Diagnostic Immunohistochemistry: what can go wrong?

Correlation Between ImageJ and Conventional Manual Scoring Methods for Programmed Death-Ligand 1 Immuno-Histochemically Stained Sections

Background: One of the most frequently used methods for quantifying PD-L1 (programmed cell death-ligand 1) expression in tumor tissue is IHC (immunohistochemistry). This may predict the patient's response to anti-PD1/PD-L1 therapy in cancer. Methods: ImageJ software was used to score IHC-stained sections for PD-L1 and compare the results with the conventional manual method. Results: In diffuse large B cell lymphoma, no significant difference between the scores obtained by the conventional method and ImageJ scores obtained using the option "RGB" or "Brightness/Contrast." On the other hand, a significant difference was found between the conventional and HSB scoring methods. ImageJ faced some challenges in analyzing head and neck squamous cell carcinoma tissues because of tissue heterogenicity. A significant difference was found between the conventional and ImageJ scores using HSB or RGB but not with the "Brightness/Contrast" option. Scores obtained by ImageJ analysis after taking images using 20 × objective lens gave significantly higher readings compared to 40 × magnification. A significant difference between camera-captured images' scores and scanner whole slide images' scores was observed. Conclusion: ImageJ can be used to score homogeneous tissues. In the case of highly heterogeneous tissues, it is advised to use the conventional method rather than ImageJ scoring.

Clinical Proteomics for Solid Organ Tissues

The evaluation of biopsied solid organ tissue has long relied on visual examination using a microscope. Immunohistochemistry is critical in this process, labeling and detecting cell lineage markers and therapeutic targets. However, while the practice of immunohistochemistry has reshaped diagnostic pathology and facilitated improvements in cancer treatment, it has also been subject to pervasive challenges with respect to standardization and reproducibility. Efforts are ongoing to improve immunohistochemistry, but for some applications, the benefit of such initiatives could be impeded by its reliance on monospecific antibody-protein reagents and limited multiplexing capacity. This perspective surveys the relevant challenges facing traditional immunohistochemistry and describes how mass spectrometry, particularly liquid chromatography-tandem mass spectrometry, could help alleviate problems. In particular, targeted mass spectrometry assays could facilitate measurements of individual proteins or analyte panels, using internal standards for more robust quantification and improved interlaboratory reproducibility. Meanwhile, untargeted mass spectrometry, showcased to date clinically in the form of amyloid typing, is inherently multiplexed, facilitating the detection and crude quantification of 100s to 1000s of proteins in a single analysis. Further, data-independent acquisition has yet to be applied in clinical practice, but offers particular strengths that could appeal to clinical users. Finally, we discuss the guidance that is needed to facilitate broader utilization in clinical environments and achieve standardization.

Advances and Emerging Medical Applications of Direct Mass Spectrometry Technologies for Tissue Analysis

Offering superb speed, chemical specificity, and analytical sensitivity, direct mass spectrometry (MS) technologies are highly amenable for the molecular analysis of complex tissues to aid in disease characterization and help identify new diagnostic, prognostic, and predictive markers. By enabling detection of clinically actionable molecular profiles from tissues and cells, direct MS technologies have the potential to guide treatment decisions and transform sample analysis within clinical workflows. In this review, we highlight recent health-related developments and applications of direct MS technologies that exhibit tangible potential to accelerate clinical research and disease diagnosis, including oncological and neurodegenerative diseases and microbial infections. We focus primarily on applications that employ direct MS technologies for tissue analysis, including MS imaging technologies to map spatial distributions of molecules in situ as well as handheld devices for rapid in vivo and ex vivo tissue analysis.

Differential remodeling in small and large murine airways revealed by novel whole lung airway analysis

Airway remodeling occurs in chronic asthma leading to increased airway smooth muscle (ASM) mass and extracellular matrix (ECM) deposition. Although extensively studied in murine airways, studies report only selected larger airways at one time-point meaning the spatial distribution and resolution of remodeling are poorly understood. Here we use a new method allowing comprehensive assessment of the spatial and temporal changes in ASM, ECM, and epithelium in large numbers of murine airways after allergen challenge. Using image processing to analyze 20-50 airways per mouse from a whole lung section revealed increases in ASM and ECM after allergen challenge were greater in small and large rather than intermediate airways. ASM predominantly accumulated adjacent to the basement membrane, whereas ECM was distributed across the airway wall. Epithelial hyperplasia was most marked in small and intermediate airways. After challenge, ASM changes resolved over 7 days, whereas ECM and epithelial changes persisted. The new method suggests large and small airways remodel differently, and the long-term consequences of airway inflammation may depend more on ECM and epithelial changes than ASM. The improved quantity and quality of unbiased data provided by the method reveals important spatial differences in remodeling and could set new analysis standards for murine asthma models.

Enabling automated and reproducible spatially resolved transcriptomics at scale

Spatial information of tissues is an essential component to reach a holistic overview of gene expression mechanisms. The sequencing-based Spatial transcriptomics approach allows to spatially barcode the whole transcriptome of tissue sections using microarray glass slides. However, manual preparation of high-quality tissue sequencing libraries is time-consuming and subjected to technical variability. Here, we present an automated adaptation of the 10x Genomics Visium library construction on the widely used Agilent Bravo Liquid Handling Platform. Compared to the manual Visium library preparation, our automated approach reduces hands-on time by over 80% and provides higher throughput and robustness. Our automated Visium library preparation protocol provides a new strategy to standardize spatially resolved transcriptomics analysis of tissues at scale.

Current methods and emerging approaches for detection of programmed death ligand 1

Various tumor cells overexpress programmed death ligand 1 (PD-L1), a main immune checkpoint protein (ICP) embedded in the tumor cells membrane, to evade immune recognition through the interaction between PD-L1 and its receptor programmed death 1 (PD-1) which is from T-cells for maintaining immune tolerance. So inhibitors targeting the PD-1 or PD-L1 can block the PD-1/PD-L1 signaling pathway to restore the recognition activity of the immune system to tumor cells, which also have been utilized as a novel approach to improve the clinical therapeutic effect for cancer patients. Since not all cancer patients can respond to these inhibitors effectively, previous diagnosis of PD-L1 is significant to target the right treatments for cancer patients. This review pays attention to the PD-L1 detection and recent progress in the measurement of PD-L1 concentration, including various detection methods based on optical sensors as well as electrochemical assays. Apart from above those, we also focus on the prospects of PD-L1 detection in precision medicine.

Nucleic acid amplification-integrated single-molecule fluorescence imaging for in vitro and in vivo biosensing

Single-molecule fluorescence imaging is among the most advanced analytical technologies and has been widely adopted for biosensing due to its distinct advantages of simplicity, rapidity, high sensitivity, low sample consumption, and visualization capability. Recently, a variety of nucleic acid amplification approaches have been developed to provide a straightforward and highly efficient way for amplifying low abundance target signals. The integration of single-molecule fluorescence imaging with nucleic acid amplification has greatly facilitated the construction of various fluorescent biosensors for in vitro and in vivo detection of DNAs, RNAs, enzymes, and live cells with high sensitivity and good selectivity. Herein, we review the advances in the development of fluorescent biosensors by integrating single-molecule fluorescence imaging with nucleic acid amplification based on enzyme (e.g., DNA polymerase, RNA polymerase, exonuclease, and endonuclease)-assisted and enzyme-free (e.g., catalytic hairpin assembly, entropy-driven DNA amplification, ligation chain reaction, and hybridization chain reaction) strategies, and summarize the principles, features, and in vitro and in vivo applications of the emerging biosensors. Moreover, we discuss the remaining challenges and future directions in this area. This review may inspire the development of new signal-amplified single-molecule biosensors and promote their practical applications in fundamental and clinical research.

