From Formalin-fixed Paraffin-embedded Tissue Research Articles

Targeted microscopic rare cell retrieval yields sufficient deoxyribonucleic acid for molecular testing in fixed tissue with low tumor fraction

Abstract Introduction/Objective DNA extracted from formalin-fixed paraffin-embedded tissue (FFPE) blocks is often utilized for molecular oncologic testing. Cases with low tumor fraction often fail to obtain adequate tumor for molecular testing. We hypothesized that targeted retrieval of visualized tumor cells from FFPE sections, including those with low tumor fraction, could yield sufficient DNA for molecular testing. Methods/Case Report Unstained sections of various thicknesses were cut from low tumor fraction blocks and visualized by light microscopy and the RareCyte CyteFinder II (Seattle, WA). Microscopic cell retrieval was performed on the RareCyte using 40 µm diameter needles from identified regions of interest. Samples were deparaffinized using Zymo Research (Tustin, CA) solution, and digested and purified using Zymo-Spin Column technology. Sample DNA was quantified with NanoDrop Spectrophotometer (Chino, CA). Results (if a Case Study enter NA) Regions of interest were morphologically identifiable on 4-10 µm thick sections and harder to visualize on 12 µm thick sections. Targeted microscopic cell retrieval was performed with 40 µm diameter needles. Retrieval was performed from 26 to 34 regions of interest per sample and pooled for molecular testing. Samples (n=4) yielded a mean of 81.0 ng of DNA ± 18.4 ng (1.8 ng/µL ± 0.4 ng/µL) and a median of 87.75 ng (1.95 ng/µL). Conclusion Targeted microscopic cell retrieval from low tumor fraction FFPE slides using the RareCyte CyteFinder II can provide sufficient DNA material for molecular testing. Application of this technology has the possibility of recovering sufficient tumor DNA for molecular testing from specimens that may be deemed unsuitable for molecular testing according to current standards. We aim to focus on increasing sample size and completing comprehensive molecular analysis as we continue to expand this work.

B-231 Evaluation of the KingFisher Flex for DNA Isolation From FFPE Tissue Utilizing Autolys M Tubes and the MagMAX FFPE DNA/RNA Ultra Kit

Abstract Background Our institution is facing increasing demand for oncology testing that requires high quality DNA extracted from formalin-fixed paraffin-embedded (FFPE) tissue. The current DNA extraction workflow involves a time and labor-intensive manual process that limits our ability to accommodate increasing downstream clinical testing volumes. We evaluated the KingFisher (KF) Flex utilizing Autolys M Tubes and the MagMAX FFPE DNA/RNA Ultra Kit as a possible high-throughput, automated DNA isolation workflow option that would decrease hands-on time and be conducive to volume growth without the need for additional staff. Methods DNA from 52 FFPE tissue samples (n=24 unique cases previously extracted by the current “manual method”) were extracted using Autolys M tubes, the MagMAX FFPE DNA/RNA Ultra Kit, and the KF Flex (Thermo Fisher Scientific Waltham, MA) over 4 “automated method” runs. Method modifications to the published procedure were introduced over the runs to determine any effects on DNA quality/quantity. Timings were taken during each run to compare hands-on and total run time against that of the manual method. Precision experiments were performed by extracting 4 replicates of sample on a single run (intra-assay precision) and 2 samples from 2 cases over 2 runs (inter-assay precision). Three cases were processed using varying tissue input levels to assess input-yield correlation. DNA yield was measured using HS dsDNA Qubit (Thermo Fisher Scientific, Waltham, MA). A subset of samples was tested by digital droplet PCR (ddPCR) (n=10), chromosomal microsomal microarray (CMA) (n=1), and next-generation sequencing (NGS) (n=3). Variants and QC metrics of the KF DNA were compared to those of the manual method DNA. Results The average total DNA yield was 3% lower from samples extracted following the manufacturer recommended KF procedure compared to matched samples extracted using the manual method (n=28 samples from 23 unique cases). A CV of 2.8% was observed in an intra-assay experiment (n=4 replicates from 1 case) and 3.0% in an average inter-assay experiment (n=2 replicates from 2 cases). There was a direct correlation between the tissue input amount (4 amounts of varied tissue input) and the total DNA yield (n=3 samples). We observed concordant fractional abundance values for ddPCR samples and concordant variant detection for NGS and CMA samples. We did not see a significant difference in the quality metrics tracked for any of the downstream testing assays. Conclusions This evaluation demonstrated that, as compared to our manual method, the automated method resulted in comparable DNA yields and downstream assay results. The incorporation of this automation would significantly increase our FFPE DNA extraction capacity without requiring additional staff while reducing hands-on time per run by about six hours. We would also be able to reduce ergonomic hazards related to tube cap manipulation, eliminate use of hazardous reagents, and leverage the plate format to better integrate extracted DNA into our clinical sample preparation workflows. These operational benefits highlight the value of automating high-throughput workflows.

Internal Overview of Prostatic Cancer Cases and Quality of BRCA1 and BRCA2 NGS Data from the FFPE Tissue.

