Increased expression of CCN2, epithelial membrane antigen, and fibroblast activation protein in hepatocellular carcinoma with fibrous stroma showing aggressive behavior. PLoS One. 2014;9:e105094. [PMID: 25126747 PMCID: PMC4134271 DOI: 10.1371/journal.pone.0105094]

Diagnostic Performances of PET/CT Using Fibroblast Activation Protein Inhibitors in Patients with Primary and Metastatic Liver Tumors: A Comprehensive Literature Review

PET/CT using radiolabeled fibroblast activation protein inhibitors (FAPIs) is a promising diagnostic tool in oncology, especially when non-increased and/or physiologically high [18F]FDG uptake (as in liver parenchyma) is observed. We aimed to review the role of PET/CT using radiolabeled FAPIs in primary and/or metastatic liver lesions, and to compare their performances with more "conventional" radiopharmaceuticals. A search algorithm based on the terms "FAPI" AND ("hepatic" OR "liver") was applied, with the last update on 1st January 2024. Out of 177 articles retrieved, 76 studies reporting on the diagnostic application of radiolabeled FAPI PET/CT in at least one patient harboring primary or metastatic liver lesion(s) were fully analyzed. Although there was some heterogeneity in clinical conditions and/or study methodology, PET/CT with radiolabeled FAPIs showed an excellent performance in common primary liver malignancies (hepatocarcinoma, intrahepatic cholangiocarcinoma) and liver metastases (mostly from the gastrointestinal tract and lungs). A higher tumor-to-background ratio for FAPIs than for [18F]FDG was found in primary and metastatic liver lesions, due to lower background activity. Despite limited clinical evidence, radiolabeled FAPIs may be used to assess the suitability and effectiveness of FAPI-derived therapeutic agents such as [177Lu]Lu-FAPI. However, future prospective research on a wider population is needed to confirm the excellent performance.

Havoc in harmony: Unravelling the intricacies of angiogenesis orchestrated by the tumor microenvironment

Cancer cells merely exist in isolation; rather, they exist in an intricate microenvironment composed of blood vessels, signalling molecules, immune cells, stroma, fibroblasts, and the ECM. The TME provides a setting that is favourable for the successful growth and survivance of tumors. Angiogenesis is a multifaceted process that is essential for the growth, invasion, and metastasis of tumors. TME can be visualized as a "concert hall," where various cellular and non-cellular factors perform in a "symphony" to orchestrate tumor angiogenesis and create "Havoc" instead of "Harmony". In this review, we comprehensively summarized the involvement of TME in regulating tumor angiogenesis. Especially, we have focused on immune cells and their secreted factors, inflammatory cytokines and chemokines, and their role in altering the TME. We have also deciphered the crosstalk among various cell types that further aids the process of tumor angiogenesis. Additionally, we have highlighted the limitations of existing anti-angiogenic therapy and discussed various potential strategies that could be used to overcome these challenges and improve the efficacy of anti-angiogenic therapy.

Interleukin-17A educated hepatic stellate cells promote hepatocellular carcinoma occurrence through fibroblast activation protein expression

BACKGROUND

Liver cancer is typified by a complex inflammatory tumor microenvironment, where an array of cytokines and stromal cells orchestrate a milieu that significantly influences tumorigenesis. Interleukin-17A (IL-17A), a pivotal pro-inflammatory cytokine predominantly secreted by Th17 cells, is known to play a substantial role in the etiology and progression of liver cancer. However, the precise mechanism by which IL-17A engages with hepatic stellate cells (HSCs) to facilitate the development of hepatocellular carcinoma (HCC) remains to be fully elucidated. This investigation seeks to unravel the interplay between IL-17A and HSCs in the context of HCC.

METHODS

An HCC model was established in male Sprague-Dawley rats using diethylnitrosamine to explore the roles of IL-17A and HSCs in HCC pathogenesis. In vivo overexpression of Il17a was achieved using adeno-associated virus. A suite of molecular techniques, including RT-qPCR, enzyme-linked immunosorbent assays, Western blotting, cell counting kit-8 assays and colony formation assays, was employed for in vitro analyses.

RESULTS

The study findings indicate that IL-17A is a key mediator in HCC promotion, primarily through the activation of hepatic progenitor cells (HPCs). This pro-tumorigenic influence appears to be mediated by HSCs, rather than through a direct effect on HPCs. Notably, IL-17A-induced expression of fibroblast activation protein (FAP) in HSCs emerged as a critical factor in HCC progression. Silencing Fap in IL-17A-stimulated HSCs was observed to reverse the HCC-promoting effects of HSCs.

CONCLUSIONS

The collective evidence from this study implicates the IL-17A/FAP signaling axis within HSCs as a contributor to HCC development by enhancing HPC activation. These findings bolster the potential of IL-17A as a diagnostic and preventative target for HCC, offering new avenues for therapeutic intervention.

Association of future cancer metastases with fibroblast activation protein-α: a systematic review and meta-analysis

Introduction

Fibroblast activation protein-α (FAP-α) is a vital surface marker of cancer-associated fibroblasts, and its high expression is associated with a higher tumor grade and metastasis. A systematic review and a meta-analysis were performed to associate future metastasis with FAP-α expression in cancer.

Methods

In our meta-analysis, relevant studies published before 20 February 2024 were systematically searched through online databases that included PubMed, Scopus, and Web of Science. The association between FAP-α expression and metastasis, including distant metastasis, lymph node metastasis, blood vessel invasion, vascular invasion, and neural invasion, was evaluated. A pooled odds ratio (OR) with 95% confidence intervals (CI) was reported as the measure of association.

Results

A total of 28meta-analysis. The random-effects model for five parameters showed that a high FAP-α expression was associated with blood vessel invasion (OR: 3.04, 95% CI: 1.54-5.99, I 2 = 63%, P = 0.001), lymphovascular invasion (OR: 3.56, 95% CI: 2.14-5.93, I 2 = 0.00%, P < 0.001), lymph node metastasis (OR: 2.73, 95% CI: 1.96-3.81, I 2 = 65%, P < 0.001), and distant metastasis (OR: 2.59; 95% CI: 1.16-5.79, I 2 = 81%, P < 0.001). However, our analysis showed no statistically significant association between high FAP-α expression and neural invasion (OR: 1.57, 95% CI: 0.84-2.93, I 2 = 38%, P = 0.161).

Conclusions

This meta-analysis indicated that cancer cells with a high FAP-α expression have a higher risk of metastasis than those with a low FAP-α expression. These findings support the potential importance of FAP-α as a biomarker for cancer metastasis prediction.