Prognostic Value of Serum Thyroglobulin and Anti-Thyroglobulin Antibody in Thyroid Carcinoma Patients following Thyroidectomy

Well-differentiated thyroid cancer (WDTC) is a malignant head and neck tumor with a very high incidence. Thyroidectomized WDTC patients have been referred to nuclear medicine for radioactive iodine (RAI) ablation therapy and/or annual follow-up with diagnostic whole-body imaging. Serum thyroglobulin (TG) and thyroglobulin antibodies (TGAb) are biochemical tumor markers used to monitor WDTC. A global rise in the prevalence of WDTC is increasing the number of thyroidectomized patients requiring lifelong monitoring for persistent or recurrent diseases. The present study aimed to identify the most successful prognostic factors in well-defined thyroid carcinoma patients following total thyroidectomy and RAI therapy, followed by an estimation of the cutoff value of TG and TGAb. In this context, a total of 100 subjects were recruited and classified as follows: 60 thyroid carcinoma patients underwent total thyroidectomy and successful RAI therapy, while 40 normal healthy individuals matched for age, sex, and socioeconomic status constituted the control group. Interestingly, the levels of TG did not differ significantly between the relapsed and non-relapsed cases, but the levels of TGAb differed significantly between the relapsed and non-relapsed cases. Collectively, TG and TGAb are considered the most successful prognostic factors in well-defined thyroid carcinoma patients after total thyroidectomy and RAI therapy. The present study also concluded that the TGAb determination was better than that of the TG level, with a cutoff value of 10 ng/mL. These findings provide baseline information for follow-up and lifelong monitoring of thyroidectomized WDTC patients. Further research is warranted to explore more about serum TG and TGAb in thyroid carcinoma patients on a larger scale.

Progression Risk Score Estimation Based on Immunostaining Data in Oral Cancer Using Unsupervised Hierarchical Clustering Analysis: A Retrospective Study in Taiwan

This study aimed to investigate whether the progression risk score (PRS) developed from cytoplasmic immunohistochemistry (IHC) biomarkers is available and applicable for assessing risk and prognosis in oral cancer patients. Participants in this retrospective case-control study were diagnosed between 2012 and 2014 and subsequently underwent surgical intervention. The specimens from surgery were stained by IHC for 16 cytoplasmic target markers. We evaluated the results of IHC staining, clinical and pathological features, progression-free survival (PFS), and overall survival (OS) of 102 oral cancer patients using a novel estimation approach with unsupervised hierarchical clustering analysis. Patients were stratified into high-risk (52) and low-risk (50) groups, according to their PRS; a metric consisting of cytoplasmic PLK1, PhosphoMet, SGK2, and SHC1 expression. Moreover, PRS could be extended for use in the Cox proportional hazard regression model to estimate survival outcomes with associated clinical parameters. Our study findings revealed that the high-risk patients had a significantly increased risk in cancer progression compared with low-risk patients (hazard ratio (HR) = 2.20, 95% confidence interval (CI) = 1.10-2.42, p = 0.026). After considering the influences of demographics, risk behaviors, and tumor characteristics, risk estimation with PRS provided distinct PFS groups for patients with oral cancer (p = 0.017, p = 0.019, and p = 0.020). Our findings support that PRS could serve as an ideal biomarker for clinical use in risk stratification and progression assessment in oral cancer.

How well do brain organoids capture your brain?

Brain organoids closely recapitulate many features and characteristics of in vivo brain tissue. This technology in turn allows unprecedented possibilities to investigate brain development and function in the dish. Several brain organoid protocols have been established, and the studies have focused on validating the architecture, cellular composition, and function of the organoids. In future, the improved and advanced organoid models will enable us to understand cellular and molecular features of the developing brain. However, several obstacles, such as the quality of the organoids, 3D structural analysis, and measurement of the neural connectivity need to be improved. In this perspective, we will provide an overview of the current state of the art of the brain organoid field, with a focus on protocols and organoid characterization. Additionally, we will address the current limitations of this evolving field and provide an understanding of the current brain organoid landscape and insight toward the next steps.

Correlation of VEGF and MMP-2 levels in oral lichen planus: An in vivo immunohistochemical study

Background

This study aimed to investigate the relation between vascular endothelial growth factors (VEGF) and matrix metalloproteinase-2 (MMP-2) in different oral lichen planus (OLP) forms compared to control patients.

Methods

Biopsies from 60 patients were selected and equally distributed as follows: reticular/popular OLP (R/PLP), atrophic/erosive OLP (A/ELP) patients, healthy subjects (Control). All biopsies were immune-histochemical stained and statistically analyzed for VEGF and MMP-2 expression.

Results

Immune-expression of VEGF was significant between OLP and control (P-value <0.001). OLP showed a higher epithelial expression of VEGF in A/ELP compared to R/PLP (15.19 ± 2.53). In connective tissue (CT), R/PLP showed a higher VEGF expression (11.57 ± 2.32) compared to A/ELP (9.87 ± 2.48); (p < 0.001), with no significant difference (P-value ≥ 0.05). A significant epithelial expression of MMP-2 was seen in A/ELP compared to R/PLP (21.32 ± 7.08). R/PLP showed a higher expression of MMP-2 (20.45 ± 6.28) in CT compared to A/ELP group (17.66 ± 6.94), with a non-significant difference (P-value = 1.000). In A/ELP, a positive correlation between VEGF and MMP-2 was detected in CT, r = 0.761, with a weak correlation was noticed in epithelium r = 0.163. A negative correlation was noted between VEGF and MMP-2 in R/PLP in CT, r = -0.368, with a moderate positive correlation in epithelium, r = 0.655.

Conclusion

MMP-2 and VEGF protein profiles support a role in the pathogenesis of OLP. Based the MMP-2 and VEGF findings in the A/ELP group, this pathway may have a role in the malignant transformation of these lesions. Both observations invite further study.

CARGEL Bioscaffold improves cartilage repair tissue after bone marrow stimulation in a minipig model

Purpose

To gain knowledge of the repair tissue in critically sized cartilage defects using bone marrow stimulation combined with CARGEL Bioscaffold (CB) compared with bone marrow stimulation (BMS) alone in a validated animal model.

Methods

Six adult Göttingen minipigs received two chondral defects in each knee. The knees were randomized to either BMS combined with CB or BMS alone. The animals were euthanized after 6 months. Follow-up consisted of histomorphometry, immunohistochemistry, semiquantitative scoring of the repair tissue (ICRS II), and μCT of the trabecular bone beneath the defect.

Results

There was significantly more fibrocartilage (80% vs 64%, p = 0.04) and a trend towards less fibrous tissue (15% vs 30%, p = 0.05) in the defects treated with CB. Hyaline cartilage was only seen in one defect treated with CB and none treated with BMS alone.