Background: Comprehensive genomic profiling (CGP) has gained an important role in patients with advanced prostate cancer following the introduction of PARP inhibitors in daily clinical practice. Here, we report an overview of CGP results, specifically of BRCA1 and BRCA2 HRD-repair system genes, from patients with prostate cancer analyzed in our institution, and we compare our results with those available from more recent scientific literature. Methods: The study cohort consisted of 70 patients. Somatic DNA was extracted from Formalin-Fixed Paraffin-Embedded (FFPE) tissue using a MagCore Genomic DNA FFPE One-Step Kit for MagCore System. The DNA was quantified by EasyPGX® Real-Time qPCR and EasyPGX® Analysis Software (version 4.0.13). Tissue somatic DNA libraries were prepared with Myriapod® NGS BRCA1-2 panel-NG035 and sequenced in a Mi-Seq® System. The sequence alignment in hg19 and the variant calling were performed using Myriapod® NGS Data Analysis Software version 5.0.8 NG900-SW 5.0.8 with a software detection limit (LoD) of 95%. Variants with a coverage of 500 and VAF% ≥ 5 were evaluated. Results: Tumor tissue NGS was unsuccessful in 46/70 patients (66%). Mutations of the BRCA2 gene were detected in 4 of the samples: (1) BRCA2 ex10 c.1244A>G p.His415Arg VAF = 51.03%; (2) BRCA2 ex11 c.5946delT p.Ser1982fs VAF = 72.1%; (3) BRCA2 ex11 c.3302A>G p.His1101Arg VAF = 52.9%; and (4) BRCA2 ex11 c.3195_3198delTAAT p.Asn1066fs VAF = 51.1%. Conclusions: The results from our internal overview seem to support the data and to confirm the performance of the technical issues reported in the literature. Considering the advanced age of our patients, with 84% of men over the age of 65, the application of alternative and less invasive procedures such as liquid biopsy, could be a more suitable solution for some cases.

Histopathologic and molecular profile of gliomas diagnosed in Lagos, Nigeria

Abstract Background The optimal diagnosis and management of patients with brain tumors currently uses the 2021 WHO integrated diagnosis of histomorphologic and molecular features. However, neuro-oncology practice in resource-limited settings usually relies solely on histomorphology. This study aimed to classify glioma cases diagnosed in the Department of Anatomic and Molecular Pathology, Lagos University Teaching Hospital, using the 2021 WHO CNS tumor classification. Methods Fifty-six brain tumors from 55 patients diagnosed with glioma between 2013 and 2021 were reevaluated for morphologic diagnosis. Molecular features were determined from formalin-fixed paraffin-embedded (FFPE) tissue using immunohistochemistry (IHC) for IDH1-R132H, ATRX, BRAF-V600E, p53, Ki67, and H3-K27M, OncoScan chromosomal microarray for copy number, targeted next generation sequencing for mutation and fusion and methylation array profiling. Results Of 55 central nervous system tumors, 3 were excluded from histomorphologic reevaluation for not being of glial or neuroepithelial origin. Of the remaining 52 patients, the median age was 20.5 years (range: 1 to 60 years), 38(73%) were males and 14(27%) were females. Seventy-one percent of the gliomas evaluated provided adequate DNA from archival FFPE tissue blocks. After applying the 2021 WHO diagnostic criteria the initial morphologic diagnosis changed for 35% (18/52) of cases. Diagnoses of 5 (9.6%) gliomas were upgraded, and 7 (14%) were downgraded. Conclusions This study shows that the incorporation of molecular testing can considerably improve brain tumor diagnoses in Nigeria. Furthermore, this study highlights the diagnostic challenges in resource-limited settings and what is at stake in the global disparities of brain tumor diagnosis.

LINCATRA: Two-cycle method to amplify RNA for transcriptome analysis from formalin-fixed paraffin-embedded tissue

Whole transcriptome analysis (WTA) using RNA extracted from Formalin Fixed Paraffin Embedded (FFPE) tissue is an invaluable tool to understand the molecular pathology of disease. RNA extracted from FFPE tissue is either degraded and/or in very low quantities hampering gene expression analysis. Earlier studies described protocols applied for cellular RNA using poly-A primer-based linear amplification. The current study describes a method, LINCATRA (LINear amplifiCAtion of RNA for whole TRAnscriptome analysis). It employs random nonamer primer based method which can amplify short, fragmented RNA with high fidelity from as low as 5 ng to obtain enough material for WTA. The two-cycle method significantly amplified RNA at ∼1000 folds (p < 0.0001) improving the mean read lengths (p < 0.05) in WTA. Overall, increased mean read length positively correlated with on-target reads (Pearson's r = 0.71, p < 0.0001) in both amplified and unamplified RNA-seq analysis. Gene expression analysis compared between unamplified and amplified group displayed substantial overlap of the differentially expressed genes (DEGs) (log2 fold change cut-off < −2 and >2, p < 0.05) identified between lung cancer and asthma cohorts validating the method developed. This method is applicable in clinical molecular pathology field for both diagnostics and elucidation of disease mechanisms.

