Prognostic significance of the co-overexpression of fibroblast growth factor receptors 1, 2 and 4 in gastric cancer

Clinical Developments and Challenges in Treating FGFR2-Driven Gastric Cancer

Recent advances in the treatment of gastric cancer (GC) with chemotherapy, immunotherapy, anti-angiogenic therapy and targeted therapies have yielded some improvement in survival outcomes; however, metastatic GC remains a lethal malignancy and amongst the leading causes of cancer-related mortality worldwide. Importantly, the ongoing molecular characterisation of GCs continues to uncover potentially actionable molecular targets. Among these, aberrant FGFR2-driven signalling, predominantly arising from FGFR2 amplification, occurs in approximately 3-11% of GCs. However, whilst several inhibitors of FGFR have been clinically tested to-date, there are currently no approved FGFR-directed therapies for GC. In this review, we summarise the significance of FGFR2 as an actionable therapeutic target in GC, examine the recent pre-clinical and clinical data supporting the use of small-molecule inhibitors, antibody-based therapies, as well as novel approaches such as proteolysis-targeting chimeras (PROTACs) for targeting FGFR2 in these tumours, and discuss the ongoing challenges and opportunities associated with their clinical development.

Role of the long non-coding RNAs in regulation of Gemcitabine response in tumor cells

Chemotherapy is widely used as one of the first line therapeutic methods in cancer patients. However, chemotherapeutic resistance is one of the most common problems in cancer patients, which leads to the therapeutic failure and tumor relapse. Considering the side effects of chemotherapy drugs in normal tissues, it is required to investigate the molecular mechanisms involved in drug resistance to improve the therapeutic strategies in cancer patients. Long non-coding RNAs (lncRNAs) have pivotal roles in regulation of cellular processes associated with drug resistance. LncRNAs deregulations have been frequently reported in a wide range of chemo-resistant tumors. Gemcitabine (GEM) as a nucleoside analog has a wide therapeutic application in different cancers. However, GEM resistance is considered as a therapeutic challenge. Considering the role of lncRNAs in the occurrence of GEM resistance, in the present review we discussed the molecular mechanisms of lncRNAs in regulation of GEM response among cancer patients. It has been reported that lncRNAs have mainly an oncogenic role as the inducers of GEM resistance through direct or indirect regulation of transcription factors, autophagy, polycomb complex, and signaling pathways such as PI3K/AKT, MAPK, WNT, JAK/STAT, and TGF-β. This review paves the way to present the lncRNAs as non-invasive markers to predict GEM response in cancer patients. Therefore, lncRNAs can be introduced as the efficient markers to reduce the possible chemotherapeutic side effects in GEM resistant cancer patients and define a suitable therapeutic strategy among these patients.

Predictive biomarkers in gastric cancer

Predictive biomarkers are the mainstay of precision medicine. This review summarizes the advancements in tissue-based diagnostic biomarkers for gastric cancer, which is considered the leading cause of cancer-related deaths worldwide. A disease seen in the elderly, it is often diagnosed at an advanced stage, thereby limiting therapeutic options. In Western countries, neoadjuvant/perioperative (radio-)chemotherapy is administered, and adjuvant chemotherapy is administered in the East. The morpho-molecular classification of gastric cancer has opened novel avenues identifying Epstein-Barr-Virus (EBV)-positive, microsatellite instable, genomically stable and chromosomal instable gastric cancers. In chromosomal instable tumors, receptor tyrosine kinases (RKTs) (e.g., EGFR, FGFR2, HER2, and MET) are frequently overexpressed. Gastric cancers such as microsatellite instable and EBV-positive types often express immune checkpoint molecules, such as PD-L1 and VISTA. Genomically stable tumors show alterations in claudin 18.2. Next-generation sequencing is increasingly being used to search for druggable targets in advanced palliative settings. However, most tissue-based biomarkers of gastric cancer carry the risk of a sampling error due to intratumoral heterogeneity, and adequate tissue sampling is of paramount importance.

Phase I study of the irreversible fibroblast growth factor receptor 1-4 inhibitor futibatinib in Japanese patients with advanced solid tumors

This phase I study was designed to: (1) determine the maximum tolerated dose (MTD) and recommended dose (RD) of the fibroblast growth factor receptor (FGFR) inhibitor futibatinib in Japanese patients with advanced solid tumors, and (2) examine the antitumor activity of the RD in patients with gastric cancer (GC) or other advanced solid tumors who have FGFR or FGF/FGFR abnormalities, respectively. In the dose-escalation phase, patients were assigned to 21-day cycles of oral futibatinib 8-160 mg three times a week (TIW) or 16 or 20 mg once daily (QD). In the expansion phase, patients received oral futibatinib 56, 80, or 120 mg TIW, or 16 or 20 mg QD. Eighty-three patients received futibatinib TIW (n = 40) or QD (n = 43). No dose-limiting toxicities were observed according to the final study protocol definition, and the MTD was not reached. The most common adverse events with both regimens were hyperphosphatemia (TIW, 82.5%; QD, 100.0%) and decreased appetite (TIW, 40.0%; QD, 58.1%). Hyperphosphatemia was asymptomatic, not leading to futibatinib discontinuation. The overall response rate (ORR) was 11.5% in patients with FGF/FGFR abnormalities. Notably, in GC patients harboring FGFR2 copy number (CN) ≥10, the ORR was 36.4% versus 0 in patients with CN <10. Therefore, futibatinib had a generally predictable and manageable safety profile in patients with advanced solid tumors. Antitumor activity was seen in patients with FGF/FGFR abnormalities, particularly those with GC and high FGFR2 CNs. Thus, futibatinib 20 mg QD was chosen as the RD for phase II studies.

Targeting FGFR2 Positive Gastroesophageal Cancer: Current and Clinical Developments

Despite recent advances in the systemic treatment of gastroesophageal cancers, prognosis remains poor. Comprehensive molecular analyses have characterized the genomic landscape of gastroesophageal cancer that has established therapeutic targets such as human epidermal growth factor receptor 2 (HER2), vascular endothelial growth factor receptor (VEGFR) and programmed death ligand 1 (PD-L1). The aberrant fibroblast growth factor receptor 2 (FGFR2) pathway is attractive for targetable therapy with FGFR inhibition based on preclinical data showing a pivotal role in the progression of gastric cancer (GC). FGFR2 amplification is the most common FGFR2 gene aberration in gastroesophageal cancer, and most associated with diffuse GC, which is often linked to poorer prognostic outcomes. There has been considerable progress with drug development focused on FGFR inhibition. At present, there is no approved FGFR inhibitor for FGFR2 positive gastroesophageal cancer. A selective FGFR2b monoclonal antibody bemarituzumab is currently being investigated in the first phase III randomized trial for patients with first line advanced GC, which may change the treatment paradigm for FGFR2b positive GC. The role of FGFR signalling, specifically FGFR2, is less established in oesophageal squamous cell cancer (ESCC) with a paucity of evidence for clinical benefit in these patients. Precision medicine is part of the wider approach in gastrointestinal cancers; however, it can be challenging due to heterogeneity and here circulating tumour DNA (ctDNA) for patient selection may have future clinical utility. In our review, we outline the FGFR pathway and focus on the developments and challenges of targeting FGFR2 driven gastroesophageal cancers.

FGFR1-4 RNA-Based Gene Alteration and Expression Analysis in Squamous Non-Small Cell Lung Cancer

While fibroblast growth factor receptors (FGFRs) are involved in several biological pathways and FGFR inhibitors may be useful in the treatment of squamous non-small cell lung cancer (Sq-NSCLC), FGFR aberrations are not well characterized in Sq-NSCLC. We comprehensively evaluated FGFR expression, fusions, and variants in 40 fresh-frozen primary Sq-NSCLC (stage IA3−IV) samples and tumor-adjacent normal tissues using real-time PCR and next-generation sequencing (NGS). Protein expression of FGFR1−3 and amplification of FGFR1 were also analyzed. FGFR1 and FGFR4 median gene expression was significantly (p < 0.001) decreased in tumors compared with normal tissue. Increased FGFR3 expression enhanced the recurrence risk (hazard ratio 4.72, p = 0.029), while high FGFR4 expression was associated with lymph node metastasis (p = 0.036). Enhanced FGFR1 gene expression was correlated with FGFR1 protein overexpression (r = 0.75, p = 0.0003), but not with FGFR1 amplification. NGS revealed known pathogenic FGFR2,3 variants, an FGFR3::TACC3 fusion, and a novel TACC1::FGFR1 fusion together with FGFR1,2 variants of uncertain significance not previously reported in Sq-NSCLC. These findings expand our knowledge of the Sq-NSCLC molecular background and show that combining different methods increases the rate of FGFR aberrations detection, which may improve patient selection for FGFRi treatment.

