Vascular endothelial growth factor receptor 2 as a marker for malignant vascular tumors and mesothelioma: an immunohistochemical study of 262 vascular endothelial and 1640 nonvascular tumors

The expansion of targetable biomarkers for CAR T cell therapy

Biomarkers are an integral part of cancer management due to their use in risk assessment, screening, differential diagnosis, prognosis, prediction of response to treatment, and monitoring progress of disease. Recently, with the advent of Chimeric Antigen Receptor (CAR) T cell therapy, a new category of targetable biomarkers has emerged. These biomarkers are associated with the surface of malignant cells and serve as targets for directing cytotoxic T cells. The first biomarker target used for CAR T cell therapy was CD19, a B cell marker expressed highly on malignant B cells. With the success of CD19, the last decade has shown an explosion of new targetable biomarkers on a range of human malignancies. These surface targets have made it possible to provide directed, specific therapy that reduces healthy tissue destruction and preserves the patient's immune system during treatment. As of May 2018, there are over 100 clinical trials underway that target over 25 different surface biomarkers in almost every human tissue. This expansion has led to not only promising results in terms of patient outcome, but has also led to an exponential growth in the investigation of new biomarkers that could potentially be utilized in CAR T cell therapy for treating patients. In this review, we discuss the biomarkers currently under investigation and point out several promising biomarkers in the preclinical stage of development that may be useful as targets.

Nanoparticle-Cell Interaction: A Cell Mechanics Perspective

Progress in the field of nanoparticles has enabled the rapid development of multiple products and technologies; however, some nanoparticles can pose both a threat to the environment and human health. To enable their safe implementation, a comprehensive knowledge of nanoparticles and their biological interactions is needed. In vitro and in vivo toxicity tests have been considered the gold standard to evaluate nanoparticle safety, but it is becoming necessary to understand the impact of nanosystems on cell mechanics. Here, the interaction between particles and cells, from the point of view of cell mechanics (i.e., bionanomechanics), is highlighted and put in perspective. Specifically, the ability of intracellular and extracellular nanoparticles to impair cell adhesion, cytoskeletal organization, stiffness, and migration are discussed. Furthermore, the development of cutting-edge, nanotechnology-driven tools based on the use of particles allowing the determination of cell mechanics is emphasized. These include traction force microscopy, colloidal probe atomic force microscopy, optical tweezers, magnetic manipulation, and particle tracking microrheology.

Increased tumor vascularization is associated with the amount of immune competent PD-1 positive cells in testicular germ cell tumors

Testicular germ cell cancer in a metastatic state is curable with a cisplatin-based first line chemotherapy. However, 10-15% of these patients are resistant to first line chemotherapy and are thus left with only palliative options. Immunotherapies and inhibition of angiogenesis used in multiple types of cancer; however, the molecular context of angiogenesis and immune checkpoints in the development and progression of testicular cancers is still unknown. Therefore, the present study performed tissue micro array based analysis of 84 patients with immunohistochemistry of programmed cell death protein 1 (PD-1), programmed cell death ligand 1 (PD-L1) and vascular endothelial growth factor receptor 2 (VEGFR2) of testicular cancer and corresponding normal appearing testis tissue, matching the results with clinical data. The results demonstrated that PD-L1 was significantly upregulated in testicular tumors and that PD-1 positive cells significantly infiltrated the testicular tumor when compared with normal testicular tissue. VEGFR2 was significantly upregulated in testicular cancer. It was indicated that PD-1 expressing cytotoxic cells may require pathologic tumor vessels to pass the blood-testis-barrier in order to migrate into the tumor. Notably, when matching the clinical data for PD-1, PD-L1 and VEGFR2 there were no differences in expression in the different International Germ Cell Cancer Collaborative Group stages of non-seminoma. These data suggested that the anti-PD-1/PD-L1 immunotherapy and the anti-angiogenic therapy, sequentially or in combination, may be a promising option in the treatment of testicular cancer.

Vascular Tumors of Bone: The Evolvement of a Classification Based on Molecular Developments

The classification of vascular tumors of bone has been under debate over time. Vascular tumors in bone are rare, display highly overlapping morphology, and, therefore, are considered difficult by pathologists. Compared with their soft tissue counterparts, they are more often multifocal and sometimes behave more aggressively. Over the past decade, with the advent of next-generation sequencing, recurrent molecular alterations have been found in some of the entities. The integration of morphology and molecular changes has led to a better characterization of these separate entities.

