Search

The immunosuppressive effect of the programmed death (PD)-1/PD-L1 pathway plays an important role in the treatment of a variety of tumors, such as lung and breast cancer, but there is little literature about PD-1/PD-L1 in pheochromocytomas/paragangliomas (PCCs/PGLs). We explored the relationship of PD-L1 and malignant behavior in 77 cases of PCC/PGL using immunohistochemistry (IHC) to assess protein expression and RNAscope to detect mRNA expression in 20 cases. The IHC data showed that 59.74% of the PCCs/PGLs expressed PD-L1, and the extent of expression was highly correlated with Ki-67 (P = .019) and hypertension (P = .013) but not with age, sex, tumor size, capsular invasion, tumor necrosis, relapse/distant metastasis, secretion of noradrenaline/adrenaline/dopamine, or diabetes mellitus. In addition, we found an excellent correlation of PD-L1 mRNA and protein expression with a κ coefficient of 0.828, and further stratification of the IHC and RNAscope findings showed high consistency (Pearson coefficient 0.753). The correlation of PD-L1 and Ki-67 indicated that PD-L1 could be considered a malignant proliferation biomarker for PCCs/PGLs, which would be a putative biomarker for anti-PD-L1 therapies., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Fluorescent detection of transcripts using RNAscope has quickly become a standard in situ hybridization (ISH) approach in neuroscience with over 400 publications since its introduction in 2012. RNAscope's sensitivity and specificity allow the simultaneously detection of up to three low abundance mRNAs in single cells (i.e., multiplexing) and, in contrast to other ISH techniques, RNAscope is performed in 1 day. BaseScope, a newer ultrasensitive platform, uses improved amplification chemistry of single oligonucleotide probe pairs (∼50 bases). This technique allows discrimination of single nucleotide polymorphisms or splice variants that differ by short exons. A present limitation of BaseScope is that expression analysis is limited to a single gene (i.e., single-plexing). This article outlines detailed protocols for both RNAscope and BaseScope in neuronal tissue. We discuss how to perform ISH experiments using either fresh-frozen or formalin-fixed paraffin-embedded sections, as well as dissociated cultured neurons. We also outline how to obtain quantitative data from hybridized tissue sections. © 2019 by John Wiley & Sons, Inc., (© 2019 John Wiley & Sons, Inc.)

Although antiretroviral therapy (ART) greatly suppresses HIV replication, lymphoid tissues remain a sanctuary site where the virus may replicate. Tracking the earliest steps of HIV spread from these cellular reservoirs after drug cessation is pivotal for elucidating how infection can be prevented. In this study, we developed an in vivo model of HIV persistence in which viral replication in the lymphoid compartments of humanized mice was inhibited by the HIV reverse transcriptase inhibitor 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA) to very low levels, which recapitulated ART-suppression in HIV-infected individuals. Using a combination of RNAscope in situ hybridization (ISH) and immunohistochemistry (IHC), we quantitatively investigated the distribution of HIV in the lymphoid tissues of humanized mice during active infection, EFdA suppression, and after drug cessation. The lymphoid compartments of EFdA-suppressed humanized mice harbored very rare transcription/translation-competent HIV reservoirs that enable viral rebound. Our data provided the visualization and direct measurement of the early steps of HIV reservoir expansion within anatomically intact lymphoid tissues soon after EFdA cessation and suggest a strategy to enhance therapeutic approaches aimed at eliminating the HIV reservoir.