Comprehensive analysis of the prognostic value and immune infiltration of FGFR family members in gastric cancer

Background

Fibroblast growth factor receptors (FGFRs) modulate numerous cellular processes in tumor cells and tumor microenvironment. However, the effect of FGFRs on tumor prognosis and tumor-infiltrating lymphocytes in gastric cancer (GC) remains controversial.

Methods

The expression of four different types of FGFRs was analyzed via GEPIA, TCGA-STAD, and GTEX databases and our 27 pairs of GC tumor samples and the adjacent normal tissue. Furthermore, the Kaplan–Meier plot and the TCGA database were utilized to assess the association of FGFRs with clinical prognosis. The R software was used to evaluate FGFRs co-expression genes with GO/KEGG Pathway Enrichment Analysis. In vitro and in vivo functional analyses and immunoblotting were performed to verify FGFR4 overexpression consequence. Moreover, the correlation between FGFRs and cancer immune infiltrates was analyzed by TIMER and TCGA databases. And the efficacy of anti-PD-1 mAb treatment was examined in NOG mouse models with overexpressed FGFR1 or FGFR4.

Results

The expression of FGFRs was considerably elevated in STAD than in the normal gastric tissues and was significantly correlated with poor OS and PFS. ROC curve showed the accuracy of the FGFRs in tumor diagnosis, among which FGFR4 had the highest ROC value. Besides, univariate and multivariate analysis revealed that FGFR4 was an independent prognostic factor for GC patients. According to a GO/KEGG analysis, the FGFRs were implicated in the ERK/MAPK, PI3K-AKT and extracellular matrix (ECM) receptor signaling pathways. In vivo and in vitro studies revealed that overexpression of FGFR4 stimulated GC cell proliferation, invasion, and migration. In addition, FGFR1 expression was positively correlated with infiltrating levels of CD8+ T-cells, CD4+ T-cells, macrophages, and dendritic cells in STAD. In contrast, FGFR4 expression was negatively correlated with tumor-infiltrating lymphocytes. Interestingly, overexpression of FGFR1 in the NOG mouse model improved the immunotherapeutic impact of GC, while overexpression of FGFR4 impaired the effect. When combined with an FGFR4 inhibitor, the anti-tumor effect of anti-PD-1 treatment increased significantly in a GC xenograft mouse model with overexpressed FGFR4.

Conclusions

FGFRs has critical function in GC and associated with immune cell infiltration, which might be a potential prognosis biomarker and predictor of response to immunotherapy in GC.

Fibroblast growth factor receptor 3 overexpression mediates ALK inhibitor resistance in ALK-rearranged non-small cell lung cancer

The rearrangement of anaplastic lymphoma kinase (ALK) occurs in 3%‐5% of patients with non–small cell lung cancer (NSCLC) and confers sensitivity to ALK–tyrosine kinase inhibitors (TKIs). For the treatment of patients with ALK‐rearranged NSCLC, various additional ALK‐TKIs have been developed. Ceritinib is a second‐generation ALK‐TKI and has shown great efficacy in the treatment of patients with both newly diagnosed and crizotinib (a first‐generation ALK‐TKI)‐refractory ALK‐rearranged NSCLC. However, tumors can also develop ceritinib resistance. This may result from secondary ALK mutations, but other mechanisms responsible for this have not been fully elucidated. In this study, we explored the mechanisms of ceritinib resistance by establishing ceritinib‐resistant, echinoderm microtubule‐associated protein‐like 4 (EML4)‐ALK–positive H3122 cells and ceritinib‐resistant patient‐derived cells. We identified a mechanism of ceritinib resistance induced by bypass signals that is mediated by the overexpression and activation of fibroblast growth factor receptor 3 (FGFR3). FGFR3 knockdown by small hairpin RNA or treatment with FGFR inhibitors was found to resensitize the resistant cells to ceritinib in vitro and in vivo. FGFR ligands from either human serum or fetal bovine serum were able to activate FGFR3 and induce ceritinib resistance. A detailed analysis of ceritinib‐resistant patient‐derived specimens confirmed that tyrosine‐protein kinase Met (cMET) amplification induces ceritinib resistance. Amplified cMET counteractivated EGFR and/or Her3 and induced ceritinib resistance. These results reveal multiple ceritinib resistance mechanisms and suggest that ceritinib resistance might be overcome by identifying precise resistance mechanisms.

FGFR2 overexpression and compromised survival in diffuse-type gastric cancer in a large central European cohort

The significance of fibroblast growth factor receptor 2 (FGFR2) in gastric cancer (GC) has been studied predominantly in Asian patient cohorts. Data on White patients are scarce. Here, we aimed to independently validate the expression and putative tumor biological significance of FGFR2 in a large non-Asian GC cohort. Immunohistochemistry (IHC) was performed on large-area tissue sections from 493 patients with GC and evaluated using the HScore. GCs with moderate and strong FGFR2 expression were studied for Fgfr2 amplification using chromogenic in situ hybridization (CISH). Median overall survival was determined using the Kaplan–Meier method. The majority [240 (99.1%)] of FGFR2-positive GCs showed a variable combination of staining intensities with marked intratumoral heterogeneity, including weak [198 (40.2%) cases], moderate [145 (29.4%)], and strong [108 (21.9%)] staining in diverse combinations. 250 (50.9%) GCs expressed no FGFR2. Fgfr2 gene amplification was found in 40% of selected cases with high protein expression and was also heterogeneous at the cell level. FGFR2 protein expression did not correlate with patient survival in the entire cohort However, using different cutoff values, a negative correlation between FGFR2-expression and patient outcome was found for diffuse-type GC. FGFR2 expression was associated with a lower tumor grade and intestinal phenotype (p≤0.0001). FGFR2–positive diffuse-type GCs classify a small subset of patients with a poor tumor specific survival (5.29±1.3 vs. 14.67±1.9 months; p = 0.004).

Peptibody Based on FGFR1-Binding Peptides From the FGF4 Sequence as a Cancer-Targeting Agent

Targeted therapies are a promising alternative to conventional chemotherapy, with an increasing number of therapeutics targeting specific molecular aberrancies in cancer cells. One of the emerging targets for directed cancer treatments is fibroblast growth factor receptors (FGFRs), which are known to be involved in the pathogenesis and progression of multiple cancer types, specially in lung, bladder, and breast cancers. Here, we are demonstrating the development of the FGFR1-targeting agent based on the interactome screening approach, based on the isolation of binding regions from ligands interacting with the receptor. The parallel analysis by FGFR1 pull-down of chymotryptic peptides coupled with MS analysis, and PepSpot analysis yielded equivalent peptide sequences from FGF4, one of the FGFR1 ligands. Three sequences served as a basis for peptibody (Fc-fusion) generation, to overcome clinical limitations of peptidic agents, and two of them showed favorable FGFR1-binding in vitro and FGFR1-dependent internalization into cells. To validate if developed FGFR1-targeting peptibodies can be used for drug delivery, similar to the well-established concept of antibody–drug conjugates (ADCs), peptibodyF4_1 was successfully conjugated with monomethylauristatin E (MMAE), and has shown significant and specific toxicity toward FGFR1-expressing lung cancer cell lines, with nanomolar EC₅₀ values. Essentially, the development of new effective FGFR1 binders that comprise the naturally occurring FGFR-recognition peptides and Fc region ensuring high plasma stability, and long bloodstream circulation is an interesting strategy expanding targeted anticancer agents’ portfolio. Furthermore, identifying peptides effectively binding the receptor from sequences of its ligands is not limited to FGFRs and is an approach versatile enough to be a basis for a new peptide/peptibodies development strategy.

miR-301a-3p induced by endoplasmic reticulum stress mediates the occurrence and transmission of trastuzumab resistance in HER2-positive gastric cancer

Trastuzumab resistance negatively influences the clinical efficacy of the therapy for human epidermal growth factor receptor 2 (HER2) positive gastric cancer (GC), and the underlying mechanisms remain elusive. Exploring the mechanisms and finding effective approaches to address trastuzumab resistance are of great necessity. Here, we confirmed that endoplasmic reticulum (ER) stress-induced trastuzumab resistance by up-regulating miR-301a-3p in HER2-positive GC cells. Moreover, we elucidated that miR-301a-3p mediated trastuzumab resistance by down-regulating the expression of leucine-rich repeats and immunoglobulin-like domains containing protein 1 (LRIG1) and subsequently activating the expression of insulin-like growth factor 1 receptor (IGF-1R) and fibroblast growth factor receptor 1 (FGFR1) under ER stress. We also found that intercellular transfer of miR-301a-3p by exosomes disseminated trastuzumab resistance. The present study demonstrated that exosomal miR-301a-3p could serve as a non-invasive biomarker for trastuzumab resistance, which was maybe a novel potential therapeutic target to overcome trastuzumab resistance and improve the curative effect of trastuzumab in HER2-positive GC patients.