Epithelioid peritoneal mesothelioma: a hybrid phenotype within a mesenchymal-epithelial/epithelial-mesenchymal transition framework

The aim of this study was to reconsider the biological characteristics of epithelioid malignant peritoneal mesothelioma (E-MpM) in the light of new concepts about epithelial mesenchymal transition and mesenchymal epithelial reverse transition (EMT/MErT) and the role of epigenetic reprogramming in this context. To this end we profiled surgical specimens and derived cells cultures by a number of complementary approaches i.e. immunohistochemistry, immunofluorescence, in situ hybridization, biochemistry, pluripotent stem cell arrays, treatments with cytokines, growth factors and specific inhibitors.The analyses of the surgical specimens showed that i) EZH2 is expressed throughout the spectrum of MpM, ii) that E-MpM (including the high-grade undifferentiated form) are characterised by c-MYC and miRNA 17-5p expression, and iii) that progression to sarcomatoid MpM is dictated by EMT regulators. They also showed that E-MpM expressed c-MET and are enriched in E- and P-cadherins- and VEGFR2-expressing CSCs, thus strongly supporting a role for MErT reprogramming in endowing E-MpM tumour cells with stemness and plasticity, and hence with a drug resistant phenotype. The cell culture-based experiments confirmed the stemness traits and plasticity of E-MpM, and support the view that EZH2 is a druggable target in this tumor.

Histopathological vascular investigation of the peritumoral brain zone of glioblastomas

To date, no histopathological vascular investigation focusing on peritumoral brain zone (PBZ) has been reported for glioblastoma. We analyzed 10 newly diagnosed cases of glioblastomas. For these PBZs, histopathological investigation was performed by hematoxylin-eosin (H&E) staining and immunohistochemistry was analyzed for CD31, CD34, Factor VIII, VEGF, VEGFR-1/2, Ki67, p53 and nestin. Although it was difficult to identify PBZ by H&E, Ki67 and p53 staining, there were apparent differences in nestin staining among PBZ, tumor core (TC), and normal zone (NZ). Therefore, in this study, we divided PBZ from TC and NZ by nestin staining. Differences in histological features, microvessel density, expression of VEGF and its receptors were assessed for PBZ, TC and NZ. The microvessel density, as determined by counting CD31, CD34 and VEGF receptors, and VEGF-A expression were lower in PBZ than TC. The expression patterns for CD31, CD34 and VEGF receptors in vessels show dissociation in PBZ. In addition, the vascular characteristics of the PBZ may correlate with findings of radiographic imaging. We provide the first clinicopathological evidence that PBZ exhibits unique angiogenic characteristics. These in situ observations will help to elucidate the mechanisms of tumor recurrence.

Sindbis Virus-Pseudotyped Lentiviral Vectors Carrying VEGFR2-Specific Nanobody for Potential Transductional Targeting of Tumor Vasculature

Introduction of selectivity/specificity into viral-based gene delivery systems, such as lentiviral vectors (LVs), is crucial in their systemic administration for cancer gene therapy. The pivotal role of tumor-associated endothelial cells (TAECs) in tumor angiogenesis and overexpression of vascular endothelial growth factor receptor-2 (VEGFR2 or KDR) in TAECs makes them a potent target in cancer treatment. Herein, we report the development of VEGFR2-targeted LVs pseudotyped with chimeric sindbis virus E2 glycoprotein (cSVE2s). For this purpose, either sequence of a VEGFR2-specific nanobody or its natural ligand (VEGF₁₂₁) was inserted into the binding site of sindbis virus E2 glycoprotein. In silico modeling data suggested that the inserted targeting motifs were exposed in the context of cSVE2s. Western blot analysis of LVs indicated the incorporation of cSVE2s into viral particles. Capture ELISA demonstrated the specificity/functionality of the incorporated cSVE2s. Transduction of 293/KDR (expressing VEGFR2) or 293T cells (negative control) by constructed LVs followed by fluorescent microscopy and flow cytometric analyses indicated selective transduction of 293/KDR cells (30 %) by both targeting motifs compared to 293T control cells (1-2 %). These results implied similar targeting properties of VEGFR2-specific nanobody compared to the VEGF₁₂₁ and indicated the potential for transductional targeting of tumor vasculature by the nanobody displaying LVs.

Littoral cell angioma of the spleen: a study of 25 cases with confirmation of frequent association with visceral malignancies

AIMS

Littoral cell angioma (LCA) is a rare primary splenic tumour that is frequently associated with internal malignancies. Immunohistochemistry can demonstrate a distinct hybrid endothelial-histiocytic phenotype of littoral cells, and is a helpful adjunct for making the correct diagnosis. The aims of this study were to present a series of 25 LCAs, with an emphasis on the frequent association of the neoplasm with visceral malignancies, and to provide a detailed immunohistochemical analysis by employing new markers.