DNA Quantity and Quality Comparisons between Cryopreserved and FFPE Tumors from Matched Pan-Cancer Samples.

Personalized cancer care requires molecular characterization of neoplasms. While the research community accepts frozen tissues as the gold standard analyte for molecular assays, the source of tissue for testing in clinical cancer care comes almost universally from formalin-fixed, paraffin-embedded tissue (FFPE). As newer technologies emerge for DNA characterization that requires higher molecular weight DNA, it was necessary to compare the quality of DNA in terms of DNA length between FFPE and cryopreserved samples. We hypothesized that cryopreserved samples would yield higher quantity and superior quality DNA compared to FFPE samples. We analyzed DNA metrics by performing a head-to-head comparison between FFPE and cryopreserved samples from 38 human tumors representing various cancer types. DNA quantity and purity were measured by UV spectrophotometry, and DNA from cryopreserved tissue demonstrated a 4.2-fold increase in DNA yield per mg of tissue (p-value < 0.001). DNA quality was measured on a fragment microelectrophoresis analyzer, and again, DNA from cryopreserved tissue demonstrated a 223% increase in the DNA quality number and a 9-fold increase in DNA fragments > 40,000 bp (p-value < 0.0001). DNA from the cryopreserved tissues was superior to the DNA from FFPE samples in terms of DNA yield and quality.

Optimized Method for High‐Quality RNA Extraction from Formalin‐Fixed Paraffin‐Embedded Tissues

AbstractRNA extraction from formalin‐fixed paraffin‐embedded tissues (FFPE) presents a notable challenge. Extracting RNA from FFPE tissues has been challenging due to RNA degradation and chemical bonding between RNA and proteins during the fixation process. This results in reduced concentration and quality of the extracted RNA from FFPE tissues, impacting subsequent downstream analyses. In this study, we present an optimized approach involves replacing the tissue temperature‐digestion step with tissue crushing and homogenization. RNA extraction was performed on 100 FFPE tissue blocks obtained from the archive of Pathology Department of Shiraz University of Medical Sciences. After deparafinization of the tissues, RNA was extracted using this modified method, and the results compared to those of a standard extraction procedure and commercial kits used for FFPE tissue. Then gel electrophoresis and Real time PCR were done to check the quality and integrity of the extracted RNA. The results show that the concentration of RNA obtained from this method was significantly (P value &lt;0.0001) higher than the other methods. In conclusion, we have successfully introduced a modified method that enables the extraction of high‐quality and intact RNA from FFPE tissue. This method stands as a reliable option for molecular biology studies necessitating precise RNA extraction.

Abstract 4957: DNA quality control metrics in cryopreserved tissue outperform DNA extracted from FFPE tissue

Abstract Personalized cancer care requires molecular characterization of neoplasms. While the research community accepts frozen tissues as the gold standard analyte for molecular assays, the source of tissue for testing of tumor tissue in clinical cancer care comes primarily from formalin-fixed, paraffin-embedded tissue (FFPE). Specific to genomics assays, numerous studies have shown significant discordance in genetic information obtained from FFPE samples and frozen samples. To explain the discordance between FFPE samples and cryopreserved samples, a head-to-head comparison between FFPE and cryopreserved tissues was performed to analyze the DNA yield, DNA purity and DNA quality in terms of DNA length. Additionally, short-read sequencing was performed on matched samples and quality control metrics were compared between the two sample types. Matched human tumors (n = 50) were processed either by formalin fixation and paraffin embedding or placed in cryovials containing cryopreservation medium. These cryovials were cooled slowly to -80°C and stored in liquid nitrogen. DNA was extracted using the same protocol for both tissue types with the exception that tissues embedded in paraffin were first dewaxed followed by a multistep rehydration protocol. Samples were weighed and calibrated for mass. After the column purification and elution, sample concentration and purity were measured. DNA fragment length was measured on a fragment microelectrophoresis analyzer. Graded amounts of tumor tissue were used to determine the lowest starting material needed to extract 200 ng of DNA. The average of all the samples reached the minimal threshold of 200 ng. However,74% of FFPE specimens failed to meet the minimum 40 ng/mg, whereas only 21% were below the threshold in the cryopreserved samples. In the cryopreserved group, the average DNA yield was 222.1 ng/mg, whereas 52.8 ng/mg was obtained from FFPE tissue. For DNA purity in cryopreserved tissues, the 260/280 ratio was 1.76, and in FFPE tissues the mean was 1.78. The DNA Quality Number (DQN) is a measurement of DNA fragment length and the percentage that exceeds the threshold of 300 bp. For FFPE, the DQN was 4.4 compared to a DQN of 9.8 for the cryopreserved samples. Setting a higher threshold of DNA length to 40,000 bp and measuring the area under the curve (AUC), it was observed that cryopreserved samples were 9-fold higher in fragments greater than 40,000 bp. Cryopreserved cancer tissue provides superior quality assurance measurements of DNA over FFFPE. Treatment decisions based on molecular results demand accuracy and validity. The pathology community should support efforts to cryopreserve cancer biospecimens in the clinical setting to provide valid molecular testing results. The automatic pickling of tumor specimens in formalin is no longer an acceptable default. Citation Format: Jared James Barrott, Nikole O'Neal, Jeffrey Okojie, David Booker, Ken Dixon. DNA quality control metrics in cryopreserved tissue outperform DNA extracted from FFPE tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4957.

