Double immunofluorescence labelling of routinely processed paraffin sections

Integrating network pharmacology and bioinformatics to explore and experimentally verify the regulatory effect of Buyang Huanwu decoction on glycolysis and angiogenesis after cerebral infarction

ETHNOPHARMACOLOGICAL RELEVANCE

Promoting the recovery of cerebral blood circulation after cerebral infarction (CI) is an important intervention. Buyang Huanwu decoction (BHD) is a classic prescription for treating CI that promotes angiogenesis. Cytoplasmic glycolysis ischaemic-region cells after CI may be highly activated to maintain metabolic activity under hypoxia. From the perspective of long-term maintenance of glycolytic metabolism in the ischaemic area after CI, it may be beneficial to promote angiogenesis and maintain glial cell activation and neuronal survival. In this context, the regulatory relationship of lncRNAs and miRNAs with mRNAs is worthy of attention. Mining the competitive binding relationships among RNAs will aid in the screening of key gene targets post-CI. In this study, network pharmacology and bioinformatics were used to construct a ceRNA network, screen key targets, and explore the effect of glycolysis on angiogenesis during BHD-mediated CI regulation.

AIM OF THE STUDY

This study aimed to explore the effect of BHD on angiogenesis after glycolysis regulation in CI.

MATERIALS AND METHODS

According to the 21 active BHD ingredients we identified by our research team, we conducted network pharmacology. BHD targets that can regulate glycolysis and angiogenesis after CI were screened from the GeneCards, CTD and OMIM databases. We retrieved CI-related datasets from the GEO database and screened for differentially expressed lncRNAs and miRNAs. LncRNA‒miRNA-mRNA/TF targeting relationships were screened and organized with the miRcode, miRDB, TargetScan, miRWalk, and TransmiR v2.0 databases. Cytoscape was used to construct an lncRNA‒miRNA-mRNA/TF ceRNA network. Through BioGPS, key mRNAs/TFs in the network were screened for enrichment analysis. Animal experiments were then conducted to validate some key mRNAs/TFs and enriched signalling pathways.

RESULTS

PFKFB3 and other genes may help regulate glycolysis and angiogenesis through AMPK and other signalling pathways. The anti-CI effect of BHD may involve maintaining activation of genes such as AMPK and PFKFB3 in the ischaemic cortex, maintaining moderate glycolysis levels in brain tissue, and promoting angiogenesis.

CONCLUSION

BHD can regulate glycolysis and promote angiogenesis after CI through multiple pathways and targets, in which AMPK signalling pathway activation may be important.

Pathological roles of bone marrow adipocyte-derived monocyte chemotactic protein-1 in type 2 diabetic mice

Type 2 diabetes mellitus (T2DM) has become a prevalent public health concern, with beta-cell dysfunction involved in its pathogenesis. Bone marrow adipose tissue (BMAT) increases in both the quantity and area in individuals with T2DM along with heightened monocyte chemotactic protein-1 (MCP-1) secretion. This study aims to investigate the influence and underlying mechanisms of MCP-1 originating from bone marrow adipocytes (BMAs) on systemic glucose homeostasis in T2DM. Initially, a substantial decrease in the proliferation and glucose-stimulated insulin secretion (GSIS) of islet cells was observed. Moreover, a comparative analysis between the control (Ctrl) group and db/db mice revealed significant alterations in the gene expression profiles of whole bone marrow cells, with a noteworthy upregulation of Mcp-1. And the primary enriched pathways included chemokine signaling pathway and AGE-RAGE signaling pathway in diabetic complications. In addition, the level of MCP-1 was distinctly elevated in BMA-derived conditional media (CM), leading to a substantial inhibition of proliferation, GSIS and the protein level of phosphorylated Akt (p-Akt) in Min6 cells. After blocking MCP-1 pathway, we observed a restoration of p-Akt and the proliferation of islet cells, resulting in a marked improvement in disordered glucose homeostasis. In summary, there is an accumulation of BMAs in T2DM, which secrete excessive MCP-1, exacerbating the abnormal accumulation of BMAs in the bone marrow cavity through paracrine signaling. The upregulated MCP-1, in turn, worsens glucose metabolism disorder by inhibiting the proliferation and insulin secretion of islet cells through an endocrine pathway. Inhibiting MCP-1 signaling can partially restore the proliferation and insulin secretion of islet cells, ultimately ameliorating glucose metabolism disorder. It's worth noting that to delve deeper into the impact of MCP-1 derived from BMAs on islet cells and its potential mechanisms, it is imperative to develop genetically engineered mice with conditional Mcp-1 knockout from BMAs.

Developing Digital Photomicroscopy

(1) The need for efficient ways of recording and presenting multicolour immunohistochemistry images in a pioneering laboratory developing new techniques motivated a move away from photography to electronic and ultimately digital photomicroscopy. (2) Initially broadcast quality analogue cameras were used in the absence of practical digital cameras. This allowed the development of digital image processing, storage and presentation. (3) As early adopters of digital cameras, their advantages and limitations were recognised in implementation. (4) The adoption of immunofluorescence for multiprobe detection prompted further developments, particularly a critical approach to probe colocalization. (5) Subsequently, whole-slide scanning was implemented, greatly enhancing histology for diagnosis, research and teaching.

Fluorescent Immunohistochemistry

Immunofluorescence is an important immunochemical technique that utilizes fluorescence-labeled antibodies to detect specific target antigens. It is used widely in both scientific research and clinical laboratories. Immunofluorescence allows for excellent sensitivity and amplification of signal in comparison to immunohistochemistry. However, analysis of samples labeled with fluorescence-labeled antibodies has to be performed using a fluorescence microscope or other type of fluorescence imaging. There are two methods available: direct (primary) and indirect (secondary) immunofluorescence. Here, we describe the principle of immunofluorescence methods as well as the preparation of fresh-frozen and formalin-fixed, paraffin embedded tissues for both direct and indirect immunofluorescence labeling.