Introduction: Patient suitability to anti-programmed death ligand 1 (PD-L1) immune checkpoint inhibition is key to the treatment of NSCLC. We present, applied to PD-L1 testing: a comprehensive cross-validation of two immunohistochemistry (IHC) clones; our descriptive experience in diagnostic reflex testing; the concordance of IHC to in situ RNA (RNA-ISH); and application of digital pathology., Methods: Eight hundred thirteen NSCLC tumor samples collected from 564 diagnostic samples were analyzed prospectively, and 249 diagnostic samples analyzed retrospectively in tissue microarray format. Validated methods for IHC and RNA-ISH were tested in tissue microarrays and full sections and the QuPath system were used for digital pathology analysis., Results: Antibody concordance of clones SP263 and 22C3 validation was 97% to 98% in squamous cell carcinoma and adenocarcinomas, respectively. Clinical NSCLC cases were reported as PD-L1-negative (48%), 1% to 49% (23%), and more than 50% (29%), with differences associated to tissue-type and EGFR status. Comparison of IHC and RNA-ISH was highly concordant in both subgroups. Comparison of digital assessment versus manual assessment was highly concordant. Discrepancies were mostly around the 1% clinical threshold. Challenging IHC interpretation included 1) calculating the total tumor cell denominator and the nature of PD-L1 expressing cell aggregates in cytology samples; 2) peritumoral expression of positive immune cells; 3) calculation of positive tumor percentages around clinical thresholds; and 4) relevance of the 100 malignant cell rule., Conclusions: Sample type and EGFR status dictate differences in the expected percentage of PD-L1 expression. Analysis of PD-L1 is challenging, and interpretative guidelines are discussed. PD-L1 evaluations by RNA-ISH and digital pathology appear reliable, particularly in adenocarcinomas., (Copyright © 2018 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

While the highly conserved FOXO transcription factors have been studied in Drosophila melanogaster for decades, the ability to accurately control and measure their tissue-specific expression is often cumbersome due to a lack of reagents and to limited, nonhomogeneous samples. The need for quantitation within a distinct cell type is particularly important because transcription factors must be expressed in specific amounts to perform their functions properly. However, the inherent heterogeneity of many samples can make evaluating cell-specific FOXO and/or FOXO load difficult. Here, we describe an extremely sensitive fluorescence in situ hybridization (FISH) approach for visualizing and quantifying multiple mRNAs with single-cell resolution in adult Drosophila cardiomyocytes. The procedure relies upon branched DNA technology, which allows several fluorescent molecules to label an individual transcript, drastically increasing the signal-to-noise ratio compared to other FISH assays. This protocol can be modified for use in various small animal models, tissue types, and for assorted nucleic acids.

Identifying the source and dynamics of persistent HIV-1 at single-cell resolution during cART is crucial for the design of strategies to eliminate the latent HIV-1 reservoir. An assay to measure latent HIV-1 that can distinguish inducible from defective proviruses with high precision is essential to evaluate the efficacy of HIV-1 cure efforts but is presently lacking. The primary aim of this study was therefore to identify transcription and translation competent latently infected cells through detection of biomolecules that are dependent on transcriptional activation of the provirus. We investigated the applicability of two commercially available assays; PrimeFlow TM RNA Assay (RNAflow) and RNAscope ® ISH (RNAscope) for evaluation of the efficacy of latency reversal agents (LRAs) to reactivate the HIV-1 latent reservoir. The J-Lat cell model (clones 6.3, 9.3, and 10.6) and four LRAs was used to evaluate the sensitivity, specificity, and lower detection limit of the RNAflow and RNAscope assays for the detection and description of the translation-competent HIV-1 reservoir. We also checked for HIV-1 subtype specificity of the RNAscope assay using patient-derived subtype A1, B, C, and CRF01_AE recombinant plasmids following transfection in 293T cells and the applicability of the method in patient-derived peripheral blood mononuclear cells (PBMCs). The lower detection limit of RNAflow was 575 HIV-1 infected cells/million and 45 cells/million for RNAscope. The RNAscope probes, designed for HIV-1B, also detected other subtypes (A1, B, C, and CRF01_AE). RNAscope was applicable for the detection of HIV-1 in patient-derived PBMCs following LRA activation. In conclusion, our study showed that RNAscope can be used to quantify the number of directly observed individual cells expressing HIV-1 mRNA following LRA activation. Therefore, it can be a useful tool for characterization of translation-competent HIV-1 in latently infected cell at single-cell resolution in the fields of HIV-1 pathogenesis and viral persistence.

