Further observations on the relationship between the FGFR4 Gly388Arg polymorphism and lung cancer prognosis

The endocrine FGFs axis: A systemic anti-fibrotic response that could prevent pulmonary fibrogenesis?

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal disease for which therapeutic options are limited, with an unmet need to identify new therapeutic targets. IPF is thought to be the consequence of repeated microlesions of the alveolar epithelium, leading to aberrant epithelial-mesenchymal communication and the accumulation of extracellular matrix proteins. The reactivation of developmental pathways, such as Fibroblast Growth Factors (FGFs), is a well-described mechanism during lung fibrogenesis. Secreted FGFs with local paracrine effects can either exert an anti-fibrotic or a pro-fibrotic action during this pathological process through their FGF receptors (FGFRs) and heparan sulfate residues as co-receptors. Among FGFs, endocrine FGFs (FGF29, FGF21, and FGF23) play a central role in the control of metabolism and tissue homeostasis. They are characterized by a low affinity for heparan sulfate, present in the cell vicinity, allowing them to have endocrine activity. Nevertheless, their interaction with FGFRs requires the presence of mandatory co-receptors, alpha and beta Klotho proteins (KLA and KLB). Endocrine FGFs are of growing interest for their anti-fibrotic action during liver, kidney, or myocardial fibrosis. Innovative therapies based on FGF19 or FGF21 analogs are currently being studied in humans during liver fibrosis. Recent data report a similar anti-fibrotic action of endocrine FGFs in the lung, suggesting a systemic regulation of the pulmonary fibrotic process. In this review, we summarize the current knowledge on the protective effect of endocrine FGFs during the fibrotic processes, with a focus on pulmonary fibrosis.

FGFR4 Gly388Arg Polymorphism Reveals a Poor Prognosis, Especially in Asian Cancer Patients: A Meta-Analysis

The fibroblast growth factor-4 receptor (FGFR4) is a member of receptor tyrosine kinase. The FGFR4 Gly388Arg polymorphism in the transmembrane domain of the receptor has been shown to increase genetic susceptibility to cancers. However, its prognostic impact in cancer patients still remains controversial. Herein, we performed this meta-analysis to evaluate the clinicopathological and prognostic impacts of the FGFR4 Gly388Arg polymorphism in patients with cancer. We carried out a computerized extensive search using PubMed, Medline, and Ovid Medline databases up to July 2021. From 44 studies, 11,574 patients were included in the current meta-analysis. Regardless of the genetic models, there was no significant correlation of the FGFR4 Gly388Arg polymorphism with disease stage 3/4. In the homozygous model (Arg/Arg vs. Gly/Gly), the Arg/Arg genotype tended to show higher rate of lymph node metastasis compared with the Gly/Gly genotype (odds ratio = 1.21, 95% confidence interval (CI): 0.99-1.49, p = 0.06). Compared to patients with the Arg/Gly or Arg/Arg genotype, those with the Gly/Gly genotype had significantly better overall survival (hazard ratios (HR) = 1.19, 95% CI: 1.05-1.35, p = 0.006) and disease-free survival (HR = 1.25, 95% CI: 1.03-1.53, p = 0.02). In conclusion, this meta-analysis showed that the FGFR4 Gly388Arg polymorphism was significantly associated with worse prognosis in cancer patients. Our results suggest that this polymorphism may be a valuable genetic marker to identify patients at higher risk of recurrence or mortality.

Effect of Lenvatinib on a Hepatocellular Carcinoma with Fibroblast Growth Factor Receptor 4 Expression: A Case Report and Review of the Literature

Basic and clinical research have shown that the expression of molecules involved in the hepatocellular carcinoma (HCC) cell signaling pathway is related to the sensitivity to molecular-targeted agents. We herein report a case of HCC that was effectively treated with lenvatinib after a poor response to sorafenib. The tumor showed a high expression of fibroblast growth factor receptor 4, which is reportedly related to the sensitivity to lenvatinib in vitro. The information obtained from this case and from our literature review highlights the importance of assessing the expression of the molecules involved in tumors for effective precision medicine.