From basic research to clinical application: targeting fibroblast activation protein for cancer diagnosis and treatment

PURPOSE

This study aims to review the multifaceted roles of a membrane protein named Fibroblast Activation Protein (FAP) expressed in tumor tissue, including its molecular functionalities, regulatory mechanisms governing its expression, prognostic significance, and its crucial role in cancer diagnosis and treatment.

METHODS

Articles that have uncovered the regulatory role of FAP in tumor, as well as its potential utility within clinical realms, spanning diagnosis to therapeutic intervention has been screened for a comprehensive review.

RESULTS

Our review reveals that FAP plays a pivotal role in solid tumor progression by undertaking a multitude of enzymatic and nonenzymatic roles within the tumor stroma. The exclusive presence of FAP within tumor tissues highlights its potential as a diagnostic marker and therapeutic target. The review also emphasizes the prognostic significance of FAP in predicting tumor progression and patient outcomes. Furthermore, the emerging strategies involving FAPI inhibitor (FAPI) in cancer research and clinical trials for PET/CT diagnosis are discussed. And targeted therapy utilizing FAP including FAPI, chimeric antigen receptor (CAR) T cell therapy, tumor vaccine, antibody-drug conjugates, bispecific T-cell engagers, FAP cleavable prodrugs, and drug delivery system are also introduced.

CONCLUSION

FAP's intricate interactions with tumor cells and the tumor microenvironment make it a promising target for diagnosis and treatment. Promising strategies such as FAPI offer potential avenues for accurate tumor diagnosis, while multiple therapeutic strategies highlight the prospects of FAP targeting treatments which needs further clinical evaluation.

HCC-Check: A Novel Diagnostic Tool for Early Detection of Hepatocellular Carcinoma Based on Cytokeratin-1 and Epithelial Membrane Antigen: A Cross-Sectional Study

Background: Hepatocellular carcinoma is frequently diagnosed in advanced stages, leading to a poorer prognosis. Therefore, early diagnosis and identification of biomarkers may significantly improve outcomes. Methods: This cross-sectional study enrolled 486 participants distributed among 3 groups: F1 to F3 = 184, F4 = 183, and hepatocellular carcinoma = 119. Liver fibrosis staging was performed using FibroScan, while imaging features were used for hepatocellular carcinoma detection. Epithelial membrane antigen and cytokeratin-1 levels in serum were quantified through Western blot and ELISA, respectively. Results: Patients diagnosed with hepatocellular carcinoma exhibited significantly elevated levels of epithelial membrane antigen and cytokeratin-1 compared to non-hepatocellular carcinoma patients, with a highly significant statistical difference (P < .0001). Epithelial membrane antigen demonstrated diagnostic performance with an area under the curve of 0.75, a sensitivity of 69.0%, and a specificity of 68.5%. Cytokeratin-1 for the identification of hepatocellular carcinoma showed a sensitivity of 79.0% and a specificity of 81.4%, resulting in an area under the curve of 0.87. The developed HCC-Check, which incorporates epithelial membrane antigen, cytokeratin-1, albumin, and alpha-fetoprotein, displayed a higher area under the curve of 0.95 to identify hepatocellular carcinoma, with a sensitivity of 89.8% and a specificity of 83.9%. Notably, HCC-Check values exceeding 2.57 substantially increased the likelihood of hepatocellular carcinoma, with an estimated odds ratio of 50.65, indicating a higher susceptibility to hepatocellular carcinoma development than those with lower values. The HCC-Check diagnostic test exhibited high precision in identifying patients with hepatocellular carcinoma, particularly those with small tumor sizes (<5 cm) and a single nodule, as reflected in area under the curve values of 0.92 and 0.85, respectively. HCC-Check was then applied to the validation study to test its accuracy and reproducibility, showing superior area under the curves for identifying different stages of hepatocellular carcinoma. These outcomes underscore the effectiveness of the test in the early detection of hepatocellular carcinoma. Conclusion: The HCC-Check test presents a highly accurate diagnostic method for detecting hepatocellular carcinoma in its early stages.

Advances in Histological and Molecular Classification of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a primary liver cancer characterized by hepatocellular differentiation. HCC is molecularly heterogeneous with a wide spectrum of histopathology. The prognosis of patients with HCC is generally poor, especially in those with advanced stages. HCC remains a diagnostic challenge for pathologists because of its morphological and phenotypic diversity. However, recent advances have enhanced our understanding of the molecular genetics and histological subtypes of HCC. Accurate diagnosis of HCC is important for patient management and prognosis. This review provides an update on HCC pathology, focusing on molecular genetics, histological subtypes, and diagnostic approaches.

Role of 68 Ga-FAPI PET/CT in Assessing Hepatobiliary Malignancies : A Prospective Pilot Study

INTRODUCTION AND AIM

Preliminary studies showed good expression of fibroblast activating protein inhibitor (FAPI) in hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC). Our aims were to study the diagnostic performance of 68 Ga-FAPI PET/CT in diagnosing the primary hepatobiliary malignancies and to compare its performance with 18 F-FDG PET/CT.

PATIENTS AND METHODS

Patients suspected to have HCC and CC were recruited prospectively. FDG and FAPI PET/CT studies were completed within 1 week. Final diagnosis of malignancy was achieved by tissue diagnosis (either histopathological examination or fine-needle aspiration cytology) and radiological correlation from conventional modalities. Results were compared with final diagnosis and expressed as sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy.

RESULTS

Forty-one patients were included. Thirty-one were positive for malignancy and 10 were negative. Fifteen were metastatic. Of 31, 18 were CC and 6 were HCC. For overall diagnosis of the primary disease, FAPI PET/CT performed exceptionally compared with FDG PET/CT with sensitivity, specificity, and accuracy of 96.77%, 90%, and 95.12%, respectively, versus 51.61%, 100%, and 63.41% for FDG PET/CT. FAPI PET/CT clearly outperformed FDG PET/CT for the evaluation of CC with sensitivity, specificity, and accuracy of 94.4%, 100%, and 95.24%, respectively, whereas for FDG PET/CT sensitivity, specificity, and accuracy were 50%, 100%, and 57.14%, respectively. Diagnostic accuracy of FAPI PET/CT was 61.54% for metastatic HCC compared with 84.62% for FDG PET/CT.

CONCLUSIONS

Our study highlights the potential role of FAPI-PET/CT in evaluating CC. It also ascertains its usefulness in the cases of mucinous adenocarcinoma. Although it showed a higher lesion detection rate than FDG in primary HCC, its diagnostic performance in the metastatic setting is questionable.

