Glypican-1 immunohistochemistry is a novel marker to differentiate epithelioid mesothelioma from lung adenocarcinoma

Diagnostic Utility of Podoplanin Immunohistochemistry Combined with the NanoSuit-Correlative Light and Electron Microscopy Method for Thoracic Malignant Tumors

Background/Objectives: Differentiating thoracic malignant tumors, such as epithelioid malignant pleural mesothelioma (EMPM) and non-small-cell lung carcinoma (NSCLC), primarily comprising lung adenocarcinoma (LAC) and lung squamous cell carcinoma (LSCC), remains a challenge in routine pathological diagnosis. This study aimed to evaluate whether podoplanin (PDPN) immunohistochemistry combined with scanning electron microscopy (SEM) using the NanoSuit-correlative light and electron microscopy (CLEM) methods could serve as a reliable tool for distinguishing these thoracic malignancies. Methods/Results: Initially, PDPN expression was assessed by immunohistochemical analysis in 11 EMPM, 100 LAC, and 23 LSCC cases. PDPN positivity was predominantly observed in the cell membrane and was significantly more frequent in EMPM (100%) than in LAC (2%; p < 0.0001) or LSCC (43.5%; p = 0.0018). Subsequently, field emission-SEM (FE-SEM) observations of PDPN-positive sites on immunohistochemical slides, conducted using the NanoSuit-CLEM method, revealed distinctive ultrastructural features. EMPM exhibited densely packed, elongated microvilli, whereas such structures were absent in LAC and LSCC. Furthermore, analysis of thick-cut sections (20 μm) demonstrated extensive microvilli coverage characteristic of EMPM. Conclusions: These findings suggest that the combined approach of PDPN immunohistochemistry and FE-SEM observation of PDPN-positive sites, using the NanoSuit-CLEM method, constitutes an effective diagnostic strategy for enhancing the accuracy of distinguishing EMPM from NSCLCs.

Development of CAR-T Therapies and Personalized Vaccines for the Treatment of Cholangiocarcinoma: Current Progress, Mechanisms of Action, and Challenges

Cholangiocarcinoma (CCA) is a highly fatal malignancy with an increasing prevalence, a high mortality rate, poor overall survival, and limited responsiveness to conventional chemoradiotherapy. Targeted therapies addressing specific gene mutations have expanded treatment options for some patient populations. The introduction of chimeric antigen receptor-modified T-cell (CAR-T) immunotherapy and personalized vaccines have opened up a new avenue for managing various cancers. Considerable efforts have been dedicated to preclinical research and ongoing clinical trials of immunotherapeutic approaches including CAR-T therapy, vaccines, and antibody-based therapies such as antibody drug conjugates. However, the potential of CAR-T therapy and vaccines in treating advanced unresectable/metastatic cholangiocarcinoma remains largely unexplored. This article offers an overview of the current landscape of antibody-based immunotherapy, particularly CAR-T therapy and vaccines in the context of cholangiocarcinoma treatment. It outlines a framework for selecting CAR-T and vaccine targets and delves into the biology of promising targetable antigens, as well as potential future therapeutic targets.

Diagnostic value of glypican-1; a new marker differentiating pulmonary squamous cell carcinoma from adenocarcinoma: immunohistochemical study on Egyptian series

Lung cancer is one of the major causes of cancer morbidity and mortality. Subtyping of non-small cell lung cancer is necessary owing to different treatment options. This study is to evaluate the value of immunohistochemical expression of glypican-1 in the diagnosis of lung squamous cell carcinoma (SCC). This retrospective study included a total of 68 cases, of which 36 were diagnosed as SCC and 32 as adenocarcinoma (ADC). Furthermore, glypican-1 expression was compared with the expressions of p63, thyroid transcription factor-1 (TTF-1), and napsin A. All cases of SCC except one showed positive immunostaining to glypican-1; 35/36 (97.2%) cases, and predominantly scored 3 + . While only 5 cases of ADC showed positive immunostaining to glypican-1, having a score of 1 + or 2 + . The difference between glypican-1 expression of the two tumor types was highly significant (p value < 0.001). The sensitivity, specificity, and overall accuracy of glypican-1 expression for differentiating lung SCC from ADC were 97.2%, 84.4%, and 91.2%, respectively. The sensitivity of glypican-1 is more than p63 in the diagnosis of lung SCC. Glypican-1 can be added as a new diagnostic marker to help in the accurate discrimination between poorly differentiated lung SCC and solid predominant adenocarcinoma cases.