FGFR4 Gene Polymorphism Reduces the Risk of Distant Metastasis in Lung Adenocarcinoma in Taiwan

Fibroblast growth factor receptor 4 (FGFR4) is involved in multiple physiological and pathological processes. Several genetic variants of FGFR4 have been shown to be associated with tumor progression in many cancers. However, its association, such as genetic variants and expression levels, with lung cancer is controversial. The present study examined the relationship between four single-nucleotide polymorphisms (SNPs; rs2011077 T/C, rs351855 G/A, rs7708357 G/A, and rs1966265 A/G) of FGFR4 and the risk of lung adenocarcinoma with the epidermal growth factor receptor (EGFR) mutation status in a Taiwanese cohort. The results demonstrated that FGFR4 rs2011077 (odds ratio (OR) = 0.348, 95% confidence interval (CI) = 0.136–0.891, p = 0.024), and rs351855 (OR = 0.296, 95% CI = 0.116–0.751, p = 0.008) showed an inverse association with distant metastasis in wild-type EGFR lung adenocarcinoma. Furthermore, a database analysis using The Cancer Genome Atlas revealed that the higher FGFR4 expression level was correlated with poor survival rates in wild-type EGFR lung adenocarcinoma. In conclusion, the data suggest that FGFR4 SNPs may help in identifying patient subgroups at low-risk for tumor metastasis, among carriers of lung adenocarcinoma bearing wild-type EGFR.

FGF19-FGFR4 Signaling in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common type of cancer, with an increasing mortality rate. Aberrant expression of fibroblast growth factor 19-fibroblast growth factor receptor 4 (FGF19-FGFR4) is reported to be an oncogenic-driver pathway for HCC patients. Thus, the FGF19-FGFR4 signaling pathway is a promising target for the treatment of HCC. Several pan-FGFR (1-4) and FGFR4-specific inhibitors are in different phases of clinical trials. In this review, we summarize the information, recent developments, binding modes, selectivity, and clinical trial phases of different available FGFR4/pan-FGF inhibitors. We also discuss future perspectives and highlight the points that should be addressed to improve the efficacy of these inhibitors.

Fibroblast growth factor receptor 4 single nucleotide polymorphism Gly388Arg in head and neck carcinomas

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is considered to be a progressive disease resulting from alterations in multiple genes regulating cell proliferation and differentiation like receptor tyrosine kinases (RTKs) and members of the fibroblast growth factor receptors (FGFR)-family. Single-nucleotide polymorphism (SNP) Arg388 of the FGFR4 is associated with a reduced overall survival in patients with cancers of various types. We speculate that FGFR4 expression and SNP is associated with worse survival in patients with HSNCC.

AIM

To investigate the potential clinical significance of FGFR4 Arg388 in the context of tumors arising in HNSCC, a comprehensive analysis of FGFR4 receptor expression and genotype in tumor tissues and correlated results with patients’ clinical data in a large cohort of patients with HNSCC was conducted.

METHODS

Surgical specimens from 284 patients with HNSCC were retrieved from the Institute of Pathology at the Ludwig-Maximilian-University in Germany. Specimens were analyzed using immunohistochemistry and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The expression of FGFR4 was analyzed in 284 surgical specimens of HNSCC using immunohistochemstry. FGFR4 polymorphism was detected by PCR-RFLP. Patients’ clinical data with a minimum follow-up of 5 years were statistically evaluated with a special emphasis on survival analysis employing Kaplan-Meier estimator and Cox regression analysis.

RESULTS

Concerning the invasive tumor areas the intensity of the FGFR4 expression was evaluated in a four-grade system: no expression, low expression, intermediate and high expression. FGFR4 expression was scored as “high” (+++) in 74 (26%), “intermediate” (++) in 103 (36.3%), and “low” (+) in 107 (36.7%) cases. Analyzing the FGFR4 mutation it was found in 96 tumors (33.8%), 84 of them (29.6%) having a heterozygous and 12 (4.2%) homozygous mutated Arg388 allele. The overall frequency concerning the mutant alleles demonstrated 65% vs 34% mutated alleles in general. FGFR4 Arg388 was significantly associated with advanced tumor stage (P < 0.004), local metastasis (P < 0.0001) and reduced disease-free survival (P < 0.01). Furthermore, increased expression of FGFR4 correlated significantly with worse overall survival (P < 0.003).

CONCLUSION

In conclusion, the FGFR4 Arg388 genotype and protein expression of FGFR4 impacts tumor progression in patients with HNSCC and may present a useful target within a multimodal therapeutic intervention.