For histological semiquantitative score (ICRS II), defects treated with CB scored lower on subchondral bone (69 vs. 44, p = 0.04). No significant differences were seen on the other parameters of the ICRS II. Immunohistochemistry revealed a trend towards more positive staining for collagen type II in the CB group (p = 0.08). μCT demonstrated thicker trabeculae (p = 0.029) and a higher bone material density (p = 0.028) in defects treated with CB.

Conclusion

Treatment of cartilage injuries with CARGEL Bioscaffold seems to lead to an improved repair tissue and a more pronounced subchondral bone response compared with bone marrow stimulation alone. However, the CARGEL Bioscaffold treatment did not lead to formation of hyaline cartilage.

Does Diabetes Induce the Vascular Endothelial Growth Factor (VEGF) Expression in Periodontal Tissues? A Systematic Review

Aim: Diabetes and periodontal disease are both chronic pathological conditions linked by several underlying biological mechanisms, in which the inflammatory response plays a critical role, and their association has been largely recognized. Recently, attention has been given to diabetes as an important mediator of vascular endothelial growth factor (VEGF) overexpression in periodontal tissues, by virtue of its ability to affect microvasculature. This review aims to summarize the findings from studies that explored VEGF expression in diabetic patients with periodontitis, compared to periodontally healthy subjects. Materials and Methods: A systematic literature review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A PubMed search of select medical subject heading (MeSH) terms was carried out to identify all studies reporting findings about VEGF expression in periodontal tissues of diabetic patients up to May 2018. The inclusion criteria were studies on VEGF expression in periodontally diseased tissues of diabetic patients compared with nondiabetic subjects, with any method of analysis, and published in the English language. Results: Eight articles met the inclusion criteria. Immunohistochemistry was used in six of the studies, reverse transcriptase polymerase chain reaction (real-time RT-PCR) aiming to quantify mRNA VEGF expression was used in one study, and ELISA analysis was used for one study. Compared with nondiabetic patients, a higher VEGF expression in gingival tissue and gingival crevicular fluid (GCF) samples in diabetic patients with periodontitis was reported. Conclusions: Overall, novel evidence for the VEGF expression within the periodontal tissue of diabetic patients paves the way for further studies on the role of this protein in neovascularization physiology and pathophysiology in microvasculature of the periodontium.

Multi-target immunofluorescence by separation of antibody cross-labelling via spectral-FLIM-FRET

In biomedical research, indirect immunofluorescence labelling by use of primary and secondary antibodies is central for revealing the spatial distribution of multiple cellular antigens. However, labelling is regularly restricted to few antigens since species variation of primary and corresponding secondary antibodies is limited bearing the risk of unspecific cross-labelling. Here, we introduce a novel microscopic procedure for leveraging undesirable cross-labelling effects among secondary antibodies thereby increasing the number of fluorophore channels. Under cross-labelling conditions, commonly used fluorophores change chemical-physical properties by ‘Förster resonance energy transfer’ leading to defined changes in spectral emission and lifetime decay. By use of spectral fluorescence lifetime imaging and pattern-matching, we demonstrate precise separation of cross-labelled cellular antigens where conventional imaging completely fails. Consequently, this undesired effect serves for an innovative imaging procedure to separate critical antigens where antibody species variation is limited and allows for multi-target labelling by attribution of new fluorophore cross-labelling channels.

A method for semi-automated image analysis of HLA class I tumour epithelium expression in rectal cancer

Biomarkers may hold the key towards development and improvement of personalized cancer treatment. For instance, tumour expression of immune system-related proteins may reveal the tumour immune status and, accordingly, determine choice for type of immunotherapy. Therefore, objective evaluation of tumour biomarker expression is needed but often challenging. For instance, human leukocyte antigen (HLA) class I tumour epithelium expression is cumbersome to quantify by eye due to its presence on both tumour epithelial cells and tumour stromal cells, as well as tumourinfiltrating immune cells. In this study, we solved this problem by setting up an immunohistochemical (IHC) double staining using a tissue microarray (TMA) of rectal tumours wherein HLA class I expression was coloured with a blue chromogen, whereas non-epithelial tissue was visualized with a brown chromogen. We subsequently developed a semi-automated image analysis method that identified tumour epithelium as well as the percentage of HLA class I-positive tumour epithelium. Using this technique, we compared HCA2/HC10 and EMR8-5 antibodies for the assessment of HLA class I tumour expression and concluded that EMR8-5 is the superior antibody for this purpose. This IHC double staining can in principle be used for scoring of any biomarker expressed by tumour epithelium.

Evaluation of Formalin Fixation for Tissue Biopsies Using Shear Wave Laser Speckle Imaging System

Chemical fixation is the slowest and often the most uncontrolled step in the multi-step process of preparing tissue for histopathology. In order to reduce the time from taking a core needle biopsy to making a diagnosis, a new approach is proposed that optically monitors the common formalin fixation process. A low-cost and highly-sensitive laser speckle imaging technique is developed to measure shear wave velocity in a biospecimen as small as 0.5 mm in thickness submerged in millifluidic channels. Shear wave velocity, which is the indicator of tissue mechanical property and induced by piezoelectric-actuation, was monitored using gelatin phantom and chicken breast during fixation, as well as post-fixed liver and colon tissues from human. Fixation levels in terms of shear wave velocity increased by approximately 271.0% and 130.8% in gelatin phantom and chicken breast, respectively, before reaching the plateaus at 10.91 m/s and 7.88 m/s. Within these small specimens, the plateaus levels and times varied with location of measurement, and between gelatin and chicken breast. This optical-based approach demonstrates the feasibility of fine-tuning preanalytical variables, such as fixation time, for a rapid and accurate histopathological evaluation; provides a quality metric during the tissue preparation protocol performed in most pathology labs; and introduces the millifluidic chamber that can be engineered to be a future disposable device that automates biopsy processing and imaging.

Can CpG methylation serve as surrogate markers for immune infiltration in cancer?

Recent reports describe how genome-wide transcriptional analysis of cancer tissues can be exploited to identify molecular signatures of immune infiltration in cancer. We hypothesize that immune infiltration in cancer may also be defined by changes in certain epigenetic signatures. In this context, a primary objective is to identify site-specific CpG markers whose levels of methylation may be highly indicative of known transcriptional markers of immune infiltration such as GZMA, PRF1, T cell receptor genes, PDCD1, and CTLA4. This has been accomplished by integrating genome-wide transcriptional expression and methylation data for different types of cancer (melanoma, kidney cancers, lung cancers, gliomas, head and neck cancer). Our findings establish that cancers of related histology also have a high degree of similarity in immune-infiltration CpG markers. For example, the epigenetic immune infiltration signatures in lung adenocarcinoma (LUAD), mesothelioma (MESO), lung squamous cell carcinoma (LUSC), and head and neck squamous cell carcinoma (HNSC) are distinctly similar. So are glioblastoma multiforme (GBM) and brain lower grade glioma (LGG); and kidney renal papillary cell carcinoma (KIRP) and kidney renal clear cell carcinoma (KIRC). Kidney chromophobe (KICH), on the other hand has markers that are unique to this cohort. The strong relationships between immune infiltration and CpG methylation (for certain sites) in cancer tissues were not observed upon integrated analysis of publicly available cancer cell line datasets. Results from comparative pathways analyses offer further justification to methylation at certain CpG sites as being indicators of cancer immune infiltration, and possibly of predicting patient response to immunotherapeutic drugs. Achieving this target objective would significantly enhance therapeutic outcomes employing immunotherapy through focused patient-centric personalized medicine.