METHODS AND RESULTS

All 25 cases with available tissue blocks were immunohistochemically stained for endothelial and histiocytic markers. Clinical and follow-up data were retrieved from the respective institutions. The tumours were obtained from 16 males and nine females, whose age ranged from 32 to 86 years (mean 56.2 years). Clinical information was available for 24 of 25 patients, and follow-up for 11 of 25 patients (range 2-19 years; mean 11.6 years). Immunohistochemically, all cases were positive for LYVE-1, factor VIII, FLI-1, vascular endothelial growth factor receptor (VEGFR)-2, VEGFR-3, claudin-5, ERG, LMO2, CD31, CD163, lysozyme, and CD4, but negative for D2-40, CD8, and factor XIIIa. Fifteen of 25 cases were associated with various malignancies, including epithelial, mesenchymal and haematological tumours.

CONCLUSIONS

The cohort of 25 patients is the largest series of LCAs published to date. By using antibodies against recently introduced endothelial markers, we have expanded the immunoprofile of LCA. We have further highlighted the clinical significance of LCA, as more than half of the patients in this study also harboured a coexisting visceral malignancy. Therefore, we conclude that the finding of splenic LCA mandates a thorough clinical evaluation for a concomitant malignancy.

Expression and prognostic significance of VEGFR-2 in breast cancer

Breast cancer is one of the most common cancers among women in the world. Vascular endothelial growth factor receptor 2 (VEGFR-2) was not only found to play a key role in the development of tumor angiogenesis, but has also been located in tumor cells of a variety of tumors. This study investigated the expression pattern of VEGFR-2 in breast cancer tissue specimens in order to evaluate the role of VEGFR-2 in the prognosis of breast cancer. Expression and localization of VEGFR-2 in tumor cells of breast cancer specimens from 98 invasive breast cancer patients were determined by immunohistochemistry. The relationships between VEGFR-2 expression and clinicopathological features were also analyzed. The results showed that VEGFR-2 expression correlated positively with lymph node (LN) metastasis of breast cancer. Patients with high expression of VEGFR-2 had a significantly worse OS. It was also observed that the expression of epithelial-mesenchymal transition (EMT) marker, including Twist1 and Vimentin, was higher in the tumors with higher VEGFR-2 expression, while the E-cadherin expression was lower in the same tumors, suggesting that VEGFR-2 may serve as a possible mediator of EMT in breast cancer.

Microvessel density, lymphovascular density, and lymphovascular invasion in primary cutaneous melanoma-correlation with histopathologic prognosticators and BRAF status

The relationship between microvessel density (MVD), lymphovascular density (LVD), and lymphovascular invasion (LVI) in primary cutaneous melanoma (PCM) remains unclear. Given this, a total of 102 PCMs were assessed for MVD (vascular endothelial growth factor receptor 2 and Endocan), LVD (D2-40), and LVI (immunostaining with D2-40/S-100 and hematoxylin and eosin); tumoral S-100A13, vascular endothelial growth factor receptor 2, and Endocan; and BRAF status. LVD was associated with MVD (P = .01). MVD was higher in PCMs with depth greater than or equal to 2 mm and ulceration (P = .04, .05), whereas LVD was higher in PCMs with depth greater than or equal to 2 mm and mitoses (P = .03, .02). After adjusting for MVD and LVD, only ulceration was associated with LVI (P < .02). A BRAF mutation was seen in 30.4% cases, and when present, both LVD and host response (P = .0008 and .04, respectively) were significantly associated with MVD. Immunostaining with S-100A13 was noted in 99% of cases and a significant association noted only with ulceration (P = .05). Immunostaining increased LVI positivity (46.5% versus 4.9% by hematoxylin and eosin, P < .0001). MVD and LVD are not associated with LVI, appear to be closely related with each other, and are associated with select markers of poor prognosticative value. The association between a host response and LVD and MVD in PCMs with a BRAF mutation suggests that they exhibit potential for strategizing immunotherapies.

The Utility of Immunohistochemistry in the Differential Diagnosis of Gynecologic Disorders

Context

Immunohistochemistry has assumed an increasing role in the identification and characterization of gynecologic disorders including lesions with deceptively bland morphology, uncommon and underdiagnosed neoplasms, and neoplasms with specific genetic alterations associated with overexpression or loss of expression of specific proteins. The diagnostic accuracy has been significantly improved owing to the discovery and increasing experience with the tumor-associated biomarkers, and the increasing demand for precise tumor classification to assess suitability for the expanding therapeutic modalities including clinical trials.

Objective

To differentiate lesions of the gynecologic tract through the use of effective immunohistochemical panels.