The FGFR4-388arg Variant Promotes Lung Cancer Progression by N-Cadherin Induction

The FGFR4-388Arg variant has been related to poor prognosis in several types of cancer, including lung cancer. The mechanism underlying this association has not been addressed in detail in patients with this pathology. Here, we report that this FGFR4 variant induces MAPK and STAT3 activation and causes pro-oncogenic effects in NSCLC in vitro and in vivo. This variant induces the expression of EMT-related genes, such as N-cadherin, vimentin, Snail1 and Twist1. Indeed, the induction of N-cadherin protein expression by this variant is essential for its pro-tumorigenic role. The presence of the FGFR4-388Arg variant correlates with higher N-cadherin expression levels in clinical NSCLC samples and with poorer outcome in patients with FGFR expression. These results support the prognostic role of this FGFR variant in lung cancer and show that these effects may be mediated by the induction of N-cadherin expression and an EMT phenotype.

Prognostic Role of the FGFR4-388Arg Variant in Lung Squamous-Cell Carcinoma Patients With Lymph Node Involvement

BACKGROUND

The identification of prognostic biomarkers for lung squamous-cell carcinoma (SCC) pathology is crucial because of its poor prognosis. A variant of the FGFR4 (fibroblast growth factor receptor 4) gene, FGFR4-388Arg, has been associated with prognosis and is linked to oncogenesis in vitro in several types of cancer. We analyzed the association of this variant with prognosis and downstream signaling alteration in lung SCC patients.

METHODS

The presence of the FGFR4-388Arg variant was determined in 114 formalin-fixed, paraffin-embedded lung SCC tissue samples by DNA genotyping and was correlated with clinicopathologic data. The activation of the protein kinase B (AKT) and mitogen-activated protein kinase (MAPK) pathways was determined by immunohistochemistry, and its association with the presence of FGFR4-388Arg was analyzed.

RESULTS

We found that tumor differentiation status and adjuvant chemotherapy administration could be independent prognostic factors for overall survival (OS) in lymph node-affected patients, as expected. The progression-free survival and OS of patients with lymph node involvement (n = 41) and the FGFR4-388Arg genotype were significantly lower than those of patients lacking this variant (P = .035 and P = .042, respectively). Importantly, multivariate analysis supported the independent prognostic role of the FGFR4-388Arg genotype in OS (P = .025). Regarding downstream signaling, the FGFR4-388Arg genotype was not correlated with altered AKT signaling but was associated with increased MAPK activation in the SCC tumor samples (P = .017).

CONCLUSION

The FGFR4-388Arg variant may represent a promising prognostic biomarker in SCC patients with lymph node involvement. For these patients, FGFR4 may be a potential therapeutic target.

Prognostic significance of fibroblast growth factor receptor 4 polymorphisms on biochemical recurrence after radical prostatectomy in a Chinese population

Fibroblast growth factor receptor 4 (FGFR4) is a transmembrane receptor with ligand-induced tyrosine kinase activity and is involved in various biological and pathological processes. Several polymorphisms of FGFR4 are associated with the incidence and mortality of numerous cancers, including prostate cancer. In this study, we investigated whether the polymorphisms of FGFR4 influence the biochemical recurrence of prostate cancer in Chinese men after radical prostatectomy. Three common polymorphisms (rs1966265, rs2011077, and rs351855) of FGFR4 were genotyped from 346 patients with prostate cancer by using the Sequenom MassARRAY system. Kaplan–Meier curves and Cox proportional hazard models were used for survival analysis. Results showed biochemical recurrence (BCR) free survival was significantly affected by the genotypes of rs351855 but not influenced by rs1966265 and rs2011077. After adjusting for other variables in multivariable analysis, patients with rs351855 AA/AG genotypes showed significantly worse BCR-free survival than those with the GG genotype (HR = 1.873; 95% CI, 1.209–2.901; P = 0.005). Hence, FGFR4 rs351855 could be a novel independent prognostic factor of BCR after radical prostatectomy in the Chinese population. This functional polymorphism may also provide a basis for surveillance programs. Additional large-scale studies must be performed to validate the significance of this polymorphism in prostate cancer.