Evaluation of antitumor potential of an anti-glypican-1 monoclonal antibody in preclinical lung cancer models reveals a distinct mechanism of action

Aim

The main objective of this study was to investigate the antitumor effect of a mouse anti-human glypican-1 (GPC1) monoclonal antibody (mAb) on non-small cell lung carcinoma (NSCLC) and associated molecular mechanisms.

Methods

The anti-proliferative and anti-migratory activities of anti-GPC1 mAb were examined in A549 and H460 NSCLC cells and LL97A lung fibroblasts. The inhibitory effect of anti-GPC1 mAb on tumor growth was evaluated in an orthotopic lung tumor model.

Results

The in vitro study showed that anti-GPC1 mAb profoundly inhibited the anchorage-independent growth of A549 and H460 NSCLC cells and exhibited relatively high cytotoxic activities towards LL97A lung fibroblasts, A549/LL97A and H460/LL97A coculture spheroids. Moreover, anti-GPC1 mAb significantly decreased the expression of phospho-Src (p-Src; Tyr416), p-Akt (Ser473) and β-catenin in the co-cultured LL97A lung fibroblasts, and the expression of phospho-mitogen-activated protein kinase kinase (p-MEK; Ser217/221) and phospho-90 kDa ribosomal s6 kinase (p-p90RSK; Ser380) in co-cultured A549 cells. When anti-GPC1 mAb was administered to tumor-bearing mice, the inhibitory effect of anti-GPC1 mAb on the orthotopic lung tumor growth was not statistically significant. Nonetheless, results of Western blot analysis showed significant decrease in the phosphorylation of fibroblast growth factor receptor 1 (FGFR1) at Tyr766, Src at Tyr416, extracellular signal-regulated kinase (ERK) at Thr202/Tyr204, 90 kDa ribosomal S6 kinase (RSK) at Ser380, glycogen synthase kinases 3α (GSK3α) at Ser21 and GSK3β at Ser9 in tumor tissues. These data implicate that anti-GPC1 mAb treatment impairs the interaction between tumor cells and tumor associated fibroblasts by attenuating the paracrine FGFR signal transduction.

Conclusions

The relatively potent cytotoxicity of anti-GPC1 mAb in lung fibroblasts and its potential inhibitory effect on the paracrine FGFR signal transduction warrant further studies on the combined use of this mAb with targeted therapeutics to improve therapeutic outcomes in lung cancer.

Diagnostic performance of immunohistochemistry markers for malignant pleural mesothelioma diagnosis and subtypes. A systematic review and meta-analysis

BACKGROUND

Malignant pleural mesothelioma (MPM) poses diagnostic challenges due to its resemblance to benign pleural pathologies and different histological subtypes. Several immunohistochemistry markers have been employed to aid in accurate diagnosis.

METHODS

The present systematic review and meta-analysis aimed to assess the diagnostic performance of various immunohistochemistry markers in malignant pleural mesothelioma diagnosis and its histological subtypes. Following the PRISMA guidelines, we systematically searched the literature for articles on using different immunohistochemical markers in MPM and its histological subtypes. EMBASE, LILACS, MEDLINE, and Virtual Health Library were searched for studies published up to August 2023. We used the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies) criteria to assess the quality of the included articles. Meta-analyses were performed to determine prevalence using a random-effects model.