Efficiency of Promoters of Human Genes FAP and CTGF at Organism Level in a Danio rerio Model

The identification of tissue-specific promoters for gene therapeutic constructs is one of the aims of complex tumor therapy. The genes encoding the fibroblast activation protein (FAP) and the connective tissue growth factor (CTGF) can function in tumor-associated stromal cells but are practically inactive in normal adult cells. Accordingly, the promoters of these genes can be used to develop vectors targeted to the tumor microenvironment. However, the efficiency of these promoters within genetic constructs remains underexplored, particularly, at the organism level. Here, we used the model of Danio rerio embryos to study the efficiency of transient expression of marker genes under the control of promoters of the FAP, CTGF, and immediate early genes of Human cytomegalovirus (CMV). Within 96 h after the injection of vectors, the CTGF and CMV promoters provided similar equal efficiency of reporter protein accumulation. In the case of the FAP promoter, a high level of reporter protein accumulation was observed only in certain zebrafish individuals that were considered developmentally abnormal. Disturbed embryogenesis was the factor of changes in the exogenous FAP promoter function. The data obtained make a significant contribution to understanding the function of the human CTGF and FAP promoters within vectors to assess their potential in gene therapy.

Ultrasensitive Fibroblast Activation Protein-α-Activated Fluorogenic Probe Enables Selective Imaging and Killing of Melanoma In Vivo

Melanoma is a malignant cancer with a high risk of metastasis and continued increase in death rates over the past decades, and its prognosis is highly related to the disease's stage, while early detection and treatment of melanoma are significant to the improvement of its therapy outcome. Different from the traditional methods for disease diagnosis, enzyme-activated fluorescent probes were developed rapidly due to their high sensitivity and temporal-spatial ratio and have been widely applied in tumor detection, surgical navigation, and cancer-related research. Fibroblast activation protein-α (FAPα), a serine-type cell surface protease that plays important roles in cell invasion and extracellular matrix degradation, is widely involved in tumor progression such as malignant melanoma, so developing a FAPα activity-based molecular tool would be of great potential for the early diagnosis and therapy of melanoma. However, few fluorescent probes targeting FAPα have been applied in melanoma-related studies, and thus, the construction of FAPα activity-based fluorescent probes for melanoma detection is in urgent need. By incorporating the selective recognition unit with a red-emission fluorophore, cresyl violet, we herein report an ultrasensitive (limit of detection = 5.3 ng/mL) fluorogenic probe for FAPα activity sensing, named CV-FAP; the acquired probe showed a significantly higher binding affinity (15.7-fold) and overall catalytic efficiency (2.6-fold) when compared with those of the best reported FAPα probes. The good performance of CV-FAP made it possible to discriminate malignant melanoma cells and tumor-bearing mice from normal cells and mice with high contrast. More importantly, CV-FAP showed significant antitumor activity toward melanoma in cultured cells and tumor-bearing nude mice (over 95% inhibited tumor growth) with good safety, which made it an ideal theranostic agent for melanoma.

The role of epithelial membrane antigen (EMA) overexpression in the prognosis of prostatic adenocarcinoma

Prostatic adenocarcinoma is the second-most common cancer in men and the fifth most common cause of cancer death. Its incidence increases with age; 75% of patients are 65 years and older. The aim of the study was to assess epithelial membrane antigen (EMA) expression in prostatic adenocarcinoma as a poor prognostic marker and its correlation to some pathological parameters. The formalin-fixed, paraffin-surrounded tissue blocks were retrospectively collected from 40 men diagnosed with prostate carcinoma. All cases were collected from Al Hilla Teaching Hospital and some private labs between October 2018 - November 2020, with ages ranging from 30-89 years. Statistical analysis was done using SPSS 22, frequency and percentage were used for categorical data, and Chi-square was used to evaluate connotation between variables. P-value ≤0.05 was significant. The blocks were sectioned for EMA immunohistochemical staining using monoclonal mouse anti-human EMA protein. EMA protein overexpression was detected in 75% (n=30/40) of prostatic adenocarcinoma cases. EMA expression showed no correlation with the patient's age (P=0.09) and a positive correlation with the cancer grade (P=0.003). In prostatic adenocarcinoma patients, EMA could be seen as a potential prognostic predictor for disease progression.

Prognostic value of the immunohistochemistry markers CD56, TTF-1, synaptophysin, CEA, EMA and NSE in surgically resected lung carcinoid tumors

Lung carcinoid tumor is a type of neuroendocrine tumor, which is subdivided into typical carcinoid (TC) and atypical carcinoid (AT), based on the rate of mitosis and the presence of necrosis. Several prognostic factors for lung carcinoids have been reported in the literature, including the type, Ki67 index, stage, chemotherapy and radiation therapy. In the present study, 108 cases with resected carcinoid lung tumors were enrolled and the expression of CD56, thyroid transcription factor 1, synaptophysin, carcinoembryonic antigen, epithelial membrane antigen and neuron-specific enolase (NSE) in the resected tissue specimens was immunohistochemically analyzed. Patients with positive staining for NSE had an unfavorable survival prognosis compared with patients with negative staining for NSE (137.2 vs. 150.0 months, P=0.044). According to univariate analysis, none of the above immunohistochemistry markers was associated with survival, and according to multivariate analysis, NSE was an independent influencing factor for survival inpatients with AT (P=0.046) and furthermore, the stage was an independent factor of survival in patients with TC (P=0.005).

Targeting Immune Cells in the Tumor Microenvironment of HCC: New Opportunities and Challenges

Immune associated cells in the microenvironment have a significant impact on the development and progression of hepatocellular carcinoma (HCC) and have received more and more attention. Different types of immune-associated cells play different roles, including promoting/inhibiting HCC and several different types that are controversial. It is well known that immune escape of HCC has become a difficult problem in tumor therapy. Therefore, in recent years, a large number of studies have focused on the immune microenvironment of HCC, explored many mechanisms worth identifying tumor immunosuppression, and developed a variety of immunotherapy methods as targets, laying the foundation for the final victory in the fight against HCC. This paper reviews recent studies on the immune microenvironment of HCC that are more reliable and important, and provides a more comprehensive view of the investigation of the immune microenvironment of HCC and the development of more immunotherapeutic approaches based on the relevant summaries of different immune cells.