It is now established that human papillomavirus (HPV) plays a role in the development of a subset of head and neck squamous cell carcinomas (SCCs), notably oropharyngeal (OP) SCCs. However, it is not clear which test one should use to detect HPV in OP and non-OP SCCs. In this study, using 348 head and neck SCCs (126 OP SCCs and 222 non-OP SCCs), we evaluated diagnostic performances of different HPV tests in OP and non-OP SCCs: polymerase chain reaction, p16 immunostaining, in situ hybridization targeting DNA (DNA-CISH) and RNA (RNA-CISH), combined p16 + DNA-CISH, and combined p16 + RNA-CISH. HPV DNA (polymerase chain reaction) was detected in 26% of all tumors (44% of OP SCCs and 17% of non-OP SCCs). For OP SCCs, RNA-CISH was the most sensitive stand-alone test (88%), but p16 + RNA-CISH was even more sensitive (95%). Specificities were the same for RNA-CISH and DNA-CISH (97%), but it was better for p16 + RNA-CISH (100%). For non-OP SCCs, all tests had sensitivities less than 50%, and RNA-CISH, DNA-CISH, and p16 + DNA-CISH had 100%, 97%, and 99% specificities, respectively. As a stand-alone test, RNA-CISH is the most performant assay to detect HPV in OP SCCs, and combined p16 + RNA-CISH test slightly improves its performances. However, RNA-CISH has the advantage of being one single test. Like p16 and DNA-CISH, RNA-CISH performances are poor in non-OP SCCs to detect HPV, and combining tests does not improve performances., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Elucidating the spatial resolution of gene transcripts provides important insight into potential gene function. MicroRNAs are short, singled-stranded noncoding RNAs that control gene expression through base-pair complementarity with target mRNAs in the 3' untranslated region (UTR) and inhibiting protein expression. However, given their small size of ~22- to 24-nt and low expression levels, standard in situ hybridization detection methods are not amendable for microRNA spatial resolution. Here, I describe a technique that employs RNAscope probe design and propriety amplification technology that provides simultaneous single molecule detection of individual microRNA and its target gene. This method allows for rapid and sensitive detection of noncoding RNA transcripts in frozen tissue sections.

Microglia and macrophage cells are the primary producers of cytokines in response to neuroinflammatory processes. But these cytokines are also produced by other glial cells, endothelial cells, and neurons. It is essential to identify the cells that produce these cytokines to target their different levels of activation. We used dual RNAscope ® fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) techniques to visualize the mRNA expression pattern of pro- and anti-inflammatory cytokines in microglia/macrophages cells. Using these methods, we can associate one mRNA to specific cell types when combining with different cellular markers by immunofluorescence. Results from RNAscope ® probes IL-1β, TNFα, TGFβ, IL-10 or Arg1, showed colocalization with antibodies for microglia/macrophage cells. These target probes showed adequate sensitivity and specificity to detect mRNA expression. New FISH detection techniques combined with immunohistochemical techniques will help to jointly determine the protein and mRNA localization, as well as provide reliable quantification of the mRNA expression levels., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Advanced molecular probing techniques such as single molecule fluorescence in situ hybridization (smFISH) or RNAscope can be used to assess the quantity and spatial location of mRNA transcripts within cells. Quantifying mRNA expression in large image sets usually involves automated counting of fluorescent spots. Though conventional spot counting algorithms may suffice, they often lack high-throughput capacity and accuracy in cases of crowded signal or excessive noise. Automatic identification of cells and processing of many images is still a challenge. We have developed a method to perform automatic cell boundary identification while providing quantitative data about mRNA transcript levels across many images. Comparisons of mRNA transcript levels identified by the method highly correlate to qPCR measurements of mRNA expression in Drosophila genotypes with different levels of Rhodopsin 1 transcript. We also introduce a graphical user interface to facilitate analysis of large data sets. We expect these methods to translate to model systems where automated image processing can be harnessed to obtain single-cell data. The described method: •Provides relative intensity measurements that scale directly with the number of labeled transcript probes within individual cells.•Allows quantitative assessment of single molecule data from images with crowded signal and moderate signal to noise ratios.