A nuclear shift of GSK3β protein is an independent prognostic factor in prostate cancer

Glycogen synthase kinase 3ß (GSK3ß) regulates many cancer relevant cellular processes and represents a potential therapeutic target. GSK3ß overexpression has been linked to adverse tumor features in many cancers, but its role in prostate cancer remains uncertain. We employed immunohistochemical GSK3ß expression analysis on a tissue microarray with 12,427 prostate cancers. Cytoplasmic and nuclear GSK3ß staining was separately analyzed. GSK3ß staining was absent in normal prostate epithelium, whereas 57% of 9,164 interpretable cancers showed detectable GSK3ß expression. Cytoplasmic staining was considered weak, moderate, and strong in 36%, 19.5% and 1.5% of tumors and was accompanied by nuclear GSK3ß staining in 47% of cases. Cytoplasmic GSK3ß staining as well as nuclear GSK3ß accumulation was associated with advanced tumor stage, high Gleason grade, presence of lymph node metastasis and early biochemical recurrence (p < 0.0001 each for cytoplasmic staining and nu-clear accumulation). Prognosis of GSK3ß positive cancers became particularly poor if nuclear GSK3ß staining was also seen (p < 0.0001). The prognostic impact of nuclear GSK3ß accumu-lation was independent of established preoperative and postoperative parameters in multivari-ate analyses (p < 0.0001). The significant association of GSK3ß expression with deletions of PTEN, 3p13 (p < 0.0001 each), 5q21 (p = 0.0014) and 6q15 (p = 0.0026) suggest a role of GSK3ß in the development of genomic instability. In summary, the results of our study identify GSK3ß as an independent prognostic marker in prostate cancer.

Multicenter Study Using Desorption-Electrospray-Ionization-Mass-Spectrometry Imaging for Breast-Cancer Diagnosis

The histological and molecular subtypes of breast cancer demand distinct therapeutic approaches. Invasive ductal carcinoma (IDC) is subtyped according to estrogen-receptor (ER), progesterone-receptor (PR), and HER2 status, among other markers. Desorption-electrospray-ionization-mass-spectrometry imaging (DESI-MSI) is an ambient-ionization MS technique that has been previously used to diagnose IDC. Aiming to investigate the robustness of ambient-ionization MS for IDC diagnosis and subtyping over diverse patient populations and interlaboratory use, we report a multicenter study using DESI-MSI to analyze samples from 103 patients independently analyzed in the United States and Brazil. The lipid profiles of IDC and normal breast tissues were consistent across different patient races and were unrelated to country of sample collection. Similar experimental parameters used in both laboratories yielded consistent mass-spectral data in mass-to-charge ratios ( m/ z) above 700, where complex lipids are observed. Statistical classifiers built using data acquired in the United States yielded 97.6% sensitivity, 96.7% specificity, and 97.6% accuracy for cancer diagnosis. Equivalent performance was observed for the intralaboratory validation set (99.2% accuracy) and, most remarkably, for the interlaboratory validation set independently acquired in Brazil (95.3% accuracy). Separate classification models built for ER and PR statuses as well as the status of their combined hormone receptor (HR) provided predictive accuracies (>89.0%), although low classification accuracies were achieved for HER2 status. Altogether, our multicenter study demonstrates that DESI-MSI is a robust and reproducible technology for rapid breast-cancer-tissue diagnosis and therefore is of value for clinical use.

High red blood cell composition in clots is associated with successful recanalization during intra-arterial thrombectomy

We evaluated the composition of individual clots retrieved during intra-arterial thrombectomy in relation to recanalization success, stroke subtype, and the presence of clot signs on initial brain images. We analyzed clot and interventional data from 145 retrieval trials performed for 37 patients (69.5±14.0 years, 20 men, large artery atherosclerosis, n = 7; cardioembolism, n = 22; undetermined etiology, n = 8) who had undergone intra-arterial thrombectomy. Rates of clot retrieval and successful recanalization (Arterial Occlusive Lesion score of 2–3) for separate retrieval trials were evaluated. The area occupied by red blood cell (RBC), fibrin/platelets, and white blood cell (WBC) was measured from digitized images of hematoxylin-eosin stained clots. Compositional differences were compared according to recanalization success, stroke subtype, and the presence of hyperdense clot sign on initial computed tomography and/or blooming artifact on magnetic resonance image. Of the 145 total retrieval trials (3.4±2.4 times per patient), clot was retrieved in 93 trials (64%), while recanalization was successful in 73 (50%). Fibrin/platelets (63%) occupied the greatest area in retrieved clots, followed by RBCs (33%) and WBCs (4%). Clots retrieved from successful recanalization exhibited higher RBC composition (37%) than those retrieved from non-recanalization trials (20%, p = 0.001). RBC composition was higher in cardioembolic stroke (38%) rather than large artery atherosclerosis (23%) and undetermined etiology (26%, p = 0.01). Clots exhibiting clot signs (40%) had higher RBC composition than those without clot signs (19%, p = 0.001). RBC-rich clots were associated with successful recanalization of intra-arterial thrombectomy, cardioembolic stroke, and the presence of clot-signs on initial brain images.

Regulation of brachyury by fibroblast growth factor receptor 1 in lung cancer

Recent evidence suggests that T-box transcription factor brachyury plays an important role in lung cancer development and progression. However, the mechanisms underlying brachyury-driven cellular processes remain unclear. Here we found that fibroblast growth factor receptor 1/mitogen-activated protein kinase (FGFR1/MAPK) signaling regulated brachyury in lung cancer. Analysis of FGFR1-4 and brachyury expression in human lung tumor tissue and cell lines found that only expression of FGFR1 was positively correlated with brachyury expression. Specific knockdown of FGFR1 by siRNA suppressed brachyury expression and epithelial-mesenchymal transition (EMT) (upregulation of E-cadherin and β-catenin and downregulation of Snail and fibronectin), whereas forced overexpression of FGFR1 induced brachyury expression and promoted EMT in lung cancer cells. Activation of fibroblast growth factor (FGF)/FGFR1 signaling promoted phosphorylated MAPK extracellular signal-regulated kinase (ERK) 1/2 translocation from cytoplasm to nucleus, upregulated brachyury expression, and increased cell growth and invasion. In addition, human lung cancer cells with higher brachyury expression were more sensitive to inhibitors targeting FGFR1/MAPK pathway. These findings suggest that FGFR1/MAPK may be important for brachyury activation in lung cancer, and this pathway may be an appealing therapeutic target for a subset of brachyury-driven lung cancer.