The Role of Cancer-Associated Fibroblasts in Hepatocellular Carcinoma and the Value of Traditional Chinese Medicine Treatment

Invasion and metastasis are the main reasons for the high mortality of liver cancer, which involve the interaction of tumor stromal cells and malignant cells. Cancer-associated fibroblasts (CAFs) are one of the major constituents of tumor stromal cells affecting tumor growth, invasion, and metastasis. The heterogeneous properties and sources of CAFs make both tumor-supporting and tumor-suppression effects possible. The mechanisms for CAFs in supporting hepatocellular carcinoma (HCC) progression can be categorized into upregulated aggressiveness and stemness, transformed metabolism toward glycolysis and glutamine reductive carboxylation, polarized tumor immunity toward immune escape of HCC cells, and increased angiogenesis. The tumor-suppressive effect of fibroblasts highlights the functional heterogenicity of CAF populations and provides new insights into tumor–stromal interplay mechanisms. In this review, we introduced several key inflammatory signaling pathways in the transformation of CAFs from normal stromal cells and the heterogeneous biofunctions of activated CAFs. In view of the pleiotropic regulation properties of traditional Chinese medicine (TCM) and heterogeneous effects of CAFs, we also introduced the application and values of TCM in the treatment of HCC through targeting CAFs.

Intratumor Heterogeneity in Hepatocellular Carcinoma: Challenges and Opportunities

Hepatocellular carcinoma (HCC) represents a leading cause of cancer-related death, but it remains difficult to treat. Intratumor genetic and phenotypic heterogeneity are inherent properties of breast, skin, lung, prostate, and brain tumors, and intratumor heterogeneity (ITH) helps define prognosis and therapeutic response in these cancers. Several recent studies estimate that ITH is inherent to HCC and attribute the clinical intractability of HCC to this heterogeneity. In this review, we examine the evidence for genomic, phenotypic, and tumor microenvironment ITH in HCC, with a focus on two of the top molecular drivers of HCC: β-catenin (CTNNB1) and Telomerase reverse transcriptase (TERT). We discuss the influence of ITH on HCC diagnosis, prognosis, and therapy, while highlighting the gaps in knowledge and possible future directions.

Scirrhous Hepatocellular Carcinoma: Systematic Review and Pooled Data Analysis of Clinical, Radiological, and Histopathological Features

Background

Aberrant subtypes of hepatocellular carcinoma (HCC) account for 20–30% of all HCCs and habitually present a challenge in diagnosis and treatment. Scirrhous hepatocellular carcinoma (s-HCC) is often misdiagnosed as cholangiocarcinoma, fibrolamellar hepatocellular carcinoma, or metastasis.

Methods

Electronic databases (PubMed, Web of Knowledge, Google Scholar, Cochrane Library, and WHO International Clinical Trials Registry Platform) were searched for publications on scirrhous hepatocellular carcinoma without date or language restrictions. Quality assessment was performed using a tool proposed by Murad et al for case reports and series. For observational studies, MINORS quality assessment tool was used. This study was registered at PROSPERO (CRD42020212323).

Results

S-HCC arises in patients with chronic hepatitis (hepatitis B in 60% and hepatitis C in 21%). S-HCC primarily affects men with a mean age of 55.8 years. Serum AFP is elevated above 20IU/mL in 66.7% of the patients. On ultrasound, s-HCC presents as hypoechoic or mosaic pattern lesions (47.6% each) and causes a retraction of the liver surface (70%) when near the capsule. Delayed enhancement of the tumor is evident in 87.0%. On MRI, 65.0% of s-HCCs show a target appearance. Histopathologic pattern is mostly irregular (97.6%). Lesions show a bulging appearance (100%), septae (85.6%) and a central scar (63.5%), and usually lack central necrosis (75%). Immunohistochemistry shows HepPar 1 positivity in 64.6%, CK7 in 40.7%, and EMA in 41.9%. The 5-year overall survival rate estimates 45.2% and 45.5% of the patients experience a recurrence after hepatectomy.

Conclusion

S-HCC is a rare subtype of HCC primarily arising in hepatitis- or cirrhosis-afflicted livers and incorporates atypical radiological and histopathological HCC features. Despite lower recurrence rates, overall survival of patients with s-HCC is poorer than generally for HCC, underlining the need for individualized treatment. Patients with atypical lesions of the liver should be referred to tertiary hospitals for interdisciplinary assessment and treatment.

Clinicopathological Features of Two Extremely Rare Hepatocellular Carcinoma Variants: a Brief Review of Fibrolamellar and Scirrhous Hepatocellular Carcinoma

PURPOSE

We aimed to distinguish between fibrolamellar hepatocellular carcinoma and scirrhous hepatocellular carcinoma histopathologically.

METHODS AND RESULTS

In this review, fibrolamellar hepatocellular carcinoma and scirrhous hepatocellular carcinoma two specific and rare variants of hepatocellular carcinoma, which are difficult to diagnose histopathologically are discussed.

CONCLUSION

The clinical, radiological, gross, histopathological, immunohistochemical, and molecular features of these two tumors, which are defined by the World Health Organization (WHO), are mentioned.

Connective Tissue Growth Factor in Digestive System Cancers: A Review and Meta-Analysis

Aim

A meta-analysis was conducted to estimate the impact of connective tissue growth factor (CTGF) on outcomes in patients with digestive system cancers.

Methods

A systemic literature survey was performed by searching the Cochrane Library and PubMed databases for articles that evaluated the impact of CTGF on outcomes in patients with digestive system cancers. Hazard ratios and 95% confidence intervals were calculated for prognostic factors, overall and recurrence-free survival using RevMan 5.3 software.

Results

This meta-analysis was conducted to evaluate a total of 11 studies that included 1730 patients. The results showed that elevated CTGF expression was significantly correlated with advanced age, larger tumor size, multiple tumors, and vascular invasion. Subgroup analysis by cancer type revealed increased risk for lymph node metastasis and advanced tumor node metastasis (TNM) stage in gastric cancer, compared with colorectal cancer. An unfavorable effect of elevated CTGF levels on overall survival was found in patients with hepatocellular carcinoma and patients with gastric cancer, while survival was improved in colorectal cancer patients with high CTGF expression, compared to those with normal levels of CTGF.

Conclusions

Elevated CTGF expression may be a novel biomarker for disease status and predicted survival outcomes in patients with specific digestive system cancers.

Fibroblast imaging of hepatic carcinoma with 68Ga-FAPI-04 PET/CT: a pilot study in patients with suspected hepatic nodules

PURPOSE

⁶⁸Ga-FAPI-04 is a rapidly evolving PET tracer for whole-body imaging in a variety of cancers. We aimed to evaluate the diagnostic performance of ⁶⁸Ga-FAPI-04 for detecting and characterizing hepatic nodules in patients with suspected carcinoma.