Background: Podoplanin (PDPN), a mucin-type transmembrane glycoprotein, is expressed in a variety of human cancer types, and contributes to tumor progression. Our goal was to evaluate PDPN expression in hepatocellular carcinoma (HCC) using both immunohistochemistry (IHC) and RNAscope in situ hybridization., Materials and Methods: Twenty patients with HCC who underwent partial hepatectomy with curative intent were retrospectively analyzed., Results: IHC gave positive results in 11 cases, while RNAscope assay for PDPN detected amplification in 16 cases. A significant association was noted between PDPN protein expression and histological tumor grade (p=0.036). Four cases that had negative PDPN results by RNAscope were also negative by IHC, while the remaining five cases with negative results by IHC were positive by RNAscope. A positive relationship was found between PDPN mRNA protein expression (p<0.001)., Conclusion: Our preliminary results suggest that PDPN contributes to the malignant potential of HCC. RNAscope proved to be a more sensitive and reliable method than IHC in PDPN detection., (Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background: ASPM is a newly reported stem cell marker and plays important roles in mitosis, cell cycle and tumorigenesis. It links with poor clinical prognosis in various tumors. However, the clinical significance of ASPM in colonic adenocarcinoma (CA) has not been fully studied. The purpose of this study was to investigate if ASPM is correlated with the clinicopathological features of CA., Methods: Primary CA tissue, adenoma and the matched normal mucosa from 99 patients, were detected using immunohistochemical analysis by primary antibodies against ASPM. Meanwhile, 20 CAs and 20 liver metastatic cases were examined by RNA in situ hybridization (RNAscope). To assess the clinical relevance of ASPM, we analyzed the survival follow-up information., Results: ASPM was found only in single cells in the base of normal colon mucosal crypts. But the expression of ASPM was detected high in colonic adenomas (49.5%, 49/99), and significantly higher in CA (56.6%, 56/ 99, P <0.001). In CAs, ASPM expression was more intense in stage III and IV than II and I stage patients ( P =0.03), and positively correlated with lymph node metastasis ( P =0.03), but not with the age at diagnosis, gender and histological grade ( P>0.05 ). We also analyzed the survival follow-up information, the data showed that ASPM-positive expression was correlated with a shorter disease-free survival (DFS) time, the average DFS time of patients with ASPM positive and negative expression was 62.79±2.32 months and 71.30±2.72 months, respectively, and there was no statistical significance between the two groups ( P >0.05). The results of ASPM mRNA measurement by RNAscope revealed ASPM mRNA expression was higher in primary CA than that in metastatic liver CA (P<0.001)., Conclusions: ASPM might play an important role in colonic carcinogenesis and be a potential marker in predicting prognosis of CA., Competing Interests: None., (IJCEP Copyright © 2017.)

Estrogen receptor α (ERα) plays a significant role in the development of breast cancer and has been used clinically as an endocrine therapeutic target. Currently, clinical laboratories use immunohistochemistry (IHC) to determine the ERα status of patients in order to distinguish those who would benefit from endocrine therapy. This method is highly subjective, requires a large amount of tumor tissue, and may generate false-negative results. To improve the detection of ERα, we used a new RNA in situ hybridization technique (RNAscope) and compared its use with IHC in 72 breast cancer tissues (47 ERα positive and 25 ERα negative). Then we evaluated ERα mRNA by RT-qPCR with RNAscope. An unobvious difference was found between reverse-transcription quantitative polymerase chain reaction (RT-qPCR) and IHC, but a positive correlation was found between RNAscope and IHC. In addition, breast cancer is a highly heterogeneous cancer, and RNAscope could easily reveal the heterogeneity in breast cancer. Moreover, we found that some ERα IHC-based negative and RNAscope-based positive test results were detected as positive after testing with IHC again. Our findings suggest that RNAscope may be a complementary method for improving the detection of patient ERα status and has potential clinical utility., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Purpose: Subsets of pituitary tumors exhibit an aggressive clinical courses and recur despite surgery, radiation, and chemotherapy. Because modulation of the immune response through inhibition of T-cell checkpoints has led to durable clinical responses in multiple malignancies, we explored whether pituitary adenomas express immune-related biomarkers that could suggest suitability for immunotherapy. Specifically, programmed death ligand 1 (PD-L1) has emerged as a potential biomarker whose expression may portend more favorable responses to immune checkpoint blockade therapies. We thus investigated the expression of PD-L1 in pituitary adenomas., Methods: PD-L1 RNA and protein expression were evaluated in 48 pituitary tumors, including functioning and non-functioning adenomas as well as atypical and recurrent tumors. Tumor infiltrating lymphocyte populations were also assessed by immunohistochemistry., Results: Pituitary tumors express variable levels of PD-L1 transcript and protein. PD-L1 RNA and protein expression were significantly increased in functioning (growth hormone and prolactin-expressing) pituitary adenomas compared to non-functioning (null cell and silent gonadotroph) adenomas. Moreover, primary pituitary adenomas harbored higher levels of PD-L1 mRNA compared to recurrent tumors. Tumor infiltrating lymphocytes were observed in all pituitary tumors and were positively correlated with increased PD-L1 expression, particularly in the functional subtypes., Conclusions: Human pituitary adenomas harbor PD-L1 across subtypes, with significantly higher expression in functioning adenomas compared to non-functioning adenomas. This expression is accompanied by the presence of tumor infiltrating lymphocytes. These findings suggest the existence of an immune response to pituitary tumors and raise the possibility of considering checkpoint blockade immunotherapy in cases refractory to conventional management.