Abstract 5049: Detecting chromosomal copy number variations and point mutations in Glioma using a single assay; sparing tissue while significantly reducing testing time and cost

Abstract We aimed to develop a single streamlined assay to detect all Glioma biomarkers. The current diagnosis of Gliomas incorporates molecular biomarkers that include whole chromosomal copy number variations (CNVs) and single nucleotide variations (SNVs). Testing CNVs and SNVs are traditionally done using different large platforms and are performed in large genomic facilities that have the suitable infrastructure. This creates delays in testing, where samples undergo lengthy referrals and the tissue is often split between institutions, which also adds substantially to the costs. We have previously used Nanopore sequencing to develop an assay to detect IDH SNVs from formalin-fixed paraffin-embedded (FFPE) tissue. Nanopore sequencing platform uses small inexpensive tools and can test for both CNVs and SNVs. However, combining both targets efficiently in FFPE tissue remains a challenge. While nanopore whole genome sequencing can detect CNVs, it does not allow for enough coverage to accurately detect small SNVs. Also, raw FFPE DNA is not compatible with the nanopore technology. To fix both challenges we used a PCR based approach that allows enrichment of the SNV targets, as well as creates new nanopore compatible DNA copies. To counteract the bias that PCR creates with uneven amplification, we used a SNP based method to call chromosomal gains and losses. Statistical analysis of probability showed that targeting 15 heterozygous SNPs per chr arm is sufficient for accurate CNV detection (error rate &amp;lt;0.1%). A total of 57 amplicons targeting CNVs on Chr 1,7, 10, 19, and EGFR gene; and IDH1 and IDH2 SNVs were pooled together in one assay and tested on 4 Glioma samples. Variant calling was performed with a custom Python script. All CNV targets were accurately detected on all samples. Losses in chr 1p, 19q and chr 10 were evident with a loss of heterozygosity (LOH) pattern on the SNP analysis. The gain in chromosome 7 was also observed as an allele gain 2:1 SNP pattern on the corresponding samples. The SNV statuses of these samples were also accurately detected when compared to reference results. Finally, the SNV and CNV calling analysis were streamlined using custom shell script, further reducing total turnaround time (including sequencing and data analysis) to less than a day for the entire batch of samples. Initial cost analysis shows &amp;lt;50% of the traditional testing costs for the assay. This work is the first to develop a streamlined single test to detect CNVs and SNVs in Gliomas using FFPE DNA on the nanopore sequencing platform. The shorter testing time, streamlined workflow, and low assay/capital cost could positively influence the care of brain cancer patients. Notably, nanopore-based sequencing tools can also be implemented in other types of tumor diagnosis, especially by smaller labs, helping to overcome many of the existing diagnostic challenges. Citation Format: Mashiat L. Mimosa, Jared T. Simpson, Karel Boissinot, Mora Tiab, Ramzi Fattouh, Rola M. Saleeb. Detecting chromosomal copy number variations and point mutations in Glioma using a single assay; sparing tissue while significantly reducing testing time and cost [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5049.

Abstract 7627: First NGS-based companion diagnostic to aid in selecting non-small cell lung cancer patients with ERBB2 (HER2) activating mutations for treatment with trastuzumab deruxtecan