18F-Trifluoromethylated D-Cysteine as a Promising New PET Tracer for Glioma Imaging: Comparative Analysis With MRI and Histopathology in Orthotopic C6 Models

Comparing MRI and histopathology, this study aims to comprehensively explore the potential application of ¹⁸F-trifluoromethylated D-cysteine (S-[¹⁸F]CF₃-D-CYS) in evaluating glioma by using orthotopic C6 glioma models. Sprague-Dawley (SD) rats (n = 9) were implanted with C6 glioma cells. Tumor growth was monitored every week by multiparameter MRI [including dynamic contrast-enhanced MRI (DCE-MRI)], [¹⁸F]FDG, S-[¹⁸F]CF₃-D-CYS, and [¹⁸F]FDOPA PET imaging. Repeated scans of the same rat with the two or three [¹⁸F]-labeled radiotracers were investigated. Initial regions of interest were manually delineated on T₂WI and set on the same level of PET images, and tumor-to-normal brain uptake ratios (TNRs) were calculated to semiquantitatively assess the tracer accumulation in the tumor. The tumor volume in PET and histopathology was calculated. HE and Ki67 immunohistochemical staining were further performed. The correlations between the uptake of S-[¹⁸F]CF₃-D-CYS and Ki67 were analyzed. Dynamic S-[¹⁸F]CF₃-D-CYS PET imaging showed tumor uptake rapidly reached a peak, maintained plateau during 10-30 min after injection, then decreased slowly. Compared with [¹⁸F]FDG and [¹⁸F]FDOPA PET imaging, S-[¹⁸F]CF₃-D-CYS PET demonstrated the highest TNRs (P < 0.05). There were no significant differences in the tumor volume measured on S-[¹⁸F]CF₃-D-CYS PET or HE specimen. Furthermore, our results showed that the uptake of S-[¹⁸F]CF₃-D-CYS was significantly positively correlated with tumor Ki67, and the poor accumulated S-[¹⁸F]CF₃-D-CYS was consistent with tumor hemorrhage. There was no significant correlation between the S-[¹⁸F]CF₃-D-CYS uptakes and the K^trans values derived from DCE-MRI. In comparison with MRI and histopathology, S-[¹⁸F]CF₃-D-CYS PET performs well in the diagnosis and evaluation of glioma. S-[¹⁸F]CF₃-D-CYS PET may serve as a valuable tool in the clinical management of gliomas.

Neurothreads: Development of supportive carriers for mature dopaminergic neuron differentiation and implantation

In this study we present the use of elastic macroporous cryogels for differentiation and transplantation of mature neurons. We develop a coating suitable for long-term neuronal culture, including stem cell differentiation, by covalent immobilization of neural adhesion proteins. In the context of cell therapy for Parkinson's disease, we show compatibility with established dopaminergic differentiation of both immortalized mesencephalic progenitors - LUHMES - and human embryonic stem cells (hESCs). We adjust structural properties of the biomaterial to create carriers - Neurothreads - favourable for cell viability during transplantation. Finally, we show feasibility of preservation of mature neurons, supported by Neurothreads, one month after in-vivo transplantation. Preliminary data suggests that the Neurothread approach could provide more mature and less proliferative cells in vivo.

Fluorescence Colocalization Analysis of Cellular Distribution of MOR-1

The interaction between neurons and glia is pivotal for the development of chronic opioid tolerance. One of the most important mechanisms of cell-to-cell interaction is the Notch signaling pathway. In this chapter we propose a double-immunofluorescence method to observe and quantify the colocalization of Notch-1 and mu-opioid receptor (MOR-1), using both neuronal and astrocyte markers.

Immunofluorescence Staining of Paraffin Sections Step by Step

Immunofluorescence staining is the most frequently applied technique to detect and visualize various molecules in biological samples. Many protocols can be found in the literature and the websites of commercial antibody producers. This can result in a time-consuming and costly methodical work to establish “simple” antibody staining. We here summarize in a stepwise manner an easy-to-follow immunofluorescence staining protocol with an improved specific fluorescent signal and a reduced background and non-specific binding signal. This will help scientists to save time, effort, and antibody costs during the application of such a valuable technique.

Advances in quantitative immunohistochemistry and their contribution to breast cancer

Introduction: Automated image analysis provides an objective, quantitative, and reproducible method of measurement of biomarkers. Image quantification is particularly well suited for the analysis of tissue microarrays which has played a major pivotal role in the rapid assessment of molecular biomarkers. Data acquired from grinding up bulk tissue samples miss spatial information regarding cellular localization; therefore, methods that allow for spatial cell phenotyping at high resolution have proven to be valuable in many biomarker discovery assays. Here, we focus our attention on breast cancer as an example of a tumor type that has benefited from quantitative biomarker studies using tissue microarray format.Areas covered: The history of immunofluorescence and immunohistochemistry and the current status of these techniques, including multiplexing technologies (spectral and non-spectral) and image analysis software will be addressed. Finally, we will turn our attention to studies that have provided proof-of-principle evidence that have been impacted from the use of these techniques.Expert opinion: Assessment of prognostic and predictive biomarkers on tissue sections and TMA using Quantitative immunohistochemistry is an important advancement in the investigation of biologic markers. The challenges in standardization of quantitative technologies for accurate assessment are required for adoption into routine clinical practice.

MicroRNA-17-92 Regulates Beta-Cell Restoration After Streptozotocin Treatment

Objective: To clarify the role and mechanism of miR-17-92 cluster in islet beta-cell repair after streptozotocin intervention. Methods: Genetically engineered mice (miR-17-92βKO) and control RIP-Cre mice were intraperitoneally injected with multiple low dose streptozotocin. Body weight, random blood glucose (RBG), fasting blood glucose, and intraperitoneal glucose tolerance test (IPGTT) were monitored regularly. Mice were sacrificed for histological analysis 8 weeks later. Morphological changes of pancreas islets, quantity, quality, apoptosis, and proliferation of beta-cells were measured. Islets from four groups were isolated. MiRNA and mRNA were extracted and quantified. Results:MiR-17-92βKO mice showed dramatically elevated fasting blood glucose and impaired glucose tolerance after streptozotocin treatment in contrast to control mice, the reason of which is reduced beta-cell number and total mass resulting from reduced proliferation, enhanced apoptosis of beta-cells. Genes related to cell proliferation and insulin transcription repression were significantly elevated in miR-17-92βKO mice treated with streptozotocin. Furthermore, genes involved in DNA biosynthesis and damage repair were dramatically increased in miR-17-92βKO mice with streptozotocin treatment. Conclusion: Collectively, our results demonstrate that homozygous deletion of miR-17-92 cluster in mouse pancreatic beta-cells promotes the development of experimental diabetes, indicating that miR-17-92 cluster may be positively related to beta-cells restoration and adaptation after streptozotocin-induced damage.

Multiplex Immunofluorescence of Bone Marrow Core Biopsies: Visualizing the Bone Marrow Immune Contexture

The ability to visualize and quantify the spatial arrangement and geographic proximity of immune cells with tumor cells provides valuable insight into the complex mechanisms underlying cancer biology and progression. Multiplexing, which involves immunofluorescence labeling and the visualization of multiple epitopes within formalin-fixed paraffin embedded tissue sections, is a methodology that is being increasingly employed. Despite the power of immunofluorescence multiplex analysis, application of this technology to bone marrow core biopsies has not yet been realized. Given our specific long term goal to identify immune cells in proximity to bone marrow malignant plasma cells in multiple myeloma patients, we describe in this study adaptation of multiplex immunofluorescence analysis to this tissue. We first identified a blocking strategy that quenched autofluorescence. We next employed a multiplex strategy that uses a simple stripping solution to remove primary and secondary antibodies prior to subsequent rounds of staining. This method was found to be highly efficient and did not significantly alter antigenicity or tissue integrity. Our studies illustrate for the first time that immunofluorescence multiplexing is achievable in bone marrow core biopsies and will provide a novel opportunity to analyze the role of the immune contexture in disease progression of the monoclonal gammopathies.