Biomarkers such as DNA, RNA, and protein are powerful tools in clinical diagnostics and therapeutic development for many diseases. Identifying RNA expression at the single cell level within the morphological context by RNA in situ hybridization provides a great deal of information on gene expression changes over conventional techniques that analyze bulk tissue, yet widespread use of this technique in the clinical setting has been hampered by the dearth of automated RNA ISH assays. Here we present an automated version of the RNA ISH technology RNAscope that is adaptable to multiple automation platforms. The automated RNAscope assay yields a high signal-to-noise ratio with little to no background staining and results comparable to the manual assay. In addition, the automated duplex RNAscope assay was able to detect two biomarkers simultaneously. Lastly, assay consistency and reproducibility were confirmed by quantification of TATA-box binding protein (TBP) mRNA signals across multiple lots and multiple experiments. Taken together, the data presented in this study demonstrate that the automated RNAscope technology is a high performance RNA ISH assay with broad applicability in biomarker research and diagnostic assay development. J. Cell. Biochem. 117: 2201-2208, 2016. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

A primary obstacle to an HIV-1 cure is long-lived viral reservoirs, which must be eliminated or greatly reduced. Cure strategies have largely focused on monitoring changes in T cell reservoirs in peripheral blood (PB), even though the lymphoid tissues (LT) are primary sites for viral persistence. To track and discriminate viral reservoirs within tissue compartments we developed a specific and sensitive next-generation in situ hybridization approach to detect vRNA, including vRNA+ cells and viral particles ("RNAscope"), vDNA+ cells ("DNAscope") and combined vRNA and vDNA with immunohistochemistry to detect and phenotype active and latently infected cells in the same tissue section. RNAscope is highly sensitive with greater speed of analysis compared to traditional in situ hybridization. The highly sensitive and specific DNAscope detected SIV/HIV vDNA+ cells, including duplexed detection of vDNA and vRNA or immunophenotypic markers in the same section. Analysis of LT samples from macaques prior to and during combination antiretroviral therapy demonstrated that B cell follicles are an important anatomical compartment for both latent and active viral persistence during treatment. These new tools should allow new insights into viral reservoir biology and evaluation of cure strategies.

Background: We aimed to validate PDGF-BB protein expression by RNAscope, a sensitive method for PDGF-BB mRNA evaluation on paraffin embedded (FFPE) specimens of ovarian tumors., Materials and Methods: Seventy-five FFPE ovarian cancer biopsies were assessed by immunohistochemistry followed by PDGF-BB mRNA RNAscope validation., Results and Conclusion: Dual PDGF-BB expression in tumor and stromal cells have been observed, being highly suggestive for PDGF-BB mediated stromal-tumor cells reciprocal interaction in ovarian cancer (p=0.008). It seems that the nuclear expression of the PDGF-BB represents a negative prognostic factor in ovarian tumors. Being a controversial issue in the literature, PDGF-BB nuclear expression detected by immunohistochemistry was validated by RNAscope in situ hybridization. More than 65% of cases had PDGF-BB mRNA amplification, confirming immunohistochemical results. We herein validated PDGF-BB as a potential therapeutic and prognostic tool of ovarian cancer aggressiveness., (Copyright© 2016, International Institute of Anticancer Research (Dr. John G. Delinasios), All rights reserved.)