Abstract Introduction The ERBB2 companion diagnostic program aims to expand the intended use of the Oncomine ™ Dx Target Test (ODxTT) to determine ERBB2 single nucleotide variants (SNVs) in exons 8, 17, 18, 19, 20, 21 and 22 and exon 20 insertions from formalin-fixed, paraffin-embedded (FFPE) tumor samples in non-small cell lung cancer (NSCLC) patients who may benefit from targeted drug therapy. Methods The ODxTT is a qualitative in vitro diagnostic test that uses targeted high throughput, parallel-sequencing technology to detect SNVs, deletions, insertions, and CNVs in genes from DNA and fusions from RNA isolated from FFPE tissue samples using the Ion PGM ™ Dx System. Analytical validation (AV) studies interrogated ODxTT’s ability to detect ERBB2 mutations. The clinical validation (CV) study involved a method comparison/concordance analysis of ERBB2 mutations between the ODxTT and the TruSight Tumor 170 (TST170) assay, as well as a series of clinical trial assays (CTAs). The CV study was conducted using clinical specimens from 91 patients enrolled in Destiny-Lung01 and 121 stage-matched commercially procured samples. The aim was to evaluate positive percent agreement (PPA), negative percent agreement (NPA) and overall percent agreement (OPA) for CTAs and TST170 assay. Results A total of 91 ERBB2 subjects were included in the full analysis of the Destiny-Lung01 clinical trial. 49 samples had valid ODxTT results available and 42 samples were unevaluable which included 13 unknowns and 29 test not performed. The 49 patient samples that were evaluable were used to assess the clinical efficacy based on ODxTT results. In the series of 121 samples that were used to assess clinical efficacy in the CV study, 109 had evaluable ODxTT results. The PPA, NPA and OPA of ODxTT to the CTAs when excluding unknowns were 98%, 100% and 99.4%, respectively, and based off the Clopper-Pearson method for binomial distribution a 95% lower bound confidence interval (CI) were 89.6%, 96.6% and 96.5%, respectively. There was one discordant sample with a negative ODxTT and a positive CTA result (false negative). The PPA, NPA and OPA of ODxTT to TST170 assay were 100%, 99.1% and 99.3% respectively with a 95% lower bound CI of 90.8%, 95.0% and 96.3%, respectively. There was one discordant sample with a negative TST170 and a positive ODxTT result (false positive). Conclusion AV and CV studies successfully verified and validated the ODxTT for the detection of ERBB2 mutations in NSCLC FFPE samples. The 6 AV studies met the necessary product requirements and acceptance criteria to detect clinical samples with ERBB2 mutations. Additionally, the CV study clinical accuracy and clinical efficacy results demonstrated the safety and effectiveness of the use of the ODxTT in FFPE samples as an aid to identify NSCLC patients eligible for treatment with the Daiichi Sankyo lung cancer therapeutic T-DXd. Citation Format: Thomas Ha. First NGS-based companion diagnostic to aid in selecting non-small cell lung cancer patients with ERBB2 (HER2) activating mutations for treatment with trastuzumab deruxtecan [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7627.

MiRNAs signature as potential biomarkers for cervical precancerous lesions in human papillomavirus positive women

Biomarkers to identify women at risk of cervical cancer among those with high-risk HPV infection (hrHPV+) are needed. Deregulated expression of microRNAs (miRNAs) contributes to hrHPV-induced cervical carcinogenesis. We aimed at identifying miRNAs with the capacity to distinguish high (CIN2+) and low (≤ CIN1) grade cervical lesions. We sequenced miRNA libraries from Formalin-Fixed Paraffin-Embedded (FFPE) tissues from women with CIN2+ (n = 10) and age-matched women with ≤ CIN1 (n = 10), randomly and retrospectively selected from a trial that followed women for 24 months after a hrHPV+ test at the screening visit. Five miRNAs differentially expressed were validated by RT-qPCR in an independent set of FFPE tissues with a reviewed diagnosis of CIN2+ (n = 105) and ≤ CIN1 (n = 105). The Ingenuity Pathway Analysis (IPA) was conducted to identify mRNAs inversely correlated with the top 25 differentially expressed miRNAs. Inverse correlations with 401 unique mRNA targets were identified for fourteen of the top 25 differentially expressed miRNAs. Eleven of these miRNAs targeted 26 proteins of pathways deregulated by HPV E6 and E7 oncoproteins and two of them, miR-143-5p and miR-29a-3p, predicted CIN2+ and CIN3+ in the independent validation by RT-qPCR of FFPE tissues from hrHPV-positive women.

A High-Throughput Workflow for FFPE Tissue Proteomics.

Laser capture microdissection (LCM) has become an indispensable tool for mass spectrometry-based proteomic analysis of specific regions obtained from formalin-fixed paraffin-embedded (FFPE) tissue samples in both clinical and research settings. Low protein yields from LCM samples along with laborious sample processing steps present challenges for proteomic analysis without sacrificing protein and peptide recovery. Automation of sample preparation workflows is still under development, especially for samples such as laser-capture microdissected tissues. Here, we present a simplified and rapid workflow using adaptive focused acoustics (AFA) technology for sample processing for high-throughput FFPE-based proteomics. We evaluated three different workflows: standard extraction method followed by overnight trypsin digestion, AFA-assisted extraction and overnight trypsin digestion, and AFA-assisted extraction simultaneously performed with trypsin digestion. The use of AFA-based ultrasonication enables automated sample processing for high-throughput proteomic analysis of LCM-FFPE tissues in 96-well and 384-well formats. Further, accelerated trypsin digestion combined with AFA dramatically reduced the overall processing times. LC-MS/MS analysis revealed a slightly higher number of protein and peptide identifications in AFA accelerated workflows compared to standard and AFA overnight workflows. Further, we did not observe any difference in the proportion of peptides identified with missed cleavages or deamidated peptides across the three different workflows. Overall, our results demonstrate that the workflow described in this study enables rapid and high-throughput sample processing with greatly reduced sample handling, which is amenable to automation.

Personalized therapy for head and neck squamous carcinoma (HNSCC) utilizing tissue proteomics profiling.