Identification of novel targets of miR-622 in hepatocellular carcinoma reveals common regulation of cooperating genes and outlines the oncogenic role of zinc finger CCHC-type containing 11

The poor prognosis of advanced hepatocellular carcinoma (HCC) is driven by diverse features including dysregulated microRNAs inducing drug resistance and stemness. Lin-28 homolog A (LIN28A) and its partner zinc finger CCHC-type containing 11 (ZCCHC11) cooperate in binding, oligouridylation and subsequent degradation of tumorsuppressive let-7 precursor microRNAs. Functionally, activation of LIN28A was recently shown to promote stemness and chemoresistance in HCC. However, the expression and regulation of LIN28A in HCC had been unclear. Moreover, the expression, regulation and function of ZCCHC11 in liver cancer remained elusive. In contrast to "one-microRNA-one-target" interactions, we identified common binding sites for miR-622 in both LIN28A and ZCCHC11, suggesting miR-622 to function as a superior pathway regulator. Applying comprehensive microRNA database screening, human hepatocytes and HCC cell lines, patient-derived tissue samples as well as "The Cancer Genome Atlas" (TCGA) patient cohorts, we demonstrated that loss of tumorsuppressive miR-622 mediates derepression and overexpression of LIN28A in HCC. Moreover, the cooperator of LIN28A, ZCCHC11, was newly identified as a prognostic and therapeutic target of miR-622 in liver cancer. Together, identification of novel miR-622 target genes revealed common regulation of cooperating genes and outlines the previously unknown oncogenic role of ZCCHC11 in liver cancer.

Discovery of 4,6-Disubstituted Pyrimidine Derivatives as Novel Dual VEGFR2/FGFR1 Inhibitors

Abnormalities in the FGFRs signaling pathway and VEGFR2 amplification often occur in a variety of tumors, and they synergistically promote tumor angiogenesis. Studies have shown that the up-regulation of FGF-2 is closely related to the resistance of VEGFR2 inhibitors. Activation of the FGFRs signal is a signal of compensatory angiogenesis after VEGFR2 resistance. Dual VEGFR2/FGFR1 inhibitors contribute to overcoming the resistance of VEGFR2 inhibitors and inhibit tumor growth significantly. Based on this, we designed and synthesized a series of 4,6-disubstituted pyrimidine derivatives as dual VEGFR2/FGFR1 inhibitors by the molecular hybridization strategy. 3-(2,6-Dichloro-3,5-dimethoxyphenyl)-1-{6-[(4-methoxyphenyl)amino]pyrimidin-4-yl}-1-methylurea (8b) had the best inhibitory activities against VEGFR2 and FGFR1 at 10 μM (82.2 % and 101.0 %, respectively), it showed moderate antiproliferative activities against A549 and KG-1 cell lines as well. Besides, molecular docking was also carried out to study the binding mode of 3-(2,6-dichloro-3,5-dimethoxyphenyl)-1-{6-[(4-methoxyphenyl)-amino]-pyrimidin-4-yl}-1-methylurea (8b) with VEGFR2 and FGFR1. These studies reveal that this series of compounds deserve further optimization.

Atractylenolide III predisposes miR-195-5p/FGFR1 signaling axis to exert tumor-suppressive functions in liver cancer

BACKGROUND

Antineoplastic activity of atractylenolide III (ATL) has been reported in several malignant tumors. However, its activity has not been completely clarified in hepatocellular carcinoma (HCC). Herein, anticancer effects and underlying molecular mechanisms of ATL were investigated in HCC cells in vitro.

METHODS

Cell viability was evaluated by CCK-8 assay. Cell migration and invasion were evaluated using the transwell assay. TUNEL staining was performed to evaluate cell apoptosis. Protein expression was measured by western blotting analysis. Online database TargetScan and luciferase reporter gene analysis were performed to validate FGFR1 as a target of miR-195-5p.

RESULTS

HepG2 and SMMC7721 cell growth, migration, and invasion were inhibited by ATL treatment in a dose-dependent pattern. ATL treatment-induced apoptosis of HepG2 and SMMC7721 cells. Intriguingly, ATL treatment unexpectedly inhibited FGFR1 protein expression in HepG2 and SMMC7721 cells. Knockdown of FGFR1 inhibited proliferation, migration, and invasion, and evoked apoptosis of HepG2 and SMMC7721 cells. We also found that ATL treatment could increase the expression of miR-195-5p, which as a posttranscriptional targeted FGFR1. In HCC tissues, miR-195-5p expression is negatively correlated with FGFR1. Furthermore, the antiproliferative and proapoptotic roles of miR-195-5p were neutralized by overexpressed FGFR1 in HCC cells.

CONCLUSION

ATL effectively repressed growth and induced apoptosis of human HCC cells through the upregulation of miR-195-5p to downregulate FGFR1 expression.

PRACTICAL APPLICATIONS

Atractylenolide III as a bioactive anticancer adjuvant medication will provide chemosensitization strategy for reversing the drug resistance of HCC.

Combined De-Repression of Chemoresistance Associated Mitogen-Activated Protein Kinase 14 and Activating Transcription Factor 2 by Loss of microRNA-622 in Hepatocellular Carcinoma

Chemoresistance is a major hallmark driving the progression and poor prognosis of hepatocellular carcinoma (HCC). Limited chemoresponse of HCC was demonstrated to be mediated by mitogen-activated protein kinase 14 (MAPK14) and activating transcription factor 2 (ATF2). Recently, we have demonstrated loss of control of RAS-RAF-ERK-signaling as a consequence of miR-622 downregulation in HCC. However, the majority of target genes of this potent tumorsuppressive microRNA had remained elusive. The MAPK14-ATF2-axis represents a collateral pathway ensuring persisting ERK-activation in the presence of sorafenib-mediated RAF-inhibition. In contrast to the function of the MAPK14-ATF2-axis, both the expression and regulation of MAPK14 and ATF2 in human HCC remained to be clarified. We found combined overexpression of MAPK14 and ATF2 in human HCC cells, tissues and in sorafenib resistant cell lines. High expression of MAPK14 and ATF2 was associated with reduced overall survival in HCC patients. Deciphering the molecular mechanism promoting combined upregulation of MAPK14 and ATF2 in HCC, we revealed that miR-622 directly targets both genes, resulting in combined de-repression of the MAPK14-ATF2-axis. Together, miR-622 represents a superior regulator of both RAS-RAF-ERK as well as MAPK14-ATF2-signaling pathways in liver cancer.

Clinical difference between fibroblast growth factor receptor 2 subclass, type IIIb and type IIIc, in gastric cancer

Fibroblast growth factor receptor 2 (FGFR2) has two isoforms: IIIb type and IIIc type. Clinicopathologic significance of these two FGFR2 subtypes in gastric cancer remains to be known. This study aimed to clarify the clinicopathologic difference of FGFR2IIIb and/or FGFR2IIIc overexpression. A total of 562 patients who underwent gastrectomy was enrolled. The expressions of FGFR2IIIb and FGFR2IIIc were retrospectively examined by immunohistochemistry or fluorescence in situ hybridization (FISH) using the 562 gastric tumors. We evaluated the correlation between clinicopathologic features and FGFR2IIIb overexpression and/or FGFR2IIIc overexpression in gastric cancer. FGFR2IIIb overexpression was observed in 28 cases (4.9%), and FGFR2IIIc overexpression was observed in four cases (0.7%). All four FGFR2IIIc cases were also positive for FGFR2IIIb, but not in the same cancer cells. FGFR2IIIb and/or FGFR2IIIc overexpression was significantly correlated with lymph node metastasis and clinical stage. Both FGFR2IIIb and FGFR2IIIc were significantly associated with poor overall survival. A multivariate analysis showed that FGFR2IIIc expression was significantly correlated with overall survival. FISH analysis indicated that FGFR2 amplification was correlated with FGFR2IIIb and/or FGFR2IIIc overexpression. These findings suggested that gastric tumor overexpressed FGFR2IIIc and/or FGFR2IIIb at the frequency of 4.9%. FGFR2IIIc overexpression might be independent prognostic factor for patients with gastric cancer.