FGF23 from bench to bedside

There is a strong association between elevated circulating fibroblast growth factor-23 (FGF23) levels and adverse outcomes in patients with chronic kidney disease (CKD) of all stages. Initially discovered as a regulator of phosphate and vitamin D homeostasis, FGF23 has now been implicated in several pathophysiological mechanisms that may negatively impact the cardiovascular and renal systems. FGF23 is purported to have direct (off-target) effects in the myocardium, as well as canonical effects on FGF receptor/α-klotho receptor complexes in the kidney to activate the renin-angiotensin-aldosterone system, modulate soluble α-klotho levels, and increase sodium retention, to cause left ventricular hypertrophy (LVH). Conversely, FGF23 could be an innocent bystander produced in response to chronic inflammation or other processes associated with CKD that cause LVH and adverse cardiovascular outcomes. Further exploration of these complex mechanisms is needed before modulation of FGF23 can become a legitimate clinical target in CKD.

Is fibroblast growth factor receptor 4 a suitable target of cancer therapy?

Fibroblast growth factors (FGF) and their tyrosine kinase receptors (FGFR) support cell proliferation, survival and migration during embryonic development, organogenesis and tissue maintenance and their deregulation is frequently observed in cancer development and progression. Consequently, increasing efforts are focusing on the development of strategies to target FGF/FGFR signaling for cancer therapy. Among the FGFRs the family member FGFR4 is least well understood and differs from FGFRs1-3 in several aspects. Importantly, FGFR4 deletion does not lead to an embryonic lethal phenotype suggesting the possibility that its inhibition in cancer therapy might not cause grave adverse effects. In addition, the FGFR4 kinase domain differs sufficiently from those of FGFRs1-3 to permit development of highly specific inhibitors. The oncogenic impact of FGFR4, however, is not undisputed, as the FGFR4-mediated hormonal effects of several FGF ligands may also constitute a tissue-protective tumor suppressor activity especially in the liver. Therefore it is the purpose of this review to summarize all relevant aspects of FGFR4 physiology and pathophysiology and discuss the options of targeting this receptor for cancer therapy.

[Advanced research of fibroblast growth factor receptor in non-small cell lung cancer]

Lung cancer is severely threatening human health. In recent years, the treatment for lung adenocarcinoma has made a great progress, targeted therapy has been widely applied in clinic, and benefits amount of patients. However, in squamous cell lung cancer, the incidence of epidermal growth factor receptor (EGFR) gene mutant and ALK fusion gene are low,and targeted therapy like Tarceva and crizotinib, can hardly work. Since the fibroblast growth factors (fibroblast growth factor, FGF) pathway is considered to be related to tumor cell proliferation, metastasis and angiogenesis, more and more researches proved the amplification of fibroblast growth factor receptor (FGFR) in squamous cell lung cancer. Experiments in vivo and in vitro found that blocking FGF pathway could reduce the proliferation of tumor cells and inhibit metastasis. The FGF pathway might be a new target for treatment of squamous cell lung cancer. This article reviews the effect of FGFR in tumorigenesis,as well as the prospect as a therapeutic target in non-small cell lung cancer.

Deficiency of metabolic regulator FGFR4 delays breast cancer progression through systemic and microenvironmental metabolic alterations

BACKGROUND

Endocrine FGF21 and FGF19 target adipocytes and hepatocytes through betaKlotho (KLB) and FGFR tyrosine kinases effecting glucose, lipid and energy metabolism. Both factors alleviate obesity and metabolic abnormalities which are contributing factors to breast tumor progression. Genomic manipulation of hepatic FGFR4 has uncovered roles of endocrine FGF signaling in both metabolic and cellular homeostasis. Here we determined whether systemic and microenvironmental metabolic alterations caused by the FGFR4 deficiency affect tumorigenesis in breast where FGFR4 is negligible. Breast tumors were induced in the bigenic mice with ablation of FGFR4 and overexpression of TGFα that activates Her2 in the ductal and lobular epithelium surrounded by adipocytes. Mammary tumorigenesis and alterations in systemic and breast microenvironmental metabolic parameters and regulatory pathways were analyzed.