Mineralocorticoid receptor excessive activation involved in glucocorticoid-related brain injury

The mechanisms involved in brain damage during chronic glucocorticoid exposure are poorly understood. Since mineralocorticoid receptor (MR) activation has been proven to be important in the pathophysiology of vascular damage and MRs are highly expressed in many brain regions, we hypothesized that the cerebral injury observed in subjects with Cushing syndrome is in part associated with the overactivation of MR. The aim of this study was to determine whether the cerebral injury observed in chronic hyperglucocorticoidemia animal models is related to excessive MR activation. Male SD rats were divided into five groups: vehicle, hydrocortisone (HC, 5 mg/kg/day, i.g.), HC + spironolactone (SL, 20 mg/kg/d in chow), dexamethasone (DXM, 0.25 mg/kg/day, i.g.), and DXM + SL (20 mg/kg/d in chow). Compared to the vehicle-treated group, HC-treated rats had higher blood pressure and higher levels of cerebral vascular fibrosis, cortical/hippocampal atrophy, reactive oxygen species (ROS) production and proinflammatory gene expression. However, in HC-treated animals, treatment with SL markedly alleviated ROS production, cerebral and cerebrovascular morphological changes and inflammation but failed to reduce blood pressure. In contrast, DXM induced no cerebral morphological changes except fibrosis in cerebral vessels, an effect that was not ameliorated by SL treatment. These findings demonstrate that the excessive MR activation observed following chronic hyperglucocorticoidemia exposure contributes to cerebrovascular fibrosis and remodeling and promotes neural apoptosis in the cerebral cortex/hippocampus.

An Exosomal Urinary miRNA Signature for Early Diagnosis of Renal Fibrosis in Lupus Nephritis

For lupus nephritis (LN) management, it is very important to detect fibrosis at an early stage. Urinary exosomal miRNAs profiling can be used as a potential multi-marker phenotyping tool to identify early fibrosis. We isolated and characterised urinary exosomes and cellular pellets from patients with biopsy-proven LN (n = 45) and healthy controls (n = 20). LN chronicity index (CI) correlated with urinary exosomal miR-21, miR-150, and miR-29c (r = 0.565, 0.840, −0.559, respectively). This miRNA profile distinguished low CI from moderate-high CI in LN patients with a high sensitivity and specificity (94.4% and 99.8%). Furthermore, this multimarker panel predicted an increased risk of progression to end-stage renal disease (ESRD). Pathway analysis identified VEGFA and SP1 as common target genes for the three miRNAs. Immunohistochemistry in LN renal biopsies revealed a significant increase of COL1A1 and COL4A1 correlated with renal chronicity. SP1 decreased significantly in the high-CI group (p = 0.002). VEGFA levels showed no differences. In vitro experiments suggest that these miRNA combinations promote renal fibrosis by increasing profibrotic molecules through SP1 and Smad3/TGFβ pathways. In conclusion, a urinary exosomal multimarker panel composed of miR-21, miR-150, and miR-29c provides a non-invasive method to detect early renal fibrosis and predict disease progression in LN.

The NOD-scid IL2rγnull Mouse Model Is Suitable for the Study of Osteoarticular Brucellosis and Vaccine Safety

Osteoarticular brucellosis is the most common complication in Brucella-infected humans regardless of age, sex, or immune status. The mechanism of bone destruction caused by Brucella species remained partially unknown due to the lack of a suitable animal model. Here, to study this complication, we explored the suitability of the use of the NOD-scid IL2rγ^null mouse to study osteoarticular brucellosis and examined the potential use of this strain to evaluate the safety of live attenuated vaccine candidates. Mice were inoculated intraperitoneally with a single dose of 1 × 10⁴, 1 × 10⁵, or 1 × 10⁶ CFU of B. abortus S19 or the vaccine candidate B. abortus S19ΔvjbR and monitored for the development of side effects, including osteoarticular disease, for 13 weeks. Decreased body temperature, weight loss, splenomegaly, and deformation of the tails were observed in mice inoculated with B. abortus S19 but not in those inoculated with S19ΔvjbR Histologically, all S19-inoculated mice had a severe dose-dependent inflammatory response in multiple organs. The inflammatory response at the tail was characterized by the recruitment of large numbers of neutrophils, macrophages, and osteoclasts with marked bone destruction. These lesions histologically resembled what is typically observed in Brucella-infected patients. In contrast, mice inoculated with B. abortus S19ΔvjbR did not show significant bone changes. Immunofluorescence, in situ hybridization, and confocal imaging demonstrated the presence of Brucella at the sites of inflammation, both intra- and extracellularly, and large numbers of bacteria were observed within mature osteoclasts. These results demonstrate the potential use of the NOD-scid IL2rγ^null mouse model to evaluate vaccine safety and further study osteoarticular brucellosis.

BpV(pic) confers neuroprotection by inhibiting M1 microglial polarization and MCP-1 expression in rat traumatic brain injury

Traumatic brain injury (TBI) is a major cause of motor and cognitive impairment in young adults. It is associated with high mortality rates and very few effective treatment options. Bisperoxovanadium (pyridine-2-carboxyl) [bpV(pic)] is an commercially available inhibitor of Phosphatase and tensin homolog (PTEN). Previous studies have shown that bpV(pic) has protective effects in central nervous system. However, the role of bpV(pic) in TBI is unclear. In this study we aimed to investigate the neuroprotective role of bpV(pic) in rat TBI model. We found that injection of bpV(pic) significantly reduces brain edema and neurological dysfunction after TBI and this is mediated by AKT pathway. TBI is known to promote the M1 pro-inflammatory phenotype of microglial polarization and this effect is inhibited by bpV(pic) treatment which, instead promotes M2 microglial polarization in vivo and in vitro. We also found evidence of bpV(pic)-regulated neuroinflammation mediated by AKT activation and NF-κB p65 inhibition. BpV(pic) treatment also suppressed microglia in the peri-TBI region. MCP-1 is known to recruit monocytes and macrophages to promote inflammation, we show that bpV(pic) can inhibit TBI-induced up-regulation of MCP-1 via the AKT/NF-κB p65 signaling pathway. Taken together, our findings demonstrate that bpV(pic) plays a neuroprotective role in rat TBI, which may be achieved by inhibiting M1 microglia polarization and MCP-1 expression by modulating AKT/NF-κB p65 signaling pathway.