RESULTS

103 studies met the inclusion criteria, comprising a diverse range of immunohistochemistry markers. EMA and desmin-loss exhibited high sensitivity (96% and 92%, respectively) in distinguishing malignant pleural mesothelioma from benign pleural pathologies. Specificity was notably high for both BAP1-loss and survivin expression at 100%. Subtype-specific analyses demonstrated that EMA and HEG1 were sensitive markers for epithelioid mesothelioma, while GLUT1 showed high sensitivity for sarcomatoid mesothelioma. In cases comparing epithelioid mesothelioma and lung adenocarcinoma, CAM5.2 and calretinin displayed high sensitivity, while WT1 and BAP1-loss demonstrated exceptional specificity for malignant epithelioid mesothelioma. In the case of sarcomatoid mesothelioma and sarcomatoid lung carcinoma, GATA3 exhibited the most heightened sensitivity, while GATA3 and D2-40 displayed the best specificity for sarcomatoid malignant mesothelioma diagnosis.

CONCLUSION

Immunohistochemistry markers are essential in accurately diagnosing malignant pleural mesothelioma and its histological subtypes. This systematic review and meta-analysis provide a comprehensive insight into the diagnostic performance of these markers, facilitating their potential clinical utility in the discrimination of malignant pleural mesothelioma from other pleural pathologies and the differentiation of malignant pleural mesothelioma subtypes.

SPARC Is a Novel Positive Immunohistochemical Marker of Epithelioid Mesothelioma to Differentiate It From Lung Adenocarcinoma and/or Squamous Cell Carcinoma

Epithelioid mesothelioma with a solid histologic pattern (solid epithelioid mesothelioma) is difficult to distinguish from a poorly differentiated squamous cell lung carcinoma and/or solid lung adenocarcinoma. Thus, immunohistochemical markers are essential for diagnosis; however, the sensitivity and specificity of pre-existing mesothelial markers are suboptimal, particularly for differentiation from squamous cell carcinoma. Using a cancer-dependency map, we analyzed gene expression data of pleural mesothelioma and non-small cell lung cancer cell lines (squamous cell carcinoma and adenocarcinoma) and identified secreted protein acidic and cysteine-rich (SPARC) as a promising candidate for the differential diagnosis of epithelioid mesothelioma from lung squamous cell carcinoma and/or lung adenocarcinoma. SPARC expression in mesothelioma and lung cancer cell lines was validated using reverse-transcription polymerase chain reaction, western blotting, and immunohistochemistry. Immunohistochemical staining was performed using anti-SPARC antibodies against solid epithelioid mesothelioma, solid lung adenocarcinoma, and poorly differentiated lung squamous cell carcinoma. SPARC positivity was seen in 42/45 (93.3%) of solid epithelioid mesothelioma, 2/40 (5%) solid lung adenocarcinoma, and 2/45 (4.5%) of lung squamous cell carcinomas. The sensitivity, specificity, and diagnostic accuracy for differentiating solid epithelioid mesothelioma from lung cancer (solid lung adenocarcinoma and poorly differentiated lung squamous cell carcinoma) were 93.3, 95.2, and 94.6%, respectively. In conclusion, SPARC is a novel mesothelial marker that can be used to differentiate epithelioid mesothelioma from squamous cell carcinoma and lung adenocarcinoma.

Attenuation of cancer proliferation by suppression of glypican-1 and its pleiotropic effects in neoplastic behavior

Glypicans (GPC1-6) are associated with tumorigenic processes and their involvement in neoplastic behavior has been discussed in different cancer types. Here, a cancer-wide GPC expression study, using clinical cancer patient data in The Cancer Genome Atlas, reveals net upregulation of GPC1 and GPC2 in primary solid tumors, whereas GPC3, GPC5 and GPC6 display lowered expression pattern compared to normal tissues. Focusing on GPC1, survival analyses of the clinical cancer patient data reveal statistically significant correlation between high expression of GPC1 and poor prognosis in 10 particular cancer types i.e., bladder urothelial carcinoma, brain lower grade glioma, liver hepatocellular carcinoma, colon adenocarcinoma, kidney renal clear cell carcinoma, lung adenocarcinoma, mesothelioma, ovarian serous cystadenocarcinoma, uterine corpus endometrial carcinoma and uveal melanoma. In vitro studies targeting GPC1 expression by CRISPR/Cas9 or siRNA or treatment with an anti-GPC1 antibody resulted in attenuation of proliferation of cancer cells from bladder carcinoma, glioma and hepatocellular carcinoma patients (T24, U87 and HepG2 cells). Further, overexpression of GPC1 exhibited a significant and negative correlation between GPC1 expression and proliferation of T24 cells. Attempt to reveal the mechanism through which downregulation of GPC1 leads to attenuation of tumor growth using systematic Ingenuity Pathway Analysis indicate that suppression of GPC1 results in ECM-mediated inhibition of specific pro-cancer signaling pathways involving TGF-β and p38 MAPK. Identified differential expression and pleiotropic effects of GPCs in specific cancer types emphasize their potential of as novel diagnostic tools and prognostic factors and open doors for future GPC targeted therapy.