MAP2 IHC detection: a marker of antigenicity in CNS tissues

Immunohistochemistry (IHC) is used to detect antibody-specific antigens in tissues; the results depend on the ability of the primary antibodies to bind to their antigens. Therefore, results depend on the quality of preservation of the specimen. Many investigators have overcome the deleterious effects of over-fixation on the binding of primary antibodies to specimen antigens using IHC, but if the specimen is under-fixed or fixation is delayed, false negative results could be obtained despite certified laboratory practices. Microtubule-associated protein 2 (MAP2) is an abundant microtubule-associate protein that participates in the outgrowth of neuronal processes and synaptic plasticity; it is localized primarily in cell bodies and dendrites of neurons. MAP2 immunolabeling has been reported to be absent in areas of the entorhinal cortex and hippocampus of Alzheimer's disease brains that were co-localized with the dense-core type of amyloid plaques. It was hypothesized that the lack of MAP2 immunolabeling in these structures was due to the degradation of the MAP2 antigen by the neuronal proteases that were released as the neurons lysed leading to the formation of these plaques. Because MAP2 is sensitive to proteolysis, we hypothesized that changes in MAP2 immunolabeling may be correlated with the degree of fixation of central nervous system (CNS) tissues. We detected normal MAP2 immunolabeling in fixed rat brain tissues, but MAP2 immunolabeling was decreased or lost in unfixed and delayed-fixed rat brain tissues. By contrast, two ubiquitous CNS-specific markers, myelin basic protein and glial fibrillary acidic protein, were unaffected by the degree of fixation in the same tissues. Our observations suggest that preservation of various CNS-specific antigens differs with the degree of fixation and that the lack of MAP2 immunolabeling in the rat brain may indicate inadequate tissue fixation. We recommend applying MAP2 IHC for all CNS tissues as a pre-screen to assess the quality of the tissue preservation and to avoid potentially false negative IHC results.

Challenges and future of biomarker tests in the era of precision oncology: Can we rely on immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH) to select the optimal patients for matched therapy?

Molecular techniques have improved our understanding of the pathogenesis of cancer development. These techniques have also fueled the rational development of targeted drugs for patient populations stratified by their genetic characteristics. These novel methods have changed the classic paradigm of diagnostic pathology; among them are IHC, FISH, polymerase chain reaction (PCR) and microarray technology. IHC and FISH detection methods for human epidermal growth factor receptor-2 (HER2), epidermal growth factor receptor (EGFR) and programmed death ligand-1 (PD-L1) were recently approved by the Food and Drug Administration (FDA) as routine clinical practice for cancer patients. Here, we discuss general challenges related to the predictive power of these molecular biomarkers for targeted therapy in cancer medicine. We will also discuss the prospects of utilizing new biomarkers for fibroblast growth factor receptor (FGFR) and hepatocyte growth factor receptor (cMET/MET) targeted therapies for developing new and robust predictive biomarkers in oncology.

Cellular mechanisms underlying cardiac engraftment of stem cells

INTRODUCTION

Over the past decade, it has become clear that long-term engraftment of any ex vivo expanded cell product transplanted into injured myocardium is modest and all therapeutic regeneration is mediated by stimulation of endogenous repair rather than differentiation of transplanted cells into working myocardium. Given that increasing the retention of transplanted cells boosts myocardial function, focus on the fundamental mechanisms limiting retention and survival of transplanted cells may enable strategies to help to restore normal cardiac function. Areas covered: This review outlines the challenges confronting cardiac engraftment of ex vivo expanded cells and explores means of enhancing cell-mediated repair of injured myocardium. Expert opinion: Stem cell therapy has already come a long way in terms of regenerating damaged hearts though the poor retention of transplanted cells limits the full potential of truly cardiotrophic cell products. Multifaceted strategies directed towards fundamental mechanisms limiting the long-term survival of transplanted cells will be needed to enhance transplanted cell retention and cell-mediated repair of damaged myocardium for cardiac cell therapy to reach its full potential.

Blue intensity matters for cell cycle profiling in fluorescence DAPI-stained images

In the past decades, there has been an amazing progress in the understanding of the molecular mechanisms of the cell cycle. This has been possible largely due to a better conceptualization of the cycle itself, but also as a consequence of technological advances. Herein, we propose a new fluorescence image-based framework targeted at the identification and segmentation of stained nuclei with the purpose to determine DNA content in distinct cell cycle stages. The method is based on discriminative features, such as total intensity and area, retrieved from in situ stained nuclei by fluorescence microscopy, allowing the determination of the cell cycle phase of both single and sub-population of cells. The analysis framework was built on a modified k-means clustering strategy and refined with a Gaussian mixture model classifier, which enabled the definition of highly accurate classification clusters corresponding to G1, S and G2 phases. Using the information retrieved from area and fluorescence total intensity, the modified k-means (k=3) cluster imaging framework classified 64.7% of the imaged nuclei, as being at G1 phase, 12.0% at G2 phase and 23.2% at S phase. Performance of the imaging framework was ascertained with normal murine mammary gland cells constitutively expressing the Fucci2 technology, exhibiting an overall sensitivity of 94.0%. Further, the results indicate that the imaging framework has a robust capacity to both identify a given DAPI-stained nucleus to its correct cell cycle phase, as well as to determine, with very high probability, true negatives. Importantly, this novel imaging approach is a non-disruptive method that allows an integrative and simultaneous quantitative analysis of molecular and morphological parameters, thus awarding the possibility of cell cycle profiling in cytological and histological samples.

PATMA: parser of archival tissue microarray

Tissue microarrays are commonly used in modern pathology for cancer tissue evaluation, as it is a very potent technique. Tissue microarray slides are often scanned to perform computer-aided histopathological analysis of the tissue cores. For processing the image, splitting the whole virtual slide into images of individual cores is required. The only way to distinguish cores corresponding to specimens in the tissue microarray is through their arrangement. Unfortunately, distinguishing the correct order of cores is not a trivial task as they are not labelled directly on the slide. The main aim of this study was to create a procedure capable of automatically finding and extracting cores from archival images of the tissue microarrays. This software supports the work of scientists who want to perform further image processing on single cores. The proposed method is an efficient and fast procedure, working in fully automatic or semi-automatic mode. A total of 89% of punches were correctly extracted with automatic selection. With an addition of manual correction, it is possible to fully prepare the whole slide image for extraction in 2 min per tissue microarray. The proposed technique requires minimum skill and time to parse big array of cores from tissue microarray whole slide image into individual core images.

Immunohistochemistry for Pathologists: Protocols, Pitfalls, and Tips

Immunohistochemistry (IHC) is an important auxiliary method for pathologists in routine diagnostic work as well as in basic and clinical research including exploration of biomarkers, as IHC allows confirmation of target molecule expressions in the context of microenvironment. Although there has been a considerable progress in automation and standardization of IHC, there are still many things to be considered in proper optimization and appropriate interpretation. In this review, we aim to provide possible pitfalls and useful tips for practicing pathologists and residents in pathology training. First, general procedure of IHC is summarized, followed by pitfalls and tips in each step and a summary of troubleshooting. Second, ways to an accurate interpretation of IHC are discussed, with introduction to general quantification and analysis methods. This review is not intended to provide complete information on IHC, but to be used as a basic reference for practice and publication.