Inflammatory cell expression of Toll-like receptor-2 (TLR2) within refractory periapical granuloma

Background: Toll-like receptor-2 (TLR2) is highly important within the immune system. Characterization of the expression of TLR2 within inflammatory cells in periapical lesions could help in diagnosis and management of refractory cases. The aim of the study is identification of Toll-like receptor (TLR2) through immunohistochemical and immunofluroscence expression in inflammatory cells within refractory periapical granuloma cases. Methods: Eight cases of refractory periapical granuloma were selected out of 772 cases. Histological examination and immunohistochemical staining with polyclonal rabbit antihuman TLR2, monoclonal mouse antihuman CD38, CD68 and CD83 primary antibodies, as well as immunofluorescence staining with goat anti-rabbit TLR2, donkey anti-mouse CD38, CD68 and CD83 primary antibodies was conducted. Positive controls, negative controls and experimental sections with no primary antibody were included in the study. Qualitative analysis and double immunofluorescence technique was used to characterize the TLR + cells. Results: In periapical granuloma, lymphocytes (CD38 cells) expressed the most amount of TLR reactivity followed by macrophages (CD68 cells), and odontogenic epithelial cells. Neutrophils, red blood cells (RBCs) and collagen ground substance were negative to TLR2.  Conclusion: TLR2 was highly expressed by lymphocytes and plasma cells indicative of their major role in the inflammatory process and antigen recognition in refractory periapical granuloma. Dendritic cells expressing TLR2 were low in number suggesting a minor role in sustaining these lesions.

Effects of the tumor suppressor PTEN on biological behaviors of activated pancreatic stellate cells in pancreatic fibrosis

Pancreatic stellate cells (PSCs), when activated, are characterized by proliferation and collagen synthesis, and contribute to extracellular matrix deposition in pancreatic fibrosis. Concomitantly, fibrosis is linked with the loss of PTEN (phosphatase and tensin homolog) protein in several organs. This study investigated the association between PTEN protein levels and the activated or apoptotic status of PSCs in a rat model of chronic pancreatitis. In addition, the activation status and biological behaviors of culture-activated PSCs were analyzed after lentiviral transfection with wildtype or mutant (G129E) PTEN for upregulation, or PTEN short hairpin RNA for downregulation, of PTEN. In vivo, PTEN levels gradually decreased during pancreatic fibrosis, which positively correlated with apoptosis of activated PSCs, but negatively with PSC activation. In vitro, activated PSCs with wildtype PTEN showed less proliferation, migration, and collagen synthesis compared with control PSCs, and greater numbers were apoptotic; activated PSCs with mutant PTEN showed similar, but weaker, effects. Furthermore, AKT and FAK/ERK signaling was involved in this process. In summary, activated PSCs during pancreatic fibrosis in vivo have lower levels of PTEN. In vitro, PTEN appears to prevent PSCs from further activation and promotes apoptosis through regulation of the AKT and FAK/ERK pathways.

ERK 1/2 Activation Mediates the Neuroprotective Effect of BpV(pic) in Focal Cerebral Ischemia-Reperfusion Injury

Bisperoxovanadium (pyridine-2-carboxyl) [bpV(pic)] is a commercially available PTEN inhibitor. Previous studies from us and others have shown that bpV(pic) confers neuroprotection in cerebral ischemia injury. We set up to determine whether ERK 1/2 activation plays a role in bpV(pic)-induced neuroprotective effect in cerebral ischemia injury. We found that the phosphorylation levels of Akt (p-AKT) and ERK1/2 (p-ERK 1/2) were down-regulated after cerebral ischemia–reperfusion injury. The injection of bpV(pic) after injury not only increased the level of p-AKT but also the level of p-ERK 1/2. While the inhibition of PTEN mediated the up-regulatation of p-AKT and p-ERK 1/2 by bpV(pic). Interestingly, the ERK 1/2 activation induced by bpV(pic) was also independent of the inhibition of PTEN. Our results indicate that bpV(pic) protects against OGD-induced neuronal death and promotes the functional recovery of stroke animals through PTEN inhibition and ERK 1/2 activation, respectively. This study suggests that the effect of bpV(pic) on ERK 1/2 signaling should be considered while using bpV(pic) as a PTEN inhibitor.

Glioblastoma recurrence correlates with NLGN3 levels

Glioblastoma (GBM) is the most aggressive glioma in the brain. Recurrence of GBM is almost inevitable within a short term after tumor resection. In a retrospective study of 386 cases of GBM collected between 2013 and 2016, we found that recurrence of GBM mainly occurs in the deep brain regions, including the basal ganglia, thalamus, and corpus callosum. But the mechanism underlying this phenomenon is not clear. Previous studies suggest that neuroligin‐3 (NLGN3) is necessary for GBM growth. Our results show that the levels of NLGN3 in the cortex are higher than those in the deep regions in a normal human brain, and similar patterns are also found in a normal mouse brain. In contrast, NLGN3 levels in the deep brain regions of GBM patients are high. We also show that an increase in NLGN3 concentration promotes the growth of U251 cells and U87‐MG cells. Respective use of the cortex neuron culture medium (C‐NCM) and basal ganglia neuron culture medium (BG‐NCM) with DMEM to cultivate U251, U87‐MG and GBM cells isolated from patients, we found that these cells grew faster after treatment with C‐NCM and BG‐NCM in which the cells treated with C‐NCM grew faster than the ones treated with BG‐NCM group. Inhibition of NLGN3 release by ADAM10i prevents NCM‐induced cell growth. Together, this study suggests that increased levels of NLGN3 in the deep brain region under the GBM pathological circumstances may contribute to GBM recurrence in the basal ganglia, thalamus, and corpus callosum.

Multiplex Staining by Sequential Immunostaining and Antibody Removal on Routine Tissue Sections

Multiplexing, labeling for multiple immunostains in the very same cell or tissue section in situ, has raised considerable interest. The methods proposed include the use of labeled primary antibodies, spectral separation of fluorochromes, bleaching of the fluorophores or chromogens, blocking of previous antibody layers, all in various combinations. The major obstacles to the diffusion of this technique are high costs in custom antibodies and instruments, low throughput, and scarcity of specialized skills or facilities. We have validated a method based on common primary and secondary antibodies and diffusely available fluorescent image scanners. It entails rounds of four-color indirect immunofluorescence, image acquisition, and removal (stripping) of the antibodies, before another stain is applied. The images are digitally registered and the autofluorescence is subtracted. Removal of antibodies is accomplished by disulfide cleavage and a detergent or by a chaotropic salt treatment, this latter followed by antigen refolding. More than 30 different antibody stains can be applied to one single section from routinely fixed and embedded tissue. This method requires a modest investment in hardware and materials and uses freeware image analysis software. Multiplexing on routine tissue sections is a high throughput tool for in situ characterization of neoplastic, reactive, inflammatory, and normal cells.