Integrated N-glycoproteomics Analysis of Human Saliva for Lung Cancer

Aberrant protein N-glycosylation is a cancer hallmark, which has great potential for cancer detection. However, large-scale and in-depth analysis of N-glycosylation remains challenging because of its high heterogeneity, complexity, and low abundance. Human saliva is an attractive diagnostic body fluid, while few efforts explored its N-glycoproteome for lung cancer. Here, we utilized a zwitterionic-hydrophilic interaction chromatography-based strategy to specifically enrich salivary glycopeptides. Through quantitative proteomics analysis, 1492 and 1234 intact N-glycopeptides were confidently identified from pooled saliva samples of 10 subjects in the nonsmall-cell lung cancer group and 10 subjects in the normal control group. Accordingly, 575 and 404 N-glycosites were revealed for the lung cancer group and normal control group. In particular, 154 N-glycosites and 259 site-specific glycoforms were significantly dysregulated in the lung cancer group. Several N-glycosites located at the same glycoprotein and glycans attached to the same N-glycosites were observed with differential expressions, including haptoglobin, Mucin-5B, lactotransferrin, and α-1-acid glycoprotein 1. These N-glycoproteins were mainly related to inflammatory responses, infectious diseases, and cancers. Our study achieved comprehensive characterization of salivary N-glycoproteome, and dysregulated site-specific glycoforms hold promise for noninvasive detection of lung cancer.

Radioimmunotherapy for solid tumors: spotlight on Glypican-1 as a radioimmunotherapy target

Radioimmunotherapy (i.e., the use of radiolabeled tumor targeting antibodies) is an emerging approach for the diagnosis, therapy, and monitoring of solid tumors. Often using paired agents, each targeting the same tumor molecule, but labelled with an imaging or therapeutic isotope, radioimmunotherapy has achieved promising clinical results in relatively radio-resistant solid tumors such as prostate. Several approaches to optimize therapeutic efficacy, such as dose fractionation and personalized dosimetry, have seen clinical success. The clinical use and optimization of a radioimmunotherapy approach is, in part, influenced by the targeted tumor antigen, several of which have been proposed for different solid tumors. Glypican-1 (GPC-1) is a heparan sulfate proteoglycan that is expressed in a variety of solid tumors, but whose expression is restricted in normal adult tissue. Here, we discuss the preclinical and clinical evidence for the potential of GPC-1 as a radioimmunotherapy target. We describe the current treatment paradigm for several solid tumors expressing GPC-1 and suggest the potential clinical utility of a GPC-1 directed radioimmunotherapy for these tumors.

Pathology of Malignant Pleural Mesothelioma

Despite multiple diagnostic toolkits, the diagnosis of diffuse malignant pleural mesothelioma relies primarily on proper histologic assessment. The definitive diagnosis of diffuse malignant pleural mesothelioma is based on the pathologic assessment of tumor tissue, which can be obtained from core biopsy sampling, pleurectomy, or other more extensive resections, such as extrapleural pneumonectomy. Given its rarity and overlapping microscopic features with other conditions, the histologic diagnosis of diffuse malignant pleural mesothelioma is challenging. This review discusses the pathologic features and the differential diagnosis of diffuse malignant pleural mesothelioma, including select diagnostic pitfalls.