The process by which the germ line is specified in the zebrafish embryo is under the control of maternal gene products that were produced during oogenesis. Zebrafish are highly amenable to microscopic observation of the processes governing maternal germ cell specification because early embryos are transparent, and the germ line is specified rapidly (within 4-5h post fertilization). Advantages of zebrafish over other models used to study vertebrate germ cell formation include their genetic tractability, the large numbers of progeny, and the easily manipulable genome, all of which make zebrafish an ideal system for studying the genetic regulators and cellular basis of germ cell formation and maintenance. Classical molecular biology techniques, including expression analysis through in situ hybridization and forward genetic screens, have laid the foundation for our understanding of germ cell development in zebrafish. In this chapter, we discuss some of these classic techniques, as well as recent cutting-edge methodologies that have improved our ability to visualize the process of germ cell specification and differentiation, and the tracking of specific molecules involved in these processes. Additionally, we discuss traditional and novel technologies for manipulating the zebrafish genome to identify new components through loss-of-function studies of putative germ cell regulators. Together with the numerous aforementioned advantages of zebrafish as a genetic model for studying development, we believe these new techniques will continue to advance zebrafish to the forefront for investigation of the molecular regulators of germ cell specification and germ line biology., (Copyright © 2016 Elsevier Inc. All rights reserved.)

High-risk human papillomavirus (hrHPV) is an etiologic agent in squamous cell carcinoma (SqCC) arising in the oropharynx and cervix, and a proven prognostic factor in oropharyngeal SqCC. Many studies have found HPV in non-small cell lung carcinoma (NSCLC). Recent studies advocate the detection of messenger RNA transcripts of E6/E7 as more reliable evidence of transcriptively active HPV in tumor cells. The clinical significance of finding HPV remains unclear in NSCLC. This study sought to determine the prevalence of biologically active HPV infection in NSCLC comparing different methodologies. Surgical pathology material from resected primary lung adenocarcinoma (ADC; n=100) and SqCC (n=96) were retrieved to construct tissue microarrays. In situ hybridization (ISH) for hrHPV DNA (DNA-ISH), hrHPV E6/E7 RNA (RNA-ISH), and p16 immunohistochemistry were performed. Cases of oropharyngeal SqCC with known HPV infection were used as positive controls. Expression of p16 was scored as positive if at least 70% of tumor cells showed diffuse and strong nuclear and cytoplasmic staining. Punctate nuclear hybridization signals by DNA-ISH in the malignant cells defined an HPV-positive carcinoma. Of the 196 patients (range, 33-87 years; 108 men), p16 was positive in 19 ADCs and 9 SqCCs, but HPV DNA-ISH and RNA-ISH were negative in all cases. Our study did not detect HPV infection by DNA-ISH or RNA-ISH in any cases of primary NSCLC despite positive p16 expression in a portion of ADC and SqCC. p16 should therefore not be used as a surrogate marker for HPV infection in NSCLC., (Copyright © 2015 Elsevier Inc. All rights reserved.)

There are no effective medical treatments for WHO grade III (anaplastic) meningioma. Patients with this high-grade malignancy have a median survival of less than two years. Therapeutics that modulate the mechanisms that inhibit local immune responses in the tumor microenvironment are showing significant and durable clinical responses in patients with treatment refractory high-grade tumors. We examined the immune infiltrate of 291 meningiomas including WHO grade I-III meningiomas using immunohistochemistry and we examined the expression of PD-L1 mRNA by RNAscope in situ hybridization and PD-L1 protein by immunohistochemistry. In meningioma, the tumor infiltrating lymphocytes are predominantly T cells. In anaplastic meningioma, there is a sharp decrease in the number of T cells, including the numbers of CD4+ and CD8+ T cells and cells expressing PD-1 and there is also an increase in the number of FOXP3 expressing immunoregulatory (Treg) cells. PD-L1 expression is increased in anaplastic meningioma - both mRNA and protein. Using patient derived meningioma cell, we confirm that PD-L1 is expressed in meningioma cells themselves, and not solely in infiltrating immune cells. This work indicates that high-grade meningioma harbor an immunosuppressive tumor microenviroment and that increased Treg cells and elevated PD-L1 may contribute to the aggressive phenotype of these tumors.