METHODS

Twenty-five patients showing suspicious hepatic lesions for malignancy underwent ⁶⁸Ga-FAPI-04 PET. The maximum and mean standardised uptake values (SUV_max, SUV_mean) were measured for all detected lesions and normal hepatic tissues, respectively. The target-to-background ratio (TBR) was calculated by dividing the lesion SUV_max with the SUV_mean of non-tumour liver tissue. Lesion uptake value was correlated with the in vitro hepatic FAP expression determined by immunohistochemistry (IHC).

RESULTS

In total, 17 patients who underwent surgery or biopsy were recruited for the final analysis. A total of 28 intrahepatic malignant lesions were detected in 16 patients; the mean SUV_max was 8.36 ± 4.21 (range 2.21 to 15.86), and mean TBR was 13.15 ± 9.48 (range 2.79 to 38.12) in all detected lesions (n = 28). One benign patient showed negligible hepatic uptake (SUV_max = 0.47), whereas 75% of the primary intrahepatic hepatocellular carcinoma (HCC) lesions (n = 6) showed prominent FAP expression, 12.5% of the lesions (n = 1) showed moderate expression in stromal cells, and one showed negligible expression.

CONCLUSIONS

⁶⁸Ga-FAPI-04 showed high sensitivity in detecting hepatic malignancies, particularly in poorly differentiated forms with concordantly elevated FAP expression.

Heterogeneity of cancer-associated fibroblasts and roles in the progression, prognosis, and therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a lethal disease, and recurrence and metastasis are the major causes of death in HCC patients. Cancer-associated fibroblasts (CAFs), a major stromal cell type in the HCC microenvironment, promote HCC progression, and have gradually become a hot research topic in HCC-targeted therapy. This review comprehensively describes and discusses the heterogeneous tissue distribution, cellular origin, phenotype, and biological functions of HCC-associated fibroblasts. Furthermore, the possible use of CAFs for predicting HCC prognosis and in targeted therapeutic strategies is discussed, highlighting the critical roles of CAFs in HCC progression, diagnosis, and therapy.

The clinicopathological characterization of small hepatocellular carcinoma with fibrous stroma

Recent studies emphasized the significance of fibrous stroma affecting tumor biology in hepatocellular carcinoma (HCC). To further clarify fibrous stroma's significance, this study investigated the clinicopathological characteristics of HCC with fibrous stroma. A total of 214 nodules of HCC smaller than 3 cm in diameter were analyzed, and 22 (10%) were regarded as HCC with fibrous stroma. Most cases of HCC with fibrous stroma were the simple nodular type without a fibrous capsule, and histologically well- or moderately-differentiated. A subset of the scirrhous variant of HCC was included in this category, and steatohepatitic features, such as Mallory-Denk body formation and lymphoid infiltrates, were also frequently found. Foci with a histological appearance corresponding to dysplastic nodules and/or early HCC were rarely observed in HCC with fibrous stroma, suggesting that some cases occurred via a de novo carcinogenic process. The immunohistochemical expression of cytokeratin 7 and the epithelial cell adhesion molecule was more significantly increased in HCC with fibrous stroma than in conventional HCC. Furthermore, the expression of C reactive protein and serum amyloid A, indicative of the activation of the IL-6/STAT pathway, was increased in HCC with fibrous stroma. Radiologically, HCC with fibrous stroma exhibited hyperdense nodules on computed tomography and did not show a nodule-in-nodule appearance. Overall survival and disease-free survival were not significantly different between cases of HCC with fibrous stroma and conventional HCC. This study elucidated the clinicopathological features of HCC with fibrous stroma, which may represent a biologically different process occurring in HCC.

The Expression of FAP in Hepatocellular Carcinoma Cells is Induced by Hypoxia and Correlates with Poor Clinical Outcomes

Fibroblast activation protein (FAP) is a serine protease that has been reported in fibroblasts and some carcinoma cells, which correlates with poor patient outcomes. FAP can be induced under hypoxia which is also vital in the malignant behaviors of cancer cells. However, the role of FAP and its correlation with hypoxia has not been investigated in HCC cancer cells. In tissues from post-surgical HCC patients in our center, we adopted immunohistochemistry staining (IHC), western blot and quantitative RT-PCR to detect the expression levels of FAP and the hypoxia related marker, hypoxia inducible factor 1α (HIF-1α). X-tile software was used for the determination of high and low expression of FAP and HIF-1α after the IHC analysis. Clinicopathological analysis, Kaplan-Meier analysis and Cox regression model were performed. In-vitro experiments were performed to confirm the relationship between FAP and hypoxia in HCC cancer cell lines (HepG2, Huh7 and MHCC97H). Results revealed that expression levels of FAP and HIF-1α were significantly correlated (Pearson r² = 0.2753, p < 0.0001) in IHC analysis of the 138-patient cohort. Western blot and quantity RT-PCR indicated parallel changes in 11 post-surgical fresh frozen tissues. The HIF-1α and FAP expression were associated with serum AFP, TNM, tumor size and vascular invasion. Cox regression analysis showed that HIF-1α/ FAP combination were the independent predictor for overall survival (OS) and time-to-recurrence (TTR) in post-surgical HCC patients. Kaplan-Meier analyses revealed that the patient with high levels of HIF-1α, FAP and combined HIF-1α/FAP had the shortest OS and TTR. In-vitro experiments showed that FAP was increased in hypoxic HCC cancer cell lines in parallel with that of HIF-1α and three EMT markers (E-cadherin, Snail and TWIST). In conclusion, the up-regulation of FAP in HCC cancer cells under hypoxia can be indicative of poor prognosis in patients.

Pro-tumorigenic roles of fibroblast activation protein in cancer: back to the basics

Fibroblast activation protein (FAP) is a cell-surface serine protease that acts on various hormones and extracellular matrix components. FAP is highly upregulated in a wide variety of cancers, and is often used as a marker for pro-tumorigenic stroma. It has also been proposed as a molecular target of cancer therapies, and, especially in recent years, a great deal of research has gone into design and testing of diverse FAP-targeted treatments. Yet despite this growing field of research, our knowledge of FAP's basic biology and functional roles in various cancers has lagged behind its use as a tumor-stromal marker. In this review, we summarize and analyze recent advances in understanding the functions of FAP in cancer, most notably its prognostic value in various tumor types, cellular effects on various cell types, and potential as a therapeutic target. We highlight outstanding questions in the field, the answers to which could shape preclinical and clinical studies of FAP.