Glypican-1 is a novel immunohistochemical marker to differentiate poorly differentiated squamous cell carcinoma from solid predominant adenocarcinoma of the lung

Background

The histological classification of non-small cell lung cancer (NSCLC) is essential in determining new cancer-specific targeted therapies. However, the accurate typing of poorly differentiated is difficult, particularly for poorly differentiated squamous cell carcinoma and adenocarcinoma of the lung with limited immunohistochemical markers. Thus, novel immunohistochemical markers are required. We assumed the possibility of the immunohistochemical expression of glypican-1 in lung squamous cell carcinoma.

Methods

The microarray dataset GSE43580 from Gene Expression Omnibus database were analyzed for confirming the gene expression of glypican-1 in lung squamous cell carcinoma. We immunohistochemically investigated the use of glypican-1 as a novel positive diagnostic marker for lung squamous cell carcinoma. Glypican-1 expression in 63 cases of poorly differentiated lung squamous cell carcinoma and 60 cases of solid predominant lung adenocarcinoma was investigated by immunohistochemistry. Additionally, we compared glypican-1 expression with the expressions of p40, cytokeratin 5/6, thyroid transcription factor-1 (TTF-1), and napsin A.

Results

All 63 cases of lung squamous cell carcinoma showed glypican-1 expression. In contrast, only 2 cases of lung adenocarcinoma showed glypican-1 expression. The sensitivity, specificity, and diagnostic accuracy of glypican-1 expression for differentiating lung squamous cell carcinoma from lung adenocarcinoma were 100%, 96.7%, and 98.4%, respectively. These were similar to those of p40 and significantly better than those of CK 5/6.

Conclusions

We recommend the use of glypican-1 as an additional positive marker of lung squamous cell carcinoma.

The feasibility of Miltuximab®-IRDye700DX-mediated photoimmunotherapy of solid tumors

BACKGROUND

Photoimmunotherapy (PIT) is an emerging method of cancer treatment based on the use of a photosensitizer near-infrared dye IRDye700DX (IR700) conjugated to a monoclonal antibody. The antibody selectively delivers IR700 to cancer cells, which can then be killed after photoexcitation. Glypican-1 (GPC-1) is a novel target expressed specifically in malignant tumors. We aimed to investigate whether anti-GPC-1 antibody Miltuximab® (Glytherix Ltd., Sydney, Australia) can be conjugated with IR700 for PIT of solid tumors.

METHODS

The dye IR700 was conjugated with Miltuximab® and characterized by spectrophotometry and flow cytometry. Miltuximab®-IR700-mediated PIT was tested in prostate (DU-145), bladder (C3 and T-24), brain (U-87 and U-251) and ovarian (SKOV-3) cancer cell lines. After 1 h incubation with Miltuximab®-IR700, the cells were washed by PBS and illuminated using a 690-nm light-emitting diode. The viability of the cells was assessed by a CCK-8 viability kit 24 h later.

RESULTS

Miltuximab®-IR700-mediated PIT caused 67.3-92.3% reduction in viability of cells with medium-high GPC-1 expression and did not affect the viability of GPC-1-low cells. Cytotoxicity was attributed to the targeted binding of the conjugate with subsequent photoactivation, as the conjugate or light exposure alone had no effect on the cell viability. Miltuximab®-IR700 did not induce cytotoxicity in cells blocked by unconjugated Miltuximab®.

CONCLUSIONS

PIT with Miltuximab®-IR700 appears to be highly specific and effective against GPC-1-expressing cancer cells, indicating that it holds promise for an effective and safe treatment of early stage solid tumors or as adjuvant therapy following surgical resection. These findings necessitate further investigation of PIT with Miltuximab®-IR700 in other GPC-1-expressing cancer cell lines in vitro and in vivo in xenograft tumor models.