Rapid Resistance of FGFR-driven Gastric Cancers to Regorafenib and Targeted FGFR Inhibitors can be Overcome by Parallel Inhibition of MEK

Amplification or overexpression of the FGFR family of receptor tyrosine kinases occurs in a significant proportion of gastric cancers. Regorafenib is a multikinase inhibitor of angiogenic and oncogenic kinases, including FGFR, which showed activity in the randomized phase II INTEGRATE clinical trial in advanced gastric cancer. There are currently no biomarkers that predict response to this agent, and whether regorafenib is preferentially active in FGFR-driven cancers is unknown. Through screening 25 gastric cancer cell lines, we identified five cell lines that were exquisitely sensitive to regorafenib, four of which harbored amplification or overexpression of FGFR family members. These four cell lines were also sensitive to the FGFR-specific inhibitors, BGJ398, erdafitinib, and TAS-120. Regorafenib inhibited FGFR-driven MAPK signaling in these cell lines, and knockdown studies confirmed their dependence on specific FGFRs for proliferation. In the INTEGRATE trial cohort, amplification or overexpression of FGFRs 1-4 was detected in 8%-19% of cases, however, this was not associated with improved progression-free survival and no objective responses were observed in these cases. Further preclinical analyses revealed FGFR-driven gastric cancer cell lines rapidly reactivate MAPK/ERK signaling in response to FGFR inhibition, which may underlie the limited clinical response to regorafenib. Importantly, combination treatment with an FGFR and MEK inhibitor delayed MAPK/ERK reactivation and synergistically inhibited proliferation of FGFR-driven gastric cancer cell lines. These findings suggest that upfront combinatorial inhibition of FGFR and MEK may represent a more effective treatment strategy for FGFR-driven gastric cancers.

Fibroblast growth factor receptor 4 as a prognostic indicator in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) constitutes up to 15% of all breast cancers. It is one of the most aggressive breast cancers and is more prone to metastasize compared with other subtypes. Breast cancer patients with this subtype usually have a poor prognosis. Fibroblast growth factor receptor 4 (FGFR4) belongs to the receptor tyrosine kinase (RTK) family, and early analyses identified that FGFR4 was involved in breast cancer. However, the prognostic effect of FGFR4 on TNBC is unknown. In the present study, we investigated the association between FGFR4 and TNBC prognosis.

Methods

A total of 282 TNBC patients were enrolled. FGFR4 protein expression was detected in these 282 TNBC patients using immunohistochemistry (IHC).

Results

In the present study, FGFR4 was highly expressed in TNBC patients. Lymph node metastasis (LNM) (P=0.033) and p53 status (P=0.019) were associated with high FGFR4 expression. Univariate analysis identified high FGFR4 expression (P=0.016) as a prognostic predictor, and multivariate analysis found that high FGFR4 expression (P=0.016) was an independent prognostic factor. The Kaplan-Meier survival curve showed that high FGFR4 protein expression was correlated with poorer overall survival (OS).

Conclusions

The results of our present study show that FGFR4 protein expression is correlated with a worse prognosis in TNBC.

The changing face of gastric cancer: epidemiologic trends and advances in novel therapies

Gastric cancer is an aggressive solid-tumor malignancy with poor prognosis. The epidemiologic face of gastric cancer is changing and further insight into its heterogenous immunohistopathologic nature is needed to develop personalized therapies for specific patient populations. In this review, we highlight changes in gastric cancer epidemiology with a special emphasis on racial and ethnic variations and discuss the implications of current clinical and preclinical treatment advances.

FGFR4: A promising therapeutic target for breast cancer and other solid tumors

The fibroblast growth factor receptor (FGFR) signaling pathway has long been known to cancer researchers because of its role in cell survival, proliferation, migration, and angiogenesis. Dysregulation of FGFR signaling is frequently reported in cancer studies, but most of these studies focus on FGFR1-3. However, there is growing evidence implicating an important and unique role of FGFR4 in oncogenesis, tumor progression, and resistance to anti-tumor therapy in multiple types of cancer. Importantly, there are several novel FGFR4-specific inhibitors in clinical trials, making FGFR4 an attractive target for further research. In this review, we focus on assessing the role of FGFR4 in cancer, with an emphasis on breast cancer. First, the structure, physiological functions and downstream signaling pathways of FGFR4 are introduced. Next, different mechanisms reported to cause aberrant FGFR4 activation and their functions in cancer are discussed, including FGFR4 overexpression, FGF ligand overexpression, FGFR4 somatic hotspot mutations, and the FGFR4 G388R single nucleotide polymorphism. Finally, ongoing and recently completed clinical trials targeting FGFRs in cancer are reviewed, highlighting the therapeutic potential of FGFR4 inhibition for the treatment of breast cancer.

Expression Atlas of FGF and FGFR Genes in Pancancer Uncovered Predictive Biomarkers for Clinical Trials of Selective FGFR Inhibitors

BACKGROUND

Clinical trials based on FGFR mutation or amplification as a druggable target of FGFR inhibitors have produced disappointing clinical outcomes. Therefore, the identification of predictive biomarkers for FGFR-targeted agents has remained a crucial issue.

METHODS

Expression profiles of FGFs and FGFRs in 8,111 patients with 24 types of solid tumors and 879 tumor cell lines along with drug sensitivity data were obtained and followed by integrative bioinformatics analysis.

RESULTS

FGFs and FGFRs were frequently dysregulated in pancancer. Most of the expression of FGFs and FGFRs were significantly associated with overall survival in at least two cancer types. Moreover, tumor cell lines with high FGFR1/3 expression were more sensitive to FGFR inhibitor PD173074, especially in breast, liver, lung and ovarian cancer. The predicted positive ratios of FGFR1-4 were generally over 10% in most tumor types, especially in squamous cell carcinoma. High positive FGFR1 or 3 expression ratios were predicted in cholangiocarcinoma (58%), followed by bladder cancer (42%), endometrial carcinoma (35%), and ovarian cancer (34%).

CONCLUSIONS

FGFR expression was a promising predictive biomarker for FGFR inhibition response in clinical trials, and different combinations of FGFR genes should be used in screening for patients in certain tumor types.

LncRNA AGAP2-AS1 augments cell viability and mobility, and confers gemcitabine resistance by inhibiting miR-497 in colorectal cancer

Background: Most recently, long non-coding RNAs (lncRNAs) emerge as crucial modulators in many biological processes, such as embryonic development, cell growth, and tumorigenesis. However, the correlations between lncRNAs and colorectal cancer (CRC) cell proliferation, metastasis, and gemcitabine resistance are not well understood.

Results: The expression of AGAP2-AS1 was overexpressed in CRC tissues and negatively correlated with the survival of patients with CRC. AGAP2-AS1 promoted CRC cell proliferation and inhibited apoptosis. Moreover, AGAP2-AS1 enhanced the chemoresistance of CRC cells to gemcitabine. In addition, AGAP2-AS1 enhanced the migration and invasion of CRC cells. Mechanistic studies showed that AGAP2-AS1 regulated fibroblast growth factor receptor 1 (FGFR1) expression by sponging miR-497 in CRC progression.

Conclusion: We identified an oncogenic role of AGAP2-AS1 in the development and progression of CRC.

Methods: qRT-PCR was used to measure the expression of AGAP2 Antisense RNA 1 (AGAP2-AS1) in 116 cases of CRC and adjacent normal tissues. Luciferase reporter assays was used to detect the interaction between AGAP2-AS1 and miR-497. The xenograft tumor experiment was used to study the in vivo function of AGAP2-AS1.

Update on gastric cancer treatments and gene therapies

Gastric cancer is an active topic of clinical and basic research due to high morbidity and mortality. To date, gastrectomy and chemotherapy are the only therapeutic options for gastric cancer patients, but drug resistance, either acquired or primary, is the main cause for treatment failure. Differences in development and response to cancer treatments have been observed among ethnically diverse GC patient populations. In spite of major incidence, GC Asian patients have a significantly better prognosis and response to treatments than Caucasian ones due to genetic discordances between the two populations. Gene therapy could be an alternative strategy to overcome such issues and especially CRISPR/Cas9 represents one of the most intriguing gene-editing system. Thus, in this review article, we want to provide an update on the currently used therapies for the treatment of advanced GC. Graphical abstract.