The influence of diet on anti-cancer immune responsiveness

Immunotherapy has matured into standard treatment for several cancers, but much remains to be done to extend the reach of its effectiveness particularly to cancers that are resistant within each indication. This review proposes that nutrition can affect and potentially enhance the immune response against cancer. The general mechanisms that link nutritional principles to immune function and may influence the effectiveness of anticancer immunotherapy are examined. This represents also the premise for a research project aimed at identifying the best diet for immunotherapy enhancement against tumours (D.I.E.T project). Particular attention is turned to the gut microbiota and the impact of its composition on the immune system. Also, the dietary patterns effecting immune function are discussed including the value of adhering to a healthy diets such as the Mediterranean, Veg, Japanese, or a Microbiota-regulating diet, the very low ketogenic diet, which have been demonstrated to lower the risk of developing several cancers and reduce the mortality associated with them. Finally, supplements, as omega-3 and polyphenols, are discussed as potential approaches that could benefit healthy dietary and lifestyle habits in the context of immunotherapy.

Selective Homogeneous Assay for Circulating Endopeptidase Fibroblast Activation Protein (FAP)

Fibroblast Activation Protein (FAP) is a membrane-bound serine protease whose expression is often elevated in activated fibroblasts associated with tissue remodeling in various common diseases such as cancer, arthritis and fibrosis. Like the closely related dipeptidyl peptidase DPPIV, the extracellular domain of FAP can be released into circulation as a functional enzyme, and limited studies suggest that the circulating level of FAP correlates with the degree of tissue fibrosis. Here we describe a novel homogeneous fluorescence intensity assay for circulating FAP activity based on a recently identified natural substrate, FGF21. This assay is unique in that it can effectively distinguish endopeptidase activity of FAP from that of other related enzymes such as prolyl endopeptidase (PREP) and was validated using Fap-deficient mice. Structural modeling was used to elucidate the mechanistic basis for the observed specificity in substrate recognition by FAP, but not by DPPIV or PREP. Finally, the assay was used to detect elevated FAP activity in human patients diagnosed with liver cirrhosis and to determine the effectiveness of a chemical inhibitor for FAP in mice. We propose that the assay presented here could thus be utilized for diagnosis of FAP-related pathologies and for the therapeutic development of FAP inhibitors.

Inflammation as target in cancer therapy

Cells of the innate immunity infiltrating tumour tissues promote, rather than halt, cancer cell proliferation and distant spreading. Tumour-Associated Macrophages (TAMs) are abundantly present in the tumour milieu and here trigger and perpetrate a state of chronic inflammation which ultimately supports disease development and contributes to an immune-suppressive environment. Therapeutic strategies to limit inflammatory cells and their products have been successful in pre-clinical tumour models. Early clinical trials with specific cytokine and chemokine inhibitors, or with strategies designed to target TAMs, are on their way in different solid malignancies. Partial clinical responses and stabilization of diseases were observed in some patients, in the absence of significant toxicity. These encouraging results open new perspectives of combination treatments aimed at reducing cancer-promoting inflammation to maximize the anti-tumour efficacy.

Morphologic Subtypes of Hepatocellular Carcinoma

Hepatocellular carcinomas can be further divided into distinct subtypes that provide important clinical information and biological insights. These subtypes are distinct from growth patterns and are on based on morphologic and molecular findings. There are 12 reasonably well-defined subtypes as well as 6 provisional subtypes, together making up 35% of all hepatocellular carcinomas. These subtypes are discussed, with an emphasis on their definitions and the key morphologic findings.

Tumour epithelial and stromal characteristics of hepatocellular carcinomas with abundant fibrous stroma: fibrolamellar versus scirrhous hepatocellular carcinoma

AIMS

The scirrhous variant of hepatocellular carcinoma (S-HCC) and fibrolamellar HCC (FL-HCC) are less common subtypes of HCC that are characterized by abundant fibrous stroma. Here, we aimed to investigate differences in the tumour microenvironment and the tumour epithelial cell characteristics of S-HCC and FL-HCC.

METHODS AND RESULTS

Whole tissue sections of 17 S-HCCs and 9 FL-HCCs were subjected to immunohistochemical stains for keratin 7 (K7), K19, EpCAM, CD56/NCAM, CD163, CD68, pSTAT3, FAP, CCN2 and Ki-67. FL-HCC patients were younger than S-HCC patients (P < 0.001), and chronic liver disease was seen in the background of 88.2% of S-HCC and in none of the FL-HCC. CD68 and CD163-positive tumour-infiltrating macrophages, and FAP-positive cancer-associated fibroblasts (CAFs) were more abundant in the stroma of S-HCCs compared to FL-HCCs (all P < 0.05). Tumour epithelial K19 expression was more frequent in S-HCCs compared to FL-HCCs (P = 0.023). Significant positive correlations were seen between pSTAT3 expression status in tumour epithelial cells and CAFs, the extent of stromal CAF and macrophage infiltration and K19 expression status. No significant differences were seen for K7, EpCAM, CD56/NCAM, CCN2 expression and Ki-67 labelling index between S-HCCs and FL-HCCs.

CONCLUSION

S-HCC and FL-HCC are subtypes of HCC with extensive fibrosis, and the nature of the fibrous stroma differs between them. While the stroma of FL-HCC is composed of dense lamellated collagenous bands with sparse cellular components, S-HCC demonstrates more abundant CAF and tumour-infiltrating macrophages and stemness-related marker expression, suggesting the presence of a complex tumour microenvironment that may influence the aggressive behaviour of S-HCCs.

Tumor stroma with senescence-associated secretory phenotype in steatohepatitic hepatocellular carcinoma

Senescence secretome was recently reported to promote liver cancer in an obese mouse model. Steatohepatitic hepatocellular carcinoma (SH-HCC), a new variant of HCC, has been found in metabolic syndrome patients, and pericellular fibrosis, a characteristic feature of SH-HCC, suggests that alteration of the tumor stroma might play an important role in SH-HCC development. Clinicopathological characteristics and tumor stroma showing senescence and senescence-associated secretory phenotype (SASP) were investigated in 21 SH-HCCs and 34 conventional HCCs (C-HCCs). The expression of α-smooth muscle actin (α-SMA), p21^Waf1/Cif1, γ-H2AX, and IL-6 was investigated by immunohistochemistry or immunofluorescence. SH-HCCs were associated with older age, higher body mass index, and a higher incidence of metabolic syndrome, compared to C-HCC (P <0.05, all). The numbers of α-SMA-positive cancer-associated fibroblasts (CAFs) (P = 0.049) and α-SMA-positive CAFs co-expressing p21^Waf1/Cif1 (P = 0.038), γ-H2AX (P = 0.065), and IL-6 (P = 0.048) were greater for SH-HCCs than C-HCCs. Additionally, non-tumoral liver from SH-HCCs showed a higher incidence of non-alcoholic fatty liver disease and a higher number of α-SMA-positive stellate cells expressing γ-H2AX and p21^Waf1/Cif1 than that from C-HCCs (P <0.05, all). In conclusion, SH-HCCs are considered to occur more frequently in metabolic syndrome patients. Therein, senescent and damaged CAFs, as well as non-tumoral stellate cells, expressing SASP including IL-6 may contribute to the development of SH-HCC.