RESULTS

Ablation of FGFR4 had no effect on cellular homeostasis and Her2 activity of normal breast tissue. However, the absence of FGFR4 reduced TGFα-driven breast tumor incidence and progression and improved host survival. Notable increases in hepatic and serum FGF21, ileal FGF15/19, adiponectin and adipsin, and decreases in systemic Fetuin A, IGF-1, IGFBP-1, RBP4 and TIMP1 were observed. The ablation affected adipogenesis and secretory function of adipocytes as well as lipogenesis, glycolysis and energy homeostasis associated with the functions of mitochondria, ER and peroxisomes in the breast and tumor foci. Treatment with a chemical inhibitor of NAMPT involved in the pathways inhibited the growth and survival of breast tumor cells and tumor-initiating cell-containing spheres. The FGFR4 ablation also caused elevation of inflammatory factors in the breast.

CONCLUSIONS

Although the primary role of FGFR4 in metabolism occurs in hepatocytes, its ablation results in a net inhibitory effect on mammary tumor progression. We suggest that the tumor-delaying effect of FGFR4 deficiency may be in large part due to elevated anti-obesogenic FGF21 that triggers tumor-suppressing signals from both peripheral and breast adipocytes. The predominant changes in metabolic pathways suggested roles of metabolic effects from both peripheral and breast adipocytes on metabolic reprogramming in breast epithelial cells that contribute to the suppression of tumor progression. These results provide new insights into the contribution of systemic and microenvironmental metabolic effects controlled by endocrine FGF signaling to breast carcinogenesis.

Fibroblast growth factor receptor 4 Gly388Arg polymorphism in Chinese gastric cancer patients

AIM: To investigate the contribution of the fibroblast growth factor receptor 4 (FGFR4) Gly388Arg polymorphism as a genetic risk factor for gastric cancer (GC) and to investigate any associations between this polymorphism and clinicopathological parameters and survival.

METHODS: Tumors and matched adjacent non-cancer tissues were collected from 304 GC patients, and 5 mL of venous blood was collected from 62 GC patients and 392 age- and sex-matched healthy controls without cancer history from the same ethnic population. DNA was extracted, and direct sequencing analyses were performed to genotype the FGFR4 Gly388Arg polymorphism in all the samples. Differences in the genotype frequencies of the FGFR4 Gly388Arg polymorphism between GC patients and healthy controls were estimated using the χ² test. Binary logistic regression was used for all analysis variables to estimate risk as the ORs with 95%CIs. The relationships between the FGFR4 genotype and clinicopathological parameters were tested with the χ² test. The Kaplan-Meier product-limit method, the log-rank test, and the Cox regression model were applied to evaluate the effect of the FGFR4 genotype on the overall survival of patients with GC.

RESULTS: In the present GC cohort, 118 patients (38.8%) were homozygous for the Gly388 allele, 124 patients (40.8%) were heterozygous, and 62 patients (20.4%) were homozygous for the Arg388 allele. The frequencies of the Gly/Gly, Gly/Arg, and Arg/Arg genotypes in the healthy controls were 33.6%, 48.0%, and 18.4%, respectively. The distributions of genotypes (χ² = 3.589, P = 0.166) and alleles (χ² = 0.342, P = 0.559) of the FGFR4 Gly388Arg polymorphism were not different between the GC patients and the healthy controls. Although we observed no correlation between the FGFR4 Gly388Arg polymorphism and clinicopathological parameters or survival in the total cohort of GC patients, the presence of the Arg388 allele was associated with shorter survival time in patients with GC if the tumor was small (log rank χ² = 5.449, P = 0.020), well differentiated (log rank χ² = 12.798, P = 0.000), T1 or T2 stage (log rank χ² = 4.745, P = 0.029), without lymph node involvement (log rank χ² = 6.647, P= 0.010), and at an early clinical stage (log rank χ² = 4.615, P = 0.032).

CONCLUSION: Our results suggest that the FGFR4 Gly388Arg polymorphism is not a risk factor for GC cancer initiation but that it is a useful prognostic marker for GC patients when the tumor is relatively small, well differentiated, or at an early clinical stage.

Targeted agents in non-small cell lung cancer therapy: What is there on the horizon?