Monoclonal Antibodies Against Porcine sIgA and Their Use in Immunohistochemistry

Secretory IgA (sIgA) is known as the predominant immunoglobulin in the mucosal system. It prevents pathogens from invading an animal's body through mucosa, making homeostasis. However, few studies examining the secretion of sIgA in mucosal-associated tissues of porcines based on immunohistochemistry methods have been done. In this study, BALB/c mice were immunized with porcine sIgA and the splenocytes were then fused with myeloma cells. Finally, three hybridoma cell lines secreting monoclonal antibody (MAb) against porcine sIgA were obtained. All three MAbs had no cross-reaction with porcine IgG confirmed by Western blot analysis. Furthermore, lungs, tracheas, and intestines were collected from healthy porcines to prepare tissue slices, followed by incubation with the MAb produced in this study. The results showed that sIgA existing in respiratory and digestive systems could be detected by this newly produced MAb. These generated MAbs against porcine sIgA might have a potential use in mucosal research of porcines.

Label-free Raman spectroscopic imaging to extract morphological and chemical information from a formalin-fixed, paraffin-embedded rat colon tissue section

Animal models and archived human biobank tissues are useful resources for research in disease development, diagnostics and therapeutics. For the preservation of microscopic anatomical features and to facilitate long-term storage, a majority of tissue samples are denatured by the chemical treatments required for fixation, paraffin embedding and subsequent deparaffinization. These aggressive chemical processes are thought to modify the biochemical composition of the sample and potentially compromise reliable spectroscopic examination useful for the diagnosis or biomarking. As a result, spectroscopy is often conducted on fresh/frozen samples. In this study, we provide an extensive characterization of the biochemical signals remaining in processed samples (formalin fixation and paraffin embedding, FFPE) and especially those originating from the anatomical layers of a healthy rat colon. The application of chemometric analytical methods (unsupervised and supervised) was shown to eliminate the need for tissue staining and easily revealed microscopic features consistent with goblet cells and the dense populations of cells within the mucosa, principally via strong nucleic acid signals. We were also able to identify the collagenous submucosa- and serosa- as well as the muscle-associated signals from the muscular regions and blood vessels. Applying linear regression analysis to the data, we were able to corroborate this initial assignment of cell and tissue types by confirming the biological origin of each layer by reference to a subset of authentic biomolecular standards. Our results demonstrate the potential of using label-free Raman microspectroscopy to obtain superior imaging contrast in FFPE sections when compared directly to conventional haematoxylin and eosin (H&E) staining.

Standardization of Diagnostic Immunohistochemistry: Literature Review and Geisinger Experience

Context

Immunohistochemistry has become an indispensable ancillary technique in anatomic pathology laboratories. Standardization of every step in preanalytic, analytic, and postanalytic phases is crucial to achieve reproducible and reliable immunohistochemistry test results.

Objective

To standardize immunohistochemistry tests from preanalytic, analytic, to postanalytic phases.

Data Sources

Literature review and Geisinger (Geisinger Medical Center, Danville, Pennsylvania) experience.

Conclusions

This review article delineates some critical points in preanalytic, analytic, and postanalytic phases; reiterates some important questions, which may or may not have a consensus at this time; and updates the newly proposed guidelines on antibody validation from the College of American Pathologists Pathology and Laboratory Quality Center. Additionally, the article intends to share Geisinger's experience with (1) testing/optimizing a new antibody and troubleshooting; (2) interpreting and reporting immunohistochemistry assay results; (3) improving and implementing a total immunohistochemistry quality management program; and (4) developing best practices in immunohistochemistry.

Computational analysis of p63(+) nuclei distribution pattern by graph theoretic approach in an oral pre-cancer (sub-mucous fibrosis)

BACKGROUND

Oral submucous fibrosis (OSF) is a pre-cancerous condition with features of chronic, inflammatory and progressive sub-epithelial fibrotic disorder of the buccal mucosa. In this study, malignant potentiality of OSF has been assessed by quantification of immunohistochemical expression of epithelial prime regulator-p63 molecule in correlation to its malignant (oral squamous cell carcinoma [OSCC] and normal counterpart [normal oral mucosa [NOM]). Attributes of spatial extent and distribution of p63(+) expression in the epithelium have been investigated. Further, a correlated assessment of histopathological attributes inferred from H&E staining and their mathematical counterparts (molecular pathology of p63) have been proposed. The suggested analytical framework envisaged standardization of the immunohistochemistry evaluation procedure for the molecular marker, using computer-aided image analysis, toward enhancing its prognostic value.

SUBJECTS AND METHODS

In histopathologically confirmed OSF, OSCC and NOM tissue sections, p63(+) nuclei were localized and segmented by identifying regional maxima in plateau-like intensity spatial profiles of nuclei. The clustered nuclei were localized and segmented by identifying concave points in the morphometry and by marker-controlled watersheds. Voronoi tessellations were constructed around nuclei centroids and mean values of spatial-relation metrics such as tessellation area, tessellation perimeter, roundness factor and disorder of the area were extracted. Morphology and extent of expression are characterized by area, diameter, perimeter, compactness, eccentricity and density, fraction of p63(+) expression and expression distance of p63(+) nuclei.

RESULTS

Correlative framework between histopathological features characterizing malignant potentiality and their quantitative p63 counterparts was developed. Statistical analyses of mathematical trends were evaluated between different biologically relevant combinations: (i) NOM to oral submucous fibrosis without dysplasia (OSFWT) (ii) NOM to oral submucous fibrosis with dysplasia (OSFWD) (iii) OSFWT-OSFWD (iv) OSFWD-OSCC. Significant histopathogical correlates and their corroborative mathematical features, inferred from p63 staining, were also investigated into.

CONCLUSION

Quantitative assessment and correlative analysis identified mathematical features related to hyperplasia, cellular stratification, differentiation and maturation, shape and size, nuclear crowding and nucleocytoplasmic ratio. It is envisaged that this approach for analyzing the p63 expression and its distribution pattern may help to establish it as a quantitative bio-marker to predict the malignant potentiality and progression. The proposed work would be a value addition to the gold standard by incorporating an observer-independent framework for the associated molecular pathology.

When tissue antigens and antibodies get along: revisiting the technical aspects of immunohistochemistry--the red, brown, and blue technique

Once focused mainly on the characterization of neoplasms, immunohistochemistry (IHC) today is used in the investigation of a broad range of disease processes with applications in diagnosis, prognostication, therapeutic decisions to tailor treatment to an individual patient, and investigations into the pathogenesis of disease. This review addresses the technical aspects of immunohistochemistry (and, to a lesser extent, immunocytochemistry) with attention to the antigen-antibody reaction, optimal fixation techniques, tissue processing considerations, antigen retrieval methods, detection systems, selection and use of an autostainer, standardization and validation of IHC tests, preparation of proper tissue and reagent controls, tissue microarrays and other high-throughput systems, quality assurance/quality control measures, interpretation of the IHC reaction, and reporting of results. It is now more important than ever, with these sophisticated applications, to standardize the entire IHC process from tissue collection through interpretation and reporting to minimize variability among laboratories and to facilitate quantification and interlaboratory comparison of IHC results.

