasms. In this study, we identify the levels of iNOS and nitrotyrosine in the sample of normal oral mucosa (NOM), oral leukoplakia (OL), and oral squamous cell carcinoma (OSCC). Quantitative polymerase chain reactions (qPCRs) were utilized to detect the NOS2 levels in fresh-frozen tissue samples of NOM (n=6), OL (n=20), and OSCC (n=15). Moreover, the immunohistochemical method was used to examine the levels of iNOS and nitrotyrosine in 85 cases of OSCC (39 cases without metastases and 46 with metastases), 42 cases of OL, and 16 cases of NOM. There are rising tendencies in the iNOS mRNA and protein levels during human oral carcinogenesis. Similar findings were obtained in the nitrotyrosine staining. Furthermore, iNOS and nitrotyrosine immunostaining are associated with several clinical-pathological features of OSCC (site, presence of metastasis, staging, recidivism, and survival). The NO-signaling pathway plays a vital role in the development and progression of human oral dysplastic and neoplastic diseases. Nitrotyrosine was a significant marker for the discrimination of OSCC prognosis and survival.

Overexpression of certain transient receptor potential and Orai channels in prostate cancer is associated with decreased risk of systemic recurrence after radical prostatectomy.

Several studies had suggested the potential role of calcium signaling in prostate cancer (PCa) prognosis and agressiveness. We aimed to investigate selected proteins contributing to calcium (Ca2+ ) signaling, (Orai, stromal interaction molecule (STIM), and transient receptor potential (TRP) channels) and involved in cancer hallmarks, as independent predictors of systemic recurrence after radical prostatectomy (RP). A case-control study including 112 patients with clinically localized PCa treated by RP between 2002 and 2009 and with at least 6-years' follow-up. Patients were divided into two groups according to the absence or presence of systemic recurrence. Expression levels of 10 proteins involved in Ca2+ signaling (TRPC1, TRPC4, TRPV5, TRPV6, TRPM8, STIM1, STIM2, Orai1, Orai2, and Orai3), were assessed by immunohistochemistry using tissue microarrays (TMAs) constructed from paraffin-embedded PCa specimens. The level of expression of the various transcripts in PCa was assessed using quantitative polymerase chain reaction (qPCR) analysis. RNA samples for qPCR were obtained from fresh frozen tissue samples of PCa after laser capture microdissection on RP specimens. Relative gene expression was analyzed using the method. Multivariate analysis showed that increased expression of TRPC1, TRPC4, TRPV5, TRPV6, TRPM8, and Orai2 was significantly associated with a lower risk of systemic recurrence after RP, independently of the prostate-specific antigen (PSA) level, percentage of positive biopsies, and surgical margin (SM) status (P = .007, P = .01, P < .001, P = .0065, P = .007, and P = .01, respectively). For TRPC4, TRPV5, and TRPV6, this association was also independent of Gleason score and pT stage. Moreover, overexpression of TRPV6 and Orai2 was significantly associated with longer time to recurrence after RP (P = .048 and .023, respectively). Overexpression of TRPC4, TRPV5, TRPV6, and Orai2 transcripts was observed in group R- (3.71-, 5.7-, 1.14-, and 2.65-fold increase, respectively). This is the first study to suggest the independent prognostic value of certain proteins involved in Ca2+ influx in systemic recurrence after RP: overexpression of TRPC1, TRPC4, TRPV5, TRPV6, TRPM8, and Orai2 is associated with a lower risk of systemic recurrence. TRPC4, TRPV5, and TRPV6 appear to be particularly interesting, as they are independent of the five commonly used predictive factors, that is, PSA, percentage of positive biopsies, SM status, Gleason score, and pT stage.

Bioinformatics and DNA-extraction strategies to reliably detect genetic variants from FFPE breast tissue samples

BackgroundArchived formalin fixed paraffin embedded (FFPE) samples are valuable clinical resources to examine clinically relevant morphology features and also to study genetic changes. However, DNA quality and quantity of FFPE samples are often sub-optimal, and resulting NGS-based genetics variant detections are prone to false positives. Evaluations of wet-lab and bioinformatics approaches are needed to optimize variant detection from FFPE samples.ResultsAs a pilot study, we designed within-subject triplicate samples of DNA derived from paired FFPE and fresh frozen breast tissues to highlight FFPE-specific artifacts. For FFPE samples, we tested two FFPE DNA extraction methods to determine impact of wet-lab procedures on variant calling: QIAGEN QIAamp DNA Mini Kit (“QA”), and QIAGEN GeneRead DNA FFPE Kit (“QGR”). We also used negative-control (NA12891) and positive control samples (Horizon Discovery Reference Standard FFPE). All DNA sample libraries were prepared for NGS according to the QIAseq Human Breast Cancer Targeted DNA Panel protocol and sequenced on the HiSeq 4000. Variant calling and filtering were performed using QIAGEN Gene Globe Data Portal. Detailed variant concordance comparisons and mutational signature analysis were performed to investigate effects of FFPE samples compared to paired fresh frozen samples, along with different DNA extraction methods.In this study, we found that five times or more variants were called with FFPE samples, compared to their paired fresh-frozen tissue samples even after applying molecular barcoding error-correction and default bioinformatics filtering recommended by the vendor. We also found that QGR as an optimized FFPE-DNA extraction approach leads to much fewer discordant variants between paired fresh frozen and FFPE samples. Approximately 92% of the uniquely called FFPE variants were of low allelic frequency range (< 5%), and collectively shared a “C > T|G > A” mutational signature known to be representative of FFPE artifacts resulting from cytosine deamination. Based on control samples and FFPE-frozen replicates, we derived an effective filtering strategy with associated empirical false-discovery estimates.ConclusionsThrough this study, we demonstrated feasibility of calling and filtering genetic variants from FFPE tissue samples using a combined strategy with molecular barcodes, optimized DNA extraction, and bioinformatics methods incorporating genomics context such as mutational signature and variant allelic frequency.