Analysis of the Germinal Center Reaction in Tissue Sections

Germinal centers are short-lived microanatomical compartments with essential roles in adaptive immunity. These lymphoid structures can be identified in secondary lymphoid organs using both flow cytometry and immunohistological analyses, but only the latter provides useful architectural and spatial information. Here we describe how to use immunofluorescence and immunohistochemistry with specific antibodies to precisely highlight the cellular and architectural features of germinal centers, both in human and mouse secondary lymphoid organs, and to study their normal development and disturbance in disease.

MicroRNA-17-92 cluster regulates pancreatic beta-cell proliferation and adaptation

MiR-17-92 cluster contributes to the regulation of mammalian development, aging and tumorigenesis. The functional roles of miR-17-92 in pancreatic beta-cells are largely unknown. In this study, we found that conditional deletion of miR-17-92 in mouse pancreatic beta-cells (miR-17-92βKO) significantly reduces glucose tolerance and the first phase of insulin secretion, despite normal ad libitum fed and fasting glucose levels. Proliferation is down-regulated in pancreatic beta-cells after deleting miR-17-92. MiR-17-92βKO mice show higher phosphatase and tensin homologue (PTEN) and lower phosphorylated AKT in islets. Under high fat diet challenge for 16 weeks, miR-17-92βKO mice lose compensation and exhibit higher glucose levels, and lower insulin secretion. Collectively, these data suggest that miR-17-92 is a critical contributor to molecular mechanisms regulating glucose-stimulated insulin secretion and pancreatic beta-cell adaptation under metabolic stress.

IFI16 Expression Is Related to Selected Transcription Factors during B-Cell Differentiation

The interferon-inducible DNA sensor IFI16 is involved in the modulation of cellular survival, proliferation, and differentiation. In the hematopoietic system, IFI16 is consistently expressed in the CD34+ stem cells and in peripheral blood lymphocytes; however, little is known regarding its regulation during maturation of B- and T-cells. We explored the role of IFI16 in normal B-cell subsets by analysing its expression and relationship with the major transcription factors involved in germinal center (GC) development and plasma-cell (PC) maturation. IFI16 mRNA was differentially expressed in B-cell subsets with significant decrease in IFI16 mRNA in GC and PCs with respect to naïve and memory subsets. IFI16 mRNA expression is inversely correlated with a few master regulators of B-cell differentiation such as BCL6, XBP1, POU2AF1, and BLIMP1. In contrast, IFI16 expression positively correlated with STAT3, REL, SPIB, RELA, RELB, IRF4, STAT5B, and STAT5A. ARACNE algorithm indicated a direct regulation of IFI16 by BCL6, STAT5B, and RELB, whereas the relationship between IFI16 and the other factors is modulated by intermediate factors. In addition, analysis of the CD40 signaling pathway showed that IFI16 gene expression directly correlated with NF-κB activation, indicating that IFI16 could be considered an upstream modulator of NF-κB in human B-cells.

Fibroblast activation protein and its prognostic significance in correlation with vascular endothelial growth factor in pancreatic adenocarcinoma

Fibroblast activation protein (FAP), a selective protein for tumor stromal fibroblasts, is expressed in >90% of human epithelial carcinomas. A characteristic feature of pancreatic cancer is an extensive fibrotic or desmoplastic reaction surrounding the primary tumor. The present study aimed to evaluate the expression levels of FAP and vascular endothelial growth factor (VEGF) and determine their correlation in pancreatic adenocarcinoma. Confocal laser scanning microscopy and conventional immunohistochemical analysis were used to quantify FAP and VEGF expression levels in formalin‑fixed and paraffin‑embedded tissue biopsies from 46 patients (male, 26; female, 20; mean age, 66 years; age range, 53‑80 years) with pancreatic adenocarcinoma stage IIA or IIB. The expression levels of FAP in the neoplastic and adjacent normal tissue were significantly higher in stage IIB patients, compared with stage IIA patients. FAP expression was correlated with positive lymph nodes, resulting in poor prognosis for stage IIB patients. The partial correlation coefficient between FAP and VEGF expression levels was 0.39 (P=0.007), and the two factors had an effect on patient survival. Multivariate analysis demonstrated the prognostic superiority of FAP over VEGF, which is considered to be the most consistently reproducible molecular marker with prognostic value in resected pancreatic adenocarcinoma. Due to the limited beneficial effect of current systemic therapies for pancreatic adenocarcinoma, targeting FAP may be a potential therapeutic strategy and requires further investigation.

Whole-slide, quadruple immunofluorescence labeling of routinely processed paraffin sections

Whole-slide images (WSI) have acquired a stable place in diagnostic histopathology and immunohistochemistry. Immunofluorescence (IF) techniques hold a limited and selective role in diagnostics (eg, renal and cutaneous pathology) and so far remain excluded from the digital pathology evolution, with notable exceptions, such as quantitative immunopathology. We explored the ability of a commercial fluorescent slide scanner to provide 4-color IF WSI from routinely processed tissues. With minor modifications and a careful match between filters and fluorochromes, we show that 4-color IF WSI can be obtained from routine material with negligible autofluorescence, good sensitivity, and diagnostic power.

Multiplexed immunohistochemistry, imaging, and quantitation: a review, with an assessment of Tyramide signal amplification, multispectral imaging and multiplex analysis

Tissue sections offer the opportunity to understand a patient's condition, to make better prognostic evaluations and to select optimum treatments, as evidenced by the place pathology holds today in clinical practice. Yet, there is a wealth of information locked up in a tissue section that is only partially accessed, due mainly to the limitations of tools and methods. Often tissues are assessed primarily based on visual analysis of one or two proteins, or 2-3 DNA or RNA molecules. Even while analysis is still based on visual perception, image analysis is starting to address the variability of human perception. This is in contrast to measuring characteristics that are substantially out of reach of human perception, such as parameters revealed through co-expression, spatial relationships, heterogeneity, and low abundance molecules. What is not routinely accessed is the information revealed through simultaneous detection of multiple markers, the spatial relationships among cells and tissue in disease, and the heterogeneity now understood to be critical to developing effective therapeutic strategies. Our purpose here is to review and assess methods for multiplexed, quantitative, image analysis based approaches, using new multicolor immunohistochemistry methods, automated multispectral slide imaging, and advanced trainable pattern recognition software. A key aspect of our approach is presenting imagery in a workflow that engages the pathologist to utilize the strengths of human perception and judgment, while significantly expanding the range of metrics collectable from tissue sections and also provide a level of consistency and precision needed to support the complexities of personalized medicine.

The comparison of methods to identify the presence of fibrocytes in formalin-fixed, paraffin-embedded archival cardiac tissue with coronary heart disease

The purpose of this study was to find the optimal technical approach to identify the presence of fibrocytes in formalin-fixed, paraffin-embedded archival cardiac tissue with CHD (coronary heart disease). Using the coexpression markers CD45 and αSMA, the presence of fibrocytes was examined by three different methods, including double immunohistochemistry staining, combination labeling of immunohistochemistry and immunofluorescence and double immunofluorescence labeling. Double immunohistochemistry staining was very difficult to identify the CD45(+)/αSMA(+) fibrocytes. Although combination staining of immunohistochemistry and immunofluorescence has made it possible to evaluate the co-localization of CD45 and αSMA in the fibrocytes, this method was prone to produce many false positive cells. In contrast, CD45(+)/αSMA(+) fibrocytes could be clearly recognized by double immunofluorescence labeling. In conclusion, double immunofluorescence labeling is the optimal technical approach to identify the presence of fibrocytes in routinely processed cardiac tissue with CHD.