Integrated Analysis of Structural Variation and RNA Expression of FGFR2 and Its Splicing Modulator ESRP1 Highlight the ESRP1amp-FGFR2norm-FGFR2-IIIchigh Axis in Diffuse Gastric Cancer

Gastric Cancer (GC) is one of the most common and deadliest types of cancer in the world. To improve GC prognosis, increasing efforts are being made to develop new targeted therapies. Although FGFR2 genetic amplification and protein overexpression in GC have been targeted in clinical trials, so far no improvement in patient overall survival has been found. To address this issue, we studied genetic and epigenetic events affecting FGFR2 and its splicing regulator ESRP1 in GC that could be used as new therapeutic targets or predictive biomarkers. We performed copy number variation (CNV), DNA methylation, and RNA expression analyses of FGFR2/ESRP1 across several cohorts. We discovered that both genes were frequently amplified and demethylated in GC, resulting in increased ESRP1 expression and of a specific FGFR2 isoform: FGFR2-IIIb. We also showed that ESRP1 amplification in GC correlated with a significant decreased expression of FGFR2-IIIc, an alternative FGFR2 splicing isoform. Furthermore, when we performed a survival analysis, we observed that patients harboring diffuse-type tumors with low FGFR2-IIIc expression revealed a better overall survival than patients with FGFR2-IIIc high-expressing diffuse tumors. Our results encourage further studies on the role of ESRP1 in GC and support FGFR2-IIIc as a relevant biomarker in GC.

Pathological and Prognostic Impacts of FGFR2 Overexpression in Gastric Cancer: A Meta-Analysis

Fibroblast growth factor receptor-2 (FGFR2) protein expression by immunohistochemistry has been reported in up to 60% of patients with gastric cancer (GC). However, the clicopathological impacts of high FGFR2 expression have not been consistent among studies. We conducted this meta-analysis to evaluate the pathological and prognostic significance of FGFR2 overexpression in patients with GC. A systematic search of the electronic databases including PubMed, PMC, EMBASE, and Google Scholar was performed. From ten studies, 4,294 patients were included in the pooled analyses of odds ratios (ORs) with 95% confidence intervals (CIs) for pathological features and hazard ratios (HRs) with 95% CIs for overall survival according to the FGFR2 expression status. Compared with tumors showing low FGFR2 expression, GCs with FGFR2 overexpression revealed deeper depth of invasion (pT3-4) (OR = 2.63, 95% CI: 1.70-4.06, p < 0.0001), higher rate of lymph node metastasis (OR = 1.87, 95% CI: 1.31-2.67, p < 0.0001), and more advanced stage (III-IV) (OR = 1.78, 95% CI: 1.07-2.96, p = 0.03). In addition, patients with FGFR2-overexpressed GC showed significantly worse survival than those with FGFR2-low tumor (HR = 1.40, 95% CI: 1.25-1.58, p < 0.00001). In conclusion, this meta-analysis indicates that FGFR2 overexpression is associated with poor pathological features and prognosis in patients with GC.

FGFR1 is an independent prognostic factor and can be regulated by miR-497 in gastric cancer progression

Fibroblast growth factor receptor 1 (FGFR1) has been reported in gastric cancer to be a prognostic factor. However, miR-497-targeted FGFR1 has not been explored in the carcinogenesis of gastric cancer. The present study intended to revalidate the prognostic significance of FGFR1 in patients with gastric cancer, and the mechanism of miR-497-regulated FGFR1 was investigated in gastric cancer cell proliferation and apoptosis. The messenger RNA (mRNA) and protein levels were assayed by RT-qPCR and western blotting, respectively. The targeted genes were predicted by a bioinformatics algorithm and confirmed by a dual luciferase reporter assay. Cell proliferation was analyzed by CCK-8 assay. Annexin V-FITC/PI staining was used to evaluate the apoptosis in AGS and SGC-7901 cells. FGFR1 was frequently up-regulated in gastric cancer tissues and associated with poor overall survival in patients with gastric cancer. Interestingly, FGFR1 loss-of-function resulted in a significant growth inhibition and apoptosis in AGS and SGC-7901 cells. In addition, we found that miR-497 was inhibited in gastric cancer tissues and cell lines, while overexpression of miR-497 could suppress proliferation and induce apoptosis in AGS and SGC-7901 cells. Importantly, bioinformatics analysis and experimental data suggested that FGFR1 was a direct target of miR-497, which could inhibit FGFR1 expression when transfected with miR-497 mimics. Furthermore, we found that overexpression of FGFR1 reversed the growth inhibition and apoptosis of miR-497 mimics in AGS and SGC-7901 cells. These findings suggested that overexpression of miR-497 inhibited proliferation and induced apoptosis in gastric cancer through the suppression of FGFR1.

Overexpression of FGFR1 Promotes Peritoneal Dissemination Via Epithelial-to-Mesenchymal Transition in Gastric Cancer

BACKGROUND

Peritoneal dissemination (PD) is one of the most common causes of cancer-related mortality in gastric cancer (GC). We aimed to identify PD-associated genes and investigate their role in GC.

MATERIALS AND METHODS

We identified FGFR1 as a putative PD-associated gene using a bioinformatics approach. The biological significance of FGFR1 in epithelial-to-mesenchymal transition (EMT) was evaluated according to the correlation with genes that participated in EMT and FGFR1 knockdown experiments. The associations between FGFR1 expression and the clinicopathological features were examined.

RESULTS

FGFR1 expression positively correlated with SNAI1, VIM and ZEB1 expression, and negatively correlated with CDH1 expression. Knockdown of FGFR1 suppressed the malignant phenotype of GC cells. High FGFR1 expression significantly correlated with the peritoneal lavage cytology and synchronous PD positivity as well as poor prognosis.

CONCLUSION

High FGFR1 expression was associated with PD via promotion of EMT and led to a poor prognosis of GC patients.

Long non-coding RNA ANRIL promotes tumorgenesis through regulation of FGFR1 expression by sponging miR-125a-3p in head and neck squamous cell carcinoma

ANRIL (CDKN2B antisense RNA 1, CDKN2B-AS1) is involved in the progression of various cancers. However, its role in head and neck squamous cell carcinoma (HNSCC) remains unclear. In this study, we found that ANRIL expression was upregulated in HNSCC and correlated with tumor progression. Further functional analysis showed that knockdown of ANRIL significantly inhibited proliferation in vivo and in vitro. ANRIL functioned as a ceRNA (competing endogenous RNAs) for miR-125a-3p and upregulated FGFR1 (fibroblast growth factor receptor-1), which could promote tumor growth. Moreover, we confirmed that ANRIL promoted HNSCC activity via FGFR1 with a FGFR1 inhibitor in vivo and in vitro. Thus, it could be concluded that ANRIL promoted the progression of HNSCC via miR-125a-3p/FGFR1/MAPK signaling, which might provide a new target for the diagnosis and treatment of HNSCC.

ODM-203, a Selective Inhibitor of FGFR and VEGFR, Shows Strong Antitumor Activity, and Induces Antitumor Immunity

Alterations in the gene encoding for the FGFR and upregulation of the VEGFR are found often in cancer, which correlate with disease progression and unfavorable survival. In addition, FGFR and VEGFR signaling synergistically promote tumor angiogenesis, and activation of FGFR signaling has been described as functional compensatory angiogenic signal following development of resistance to VEGFR inhibition. Several selective small-molecule FGFR kinase inhibitors are currently in clinical development. ODM-203 is a novel, selective, and equipotent inhibitor of the FGFR and VEGFR families. In this report we show that ODM-203 inhibits FGFR and VEGFR family kinases selectively and with equal potency in the low nanomolar range (IC₅₀ 6-35 nmol/L) in biochemical assays. In cellular assays, ODM-203 inhibits VEGFR-induced tube formation (IC₅₀ 33 nmol/L) with similar potency as it inhibits proliferation in FGFR-dependent cell lines (IC₅₀ 50-150 nmol/L). In vivo, ODM-203 shows strong antitumor activity in both FGFR-dependent xenograft models and in an angiogenic xenograft model at similar well-tolerated doses. In addition, ODM-203 inhibits metastatic tumor growth in a highly angiogenesis-dependent kidney capsule syngenic model. Interestingly, potent antitumor activity in the subcutaneous syngenic model correlated well with immune modulation in the tumor microenvironment as indicated by marked decrease in the expression of immune check points PD-1 and PD-L1 on CD8 T cells and NK cells, and increased activation of CD8 T cells. In summary, ODM-203 shows equipotent activity for both FGFR and VEGFR kinase families and antitumor activity in both FGFR and angigogenesis models.