Radiogenomics of breast cancer using dynamic contrast enhanced MRI and gene expression profiling

BackgroundImaging techniques can provide information about the tumor non-invasively and have been shown to provide information about the underlying genetic makeup. Correlating image-based phenotypes (radiomics) with genomic analyses is an emerging area of research commonly referred to as “radiogenomics” or “imaging-genomics”. The purpose of this study was to assess the potential for using an automated, quantitative radiomics platform on magnetic resonance (MR) breast imaging for inferring underlying activity of clinically relevant gene pathways derived from RNA sequencing of invasive breast cancers prior to therapy.MethodsWe performed quantitative radiomic analysis on 47 invasive breast cancers based on dynamic contrast enhanced 3 Tesla MR images acquired before surgery and obtained gene expression data by performing total RNA sequencing on corresponding fresh frozen tissue samples. We used gene set enrichment analysis to identify significant associations between the 186 gene pathways and the 38 image-based features that have previously been validated.ResultsAll radiomic size features were positively associated with multiple replication and proliferation pathways and were negatively associated with the apoptosis pathway. Gene pathways related to immune system regulation and extracellular signaling had the highest number of significant radiomic feature associations, with an average of 18.9 and 16 features per pathway, respectively. Tumors with upregulation of immune signaling pathways such as T-cell receptor signaling and chemokine signaling as well as extracellular signaling pathways such as cell adhesion molecule and cytokine-cytokine interactions were smaller, more spherical, and had a more heterogeneous texture upon contrast enhancement. Tumors with higher expression levels of JAK/STAT and VEGF pathways had more intratumor heterogeneity in image enhancement texture. Other pathways with robust associations to image-based features include metabolic and catabolic pathways.ConclusionsWe provide further evidence that MR imaging of breast tumors can infer underlying gene expression by using RNA sequencing. Size and shape features were appropriately correlated with proliferative and apoptotic pathways. Given the high number of radiomic feature associations with immune pathways, our results raise the possibility of using MR imaging to distinguish tumors that are more immunologically active, although further studies are necessary to confirm this observation.

Luminex-based quantification of Alzheimer's disease neuropathologic change in formalin-fixed post-mortem human brain tissue

The vast majority of archived research and clinical pathological specimens are stored in the form of formalin fixed, paraffin-embedded (FFPE) tissues, but, unlike fresh frozen tissue samples, highly quantitative measures in FFPE tissues are limited to immunohistochemical and immunofluorescence thresholding image analysis studies, cell counting, and ordinal ranking systems. This poses a significant obstacle for clinical investigations that aim to correlate diagnostic markers of neurodegenerative diseases like Alzheimer's disease (AD) with parameters like age, gender, drug exposures, genotype, disease stage, co-morbidities, or environmental factors. To overcome this limitation, we have developed Luminex-based techniques and protocols for the quantification of amyloid β and hyperphosphorylated Tau in FFPE brain sections. We validated the Luminex assay in FFPE sections from prefrontal cortex, hippocampus, and neostriatum from 30 cases that underwent prior neuropathological diagnostic assessment of AD following the current NIA–AA recommendations for AD: 10 cases diagnosed as not or low, 10 cases as intermediate, and 10 cases as high AD neuropathologic change. Consistent with the neuropathologic assessment, Luminex assay detected high amounts of amyloid beta in the frontal cortex and striatum, and high amounts of hyperphosphorylated Tau in the frontal cortex and hippocampus, of cases with high AD neuropathologic change. This assay can be expanded to detect diverse antigenic targets of interest, as we show here with IBA1 and GFAP. This novel approach supports multiplexed highly quantitative, molecularly specific neuropathology measures to further explore mechanisms of neurodegeneration in AD.

HMOF reduction enhances radiosensitivity through the homologous recombination pathway in non-small-cell lung cancer.