There are no effective medical treatments for WHO grade III (anaplastic) meningioma. Patients with this high-grade malignancy have a median survival of less than two years. Therapeutics that modulate the mechanisms that inhibit local immune responses in the tumor microenvironment are showing significant and durable clinical responses in patients with treatment refractory high-grade tumors. We examined the immune infiltrate of 291 meningiomas including WHO grade I-III meningiomas using immunohistochemistry and we examined the expression of PD-L1 mRNA by RNAscope in situ hybridization and PD-L1 protein by immunohistochemistry. In meningioma, the tumor infiltrating lymphocytes are predominantly T cells. In anaplastic meningioma, there is a sharp decrease in the number of T cells, including the numbers of CD4+ and CD8+ T cells and cells expressing PD-1 and there is also an increase in the number of FOXP3 expressing immunoregulatory (Treg) cells. PD-L1 expression is increased in anaplastic meningioma – both mRNA and protein. Using patient derived meningioma cell, we confirm that PD-L1 is expressed in meningioma cells themselves, and not solely in infiltrating immune cells. This work indicates that high-grade meningioma harbor an immunosuppressive tumor microenviroment and that increased Treg cells and elevated PD-L1 may contribute to the aggressive phenotype of these tumors.

Background: PROX1 is involved in cancer development and progression as both a tumor suppressor and oncogene. Immunohistochemical (IHC) PROX1 nuclear expression is a widely accepted pattern. Scattered data reported PROX1 IHC cytoplasmic expression in different tumors, including gastric cancer but it is not clear if this holds true., Materials and Methods: Evaluation of the cytoplasmic expression of PROX1 in normal gastric mucosa and gastric cancer was performed by IHC followed by RNAscope, an in situ hybridization-based method for detecting PROX1 mRNA amplification on paraffin-embedded samples and to evaluate its clinical impact., Results: Twenty five out of 48 cases of gastric cancer showed PROX1 nuclear and cytoplasmic immunohistochemical expression. Twelve out of these 20 cases positive for PROX1 on IHC (54.5%) had PROX1 mRNA gene amplification. The overlapping of PROX1 cytoplasmic expression assessed by immunohistochemistry and cytoplasmic RNAscope amplification was statistically significant (p=0.031). PROX1 mRNA gene amplification correlated with tumor grade (p=0.05) and regional lymph node metastasis as well (p=0.033). No significant correlation was obtained between PROX1 and histopathology, tumor size or distal metastasis., Conclusion: A significant correlation was found between IHC and RNAscope PROX1 expression in the cytoplasm of normal and gastric cancer cells. This strongly supports its validation as a true expression on immunohistochemistry. A strong correlation between PROX1 mRNA amplification and regional lymph node metastasis supports its implications in cancer spreading and metastasis and sustains its utility, not only as a lymphatic marker, but also as a potential tumor marker in various tumor types, including gastric cancer., (Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Premise of the Study: A novel branched DNA detection technology, RNAscope in situ hybridization (ISH), originally developed for use on human clinical and animal tissues, was adapted for use in plant tissue in an attempt to overcome some of the limitations associated with traditional ISH assays. •, Methods and Results: Zea mays leaf tissue was formaldehyde fixed and paraffin embedded (FFPE) and then probed with the RNAscope ISH assay for two endogenous genes, phosphoenolpyruvate carboxylase (PEPC) and phosphoenolpyruvate carboxykinase (PEPCK). Results from both manual and automated methods showed tissue- and cell-specific mRNA localization patterns expected from these well-studied genes. •, Conclusions: RNAscope ISH is a sensitive method that generates high-quality, easily interpretable results from FFPE plant tissues. Automation of the RNAscope method on the Ventana Discovery Ultra platform allows significant advantages for repeatability, reduction in variability, and flexibility of workflow processes.

In a recent study, a unique gene expression signature was observed when comparing esophageal squamous cell carcinoma (ESCC) epithelial cells to normal esophageal epithelial cells using laser capture microdissection (LCM) and cDNA microarray technology. To validate the expression of several intriguing genes from that study (KRT17, cornulin, CD44, and EpCAM), we employed two new technologies, expression microdissection (xMD) for high-throughput microdissection facilitating protein analysis and RNAscope for the evaluation of low abundant transcripts in situ. For protein measurements, xMD technology was utilized to specifically procure sufficient tumor and normal epithelium from frozen human tissue for immunoblot analysis of KRT17 (CK17) and cornulin. A novel in situ hybridization method (RNAscope) was used to determine the transcript level of two relatively low expressed genes, CD44 and EpCAM in both individual formalin-fixed paraffin-embedded (FFPE) tissue sections and in an ESCC tissue microarray (TMA). The results successfully confirmed the initial expression pattern observed for all four genes, potentially implicating them in the pathogenesis of ESCC. Additionally, the study provides important methodological information on the overall process of candidate gene validation.