6045 Background: Chemotherapy is widely used in the treatment of HNSCC, yet no biomarkers for chemotherapy is used for selection of the chemo agent in the treatment of HNSCC. We examined 143 HNSCC cancer using targeted proteomics for the protein expression levels of several chemo agents. These include markers of resistance to platinum agents (ERCC1), anti-tubulin inhibitors (TUBB3) and sensitivity markers for topoisomerase inhibitors (Topo1 – irinotecan, topotecan; Topo2A – doxorubicin, etoposide). We also measured markers for several antibody-drug conjugates (EGFR, Her2, Trop2, FR-alpha, Mesothelin). Methods: Tumor areas from Formalin-fixed, paraffin-embedded (FFPE) tumor tissues from clinical samples of HNSCC that were received at our CLIA certified laboratory were microdissected and a selected reaction monitoring mass spectrometry (SRM-MS) quantitative proteomic analysis of 72 protein biomarkers were conducted concurrently from 2-3 sections of FFPE tissue. Results: Platinum agents are widely agent in HNSCC cancer. ERCC1, a resistance marker for platinum agents was expressed in 44% of HNSCC. Similarly, TUBB3, a resistance marker for Paclitaxel, docetaxel was also expressed in ~45% of HNSCC. These indicate that ~45% of HNSCC could potentially be refractory to platinum and paclitaxel-based therapy. Additionally, ALDH1A1, a marker for resistance of cyclophosphamide, was expressed in 78% of HNSCC. Temozolomide, an alkylating agent used in other cancer type could be beneficial in 14% of HNSCC because of the lack of resistance marker MGMT. On the other hand, 88% of HNSCC expressed Topo1, which is a sensitivity marker for irinotecan or topotecan based therapy. Additionally, Top1 is also the target for the payload of several ADCs (e.g. trastuzumab deruxtecan and sacituzumab govitecan). Similarly, 55% of HNSCC expressed Topo2A, a target for etoposide and doxorubicin. Additionally, 57% of HNSCC expressed hENT1, a transporter of gemcitabine. HNSCC also expressed various targets for targeted and ADC agents. These include EGFR (86% detected with 37x range of distribution), Her3 (11%), IGF1R (16%), MET (13%), Folate receptor- alpha (18%), Mesothelin (13%), and Trop2 (89% with 134x range of distribution). Her2 was overexpressed ( &gt; 750 amol/ug) in 11% of HNSCC, however, it was observed in 46% of HNSCC with a 53x range (276 – 14705 amol/ug), indicating that a significant population of HNSCC might be eligible for low Her2 clinical trials. Conclusions: Every cancer is unique, and the ability to analyze 72 protein biomarkers from 2-3 FFPE sections simultaneously at the same time provides a wealth of actionable information for clinical treatment or patient stratification for clinical trials.

Technical performance of cancer detection and TOO identification of PanSeer7, a targeted bisulfite sequencing assay for non-invasive multi-cancer detection.

e16338 Background: Many cancers are symptoms free in early clinical stages, resulting in nearly half of cancer patients diagnosed in advanced-stages when therapeutic options are limited. Early cancer detection is key to improve clinical outcomes. We developed PanSeer7, a multi-cancer detection assay based on targeted bisulfite sequencing of circulating cell-free DNA (cfDNA) and evaluated its technical performances of reproducibility and sensitivity. Methods: The panel of PanSeer7 consists of 2447 markers which were either differentially methylated between healthy and cancer samples, or distinctively methylated in a specific cancer. We assessed PanSeer7’s reproducibility by using it to sequence technical replicates of cfDNA samples. For its limit of detection (LOD), we prepared samples mimicking cancer plasma DNA by diluting fragmented cancer cell line DNA, which represent 7 common cancer types, into GM12878 control at ratios of 1/10,000 to 1/100. We further tested PanSeer7’s ability to identify tissue of origin (TOO) by analyzing DNA samples from formalin-fixed paraffin-embedded (FFPE) tissues and healthy plasma. Results: We analyzed PanSeer7’s reproducibility by sequencing 40 replicates of synthetic healthy cfDNA samples on four independent batches and with different inputs (from 2ng to 20ng). Results show that at a minimum of 10ng input, PanSeer7 produced highly consistent methylation levels among replicates. As to cancer signal detection, we found that PanSeer7’s technical LOD was 1/10,000 for lung cancer cell line H1650, liver cancer line HepG2, gastric cancer line HGC27, esophageal cancer line KYSE150 and colorectal cancer line SW480; it was slightly lower as 5/10,000 for pancreatic cancer line PANC1 and breast cancer line MDA-MB-231. To evaluate PanSeer7’s accuracy of TOO identification, we sequenced 38 healthy plasma and 121 FFPE tissues (17 of liver cancer, 13 of pancreatic cancer, 21 of gastric cancer, 18 of esophageal cancer, 16 of colorectal cancer, 14 of lung cancer, and 22 of breast cancer). Clustering analysis showed that they were segregated according to their TOO based on methylation levels. We also generated 3500 sets of simulated data by mixing the reads of cancer tissue into those of healthy plasma at ratios of 1/10,000 to 1/100, and trained TOO-predicting models with train data sets. At a ratio of 5/10,000, the model predicted TOO of test data sets with an accuracy of over 95%. Conclusions: PanSeer7 required as low as 10ng input DNA for high reproducibility. Its technical LOD in detecting cancer signal was no lower than 5/10,000 for all 7 cancer cell lines tested, and has an in silico TOO detection LOD of 5/10,000. Thus, PanSeer7 had excellent performances in both cancer signal detection and TOO identification, showing promise to be clinically applied for non-invasive multi-cancer detection after future optimization and validation.