Elution of High-affinity (>10-9 KD) Antibodies from Tissue Sections: Clues to the Molecular Mechanism and Use in Sequential Immunostaining

Inconsistent results obtained with published methods for the elution of antibodies from tissue sections prompted the assessment of both old and new methods in combination with monoclonal rabbit antibodies of known, increased affinity (above 1×10(-9) KD). We tested an acidic (pH 2) glycine buffer, a 6 M urea hot buffer and a 2-Mercaptoethanol, SDS buffer (2-ME/SDS). Some antibodies were not removed by the glycine pH 2 or 6 M urea hot buffers, indicating that antibodies survive much harsher conditions than previously believed. We found that the elution is dependent upon the antibody affinity and is reduced by species-specific crosslinking via a dimeric or Fab fragments of a secondary antibody. The high affinity bond of exogenous streptavidin with the endogenous biotin can be removed by 6 M urea but not by the other buffers. 2-ME/SDS buffer is superior to glycine pH 2 and 6 M urea hot elution buffers for all antibodies because of its irreversible effect on the structure of the antibodies. It also has a mild retrieving effect on some antigens present on routinely treated sections and no detrimental effect on the immunoreactivity of the tissue. Therefore, 2-ME/SDS buffer is the method of choice to perform multiple rounds of immunostaining on a single routine section.

Garbage in, garbage out: a critical evaluation of strategies used for validation of immunohistochemical biomarkers

The use of immunohistochemistry (IHC) in clinical cohorts is of paramount importance in determining the utility of a biomarker in clinical practice. A major bottleneck in translating a biomarker from bench-to-bedside is the lack of well characterized, specific antibodies suitable for IHC. Despite the widespread use of IHC as a biomarker validation tool, no universally accepted standardization guidelines have been developed to determine the applicability of particular antibodies for IHC prior to its use. In this review, we discuss the technical challenges faced by the use of immunohistochemical biomarkers and rigorously explore classical and emerging antibody validation technologies. Based on our review of these technologies, we provide strict criteria for the pragmatic validation of antibodies for use in immunohistochemical assays.

Variation in BCL2 protein expression in follicular lymphomas without t(14;18) chromosomal translocations

AIM

The hallmark of follicular lymphoma is the t(14;18)(q32;q21) chromosomal translocations that lead to deregulation of BCL2 expression in tumour cells. However, not all cases of follicular lymphoma express BCL2, nor is the t(14;18) translocation always present. Follicular lymphomas lacking the BCL2 rearrangement are less well studied with regards to their immunohistochemical and molecular features. This study aims to investigate the BCL2 protein expression pattern in t(14;18) negative follicular lymphomas.

METHODS

BCL2 protein expression pattern was analysed in 26 cases of t(14;18) negative follicular lymphoma [determined by fluorescence in situ hybridisation (FISH)], using antibodies against two-different epitopes, i.e., the widely-used antibody BCL2/124 and an alternative antibody E17.

RESULTS

Two of the t(14;18) negative cases showed evidence of BCL2 amplification and trisomy 18. A total of 13 cases (50%) lacked BCL2 expression. In 10 cases (38%) the expression was heterogeneous and in only three cases (12%) the BCL2 expression was strongly positive. These cases could thus be subdivided into three subgroups: Group I, normal BCL2 genes (i.e., no evidence of translocation or amplification), and BCL2 protein negative; Group II, normal BCL2 genes but BCL2 protein positive; and Group III, presence of other genetic alterations, i.e., BCL2 amplification and trisomy 18, and BCL2 protein positive.

CONCLUSIONS

This study suggests that it may be possible on the basis of staining to predict that the t(14;18) translocation is absent if a case is either negative for BCL2 protein with different antibodies or has heterogeneous BCL2 expression, possibly acquired through a physiological process of differentiation.

Quantitative in situ analysis of FoxP3+ T regulatory cells on transplant tissue using laser scanning cytometry

There is abundant evidence that immune cells infiltrating into a transplanted organ play a critical role for destructive inflammatory or regulatory immune reactions. Quantitative in situ analysis (i.e., in tissue sections) of immune cells remains challenging due to a lack of objective methodology. Laser scanning cytometry (LSC) is an imaging-based methodology that performs quantitative measurements on fluorescently and/ or chromatically stained tissue or cellular specimens at a single-cell level. In this study, we have developed a novel objective method for analysis of immune cells, including Foxp3(+) T regulatory cells (Tregs), on formalin-fixed /paraffin-embedded (FFPE) transplant biopsy sections using iCys® Research Imaging Cytometer. The development of multiple immunofluorescent staining was established using FFPE human tonsil sample. The CD4/CD8 ratio and the population of Tregs among CD4(+) cells were analyzed using iCys and compared with the results from conventional flow cytometry analysis (FCM). Our multiple immunofluorescent staining techniques allow obtaining clear staining on FFPE sections. The CD4/CD8 ratio analyzed by iCys was concordant with those obtained by FCM. This method was also applicable for liver, small intestine, kidney, pancreas, and heart transplant biopsy sections and provide an objective quantification of Tregs within the grafts.

Improved penile histology by phalloidin stain: circular and longitudinal cavernous smooth muscles, dual-endothelium arteries, and erectile dysfunction-associated changes

OBJECTIVE

To investigate whether fluorochrome-conjugated phalloidin can delineate cavernous smooth muscle (CSM) cells and whether it can be combined with immunofluorescence (IF) staining to quantify erectile dysfunction (ED)-associated changes.

METHODS

ED was induced by cavernous nerve crush in rats. Penile tissues of control and ED rats were stained with Alexa-488-conjugated phalloidin and/or with antibodies against rat endothelial cell antigen (RECA), CD31, neuronal nitric oxide synthase (nNOS), and collagen-IV (Col-IV).

RESULTS

Phalloidin was able to delineate CSM as composed of a circular and a longitudinal compartment. When combined with IF stain for CD31 or RECA, it helped the identification of the helicine arteries as covered by endothelial cells on both sides of the smooth muscle layer. When combined with IF stain for nNOS, it helped the identification that nNOS-positive nerves were primarily localized within the dorsal nerves and in the adventitia of dorsal arteries. When combined with IF stain for Col-IV, it helped identify that Col-IV was localized around smooth muscles and beneath the endothelium. Phalloidin also facilitated the quantitative analysis of ED-related changes in the penis. In rats with cavernous nerve injury, RECA or Col-IV expression did not change significantly, but CSM and nNOS nerve contents decreased significantly.