Validation of various adaptive threshold methods of segmentation applied to follicular lymphoma digital images stained with 3,3'-Diaminobenzidine&Haematoxylin

The comparative study of the results of various segmentation methods for the digital images of the follicular lymphoma cancer tissue section is described in this paper. The sensitivity and specificity and some other parameters of the following adaptive threshold methods of segmentation: the Niblack method, the Sauvola method, the White method, the Bernsen method, the Yasuda method and the Palumbo method, are calculated. Methods are applied to three types of images constructed by extraction of the brown colour information from the artificial images synthesized based on counterpart experimentally captured images. This paper presents usefulness of the microscopic image synthesis method in evaluation as well as comparison of the image processing results. The results of thoughtful analysis of broad range of adaptive threshold methods applied to: (1) the blue channel of RGB, (2) the brown colour extracted by deconvolution and (3) the ’brown component’ extracted from RGB allows to select some pairs: method and type of image for which this method is most efficient considering various criteria e.g. accuracy and precision in area detection or accuracy in number of objects detection and so on. The comparison shows that the White, the Bernsen and the Sauvola methods results are better than the results of the rest of the methods for all types of monochromatic images. All three methods segments the immunopositive nuclei with the mean accuracy of 0.9952, 0.9942 and 0.9944 respectively, when treated totally. However the best results are achieved for monochromatic image in which intensity shows brown colour map constructed by colour deconvolution algorithm. The specificity in the cases of the Bernsen and the White methods is 1 and sensitivities are: 0.74 for White and 0.91 for Bernsen methods while the Sauvola method achieves sensitivity value of 0.74 and the specificity value of 0.99. According to Bland-Altman plot the Sauvola method selected objects are segmented without undercutting the area for true positive objects but with extra false positive objects. The Sauvola and the Bernsen methods gives complementary results what will be exploited when the new method of virtual tissue slides segmentation be develop.

Virtual Slides

The virtual slides for this article can be found here: slide 1: http://diagnosticpathology.slidepath.com/dih/webViewer.php?snapshotId=13617947952577 and slide 2: http://diagnosticpathology.slidepath.com/dih/webViewer.php?snapshotId=13617948230017.

Microfluidic processor allows rapid HER2 immunohistochemistry of breast carcinomas and significantly reduces ambiguous (2+) read-outs

Biomarker analysis is playing an essential role in cancer diagnosis, prognosis, and prediction. Quantitative assessment of immunohistochemical biomarker expression on tumor tissues is of clinical relevance when deciding targeted treatments for cancer patients. Here, we report a microfluidic tissue processor that permits accurate quantification of the expression of biomarkers on tissue sections, enabled by the ultra-rapid and uniform fluidic exchange of the device. An important clinical biomarker for invasive breast cancer is human epidermal growth factor receptor 2 [(HER2), also known as neu], a transmembrane tyrosine kinase that connotes adverse prognostic information for the patients concerned and serves as a target for personalized treatment using the humanized antibody trastuzumab. Unfortunately, when using state-of-the-art methods, the intensity of an immunohistochemical signal is not proportional to the extent of biomarker expression, causing ambiguous outcomes. Using our device, we performed tests on 76 invasive breast carcinoma cases expressing various levels of HER2. We eliminated more than 90% of the ambiguous results (n = 27), correctly assigning cases to the amplification status as assessed by in situ hybridization controls, whereas the concordance for HER2-negative (n = 31) and -positive (n = 18) cases was 100%. Our results demonstrate the clinical potential of microfluidics for accurate biomarker expression analysis. We anticipate our technique will be a diagnostic tool that will provide better and more reliable data, onto which future treatment regimes can be based.

An ethanol-based fixation method for anatomical and micro-morphological characterization of leaves of various tree species

The use of formalin constitutes serious health hazards for laboratory workers. We investigated the suitability and performance of the ethanol-based fixative, FineFIX, as a substitute for formalin for anatomical and cellular structure investigations of leaves by light microscopy and for leaf surface and ultrastructural analysis by scanning electron microscopy (SEM). We compared the anatomical features of leaf materials prepared using conventional formalin fixation with the FineFIX. Leaves were collected from ornamental tree species commonly used in urban areas. FineFIX was also compared with glutaraldehyde fixation and air drying normally used for scanning electron microscopy to develop a new method for evaluating leaf morphology and microstructure in three ornamental tree species. The cytological features of the samples processed for histological analysis were well preserved by both fixatives as demonstrated by the absence of nuclear swelling or shrinkage, cell wall detachment or tissue flaking, and good presentation of cytoplasmic vacuolization. In addition, good preservation of surface details and the absence of shrinkage artefacts confirmed the efficacy of FineFIX fixation for SEM analysis. Cuticular wax was preserved only in air dried samples. Samples treated with chemical substances during the fixation and dehydration phases showed various alterations of the wax structures. In some air dried samples a loss of turgidity of the cells was observed that caused general wrinkling of the epidermal surfaces. Commercial FineFIX is an adequate substitute for formalin in histology and it can be applied successfully also for SEM investigation, while reducing the health risks of glutaraldehyde or other toxic fixatives. To investigate the potential for plants to absorb and capture particulates in air, which requires preservation of the natural morphology of trichomes and epicuticular waxes, a combination of FineFIX fixation and air drying is recommended.

The impact of immunohistochemical expression of nitric oxide synthases on clinical and pathological features of renal cell carcinoma

PURPOSE

To evaluate the immunohistochemical expression of nitric oxide synthase (NOS) types 1, 2, and 3 in intratumoral and non-neoplastic samples of renal cell carcinoma (RCC) and correlate it with the clinical and pathological features of this malignancy.

METHODS

We analyzed 110 patients with RCC underwent radical nephrectomy (RN) or partial nephrectomy (PN) by streptavidin-biotin peroxidase method, tissue microarray, and digital microscopy. As endpoints, NOS expression was correlated with pathological features, overall survival (OS), and cancer-specific survival (CSS).

RESULTS

Non-neoplastic samples had higher NOS3 and lower NOS 2 levels than RCC tissues. Greater expression of all NOS isoforms was associated with larger tumors. High NOS1 expression correlated with microscopic venous invasion (MVI) (p = 0.046) and lymph node metastases (p = 0.007). High NOS2 expression was linked to MVI, more RN performed, and male gender (p = 0.035, p = 0.003, and p = 0.027, respectively). High NOS3 expression correlated with lymph node metastases (p = 0.039), microlymphatic invasion (p = 0.029), invasion of the renal pelvis and ureter (p = 0.004), RN (p = 0.003), and shorter OS (58.1 vs. 79.4 % respectively, p = 0.033) by univariate analysis. DFS was not influenced by any NOS isoform. By multivariate analysis, the risk factors for death were TNM stages III and IV (hazard ratio [HR] = 4.5), high Fuhrman's grade (HR = 2.9), Karnofsky performance status ≤80 (HR = 2.5), progression (HR = 5.5), and recurrence (HR = 6.3). Stage III disease was an independent risk factor for recurrence (HR = 9.5).

CONCLUSIONS

High NOS expression in RCC is associated with a poor prognosis and larger tumors. NOS3 influences OS by univariate analysis.