A randomized, open-label study of the efficacy and safety of AZD4547 monotherapy versus paclitaxel for the treatment of advanced gastric adenocarcinoma with FGFR2 polysomy or gene amplification

Background

Approximately 5%-10% of gastric cancers have a fibroblast growth factor receptor-2 (FGFR2) gene amplification. AZD4547 is a selective FGFR-1, 2, 3 tyrosine kinase inhibitor with potent preclinical activity in FGFR2 amplified gastric adenocarcinoma SNU16 and SGC083 xenograft models. The randomized phase II SHINE study (NCT01457846) investigated whether AZD4547 improves clinical outcome versus paclitaxel as second-line treatment in patients with advanced gastric adenocarcinoma displaying FGFR2 polysomy or gene amplification detected by fluorescence in situ hybridization.

Patients and methods

Patients were randomized 3:2 (FGFR2 gene amplification) or 1:1 (FGFR2 polysomy) to AZD4547 or paclitaxel. Patients received AZD4547 80 mg twice daily, orally, on a 2 weeks on/1 week off schedule of a 21-day cycle or intravenous paclitaxel 80 mg/m2 administered weekly on days 1, 8, and 15 of a 28-day cycle. The primary end point was progression-free survival (PFS). Safety outcomes were assessed and an exploratory biomarker analysis was undertaken.

Results

Of 71 patients randomized (AZD4547 n = 41, paclitaxel n = 30), 67 received study treatment (AZD4547 n = 40, paclitaxel n = 27). Among all randomized patients, median PFS was 1.8 months with AZD4547 and 3.5 months with paclitaxel (one-sided P = 0.9581); median follow-up duration for PFS was 1.77 and 2.12 months, respectively. The incidence of adverse events was similar in both treatment arms. Exploratory biomarker analyses revealed marked intratumor heterogeneity of FGFR2 amplification and poor concordance between amplification/polysomy and FGFR2 mRNA expression.

Conclusions

AZD4547 did not significantly improve PFS versus paclitaxel in gastric cancer FGFR2 amplification/polysomy patients. Considerable intratumor heterogeneity for FGFR2 gene amplification and poor concordance between FGFR2 amplification/polysomy and FGFR2 expression indicates the need for alternative predictive biomarker testing. AZD4547 was generally well tolerated.

Established gastric cancer cell lines transplantable into C57BL/6 mice show fibroblast growth factor receptor 4 promotion of tumor growth

Previously no mouse gastric cancer cell lines have been available for transplantation into C57BL/6 mice. However, a gastric cancer model in immunocompetent mice would be useful for analyzing putative therapies. N-Methyl-N-nitrosourea (MNU) was given in drinking water to C57BL/6 mice and p53 heterozygous knockout mice. Only 1 tumor from a p53 knockout mouse could be cultured and the cells s.c. transplanted into a C57BL/6 mouse. We cultured this s.c. tumor, and subcloned it. mRNA expression in the most aggressive YTN16 subline was compared to the less aggressive YTN2 subline by microarray analysis, and fibroblast growth factor receptor 4 (FGFR4) in YTN16 cells was knocked out with a CRISPR/Cas9 system and inhibited by an FGFR4 selective inhibitor, BLU9931. These transplanted cell lines formed s.c. tumors in C57BL/6 mice. Four cell lines (YTN2, YTN3, YTN5, YTN16) were subcloned and established. Their in vitro growth rates were similar. However, s.c. tumor establishment rates, metastatic rates, and peritoneal dissemination rates of YTN2 and YTN3 were lower than for YTN5 and YTN16. YTN16 established 8/8 s.c. tumors, 7/8 with lung metastases, 3/8 with lymph node metastases and 5/5 with peritoneal dissemination. FGFR4 expression by YTN16 was 121-fold higher than YTN2. FGFR4-deleted YTN16 cells failed to form s.c. tumors and showed lower rates of peritoneal dissemination. BLU9931 significantly inhibited the growth of peritoneal dissemination of YTN16. These studies present the first transplantable mouse gastric cancer lines. Our results further indicate that FGFR4 is an important growth signal receptor in gastric cancer cells with high FGFR4 expression.

Low-level clonal FGFR2 amplification defines a unique molecular subtype of intrahepatic cholangiocarcinoma in a Chinese population

Intrahepatic cholangiocarcinoma (ICC) is a subtype of primary liver cancer rarely curable by surgery that is increasing rapidly in incidence. Chromosomal translocations and amplifications of the fibroblast growth factor receptor 2 (FGFR2) locus are present in several kinds of tumors including ICC, but their incidence has not been assessed in Chinese patients. Using break-apart probes and by determining the ratios of FGFR2/chromosome enumeration probe (CEP) 10 double-color probes, we evaluated 122 ICCs for the presence of FGFR2 translocations and amplifications, respectively, by fluorescence in situ hybridization. We further determined FGFR2 protein expression by immunohistochemistry and analyzed the clinicopathologic records of the patients. Eight tumors (6.6%) had FGFR2 translocations, whereas 15 (12.3%) had low-level FGFR2 amplification. Interestingly, the tumors that showed both translocation and low-level amplification frequently were of the mass-forming type. Compared with the ICCs with normal FGFR2s, tumors with amplifications secreted less mucus (P = .017) and typically were accompanied by hepatitis B virus infection (P = .004). Tumors with low-level amplification generally were of lower stage (P = .013) and associated with better overall survival (P = .017). As tumors with FGFR2 amplification exhibit different biology from lesions with a normal gene, low-level amplification of FGFR2 may play an important role in tumor progression and may be a marker for targeted therapy.

A novel gene expression-based prognostic scoring system to predict survival in gastric cancer

Analysis of gene expression patterns in gastric cancer (GC) can help to identify a comprehensive panel of gene biomarkers for predicting clinical outcomes and to discover potential new therapeutic targets. Here, a multi-step bioinformatics analytic approach was developed to establish a novel prognostic scoring system for GC. We first identified 276 genes that were robustly differentially expressed between normal and GC tissues, of which, 249 were found to be significantly associated with overall survival (OS) by univariate Cox regression analysis. The biological functions of 249 genes are related to cell cycle, RNA/ncRNA process, acetylation and extracellular matrix organization. A network was generated for view of the gene expression architecture of 249 genes in 265 GCs. Finally, we applied a canonical discriminant analysis approach to identify a 53-gene signature and a prognostic scoring system was established based on a canonical discriminant function of 53 genes. The prognostic scores strongly predicted patients with GC to have either a poor or good OS. Our study raises the prospect that the practicality of GC patient prognosis can be assessed by this prognostic scoring system.

A novel non-ATP competitive FGFR1 inhibitor with therapeutic potential on gastric cancer through inhibition of cell proliferation, survival and migration

Fibroblast growth factor receptor 1 (FGFR1), belonging to receptor tyrosine kinases (RTKs), possesses various biological functions. Over-expression of FGFR1 has been observed in multiple human malignancies. Hence, targeting FGFR1 is an attractive prospect for the advancement of cancer treatment options. Here, we present a novel small molecular FGFR1 inhibitor L16H50, which can inhibit FGFR1 kinase in an ATP-independent manner. It potently inhibits FGFR1-mediated signaling in a gastric cancer cell line, resulting in inhibition of cell growth, survival and migration. It also displays an outstanding anti-tumor activity in a gastric cancer xenograft tumor model by targeting FGFR1 signaling. These results show that L16H50 is a potent non-ATP-competitive FGFR1 inhibitor and may provide strong rationale for its evaluation in gastric cancer patients.

Prognostic roles for fibroblast growth factor receptor family members in malignant peripheral nerve sheath tumor

Background

Malignant peripheral nerve sheath tumors (MPNST) are rare, highly malignant, and poorly understood sarcomas. The often poor outcome of MPNST highlights the necessity of identifying prognostic predictors for this aggressive sarcoma. Here, we investigate the role of fibroblast growth factor receptor (FGFR) family members in human MPNSTs.

Results

aCGH and bioinformatics analysis identified frequent amplification of the FGFR1 gene. FISH analysis revealed that 26.9% MPNST samples had amplification of FGFR1, with both focal and polysomy patterns observed. IHC identified that FGFR1 protein expression was positively correlated with FGFR1 gene amplification. High expression of FGFR1 protein was associated with better overall survival (OS) and was an independent prognostic predictor for OS of MPNST patients. Additionally, combined expression of FGFR1 and FGFR2 protein characterized a subtype of MPNST with better OS. FGFR4 protein was expressed 82.3% of MPNST samples, and was associated with poor disease-free survival.

Materials and Methods

We performed microarray-based comparative genomic hybridization (aCGH) profiling of two cohorts of primary MPNST tissue samples including 25 patients treated at The University of Texas MD Anderson Cancer Center and 26 patients from Tianjin Medical University Cancer Institute and Hospital. Fluorescence in situ hybridization (FISH) was used to validate the gene amplification detected by aCGH analysis. Another cohort of 63 formalin-fixed paraffin-embedded MPNST samples (including 52 samples for FISH assay) was obtained to explore FGFR1, 2, 3, and 4 protein expression by immunohistochemical (IHC) analysis.