CONCLUSION

Phalloidin stain improved penile histology, enabling the visualization of the circular and longitudinal compartments in the CSM. It also worked synergistically with IF stain, permitting the visualization of the dual endothelial covering in helicine arteries, and facilitating the quantification of ED-related histologic changes.

Increased angiogenic sprouting in poor prognosis FL is associated with elevated numbers of CD163+ macrophages within the immediate sprouting microenvironment

Follicular lymphoma has considerable clinical heterogeneity, and there is a need for easily quantifiable prognostic biomarkers. Microvessel density has been shown to be a useful prognostic factor based on numerical assessment of vessel numbers within histologic sections in some studies, but assessment of tumor neovascularization through angiogenic sprouting may be more relevant. We therefore examined the smallest vessels, single-staining structures measuring less than 30 microm(2) in area, seen within histologic sections, and confirmed that they were neovascular angiogenic sprouts using extended focal imaging. Tissue microarrays composing diagnostic biopsies from patients at the extremes of survival of follicular lymphoma were analyzed with respect to numbers of these sprouts. This analysis revealed higher angiogenic activity in the poor prognostic group and demonstrated an association between increased sprouting and elevated numbers of infiltrating CD163(+) macrophages within the immediate microenvironment surrounding the neovascular sprout.

Multiple antigen immunostaining procedures

Detection of multiple antigens in the same tissue section can be done by combining a range of immunohisto/cytochemical techniques based either on light microscopic chromogenic precipitates or fluorochrome labeling. Light microscopic techniques preferred for this purpose use combinations of immunogold silver staining (black precipitate), immunoperoxidase, immunoalkaline phosphatase and immunogalactosidase methods using chromogens of different colors. Fluorochrome labels favored for these combinations include AMCA (blue), FITC (green), rhodamine (orange-red) and Cy5 (far red), their matching synthetic members from the Alexa series, or quantum dots. Antibodies directly labeled or those from noncross-reacting animal species (e.g., mouse, rabbit, goat, guinea pig etc.) can be applied simultaneously. When the antigens of interest are in separate cells or cell compartments (e.g., in cell membrane, cytoplasm or nucleus), and only cross-reacting antibodies are available, there have also been ways of avoiding unwanted cross-talk. These include the exploitation of the shielding effect of chromogens; inactivation of immuno-sequences of the first staining by using either acidic elution, formaldehyde fixation or microwave heating; combining unlabeled and hapten-labeled antibodies; or using labeled monovalent F(ab) secondary antibodies. In this chapter we briefly discuss the principle of multiple antigen immunolabeling and provide useful protocols for its performance.

Immunofluorescence detection of the cytoskeleton and extracellular matrix in tissue and cultured cells

"A picture is worth a thousand words" goes the proverb. A poor picture however can be worse than saying nothing at all. This is particularly true for immunofluorescence pictures that in addition to their informative character bear an esthetic component. We here provide a panel of straightforward methods to process tissue sections and cultured cells for immunostaining of cytoskeletal elements, primarily those associated with actin filaments. We want to emphasize to the reader the fact that the choice of the processing method will have an important influence on the outcome of the immunostaining and thus on the interpretation of the results. Fixation of cultured cells with cross-linking reagents such as paraformaldehyde efficiently preserves structural elements at the expense of reduced antigenicity. The degree and timing of cell permeabilization with detergents, along with chemical cross-linking, contributes to the clarity and resolution of distinct structures but can also lead to loss of information. Fixation with organic solvents like methanol will, in most cases, better preserve antigens but will produce a higher background and impact on structural integrity. Therefore, it is recommended to test different protocols for a "new" protein or epitope - the results will pay back your investment.

CD81 protein is expressed at high levels in normal germinal center B cells and in subtypes of human lymphomas

CD81 is a tetraspanin cell surface protein that regulates CD19 expression in B lymphocytes and enables hepatitis C virus infection of human cells. Immunohistologic analysis in normal hematopoietic tissue showed strong staining for CD81 in normal germinal center B cells, a cell type in which its increased expression has not been previously recognized. High-dimensional flow cytometry analysis of normal hematopoietic tissue confirmed that among B- and T-cell subsets, germinal center B cells showed the highest level of CD81 expression. In more than 800 neoplastic tissue samples, its expression was also found in most non-Hodgkin lymphomas. Staining for CD81 was rarely seen in multiple myeloma, Hodgkin lymphoma, or myeloid leukemia. In hierarchical cluster analysis of diffuse large B-cell lymphoma, staining for CD81 was most similar to other germinal center B cell-associated markers, particularly LMO2. By flow cytometry, CD81 was expressed in diffuse large B-cell lymphoma cells independent of the presence or absence of CD10, another germinal center B-cell marker. The detection of CD81 in routine biopsy samples and its differential expression in lymphoma subtypes, particularly diffuse large B-cell lymphoma, warrant further study to assess CD81 expression and its role in the risk stratification of patients with diffuse large B-cell lymphoma.

Lymphocyte-rich classical Hodgkin's lymphoma: distinctive tumor and microenvironment markers

The existence, diagnostic features, and the biological and clinical relevance of lymphocyte-rich classical Hodgkin's lymphoma remain controversial. A comparative marker analysis of lymphocyte-rich classical Hodgkin's lymphoma, nodular lymphocyte-predominance Hodgkin's lymphoma, and of other subtypes of classical Hodgkin's lymphoma was carried out. Markers were selected focusing on B-cell lineage and transcription program (OCT.1, OCT.2, BOB.1, BCL6, PAX-5, GCET1, KLHL6, and BLIMP1), the NF-kappaB signaling pathway (REL-B, C-REL, TRAF-1, p-50, and MUM-1) and the T-cell microenvironment (CD3, CD57, PD-1, CXCL-13, and CD10, BCL-6, CD23). Lymphocyte-rich classical Hodgkin's lymphoma cases displayed features intermediate between those of classical Hodgkin's lymphoma and nodular lymphocyte-predominance Hodgkin's lymphoma. The expression of B-cell transcription factors such as OCT.1, OCT.2, BOB.1, and BCL6 was more frequent in lymphocyte-rich classical Hodgkin's lymphoma than in classical Hodgkin's lymphoma. A follicular T-cell microenvironment was also identified in 50% of lymphocyte-rich classical Hodgkin's lymphoma cases. NF-kB markers were expressed at frequencies comparable with those observed in classical Hodgkin's lymphoma. The neoplastic cell immunophenotype and microenvironment in lymphocyte-rich classical Hodgkin's lymphoma closely mimic that which are observed in the outer zone of the germinal center, where B-cell blasts with germinal-center markers co-express CD30 and the B-cell transcription program, surrounded by follicular T-cell rosettes. Lymphocyte-rich classical Hodgkin's lymphoma seems to be characterized by a stronger expression of the B-cell transcription program by the neoplastic cells and by a follicular T-cell background, occupying an intermediate position between classical Hodgkin's lymphoma and nodular lymphocyte-predominance Hodgkin's lymphoma.