PurposeHuman males absent on the first (hMOF) is a histone acetyltransferase (HAT) and is responsible for acetylating histone H4 at lysine 16 (H4K16). Recent studies have indicated that hMOF is overexpressed in non-small-cell lung cancer (NSCLC) as an oncogene. The aim of this study is to profile the prognostic roles of hMOF in patients with unresectable stage III NSCLC undergoing definitive radiotherapy (RT) and in the radiosensitivity of human NSCLC cells.Materials and methodsThe expression of hMOF was detected in 24 normal and tumor-paired fresh-frozen NSCLC tissue samples. The immunohistochemistry was conducted, and the correlation of hMOF with clinicopathological parameters was studied in tissues from 90 patients with unresectable stage III NSCLC who underwent definitive RT. Radiation sensitivity was monitored using clonogenic assays in NCI-H1299 and A549 NSCLC cell lines with hMOF knockdown.ResultshMOF was overexpressed in NSCLC tissues compared with non-cancerous tissues. Compared to patients with downregulated hMOF, upregulated hMOF was observed in 51.1% (46/90) of the patients, who showed a significantly worse 5-year survival rate (5.4% vs 22.9%, P=0.025). hMOF expression was an independent prognostic factor of unresectable stage III NSCLC patients who underwent definitive RT. Silencing hMOF increased in vitro the sensitive enhancing ratio (SER) of NSCLC cell lines and downregulated the expression of phospho-ataxia telangiectasia mutated (p-ATM) and RAD51 after irradiation (IR).ConclusionOverexpression of hMOF predicts poor prognosis in patients with unresectable stage III NSCLC undergoing definitive RT. Downregulating hMOF might be a promising intervention to improve the outcome after RT.

Downregulated expression of CFHL1 is associated with unfavorable prognosis in postoperative patients with hepatocellular carcinoma.

Complement factor H-related protein 1 (CFHL1) was recently reported to be a potential biomarker in several types of cancer. CFHL1, however, has not been found to be of prognostic value in hepatocellular carcinoma (HCC) to date. In the present study, the expression levels of CFHL1 were evaluated in 8 pairs fresh frozen tissue samples using western blotting. Furthermore, the expression level of CFHL1 was evaluated in 76 pairs of formalin-fixed, paraffin-embedded (FFPE) HCC and peritumoral tissues (expression pattern cohort), and 278 FFPE HCC tissues (prognostic cohort) using tissue microarray-based immunohistochemistry. The Kaplan-Meier method, Cox regression proportional hazard model and receiver operating characteristic curve analysis were used to evaluate prognostic factors. The expression level of CFHL1 was reduced in HCC tissues in 67.1% (51/76) of the cases compared with the corresponding peritumoral tissues. Survival analyses indicated that patients with HCC with low CFHL1 expression had a worse time-to-recurrence (TTR) and overall survival (OS) compared with those with high CFHL1 expression in the prognostic cohort (P=0.002 for OS and P=0.017 for TTR). Both univariate and multivariate analyses indicated that CHFL1 was an independent prognostic factor for TTR and OS (P=0.017 and P=0.002, respectively). In addition, The Cancer Genome Atlas (TCGA) and Human Protein Atlas were used for further validation. Furthermore, a prognostic model included tumor size, tumor number, liver cirrhosis and CFHL1 expression was evaluated. The results of the present study demonstrated that CFHL1 was downregulated in HCC and its level was associated with patient prognosis; therefore, CFHL1 is a potential prognostic marker for HCC.

A Stainless Protocol for High Quality RNA Isolation from Laser Capture Microdissected Purkinje Cells in the Human Post-Mortem Cerebellum.

Laser capture microdissection (LCM) is an advantageous tool that allows for the collection of cytologically and/or phenotypically relevant cells or regions from heterogenous tissues. Captured product can be used in a variety of molecular methods for protein, DNA or RNA isolation. However, preservation of RNA from postmortem human brain tissue is especially challenging. Standard visualization techniques for LCM require histologic or immunohistochemical staining procedures that can further degrade RNA. Therefore, we designed a stainless protocol for visualization in LCM with the intended purpose of preserving RNA integrity in post-mortem human brain tissue. The Purkinje cell of the cerebellum is a good candidate for stainless visualization, due to its size and characteristic location. The cerebellar cortex has distinct layers that differ in cell density, making them a good archetype to identify under high magnification microscopy. Purkinje cells are large neurons situated between the granule cell layer, which is a densely cellular network of small neurons, and the molecular layer, which is sparse in cell bodies. Because of this architecture, the use of stainless visualization is feasible. Other organ or cell systems that mimic this phenotype would also be suitable. The stainless protocol is designed to fix fresh-frozen tissue with ethanol and remove lipids with xylene for improved morphological visualization under high magnification light microscopy. This protocol does not account for other fixation methods and is specifically designed for fresh-frozen tissue samples captured using an ultraviolet (UV)-LCM system. Here, we present a full protocol for sectioning and fixing fresh frozen post-mortem human cerebellar tissue and purification of RNA from Purkinje cells isolated by UV-LCM, while preserving RNA quality for subsequent RNA-sequencing. In our hands, this protocol produces exceptional levels of cellular visualization without the need for staining reagents and yields RNA with high RNA integrity numbers (≥8) as needed for transcriptional profiling experiments.