SOX6 is a Novel Immunohistochemical Marker for Differential Diagnosis of Epithelioid Mesothelioma From Lung Adenocarcinoma

The differential diagnosis of epithelioid mesothelioma from lung adenocarcinoma using immunohistochemistry is improving. However, immunohistochemical markers with high sensitivity and specificity have yet to be identified. In this study, we investigated the utility of sex-determining region Y box 6 (SOX6) as a novel immunohistochemical marker, identified by analyzing previous gene expression data. Immunohistochemically, SOX6 expression was present in 53 of 54 (98%) cases of epithelioid mesothelioma, compared with its expression in only 5 of 69 (7%) cases of lung adenocarcinoma. The sensitivity and specificity of SOX6 expression for differentiating epithelioid mesothelioma and lung adenocarcinoma were 98% and 93%, respectively. SOX6 expression showed similar sensitivity and far better specificity than those of calretinin or podoplanin (D2-40). In addition, SOX6 expression was more sensitive than Wilms' tumor 1 expression. The combination of SOX6 with other markers showed comparable or better sensitivity and specificity relative to other combinations. In particular, the sensitivity of positivity for both SOX6 and calretinin (96%) and the specificity of positivity for both SOX6 and Wilms' tumor 1 (93%) were higher than those of the other combinations. In conclusion, SOX6 is a novel candidate immunohistochemical marker for differentiating epithelioid mesothelioma from lung adenocarcinoma.

Targeted beta therapy of prostate cancer with 177Lu-labelled Miltuximab® antibody against glypican-1 (GPC-1)

PURPOSE

Chimeric antibody Miltuximab®, a human IgG1 engineered from the parent antibody MIL-38, is in clinical development for solid tumour therapy. Miltuximab® targets glypican-1 (GPC-1), a cell surface protein involved in tumour growth, which is overexpressed in solid tumours, including prostate cancer (PCa). This study investigated the potential of ⁸⁹Zr-labelled Miltuximab® as an imaging agent, and ¹⁷⁷Lu-labelled Miltuximab® as a targeted beta therapy, in a mouse xenograft model of human prostate cancer.

METHODS

Male BALB/c nude mice were inoculated subcutaneously with GPC-1-positive DU-145 PCa cells. In imaging and biodistribution studies, mice bearing palpable tumours received (a) 2.62 MBq [⁸⁹Zr]Zr-DFO-Miltuximab® followed by PET-CT imaging, or (b) 6 MBq [¹⁷⁷Lu]Lu-DOTA-Miltuximab® by Cerenkov imaging, and ex vivo assessment of biodistribution. In an initial tumour efficacy study, mice bearing DU-145 tumours were administered intravenously with 6 MBq [¹⁷⁷Lu]Lu-DOTA-Miltuximab® or control DOTA-Miltuximab® then euthanised after 27 days. In a subsequent survival efficacy study, tumour-bearing mice were given 3 or 10 MBq of [¹⁷⁷Lu]Lu-DOTA-Miltuximab®, or control, and followed up to 120 days.

RESULTS

Antibody accumulation in DU-145 xenografts was detected by PET-CT imaging using [⁸⁹Zr]Zr-DFO-Miltuximab® and confirmed by Cerenkov luminescence imaging post injection of [¹⁷⁷Lu]Lu-DOTA-Miltuximab®. Antibody accumulation was higher (% IA/g) in tumours than other organs across multiple time points. A single injection with 6 MBq of [¹⁷⁷Lu]Lu-DOTA-Miltuximab® significantly inhibited tumour growth as compared with DOTA-Miltuximab® (control). In the survival study, mice treated with 10 MBq [¹⁷⁷Lu]Lu-DOTA-Miltuximab® had significantly prolonged survival (mean 85 days) versus control (45 days), an effect associated with increased cancer cell apoptosis. Tissue histopathology assessment showed no abnormalities associated with [¹⁷⁷Lu]Lu-DOTA-Miltuximab®, in line with other observations of tolerability, including body weight stability.

CONCLUSION

These findings demonstrate the potential utility of Miltuximab® as a PET imaging agent ([⁸⁹Zr]Zr-DFO-Miltuximab®) and a beta therapy ([¹⁷⁷Lu]Lu-DOTA-Miltuximab®) in patients with PCa or other GPC-1 expressing tumours.