Role of alpha methylacyl-coenzyme A racemase in differentiating hepatocellular carcinoma from dysplastic and nondysplastic liver cell lesions

Distinction of hepatocellular carcinoma (HCC) from liver cell dysplasia (LCD) is one of the problems faced by pathologists. In spite of various methods claimed to differentiate between these 2 lesions, no reliable marker is available until now. The aim of the study was to assess the value of alpha methylacyl-coenzyme A (COA) racemase (AMACR) in distinguishing HCC from LCD. Formalin-fixed, paraffin-embedded tissue sections from 30 HCCs and 30 nonneoplastic liver tissues (12 dysplastic and 18 nondysplastic lesions) were immunostained for AMACR. Staining intensity was interpreted as low (negative, mild) and high expressions (moderate, marked). Alpha methylacyl-COA racemase showed high expression in 21 (70%) of 30 HCCs and 7 (58.3%) of 12 LCDs. All 18 nondysplastic lesions revealed low AMACR expression. The percentage of high AMACR expression was significantly more in HCC and LCD as compared with nondysplastic lesions (P = .001 in each). There was no significant difference in AMACR expression between HCC and LCD. Furthermore, the pattern of AMACR immunostaining was coarsely granular cytoplasmic positivity in HCC as well as LCD in comparison with the weak finely granular in nondysplastic lesions. Alpha methylacyl-COA racemase cannot discriminate HCC from LCD, although it can separate HCC and LCD from nondysplastic lesions.

Expression of the IGF axis is decreased in local prostate cancer but enhanced after benign prostate epithelial differentiation and TGF-β treatment

The insulin-like growth factor (IGF) axis is a molecular pathway intensively investigated in cancer research. Clinical trials targeting the IGF1 receptor (IGF1R) in different tumors, including prostate cancer, are under way. Although studies on the IGF axis in prostate cancer have already entered into clinical trials, the expression and functional role of the IGF axis in benign prostate and in prostate cancer needs to be better defined. We determined mRNA expression levels of the IGF axis in microdissected tissue specimens of local prostate cancer using quantitative PCR. All members of the IGF axis, including IGF1, IGF2, IGF binding proteins 1 through 6, and insulin receptor, were measured in both the stromal and epithelial compartments of the prostate. IGF1, IGF2, IGF1R, and insulin receptor were down-regulated in local prostate cancer tissue compared with matched benign tissue, suggesting that the IGF axis is not induced during prostate cancer development. Using a new prostate epithelial differentiation model, we demonstrate that the expression of the IGF axis is enhanced during normal prostate epithelial differentiation and regulated by tumor growth factor (TGF)-β. Our data reveal a functional role of the IGF axis in prostate differentiation, underscoring the importance of the IGF axis in normal development and emphasizing the importance of accurate target validation before moving to advanced clinical trials.

Effects of prolonged water washing of tissue samples fixed in formalin on histological staining

The effects of prolonged water washing after fixation for 48 h in 10% (v/v) phosphate-buffered neutral formalin on the quality of representative histological staining methods were evaluated using samples of liver, kidney, spleen and thymus collected from three male Crl:CD(SD)(IGS) rats and one male beagle dog. Because door-to-door courier services in Japan prohibit handling formalin, our goal was to confirm that formalin fixed wet tissue samples could be stored in tap water rather than formalin during transportation of the samples without decreasing the quality of their staining or immunohistochemistry. Each tissue sample was allocated randomly to one of three groups: 12 min, 3 days and 7 days of washing in running tap water; samples then were routinely embedded in paraffin and sectioned. The sections were stained with hematoxylin and eosin, perio-dic acid-Schiff, azan, and the TdT-mediated dUTP-biotin nick end labeling (TUNEL) method. Immunohistochemical staining for Factor VIII, ED-1 and CD3 also was assessed. Prolonged water washing for up to 7 days did not affect the morphology or stainability by standard histological methods, or the intensity and frequency of positive reactions using the TUNEL method. Only immunohistochemical staining of Factor VIII was altered in both the rat and dog sections after 7 days of water washing. The intensity of positive reactions of Factor VIII immunohistochemistry after 7 days water washing was still strong enough to detect microscopically. Therefore, prolonged water washing for up to 7 days after formalin fixation does not have seriously detrimental effects on the quality and characteristics of paraffin sections stained by various methods, including immunohistochemistry.

Revisiting the technical validation of tumour biomarker assays: how to open a Pandora's box

A tumour biomarker is a characteristic that is objectively measured and evaluated in tumour samples as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. The development of a biomarker contemplates distinct phases, including discovery by hypothesis-generating preclinical or exploratory studies, development and qualification of the assay for the identification of the biomarker in clinical samples, and validation of its clinical significance. Although guidelines for the development and validation of biomarkers are available, their implementation is challenging, owing to the diversity of biomarkers being developed. The term 'validation' undoubtedly has several meanings; however, in the context of biomarker research, a test may be considered valid if it is 'fit for purpose'. In the process of validation of a biomarker assay, a key point is the validation of the methodology. Here we discuss the challenges for the technical validation of immunohistochemical and gene expression assays to detect tumour biomarkers and provide suggestions of pragmatic solutions to address these challenges.

Redox atlas of the mouse. Immunohistochemical detection of glutaredoxin-, peroxiredoxin-, and thioredoxin-family proteins in various tissues of the laboratory mouse

BACKGROUND

Oxidoreductases of the thioredoxin family of proteins have been thoroughly studied in numerous cellular and animal models mimicking human diseases. Despite of their well documented role in various disease conditions, no systematic information on the presence of these proteins is available.

METHODS

Here, we have systematically analyzed the presence of some of the major constituents of the glutaredoxin (Grx)-, peroxiredoxin (Prx)-, and thioredoxin (Trx)-systems, i.e. Grx1, Grx2, Grx3 (TXNL-2/PICOT), Grx5, nucleoredoxin (Nrx), Prx1, Prx2, Prx3, Prx4, Prx5, Prx6, Trx1, thioredoxin reductase 1 (TrxR1), Trx2, TrxR2, and γ-glutamyl cysteine synthetase (γ-GCS) in various tissues of the mouse using immunohistochemistry.

RESULTS

The identification of the Trx family proteins in the central nervous system, sensory organs, digestive system, lymphatic system, reproductive system, urinary system, respiratory system, endocrine system, skin, heart, and muscle revealed a number of significant differences between these proteins with respect to their distribution in these tissues.

CONCLUSION

Our results imply more specific functions and interactions between the proteins of this family than previously assumed.

GENERAL SIGNIFICANCE

Crucial functions of Trx family proteins have been demonstrated in various disease conditions. A detailed overview on their distribution in various tissues will be helpful to fully comprehend their potential role and the interactions of these proteins in the most thoroughly studied model for human diseases-the laboratory mouse. This article is part of a Special Issue entitled Human and Murine Redox Protein Atlases.

Immunohistochemistry as an important tool in biomarkers detection and clinical practice

The immunohistochemistry technique is used in the search for cell or tissue antigens that range from amino acids and proteins to infectious agents and specific cellular populations. The technique comprises two phases: (1) slides preparation and stages involved for the reaction; (2) interpretation and quantification of the obtained expression. Immunohistochemistry is an important tool for scientific research and also a complementary technique for the elucidation of differential diagnoses which are not determinable by conventional analysis with hematoxylin and eosin. In the last couple of decades there has been an exponential increase in publications on immunohistochemistry and immunocytochemistry techniques. This review covers the immunohistochemistry technique; its history, applications, importance, limitations, difficulties, problems and some aspects related to results interpretation and quantification. Future developments on the immunohistochemistry technique and its expression quantification should not be disseminated in two languages—that of the pathologist and another of clinician or surgeon. The scientific, diagnostic and prognostic applications of this methodology must be explored in a bid to benefit of patient. In order to achieve this goal a collaboration and pooling of knowledge from both of these valuable medical areas is vital