Fate of mesenchymal stem cells transplanted to osteonecrosis of femoral head

The purpose of this study was to investigate the survival and differentiation status of MSCs transplanted to ONFH. Traumatic ONFH was surgically produced in skeletally mature mongrel dogs. Osteonecrosis was treated with either saline (control) or autologous mesenchymal stem cells (MSCs) transplantation after decompression. Green fluorescent protein (GFP) was used to track the transplanted MSCs, the differentiation of MSCs were evaluated by fluorescent double-labeling with GFP between osteocalcin or von Willebrand factor (vWF) at 2nd, 8th, and 12th week after the transplantation. It was demonstrated that GFP-positive cells were present in the necrotic area up to 12 weeks after the transplantation, their number increased from 15% at 2nd week to 38% at 12th week (p < 0.05). Neither osteocalcin nor vWF was detected by immunocytochemistry in GFP-labeled MSCs in vitro, but osteocalcin was immunohistochemically positive in 90% of the GFP-labeled MSCs in vivo, while vWF was still negative. The vWF expression was of no significant difference between the control group and MSCs-transplanted group. The percentages of trabeculae bone volume were 9.36% and 8.42% at 2nd week (p > 0.05), 22.82% and 14.72% at 8th week, and 31.08% and 20.66% at 12th week (p < 0.05) in MSCs-transplanted group and control group, respectively; new trabeculae bone in MSCs-transplanted group was significantly increased as compared to that of control group at 8th and 12th week. The results demonstrated that the transplanted MSCs could survive, proliferate, and differentiate into osteoblasts directly, which contributed to the accelerated repair process. The possible mechanism is site-dependant differentiation.

High Numbers of Tumor-Infiltrating Programmed Cell Death 1–Positive Regulatory Lymphocytes Are Associated With Improved Overall Survival in Follicular Lymphoma

Purpose

Tumor microenvironment influences the behavior of follicular lymphoma (FL), although the specific cell subsets involved are not well known. The aim of this study was to determine the impact of programmed cell death 1 (PD-1) –positive inhibitory immunoregulatory lymphoid cells in the clinicobiologic features and outcome of patients with FL.

Patients and Methods

We examined samples from 100 patients (53 men and 47 women; median age, 54 years) at diagnosis, as well as in 32 patients at first relapse, with a recently generated monoclonal antibody against PD-1. The cells were quantified using computerized image analysis. Additional analysis consisted of double immunofluorescence and flow cytometry.

Results

PD-1 expression was alternative to FOXP3 in lymphoid cells from both reactive tonsils and FL. At diagnosis, the median percentage of PD-1–positive cells was 14% (range, 0.1% to 74%). Patients with grade 3 FL, poor performance status, and high serum lactate dehydrogenase showed lower numbers of PD-1–positive cells. After a median follow-up of 6.2 years, patients with PD-1–positive cells ≤ 5% (n = 25), 6% to 33% (n = 50), and more than 33% (n = 25) had a 5-year progression-free survival rate of 20%, 46%, and 48% (P = .038) and overall survival (OS) of 50%, 77%, and 95% (P = .004), respectively. PD-1 and FL International Prognostic Index maintained prognostic value for OS in multivariate analysis. Patients with PD-1–positive cells ≤ 5% showed a higher risk of histologic transformation. At that time, transformed diffuse large B-cell lymphomas had lower percentage of PD-1–positive cells than FL.

Conclusion

A high content of PD-1–positive cells predicted favorable outcome of FL patients, whereas a marked reduction is observed in transformation.

BCL2 protein expression in follicular lymphomas with t(14;18) chromosomal translocations

The t(14;18)(q32;q21) chromosomal translocation induces BCL2 protein overexpression in most follicular lymphomas. However the expression of BCL2 is not always homogeneous and may demonstrate a variable degree of heterogeneity. This study analysed BCL2 protein expression pattern in 33 cases of t(14;18)-positive follicular lymphomas using antibodies against two different epitopes (i.e. the widely used antibody BCL2/124 and an alternative antibody E17). 16/33 (49%) cases demonstrated strong BCL2 expression. In 10/33 (30%) cases, BCL2 expression was heterogeneous and in some of these, its loss appeared to be correlated with cell proliferation, as indicated by Ki67 expression. Double immunofluorescence labelling confirmed an inverse BCL2/Ki67 relationship, where in 24/28 (86%) cases cellular expression of BCL2 and Ki67 was mutually exclusive. In addition, seven BCL2 'pseudo-negative' cases were identified in which immunostaining was negative with antibody BCL2/124, but positive with antibody E17. Genomic DNA sequencing of these 'pseudo-negative' cases demonstrated eleven mutations in four cases and nine of these were missense mutations. It can be concluded that in follicular lymphomas, despite carrying the t(14;18) translocations, BCL2 protein expression may be heterogeneous and loss of BCL2 could be related to cell proliferation. Secondly, mutations in translocated BCL2 genes appear to be common and may cause BCL2 pseudo-negative immunostaining.

Characterization of a novel anti-fatty acid synthase (FASN) antiserum in breast tissue

Fatty acid synthase (FASN) expression has been reported in many different tumors, including breast cancer. In gene microarray studies, the fatty acid synthase gene co-clustered with cytokeratins 5 and 17 and other genes that defined the basal-like subset of breast cancers. To define the use of this marker in breast pathology, a rabbit polyclonal antiserum (S143) to a peptide fragment of this gene was produced and compared with a commercially available monoclonal antibody by immunohistochemistry on various tissue microarrays and whole tissue sections. The tissue microarrays included 1090 breast cancers and 244 normal breast tissues. Whole tissue sections consisted of benign and malignant tissues from breast resection specimens. In contrast to other 'basal' markers identified by gene expression profiling data, the fatty acid synthase (FASN) expression pattern in normal breast was notable for its expression in only a small subset of basal and suprabasal cells. Dual staining experiments revealed that the subpopulation of cells labeling with FASN did not coexpress myoepithelial markers CK5/6 or p63, but did coexpress e-cadherin. In addition to staining a subset of basal and suprabasal cells, the antiserum highlighted apocrine differentiation, and stained 106/144 (74%) cases of columnar cell lesions and five of five cases of flat epithelial atypia. Despite its association with basal keratins in gene array studies, FASN expression did not correlate significantly with the outcome in breast cancer. We describe an expression pattern that highlights only a subset of basal and suprabasal cells in normal breast ducts and we show by dual expression studies that this subset of cells is different from myoepithelial and basal cytokeratin-positive cells. In addition, FASN expression is described in apocrine metaplasia, columnar cell lesions, and flat epithelial atypia.