Cancer-associated fibroblasts in hepatocellular carcinoma

The hepatic stellate cells in the liver are stimulated sustainably by chronic injury of the hepatocytes, activating myofibroblasts, which produce abundant collagen. Myofibroblasts are the major source of extracellular proteins during fibrogenesis, and may directly, or secreted products, contribute to carcinogenesis and tumor progression. Cancer-associated fibroblasts (CAFs) are one of the components of the tumor microenvironment that promote the proliferation and invasion of cancer cells by secreting various growth factors and cytokines. CAFs crosstalk with cancer cells stimulates tumor progression by creating a favorable microenvironment for progression, invasion, and metastasis through the epithelial-mesenchymal transition. Basic studies on CAFs have advanced, and the role of CAFs in tumors has been elucidated. In particular, for hepatocellular carcinoma, carcinogenesis from cirrhosis is a known fact, and participation of CAFs in carcinogenesis is supported. In this review, we discuss the current literature on the role of CAFs and CAF-related signaling in carcinogenesis, crosstalk with cancer cells, immunosuppressive effects, angiogenesis, therapeutic targets, and resistance to chemotherapy. The role of CAFs is important in cancer initiation and progression. CAFtargeted therapy may be effective for suppression not only of fibrosis but also cancer progression.

CCN family of proteins: critical modulators of the tumor cell microenvironment

The CCN family of proteins consisting of CCN1 (Cyr61), CCN2 (CTGF), CCN3 (NOV), CCN4 (WISP-1), CCN5 (WISP-2) and CCN6 (WISP-3) are considered matricellular proteins operating essentially in the extracellular microenvironment between cells. Evidence has also been gradually building since their first discovery of additional intracellular roles although the major activity is triggered at the cell membrane. The proteins consist of 4 motifs, a signal peptide (for secretion} followed consecutively by the IGFBP, VWC, TSP1 and CT (C-terminal cysteine knot domain) motifs, which signify their potential binding partners and functional connections to a variety of key regulators of physiological processes. With respect to cancer it is now clear that, whereas certain members can facilitate tumor behavior and progression, others can competitively counter the process. It is therefore clear that the net outcome of biological interactions in the matrix and what gets signaled or inhibited can be a function of the interplay of these CCN 1-6 proteins. Because the CCN proteins further interact with other key proteins, like growth factors in the matrix, the balance is not only important but can vary dynamically with the physiological states of tumor cells and the surrounding normal cells. The tumor niche with its many cell players has surfaced as a critical determinant of tumor behavior, invasiveness, and metastasis. It is in this context that CCN proteins should be investigated with the potential of being recognized and validated for future therapeutic approaches.

Proteinase-activated receptor 2 (PAR2) in hepatic stellate cells - evidence for a role in hepatocellular carcinoma growth in vivo

BACKGROUND

Previous studies have established that proteinase-activated receptor 2 (PAR2) promotes migration and invasion of hepatocellular carcinoma (HCC) cells, suggesting a role in HCC progression. Here, we assessed the impact of PAR2 in HCC stromal cells on HCC growth using LX-2 hepatic stellate cells (HSCs) and Hep3B cells as model.

METHODS

PAR2 expression and function in LX-2 cells was analysed by RT-PCR, confocal immunofluorescence, electron microscopy, and [Ca(2+)]i measurements, respectively. The impact of LX-2-expressed PAR2 on tumour growth in vivo was monitored using HCC xenotransplantation experiments in SCID mice, in which HCC-like tumours were induced by coinjection of LX-2 cells and Hep3B cells. To characterise the effects of PAR2 activation in LX-2 cells, various signalling pathways were analysed by immunoblotting and proteome profiler arrays.

RESULTS

Following verification of functional PAR2 expression in LX-2 cells, in vivo studies showed that these cells promoted tumour growth and angiogenesis of HCC xenografts in mice. These effects were significantly reduced when F2RL1 (encoding PAR2) was downregulated by RNA interference (RNAi). In vitro studies confirmed these results demonstrating RNAi mediated inhibition of PAR2 attenuated Smad2/3 activation in response to TGF-β1 stimulation in LX-2 cells and blocked the pro-mitotic effect of LX-2 derived conditioned medium on Hep3B cells. Furthermore, PAR2 stimulation with trypsin or a PAR2-selective activating peptide (PAR2-AP) led to activation of different intracellular signalling pathways, an increased secretion of pro-angiogenic and pro-mitotic factors and proteinases, and an enhanced migration rate across a collagen-coated membrane barrier. Silencing F2RL1 by RNAi or pharmacological inhibition of Src, hepatocyte growth factor receptor (Met), platelet-derived growth factor receptor (PDGFR), p42/p44 mitogen activated protein kinase (MAPK) or matrix-metalloproteinases (MMPs) blocked PAR2-AP-induced migration.

CONCLUSION

PAR2 in HSCs plays a crucial role in promoting HCC growth presumably by mediating migration and secretion of pro-angiogenic and pro-mitotic factors. Therefore, PAR2 in stromal HSCs may have relevance as a therapeutic target of HCC.