Conclusions

Our integrated genomic and molecular studies provide evidence that FGFRs play different prognostic roles in MPNST.

Evaluation of FGFR3 as a Therapeutic Target in Head and Neck Squamous Cell Carcinoma

BACKGROUND

Although head and neck squamous cell carcinoma (HNSCC) is the sixth most common tumour entity worldwide, it remains a clinical challenge. Large-scale explorative genomic projects have identified several genes as potential targets for therapy, including fibroblast growth factor receptor 3 (FGFR3).

AIMS

The aim of this study was to investigate the biological significance of wild-type and mutated FGFR3 to evaluate its potential as a novel therapeutic target in HNSCC.

METHODS

FGFR3 protein expression was analysed in a large HNSCC tissue cohort (n = 536) and FGFR3 mRNA expression from The Cancer Genome Atlas (TCGA; n = 520). Moreover, FGFR3 wild-type and mutant versions were overexpressed in vitro, and both proliferation and migration was assessed with and without BGJ398 (a specific FGFR1-3 inhibitor) treatment.

RESULTS

Although FGFR3 expression for both cohorts decreased during tumour progression, high FGFR3 expression levels were observed in a small subset of patients. In vitro, FGFR3 overexpression led to increased proliferation, whereas migration was not altered. Moreover, FGFR3-overexpressing cells were more sensitive to BGJ398. Cells overexpressing FGFR3 mutant versions showed increased proliferation compared to wild-type FGFR3 under serum-reduced conditions and were largely as sensitive as the wild-type protein to BGJ398.

CONCLUSIONS

Taken together, the results of this study demonstrate that although FGFR3 expression decreases during HNSSC progression, it plays an important role in tumour cell proliferation and thus may be a potential target for therapy in selected patients suffering from this dismal tumour entity.

FGFR Family Members Protein Expression as Prognostic Markers in Oral Cavity and Oropharyngeal Squamous Cell Carcinoma

Introduction

Fibroblast growth factor receptor family member proteins (FGFR1–4) have been identified as promising novel therapeutic targets and prognostic markers in a wide spectrum of solid tumors. The present study investigates the expression and prognostic value of four FGFR family member proteins in a large multicenter oral cavity squamous cell carcinoma (OCSCC) and oropharyngeal squamous cell carcinoma (OPSCC) cohort.

Methods

Protein expression of FGFR1–4 was determined by immunohistochemistry on tissue microarrays containing 951 formalin-fixed paraffin embedded OCSCC and OPSCC tissues from the University Medical Center Utrecht and University Medical Center Groningen. Protein expression was correlated to overall survival using Cox regression models, and bootstrapping was performed as internal validation.

Results

FGFR proteins were highly expressed in 39–64 % of OCSCC and 63–79 % of OPSCC. Seventy-three percent (299/412) of OCSCC and 85 % (305/357) of OPSCC highly co-expressed two or more FGFR family member proteins. FGFR1 protein was more frequently highly expressed in human papillomavirus (HPV)-negative OPSCC than HPV-positive OPSCC (82 vs. 65 %; p = 0.008). Furthermore, protein expression of FGFR family members was not related to overall survival in OCSCC or OPSCC (p > 0.05).

Conclusion

FGFR family members are frequently highly expressed in OCSCC and OPSCC. These FGFR family member proteins are therefore potential targets for novel therapies that are urgently required to improve survival of OCSCC and OPSCC patients.

Electronic supplementary material

The online version of this article (doi:10.1007/s40291-016-0204-5) contains supplementary material, which is available to authorized users.

Different clinical significance of FGFR1-4 expression between diffuse-type and intestinal-type gastric cancer

Background

Receptor tyrosine kinases promote tumor progression in many cancers, although oncologic activation differs between diffuse-type gastric cancer (DGC) and intestinal-type gastric cancer (IGC). Fibroblast growth factor receptor (FGFR) is one RTK, and we previously reported the clinical significance of FGFR1, 2, 3, and 4 in gastric cancer. The aim of the present study was to reevaluate the clinical significance of FGFR1–4 expression separately in DGC and IGC.

Methods

Tumor samples, including 109 DGCs and 100 IGCs, were obtained from patients who underwent gastrectomy between 2003 and 2007 in our institution. The expression levels of FGFR1, 2, 3, and 4 were measured in the tumors by immunohistochemical analysis.

Results

In DGC, high expression of FGFR1, FGFR2, or FGFR4 was significantly associated with the depth of invasion, lymph-node metastasis, pathological stage, and distant metastasis or recurrent disease. Patients with high expression of FGFR1, FGFR2, or FGFR4 had significantly poorer disease-specific survival (DSS) (p = 0.009, p = 0.001, and p = 0.023, respectively). In IGC, only FGFR4 expression was significantly associated with factors relative to tumor progression and with shorter DSS (p = 0.012).

Conclusion

In conclusion, high FGFR4 expression correlated with tumor progression and survival in both DGC and IGC, whereas high expression of FGFR1 and 2 correlated with tumor progression and survival in only DGC.

FGFR2 in gastric cancer: protein overexpression predicts gene amplification and high H-index predicts poor survival

FGFR2 gene amplification, and resulting FGFR2 protein overexpression, is rare in gastric cancer patients, and development of an accurate and widely available method for mass screening to identify patients who may respond to treatment with fibroblast growth factor receptor (FGFR) inhibitors is important. We first screened 312 gastric cancer patients with known copy number variations by FGFR2b immunohistochemistry using FPR2-D, an isoform-specific antibody. Next, we performed immunohistochemistry on tissue microarrays from 1574 gastric cancer patients. Selected cases were analyzed for FGFR2 amplification by FISH. In addition, FGFR2b overexpression was studied in 88 matched primary and metastatic gastric cancers. In the first cohort, FGFR2b immunohistochemistry results correlated very well with those of copy number variation (r=0.79) and FISH (r=1.0). In total, FGFR2b overexpression was identified in 73 of 1974 gastric cancers (4%). The concordance between immunohistochemistry and FISH was extremely high; all 2+ and 3+ cases identified by immunohistochemistry were FGFR2 amplified. In the matched primary and metastatic gastric cancer pairs, the positivity and percentage of positive tumor cells were significantly higher in metastatic gastric cancers than in primary gastric cancers (8% vs 3% and 75% vs 47%, respectively; P<0.001). FGFR2b overexpression was significantly more frequent in gastric cancers with diffuse subtype (P=0.01) and higher N stage (P=0.006). FGFR2b overexpression with H-score ≥150 were independent prognostic factors for overall survival with hazard ratio of 1.836 (95% confidence interval, 1.034-3.261; P=0.038). FGFR2b positivity in immunohistochemistry was strongly correlated with FGFR2 amplification. Given the low frequency of FGFR2 amplification in gastric cancers, FGFRb2 immunohistochemistry is an accurate screening tool to detect FGFR2 amplification, and both primary and metastatic gastric cancer tissues should be tested to select gastric cancer patients for treatment with FGFR2 inhibitors.

Upregulated lncRNA-UCA1 contributes to progression of hepatocellular carcinoma through inhibition of miR-216b and activation of FGFR1/ERK signaling pathway

The long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) has been recently shown to be dysregulated, which plays an important role in the progression of several cancers. However, the biological role and clinical significance of UCA1 in the carcinogenesis of hepatocellular carcinoma (HCC) remain unclear. Herein, we found that UCA1 was aberrantly upregulated in HCC tissues and associated with TNM stage, metastasis and postoperative survival. UCA1 depletion inhibited the growth and metastasis of HCC cell lines in vitro and in vivo. Furthermore, UCA1 could act as an endogenous sponge by directly binding to miR-216b and downregulation miR-216b expression. In addition, UCA1 could reverse the inhibitory effect of miR-216b on the growth and metastasis of HCC cells, which might be involved in the derepression of fibroblast growth factor receptor 1 (FGFR1) expression, a target gene of miR-216b, and the activation of ERK signaling pathway. Taken together, our data highlights the pivotal role of UCA1 in the tumorigenesis of HCC. Moreover, the present study elucidates a novel lncRNA-miRNA-mRNA regulatory network that is UCA1-miR-216b-FGFR1-ERK signaling pathway in HCC, which may help to lead a better understanding the pathogenesis of HCC and probe the feasibility of lncRNA-directed diagnosis and therapy for this deadly disease.