Proportion of CD44+ Subset of Tumour Cells in Single Cell Suspension Prepared from FFPET Sections Directly Correlates with Histological Subtyping of Head and Neck Squamous Cell Carcinoma

CD44 expression in tumours imparts potential to progress, metastasize, recurrence, and resistance against antineoplastic therapy. In this study, we sought to describe the variation in the immuno-expression and numeration of MDR1+ and CD44+ potential cancer stem cells in different histological grades and subtypes of head and neck squamous cell carcinoma (HNSCC). Flow-cytometric analysis was performed on single cell suspension prepared from formalin fixed paraffin embedded tissue (FFPET) sections of HNSCC using anti-CD44 and anti-MDR1/ABCB-1 primary monoclonal antibodies. Immunohistochemical (IHC) staining was also carried out using both of these antibodies on HNSCC tissue sections mounted on super frosted glass slides. On immunohistochemical analysis, the mean IRS for CD44 and MDR1 were 8.6364 ±3.02114 and 1.5909 ±1.27674 respectively. When mean immune-expression scores of CD44 antibody and MDR1/ABCB-1 were compared with histological grades and subtypes of HNSCC, the relationship was found to be statistically insignificant. Interestingly, a strong statistical difference (p = 0.000) was observed when the mean score of subset of dysplastic squamous epithelial cells with characteristics of cell stemness (CD326+CD44+) was compared among different histological subtypes of HNSCC using flowcytometric analysis. While no statistically significant association was observed when the mean score for subset of dysplastic cells with potential of drug resistance (CD44+MDR1+) was compared among different histological subtypes of HNSCC. Although potential cancer stem cell marker CD44 and the multidrug resistance maker ABCB-1/MDR1 co-expressed in HNSCC but the proportion of CD326+CD44+ subset of tumour cells (potential cancer stem cells/CSCs) significantly correlates with least aggressive to more aggressive tumour subtypes.

Development of a sensitive, high-throughput extraction protocol for qPCR detection of African swine fever virus in formalin-fixed, paraffin-embedded tissues.

African swine fever (ASF) causes fatal disease in pigs and is an escalating threat to the global swine industry. ASF has re-emerged from Africa as a transcontinental epidemic spreading through the Caucasus into Europe, Russia, China, numerous Asian countries, and the Caribbean. ASF virus (ASFV) is a U.S. select agent requiring handling in high-containment biosafety level 3 (BSL-3) laboratories for pathogen work. Formalin-fixation eliminates infectivity and preserves the genome, providing noninfectious specimens for BSL-2 work. Recovery of DNA from formalin-fixed, paraffin-embedded tissue (FFPET) is challenging and cumbersome. A reliable and easy-to-perform method for DNA recovery from FFPET would facilitate surveillance. To meet this objective, we developed a high-throughput protocol for the recovery of ASFV DNA from FFPET. Deparaffinization, tissue lysis, and reversal of cross-linking were performed in a single tube, followed by DNA purification via automated magnetic bead extraction. Quantitative PCR (qPCR) detection was used to determine the copy number of the B646L gene that encodes for the ASFV p72 protein in tissues (5 pigs, 4 tissues) from pigs with lesions consistent with acute ASF. Copy numbers obtained from FFPET were within one log of copy numbers obtained from fresh tissue, thus enabling ASF qPCR surveillance from formalin-inactivated and preserved tissues at BSL-2 at diagnostic sensitivity similar to fresh tissues tested at BSL-3.

Detection of IDH1 Mutation in cfDNA and Tissue of Adult Diffuse Glioma with Allele-Specific qPCR.

The World Health Organization (WHO) classification of central nervous system (CNS) tumors necessitates testing of isocitrate dehydrogenase (IDH) 1/2 gene mutation in patients with adult-type diffuse glioma (ADG) for better disease management. In clinical practice, the testing of IDH1 is primarily achieved using immunohistochemistry (IHC) specific to IDH1-R132, which carries a sensitivity of 80% and specificity of 100%. However, in some cases, non-specific background staining or regional heterogeneity in the protein expression of IDH1 may necessitate confirmatory genetic analysis. Robust and reliable assays are needed for IDH1/2 mutation testing. The aim of the current study was to detect IDH1 mutation in cfDNA and tissue of adult-type diffuse glioma with allele-specific qPCR. In the current study, IDH1-R132H mutation was analyzed in tumor tissue with paired cell-free DNA (cfDNA) in patients with ADG (n = 45) using IHC and competitive allele-specific Taqman PCR (CAST-PCR). Genomic DNA was extracted from formalin-fixed paraffin-embedded (FFPE) tissue and matched serum for cfDNA using commercially available kits. CAST-PCR with IHC for the detection of IDH1-R132H mutation was also compared. The IDH1-R132H mutation was detected in 46.67% (21/45) cases and 57.78% (26/45) cases using IHC and allele-specific CAST-PCR. In cfDNA of matched IDH1-mutant FFPE tissue DNA, IDH1-R132H mutation was detected in 11.54% (3/26) using CAST-PCR. The concordance rate for IDH1-R132Hmutation between IHC and CAST-PCR was 80.77% (21/26). The CAST-PCR assay is more precise and sensitive for IDH1-R132Hdetection than traditional IHC, and IDH1-R132H mutation detection using cfDNA may add to the current methods of glioma genomic characterization.