Lung cancer is a heterogeneous group of diseases. There has been much research in lung cancer over the past decade which has advanced our ability to treat these patients with a more personalized approach. The scope of this paper is to review the literature and give a broad understanding of the current molecular targets for which we currently have therapies as well as other targets for which we may soon have therapies. Additionally, we will cover some of the issues of resistance with these targeted therapies. The molecular targets we intend to discuss are epidermal growth factor receptor (EGFR), Vascular endothelial growth factor (VEGF), anaplastic large-cell lymphoma kinase (ALK), KRAS, C-MET/RON, PIK3CA. ROS-1, RET Fibroblast growth factor receptor (FGFR). Ephrins and their receptors, BRAF, and immunotherapies/vaccines. This manuscript only summarizes the work which has been done to date and in no way is meant to be comprehensive.

Differential effects of polymorphic alleles of FGF receptor 4 on colon cancer growth and metastasis

A gly(388)arg polymorphism (rs351855) in the transmembrane domain of the fibroblast growth factor receptor (FGFR4) is associated with increased risk, staging, and metastasis in several different types of cancer. To specifically assess the impact of the polymorphic FGFR4 in colorectal cancer (CRC), we engineered CRC cell lines with distinct endogenous expression patterns to overexpress either the FGFR4(gly) or FGFR4(arg) alleles. The biologic analyses revealed an oncogenic importance for both polymorphic alleles, but FGFR4(gly) was the stronger inducer of tumor growth, whereas FGFR4(arg) was the stronger inducer of migration. An evaluation of clinical specimens revealed that FGFR4 was upregulated in 20/71 patients independent of gly(388)arg status. There was no correlation between the presence of an FGFR4(arg) allele and CRC or polyp risk in 3,471 participants of the CORSA study. However, among 182 patients with CRC, FGFR4(arg)-carriers had a fivefold higher risk of tumors that were stage II or greater. Together, our results established that both allelic forms of FGFR4 exert an oncogenic impact and may serve equally well as therapeutic targets in CRC. One important implication of our findings is that FGFR4(arg)-carriers are at a higher risk for more aggressive tumors and therefore may profit from early detection measures.

Genetic network and gene set enrichment analysis to identify biomarkers related to cigarette smoking and lung cancer

OBJECTIVES

Cigarette smoking is the most demonstrated risk factor for the development of lung cancer, while the related genetic mechanisms are still unclear.

METHODS

The preprocessed microarray expression dataset was downloaded from Gene Expression Omnibus database. Samples were classified according to the disease state, stage and smoking state. A new computational strategy was applied for the identification and biological interpretation of new candidate genes in lung cancer and smoking by coupling a network-based approach with gene set enrichment analysis.

MEASUREMENTS

Network analysis was performed by pair-wise comparison according to the disease states (tumor or normal), smoking states (current smokers or nonsmokers or former smokers), or the disease stage (stages I-IV). The most activated metabolic pathways were identified by gene set enrichment analysis.

RESULTS

Panels of top ranked gene candidates in smoking or cancer development were identified, including genes involved in cell proliferation and drug metabolism like cytochrome P450 and WW domain containing transcription regulator 1. Semaphorin 5A and protein phosphatase 1F are the common genes represented as major hubs in both the smoking and cancer related network. Six pathways, e.g. cell cycle, DNA replication, RNA transport, protein processing in endoplasmic reticulum, vascular smooth muscle contraction and endocytosis were commonly involved in smoking and lung cancer when comparing the top ten selected pathways.

CONCLUSION

New approach of bioinformatics for biomarker identification and validation can probe into deep genetic relationships between cigarette smoking and lung cancer. Our studies indicate that disease-specific network biomarkers, interaction between genes/proteins, or cross-talking of pathways provide more specific values for the development of precision therapies for lung.

Fibroblast growth factor receptor 4 gene (FGFR4) 388Arg allele predicts prolonged survival and platinum sensitivity in advanced ovarian cancer

FGFR4 has been shown to play an important role in the etiology and progression of solid tumors. A single nucleotide polymorphism (SNP) within the FGFR4 gene has previously been linked to prognosis and response to chemotherapy in breast cancer and other malignancies. This study evaluates the relevance of this SNP in advanced ovarian cancer. FGFR4-genotype was analyzed in 236 patients recruited as part of the OVCAD project. Genotyping was performed on germ-line DNA using a TaqMan based genotyping assay. Results were correlated with clinicopathological variables and survival. The FGFR4 388Arg genotype was significantly associated with prolonged progression-free and overall survival (univariate: HR 0.68, p = 0.017; HR 0.49, p = 0.005; multivariate: HR 0.69, p = 0.025; HR 0.49, p = 0.006) though the positive prognostic value was restricted to patients without postoperative residual tumor. Indeed, there was a significant interaction between FGFR4 genotype and residual tumor for overall survival. Furthermore, the FGFR4 388Arg genotype significantly correlated with platinum sensitivity in the same subgroup (multivariate OR 3.81 p = 0.004). FGFR4 Arg388Gly genotype is an independent and strong context specific prognostic factor in patients with advanced ovarian cancer and could be used to predict platinum-sensitivity.