Second-line treatment of metastatic gastric cancer: Current options and future directions

Gastric cancer remains one among the leading causes of cancer-related deaths, regardless of its decreasing incidence and newly available treatment options. Most patients present at an advanced stage and are treated with upfront systemic chemotherapy. Those patients receiving first-line therapy may initially respond to treatment, but many of them relapse over time. In such condition, second-line treatment for disease progression remains the only available option. Although there exists no standard approach in the second-line setting, several phase III trials have shown modest survival benefit in patients receiving irinotecan, taxane and ramucirumab over the best supportive care or active agents. This review analyzes the currently available treatment regimens and future directions of research in the second-line setting for metastatic gastric cancer with the best available evidence. Additionally, the prognostic factors that influence patient survival in those receiving second-line therapy are discussed.

Evaluation of Fibroblast Growth Factor Receptor 2 Expression, Heterogeneity and Clinical Significance in Gastric Cancer

BACKGROUND

We aimed to evaluate the protein and mRNA expression of fibroblast growth factor receptor 2 (FGFR2) by immunohistochemistry (IHC) and mRNA in situ hybridization (ISH), respectively, and to assess the heterogeneity of FGFR2 expression in gastric cancer (GC).

METHODS

A tissue microarray containing 362 surgically resected GC tissues and 135 matched metastatic lymph nodes was evaluated using FGFR2b IHC and FGFR2 ISH. FGFR2 fluorescence ISH was also performed in 188 cases.

RESULTS

All FGFR2-amplified cases (5 of 188) showed FGFR2b protein and FGFR2 mRNA overexpression (p < 0.001), and FGFR2 amplification was not identified in FGFR2b IHC- and FGFR2 mRNA ISH-negative cases. Kaplan-Meier survival analysis revealed that FGFR2b protein and FGFR2 mRNA overexpression was significantly associated with a poor overall survival (p < 0.001 and p = 0.012, respectively), and multivariate analyses showed that FGFR2 mRNA overexpression was an independent biomarker of a poor overall survival. Intratumoral heterogeneity of FGFR2b protein and FGFR2 mRNA overexpression was observed in 5 of 9 (55.5%) and 18 of 21 (85.7%) cases, respectively. Discordant FGFR2b and FGFR2 expression results between primary and matched metastatic lymph nodes were observed in 5 of 9 (55.5%) and 4 of 14 (28.6%) cases, respectively.

CONCLUSIONS

Intratumoral heterogeneity and discordant FGFR2b expression in primary tumors and metastatic lymph nodes are common in GC.

Fibroblast growth factor receptor 1 gene amplification in gastric adenocarcinoma

Gastric adenocarcinomas are associated with a poor prognosis due to the fact that the tumor has often metastasized by the time of diagnosis. Thus, identification of novel therapeutic targets is highly desirable. Here, we examined gene copy number of fibroblast growth factor receptor 1 (FGFR1), a potential target for tyrosine kinase inhibitors, and clinicopathologic parameters in a large cohort of gastric adenocarcinomas. We performed fluorescence in situ hybridization analysis of 293 gastric adenocarcinomas using tissue microarrays. Amplification of the FGFR1 gene is a rare but noticeable event that can be found in 2% (6/293) of cases and was associated with poor 10-year survival (median 15.3 months in FGFR1-amplified cases versus 36 months in nonamplified cases, P = .047) and a higher rate of distant metastasis (P = .025). FGFR1 appears to represent a potential new therapeutic target in a subset of patients with gastric carcinoma. Identification of gastric cancers harboring FGFR1 amplification may be important in preselecting patients and/or interpreting clinical studies using tyrosine kinase inhibitors.

Emerging kinase inhibitors of the treatment of gastric cancer

INTRODUCTION

Gastric cancer (GC) is the fifth most common malignancy in the world. In the last years, for the first time in literature, the addition of a targeted therapy to standard chemotherapy has proved to prolong median overall survival. In this scenario, kinase inhibitors (KIs), smaller intracellular agents, could be an interesting and novel type of targeted treatment of metastatic GC both in first and further lines of therapy.

AREAS COVERED

Several KI have been evaluated in the preclinical setting. This review will underline the most relevant targeted pathways involved in GC tumorigenesis and disease progression including EGFR, VEGFR, c-MET, mTOR, fibroblast growth factor receptor, Src and Aurora kinases.

EXPERT OPINION

Despite the good results of TOGA, RAINBOW and REGARD trials about the addition of monoclonal antibodies to standard of care in GC, the addition of KI seems not to achieve comparable interesting results in management of GC. However, an improved patient selection before and during treatment according to molecular characteristics, as well as combination studies evaluating the synergistic effect of combination schedules of different KIs and standard chemotherapy, or KI plus KI or KI plus antibodies-based therapy may reveal interesting results and lead to understand mechanisms of multi-drug resistance.

Therapeutic targeting of fibroblast growth factor receptors in gastric cancer

Chemotherapy has become the global standard treatment for patients with metastatic or unresectable gastric cancer (GC), although outcomes remain unfavorable. Many molecular-targeted therapies inhibiting signaling pathways of various tyrosine kinase receptors have been developed, and monoclonal antibodies targeting human epidermal growth factor receptor 2 (HER2) have become standard therapy for HER2-positive GC. An inhibitor of vascular endothelial growth factor receptor 2 or MET has also produced promising results in patients with GC. Fibroblast growth factor receptors (FGFR) play key roles in tumor growth via activated signaling pathways in GC. Genomic amplification of FGFR2 leads to the aberrant activation found in GC tumors and is related to survival in patients with GC. This review discusses the clinical relevance of FGFR in GC and examines FGFR as a potential therapeutic target in patients with GC. Preclinical studies in animal models suggest that multitargeted tyrosine kinase inhibitors (TKIs), including FGFR inhibitor, suppress tumor cell proliferation and delay tumor progression. Several TKIs are now being evaluated in clinical trials as treatment for metastatic or unresectable GC harboring FGFR2 amplification.

From molecular classification to targeted therapeutics: the changing face of systemic therapy in metastatic gastroesophageal cancer

Histological classification of adenocarcinoma or squamous cell carcinoma for esophageal cancer or using the Lauren classification for intestinal and diffuse type gastric cancer has limited clinical utility in the management of advanced disease. Germline mutations in E-cadherin (CDH1) or mismatch repair genes (Lynch syndrome) were identified many years ago but given their rarity, the identification of these molecular alterations does not substantially impact treatment in the advanced setting. Recent molecular profiling studies of upper GI tumors have added to our knowledge of the underlying biology but have not led to an alternative classification system which can guide clinician's therapeutic decisions. Recently the Cancer Genome Atlas Research Network has proposed four subtypes of gastric cancer dividing tumors into those positive for Epstein-Barr virus, microsatellite unstable tumors, genomically stable tumors, and tumors with chromosomal instability. Unfortunately to date, many phase III clinical trials involving molecularly targeted agents have failed to meet their survival endpoints due to their use in unselected populations. Future clinical trials should utilize molecular profiling of individual tumors in order to determine the optimal use of targeted therapies in preselected patients.

Global transcriptome and sequenome analysis of formalin-fixed salivary epithelial-myoepithelial carcinoma specimens

Diverse microarray and sequencing technologies have been widely used to characterize molecular changes in malignant epithelial cells in salivary neoplasms. Such gene expression studies to identify markers and targets in tumor cells are, however, compromised by the cellular heterogeneity of these tumors and by the difficulties to accrue matching controls representing normal salivary glands. Seventeen samples of primary salivary epithelial-myoepithelial carcinoma along with tissue from six normal major salivary glands were microdissected from paraffin-embedded tissue. Pools of RNA from highly enriched preparations of these cell types were subjected to expression profiling using a whole-transcriptome shotgun sequencing experiment. In parallel, extracted genomic DNA was used for the 50 gene hotspot panel sequenome. KRAS mutations in three patients (18%), NRAS mutations in one patient (6%), but no HRAS, MET, PIK3CA, or BRAF mutations. Using strict and conservative criteria, 220 differentially expressed transcripts were found, with 36% up- and 64% downregulated. The transcripts were annotated using NCBI Entrez Gene, and computationally analyzed with the Ingenuity Pathway Analysis program. From these significantly changed expressions, the analysis identified 26 cancer-related transcripts and 16 transcripts related to mitochondrial dysfunction overlapping with three cancer-related genes. These 220 differentially expressed genes including microRNAs provide here a sufficiently large set to specifically define epithelial-myoepithelial carcinoma and to identify novel and potentially important targets for diagnosis, prognosis, and therapy of this cancer.