Molecular Identification of Fungi Causing Tissue Mycoses From Formalin Fixed Paraffin Embedded (FFPE) Archive Specimens

Introduction: Isolation of fungi from tissue specimens using conventional methods is time consuming. However, in some cases, the histopathological examination (HPE) of tissue alone is unable to provide a definite identity of the fungus. Alternatively, a non-culture method, such as polymerase chain reaction (PCR) detecting the internal transcribed spacer (ITS) rRNA genes of the fungi, is a promising diagnostic tool for rapid and accurate diagnosis of tissue mycoses. Methods: This work investigated the utility of panfungal PCR in identifying agents of tissue mycoses in 87 FFPE archive specimens. Deoxyribonucleic acid (DNA) extraction was performed on FFPE specimens by using QIAamp DNA FFPE Tissue Kit. The ITS2 region was amplified using ITS3/ITS4 primers. The PCR products were sequenced using the same primers and compared to the NCBI nucleotide database for species identification. Results: Fungal DNA was successfully amplified in 52 (59.8%) specimens, from which only 23 (44.0%) fungi were consistent with clinical/HPE findings. The identified fungi were Aspergillus spp., Candida spp., Penicillium spp., Cryptococcus neoformans, Talaromyces marneffei, and Rhizopus oryzae. A few rare fungi were also identified, such as Diaporthe longicolla and fungus-like oomycete such as Pythium insidiosum that are commonly associated with plant pathogens. Conclusion: Although PCR was able to offer accurate genus/species identification, utilising this method on paraffinised tissue specimens must be evaluated by considering many factors that will reduce its sensitivity and specificity. Therefore, it is important to correlate the PCR results with clinical and HPE findings to obtain a correct diagnosis and adequate treatment for tissue mycoses.

DIGE Saturation Labeling for Scarce Amounts of Protein from Formalin-Fixed Paraffin-Embedded (FFPE) Tissue.

In this chapter, we describe the utility of fluorescence two-dimensional difference gel electrophoresis (2D-DIGE) as a proteomics platform for the global detection of expressed proteins in formalin-fixed paraffin-embedded (FFPE) tissues and its use for biomarker discovery/identification of proteins that may contribute to cancer development and progression. Formalin fixation and paraffin embedding of tissue is the standard processing methodology practiced in pathology laboratories worldwide, resulting in a highly stable form of tissue that is easily stored due to its inherent stability at room temperature. Consequently, FFPE tissues represent an attractive reservoir of clinical material for conducting retrospective protein biomarker analysis. A limitation for proteomics research in this type of clinical sample is the amount of viable protein that can be obtained from fixed tissues. Tissue biopsies are precious samples that can generally be acquired in very small amounts due to the invasive nature of the sample collection, mainly during surgery or biopsy. Subsequently, the amount of extracted protein can be, in many cases, very limited. The saturation 2D-DIGE technology has emerged as a useful method for protein analysis where only scarce amounts of protein are available. This approach can be adapted successfully to label low-level protein isolated from FFPE tissue.

The extraction of Peste Des Petits Ruminants Virus RNA from paraffin-embedded tissues using a modified extraction method

Peste des petits ruminants (PPR) which is caused by small ruminant morbillivirus (PPRV) has an important economic impact on small ruminant farming due to high mortality rates, weight loss and restrictions on the export of small ruminants products. Molecular assays are commonly used in the diagnosis of the disease. Extraction of RNA from formalin-fixed paraffin-embedded (FFPE) tissues is challenging because of the RNA is often degraded by formalin fixation process. Although commercial kits have been developed for extraction of nucleic acids from FFPE tissues, they are expensive than other extraction kits. In this study, a modified extraction method was evaluated for detection of PPRV from FFPE tissues. A total of 20 FFPE tissue samples including 15 PPRV positive and 5 PPRV negative FFPE tissue samples were used. Two years ago, these selected FFPE tissue samples were analysed by nucleoprotein gene based one step real time RT-PCR method before they were fixed with formalin and embedded in paraffin. FFPE tissue samples were extracted using modified extraction method and were tested by fusion (F) gene based one step RT-PCR. PPRV specific RNA was detected in 12 FFPE tissue samples whereas 3 positive samples were found negative by one-step RT-PCR. Furthermore, 5 negative FFPE tissue samples were also found negative. Three false negative results were from samples with high real-time RT-PCR cycle threshold. Therefore, false negative results could be related with lower viral loads which might be lower than detection limit of the one-step RT-PCR. The results of the study show that modified extraction method could be used for RNA extraction from FFPE tissues which had been stored for 2 years.