TIMP-1 activated carcinoma-associated fibroblasts inhibit tumor apoptosis by activating SDF1/CXCR4 signaling in hepatocellular carcinoma

Tissue inhibitor of metalloproteinase 1 (TIMP-1) is an endogenous inhibitor for MMPs that regulates the remodeling and turnover of the ECM during normal development and pathological conditions. Intriguingly, recent studies have shown that TIMP-1 plays a dual role in cancer progression. In this study, we found that TIMP-1 expression in HCC tissues is associated with advanced TNM stage, intrahepatic metastasis, portal vein invasion, and vasculature invasion. Notably, TIMP-1 expression in HCC tissue is significantly related to worse overall survival for patients with HCC after liver resection. Ectopic TIMP1 expression promoted the growth of HCC xenografts in nude mice. Both co-culture with Huh7 cells with a high level of TIMP-1 and TIMP1 treatment resulted in up-regulation of hallmarks of carcinoma-associated fibroblasts (CAFs) and accelerated cell proliferation, migration and invasion in immortalized liver fibroblasts (LFs) isolated from human normal liver tissue. By co-culture with CAFs, SDF-1/CXCR4/PI3K/AKT signaling was activated and apoptosis was markedly repressed with an increased Bcl-2/BAX ratio in Huh7 cells. Taken together, our observations suggest that TIMP-1 induces the trans-differentiation of LFs into CAFs, suppresses apoptosis via SDF-1/CXCR4/PI3K/AKT signaling and then promotes HCC progression. This protein may be a potential prognostic biomarker and therapeutic target for HCC.

CCN: core regulatory proteins in the microenvironment that affect the metastasis of hepatocellular carcinoma?

Hepatocellular carcinoma (HCC) results from an underlying chronic liver inflammatory disease, such as chronic hepatitis B or C virus infections, and the general prognosis of patients with HCC still remains extremely dismal because of the high frequency of HCC metastases. Throughout the process of tumor metastasis, tumor cells constantly communicate with the surrounding microenvironment and improve their malignant phenotype. Therefore, there is a strong rationale for targeting the tumor microenvironment as primary treatment of HCC therapies. Recently, CCN family proteins have emerged as localized multitasking signal integrators in the inflammatory microenvironment. In this review, we summarize the current knowledge of CCN family proteins in inflammation and the tumor. We also propose that the CCN family proteins may play a central role in signaling the tumor microenvironment and regulating the metastasis of HCC.

Neuropeptide Y is a physiological substrate of fibroblast activation protein: Enzyme kinetics in blood plasma and expression of Y2R and Y5R in human liver cirrhosis and hepatocellular carcinoma

Fibroblast activation protein (FAP) is a dipeptidyl peptidase (DPP) and endopeptidase that is weakly expressed in normal adult human tissues but is greatly up-regulated in activated mesenchymal cells of tumors and chronically injured tissue. The identities and locations of target substrates of FAP are poorly defined, in contrast to the related protease DPP4. This study is the first to characterize the physiological substrate repertoire of the DPP activity of endogenous FAP present in plasma. Four substrates, neuropeptide Y (NPY), peptide YY, B-type natriuretic peptide and substance P, were analyzed by mass spectrometry following proteolysis in human or mouse plasma, and by in vivo localization in human liver tissues with cirrhosis and hepatocellular carcinoma (HCC). NPY was the most efficiently cleaved substrate of both human and mouse FAP, whereas all four peptides were efficiently cleaved by endogenous DPP4, indicating that the in vivo degradomes of FAP and DPP4 differ. All detectable DPP-specific proteolysis and C-terminal processing of these neuropeptides was attributable to FAP and DPP4, and plasma kallikrein, respectively, highlighting their combined physiological significance in the regulation of these neuropeptides. In cirrhotic liver and HCC, NPY and its receptor Y2R, but not Y5R, were increased in hepatocytes near the parenchymal-stromal interface where there is an opportunity to interact with FAP expressed on nearby activated mesenchymal cells in the stroma. These novel findings provide insights into the substrate specificity of FAP, which differs greatly from DPP4, and reveal a potential function for FAP in neuropeptide regulation within liver and cancer biology.

Fibroblast activation protein-α, a stromal cell surface protease, shapes key features of cancer associated fibroblasts through proteome and degradome alterations

Cancer associated fibroblasts (CAFs) constitute an abundant stromal component of most solid tumors. Fibroblast activation protein (FAP) α is a cell surface protease that is expressed by CAFs. We corroborate this expression profile by immunohistochemical analysis of colorectal cancer specimens. To better understand the tumor-contextual role of FAPα, we investigate how FAPα shapes functional and proteomic features of CAFs using loss- and gain-of function cellular model systems. FAPα activity has a strong impact on the secreted CAF proteome ("secretome"), including reduced levels of anti-angiogenic factors, elevated levels of transforming growth factor (TGF) β, and an impact on matrix processing enzymes. Functionally, FAPα mildly induces sprout formation by human umbilical vein endothelial cells. Moreover, loss of FAPα leads to a more epithelial cellular phenotype and this effect was rescued by exogenous application of TGFβ. In collagen contraction assays, FAPα induced a more contractile cellular phenotype. To characterize the proteolytic profile of FAPα, we investigated its specificity with proteome-derived peptide libraries and corroborated its preference for cleavage carboxy-terminal to proline residues. By "terminal amine labeling of substrates" (TAILS) we explored FAPα-dependent cleavage events. Although FAPα acts predominantly as an amino-dipeptidase, putative FAPα cleavage sites in collagens are present throughout the entire protein length. In contrast, putative FAPα cleavage sites in non-collagenous proteins cluster at the amino-terminus. The degradomic study highlights cell-contextual proteolysis by FAPα with distinct positional profiles. Generally, our findings link FAPα to key aspects of CAF biology and attribute an important role in tumor-stroma interaction to FAPα.

High ROR2 expression in tumor cells and stroma is correlated with poor prognosis in pancreatic ductal adenocarcinoma

RTK-like orphan receptor 2 (ROR2) is overexpressed in several cancers and has tumorigenic activity. However, the expression of ROR2 and its functional and prognostic significance have yet to be evaluated in pancreatic ductal adenocarcinoma (PDAC). Quantitative real-time polymerase chain reaction was used to characterize the expression of ROR2 mRNA in PDAC, corresponding peritumoral tissues, and PDAC cell lines. Immunohistochemical analysis with tissue microarrays was used to evaluate ROR2 expression in PDAC and to investigate the relationship of this expression to clinicopathological factors and prognosis. The expression of ROR2 mRNA and protein was significantly higher in PDAC than in normal pancreatic tissues. High cytoplasmic ROR2 expression in cancer cells was significantly associated with a primary tumor, distant metastasis, and TNM stage, and high stromal ROR2 expression was significantly associated with regional lymph node metastasis and TNM stage. The Kaplan–Meier method and Cox regression analyses showed that high ROR2 expression in tumor cytoplasm or stromal cells was significantly associated with malignant attributes and reduced survival in PDAC. We present strong evidence that ROR2 could be used as an indicator of poor prognosis and could represent a novel therapeutic target for PDAC.