Data Sources

Literature review and authors' personal practice experience.

Conclusions

The application of diagnostic and prognostic immunohistochemical panels has enabled pathologists to better guide therapeutic decisions and to better predict the clinical outcome. It is now well established that the use of ancillary testing, including immunohistochemistry, has a significant power in the identification, differentiation, and classification of reactive, premalignant, and malignant gynecologic disorders. This article discusses the utilities and pitfalls of the commonly used immunohistochemical markers in the context of overlapping morphologic features encountered in the uterus, ovaries, and fallopian tubes.

Frequent truncating mutations of STAG2 in bladder cancer

Here we report the discovery of truncating mutations of the gene encoding the cohesin subunit STAG2, which regulates sister chromatid cohesion and segregation, in 36% of papillary non-invasive urothelial carcinomas and 16% of invasive urothelial carcinomas of the bladder. Our studies suggest that STAG2 has a role in controlling chromosome number but not the proliferation of bladder cancer cells. These findings identify STAG2 as one of the most commonly mutated genes in bladder cancer.

Tumor cell expression of vascular endothelial growth factor receptor 2 is an adverse prognostic factor in patients with squamous cell carcinoma of the lung

A robust immunohistochemical (IHC) assay for VEGFR2 was developed to investigate its utility for patient tailoring in clinical trials. The sensitivity, specificity, and selectivity of the IHC assay were established by siRNA knockdown, immunoblotting, mass spectrometry, and pre-absorption experiments. Characterization of the assay included screening a panel of multiple human cancer tissues and an independent cohort of non-small cell lung carcinoma (NSCLC, n = 118) characterized by TTF-1, p63, CK5/6, and CK7 IHC. VEGFR2 immunoreactivity was interpreted qualitatively (VEGFR2 positive/negative) in blood vessels and by semi-quantitative evaluation using H-scores in tumor cells (0-300). Associations were determined among combinations of VEGFR2 expression in blood vessels and tumor cells, and clinico-pathologic characteristics (age, sex, race, histologic subtype, disease stage) and overall survival using Kaplan-Meier analyses and appropriate statistical models. VEGFR2 expression both in blood vessels and in tumor cells in carcinomas of the lung, cervix, larynx, breast, and others was demonstrated. In the validation cohort, 99/118 (83.9%) NSCLC tissues expressed VEGFR2 in the blood vessels and 46/118 (39.0%) showed high tumor cell positivity (H-score ≥10). Vascular and tumor cell expression were inversely correlated (p = 0.0175). High tumor cell expression of VEGFR2 was associated with a 3.7-fold reduction in median overall survival in lung squamous-cell carcinoma (SCC, n = 25, p = 0.0134). The inverse correlation between vascular and tumor cell expression of VEGFR2 and the adverse prognosis associated with high VEGFR2 expression in immunohistochemically characterized pulmonary SCC are new findings with potential therapeutic implications. The robustness of this novel IHC assay will support further evaluation of its utility for patient tailoring in clinical trials of antiangiogenic agents.

The role of the VEGF-C/VEGFRs axis in tumor progression and therapy

Vascular endothelial growth factor C (VEGF-C) has been identified as a multifaceted factor participating in the regulation of tumor angiogenesis and lymphangiogenesis. VEGF-C is not only expressed in endothelial cells, but also in tumor cells. VEGF-C signaling is important for progression of various cancer types through both VEGF receptor-2 (VEGFR-2) and VEGF receptor-3 (VEGFR-3). Likewise, both receptors are expressed mainly on endothelial cells, but also expressed in tumor cells. The dimeric VEGF-C undergoes a series of proteolytic cleavage steps that increase the protein binding affinity to VEGFR-3; however, only complete processing, removing both the N- and C-terminal propeptides, yields mature VEGF-C that can bind to VEGFR-2. The processed VEGF-C can bind and activate VEGFR-3 homodimers and VEGFR-2/VEGFR-3 heterodimers to elicit biological responses. High levels of VEGF-C expression and VEGF-C/VEGFRs signaling correlate significantly with poorer prognosis in a variety of malignancies. Therefore, the development of new drugs that selectively target the VEGF-C/VEGFRs axis seems to be an effective means to potentiate anti-tumor therapies in the future.

Immunohistochemical endothelial markers: a review

A relatively large number of new endothelial markers that can assist in the diagnosis and classification of endothelial and vascular neoplasms have become available over the past few years. The expression of these markers, however, differs considerably among the various tumors. A selection of markers that have potential diagnostic utility or are of current interest among pathologists are reviewed and compared with some of the more traditional markers that have been employed in diagnostic pathology.