The Role of Glypican-1 in the Tumour Microenvironment

Glypican-1 (GPC-1) is a cell surface heparan sulphate proteoglycan that is critical during normal development, but which is not required for normal homoeostasis in the adult. It is, however, overexpressed in a variety of solid tumours and is known to regulate tumour growth, invasion, metastasis and progression, through modulation of tumour cell biology as well as influence on the tumour microenvironment (TME). The role of GPC-1 in the TME and on the tumour cell is broad, as GPC-1 regulates signalling by several growth factors, including FGF, HGF, TGF-β, Wnt and Hedgehog (Hh). Signalling via these pathways promotes tumour growth and invasive and metastatic ability (drives epithelial-to-mesenchymal transition (EMT)) and influences angiogenesis, affecting both tumour and stromal cells. Broad modulation of the TME via inhibition of GPC-1 may represent a novel therapeutic strategy for inhibition of tumour progression. Here, we discuss the complex role of GPC-1 in tumour cells and the TME, with discussion of potential therapeutic targeting strategies.

GPC1 specific CAR-T cells eradicate established solid tumor without adverse effects and synergize with anti-PD-1 Ab

Current xenogeneic mouse models cannot evaluate on-target off-tumor adverse effect, hindering the development of chimeric antigen receptor (CAR) T cell therapies for solid tumors, due to limited human/mouse cross-reactivity of antibodies used in CAR and sever graft-versus-host disease induced by administered human T cells. We have evaluated safety and antitumor efficacy of CAR-T cells targeting glypican-1 (GPC1) overexpressed in various solid tumors. GPC1-specific human and murine CAR-T cells generated from our original anti-human/mouse GPC1 antibody showed strong antitumor effects in xenogeneic and syngeneic mouse models, respectively. Importantly, the murine CAR-T cells enhanced endogenous T cell responses against a non-GPC1 tumor antigen through the mechanism of antigen-spreading and showed synergistic antitumor effects with anti-PD-1 antibody without any adverse effects in syngeneic models. Our study shows the potential of GPC1 as a CAR-T cell target for solid tumors and the importance of syngeneic and xenogeneic models for evaluating their safety and efficacy.

Calretinin-expressing lung adenocarcinoma: Distinct characteristics of advanced stages, smoker-type features, and rare expression of other mesothelial markers are useful to differentiate epithelioid mesothelioma

Calretinin, a mesothelioma marker, is sometimes expressed in lung cancer, which may complicate the differential diagnosis of mesothelioma. Here, the clinicopathological and immunohistochemical characteristics of calretinin-positive lung cancer were examined to reduce confusion with malignant mesothelioma. Calretinin expression in 307 consecutive cases of lung cancer was evaluated immunohistochemically. Survival was analyzed using the Kaplan-Meier method and log-rank test. Calretinin expression was identified in 67 (22%) tumors, including those with partial and weak expression [15% (37/250) of adenocarcinomas, 54% (25/46) of squamous cell carcinomas, 75% (3/4) of adenosquamous carcinomas, and 29% (2/7) of sarcomatoid carcinomas]. In calretinin-positive adenocarcinoma (n = 37), expression percentages of Wilms tumor-1, podoplanin, thyroid transcription factor-1, and claudin-4 were 6, 3, 52, 82%, respectively, whereas in calretinin-positive squamous cell carcinoma (n = 25) the percentages were 8, 12, 12, 68%, respectively, indicating that other mesothelial markers were only rarely expressed and that claudin-4 expression was common. Although not an independent marker, calretinin expression was associated with a poor prognosis for stage I tumors of adenocarcinoma (p < 0.001) and of all histological subtypes (p < 0.001). In conclusion, calretinin-positive lung tumors share characteristics with those of smokers and advanced stages and can be differentiated from mesothelioma with the use of other mesothelial and epithelial markers.

Role of glypicans in regulation of the tumor microenvironment and cancer progression

Glypicans are evolutionary conserved, cell surface heparan sulfate (HS) proteoglycans that are attached to the cell membrane via a glycosylphosphatidylinositol (GPI) anchor. Glypicans interact with a broad class of soluble and insoluble ligands, such as morphogens, growth factors, chemokines, receptors and components of the extracellular matrix (ECM). Such versatility comes from their ability to interact through both their HS chains and core protein. Glypicans are involved in cellular and tissue development, morphogenesis and cell motility. They exhibit differential expression in several cancers, acting as both tumor promoters and inhibitors in a cancer type-specific manner. They also influence tumor stroma by facilitating angiogenesis, ECM remodeling and alteration of immune cell functions. Glypicans have emerged as a new therapeutic moiety, whose functions can be exploited in the field of targeted therapies and precision medicine in cancer. This is demonstrated by the emergence of several anti-glypican antibody-based immunologics that have been recently developed and are being evaluated in clinical trials. This review will focus on glypican structure and function with an emphasis on their expression in various cancers. Discussion will also center on the potential of glypicans to be therapeutic targets for inhibition of cancer cell growth.

Glypican-1 immunohistochemistry does not separate mesothelioma from pulmonary adenocarcinoma

Immunohistochemistry (IHC) is used to help differentiate pleural mesothelioma from pulmonary adenocarcinoma in pleural biopsies and cytology specimens of pleural effusions due to overlapping morphologic features between these two malignancies. The aim of this study is to evaluate IHC glypican-1, a recently proposed marker for epithelioid mesothelioma, in our cohort of mesotheliomas and pulmonary adenocarcinoma. Tissue microarrays with duplicate cores from 33 cases of mesotheliomas (28 epithelioid type and five sarcomatoid type) and 21 cases of pulmonary adenocarcinoma were stained with glypican-1 antibody. The proportion of cases by tumor type showing staining with glypican-1 and the H-score for each tumor type were evaluated. All 33 cases of mesothelioma and all 20 cases of pulmonary adenocarcinoma with interpretable cores showed positive cytoplasmic staining. All but one case of mesothelioma and all pulmonary adenocarcinomas showed staining in at least 80% of the tumor cells. The mean H-score for glypican-1 of mesothelioma (134 ± 59, mean ± SD) was not significantly different from that for pulmonary adenocarcinoma (156 ± 60; P = 0.21). Neither epithelioid type (mean H-score 135 ± 57) nor sarcomatoid type (mean H-score 130 ± 78) of mesothelioma showed different H-scores when compared to pulmonary adenocarcinoma (P = 0.23 and 0.42, respectively). In conclusion, glypican-1 IHC does not differentiate mesothelioma from pulmonary adenocarcinoma.

Malignant Pleural Mesothelioma, Biphasic Type: An Unusual and Insidious Case of Rapidly Progressive Small Blue Cell Tumor

Malignant pleural mesothelioma (MPM) is a rare neoplasm. It predominantly affects elderly individuals aged over 70 years presenting with a unilateral pleural tumor usually associated with previous asbestos exposure. The respiratory symptoms are associated with ipsilateral pleural involvement with concomitant pleural effusions. The diagnosis of MPM is established by the morphologic and immunohistochemical features of a cytologic specimen. MPM can present as three histologic subtypes: epithelioid, sarcomatoid, or biphasic. We present a case of an 85-year-old Caucasian female with a history of occupational asbestos exposure. She complained of 1-week history of progressive sharp right flank and scapular pain with mild shortness of breath, dry cough and pleuritic chest pain. CT of the chest showed a large loculated right pleural effusion with adjacent pleural thickening. CT abdomen and pelvis was negative for other neoplastic findings. CT-guided core biopsy of the right pleural-based mass was positive for a spindle to plasmacytoid small blue cell tumor. An extensive immunohistochemical panel was non-specific. A focal OSCAR keratin and WT-1 expression in the absence of carcinoma markers, a malignant mesothelioma, biphasic type was diagnosed. Further workup with PET-CT and cytotoxic chemotherapy combined with immunotherapy or tyrosine kinase inhibitors was recommended by oncology. The patient refused further imaging and treatment, and palliative care was consulted.