FGF19 and cancer

Fibroblast growth factors (FGFs) and their cognate receptors, FGF receptors (FGFRs), play critical roles in a variety of normal developmental and physiological processes. Numerous reports support a role for deregulation of FGF-FGFR signaling, whether it is at the ligand and/or receptor level, in tumor development and progression. The FGF19-FGFR4 signaling axis has been implicated in the pathogenesis of several cancers, including hepatocellular carcinomas in mice and potentially in humans. This chapter focuses on recent progress in the understanding of the molecular mechanisms of FGF19 action and its potential involvement in cancer.

Fibroblast growth factor signaling in non-small-cell lung cancer

Despite recent progress in the treatment on non-small cell lung cancer (NSCLC), outcomes remain suboptimal. Treatment advances that target the epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) signaling pathways highlight the need to understand the multiple convergent growth factor signaling pathways involved in the pathogenesis of NSCLC. Signaling through fibroblast growth factors (FGF), long recognized for its pro-angiogenic activity, has recently emerged as a contributing factor in the pathogenesis and progression of NSCLC through an autocrine signaling loop. In addition, this pathway may function as a mechanism of resistance to anti-EGFR and anti-VEGF treatment. Clinical experience with FGF receptor (FGFR) inhibitors is mounting, and more specific inhibitors of this signaling pathway are in development. This review describes the structure of the FGF signaling pathway, delineates its dual roles in angiogenesis and proliferation in NSCLC, evaluates FGF ligand and receptor expression as prognostic biomarkers in NSCLC, and discusses the development of FGF pathway inhibitors for the treatment of lung malignancies.

Loss of heterozygosity and DNA methylation affect germline fibroblast growth factor receptor 4 polymorphism to direct allelic selection in breast cancer

Genome-wide association studies highlight the importance of the fibroblast growth factor (FGF) receptor as a risk factor for breast cancer development. In particular, FGFR4 has been implicated in membrane ruffling, cancer cell invasiveness, and clinical chemoresistance in breast cancer. In this work, we studied FGFR4 in both human breast cancers and cell lines. We examined primary human microdissected breast samples for FGFR4 mutations, polymorphisms, loss of heterozygosity (LOH), and DNA methylation status. We identified no activating somatic mutations of FGFR4; however, we did identify a high proportion of the FGFR4-R388 heterozygous germline polymorphism. Analysis of paired microdissected samples uncovered selective LOH at the FGFR4 locus in 50% of primary tumors. This LOH involved the FGFR4-WT allele as frequently as the cancer progression-associated FGFR4-G388R polymorphic allele. Further, we identified DNA methylation in one-third of cases that targeted the FGFR4-WT allele more often and occurred more frequently either in concert with or exclusively in lymph node metastases. The role of DNA methylation in silencing the FGFR4-WT allele was supported by azacytidine treatment findings and was also confirmed in mouse xenograft studies, demonstrating selective FGFR4-WT allelic methylation with corresponding gene down-regulation. These findings support a growth advantage function for FGFR4-R388 and underscore the complex role of DNA methylation and LOH in determining the penetrance of allelic selection in breast cancer progression. These findings therefore have critical therapeutic importance.

Roles of fibroblast growth factor receptors in carcinogenesis

The fibroblast growth factor receptors (FGFR) play essential roles both during development and in the adult. Upon ligand binding, FGFRs induce intracellular signaling networks that tightly regulate key biological processes, such as cell proliferation, survival, migration, and differentiation. Deregulation of FGFR signaling can thus alter tissue homeostasis and has been associated with several developmental syndromes as well as with many types of cancer. In human cancer, FGFRs have been found to be deregulated by multiple mechanisms, including aberrant expression, mutations, chromosomal rearrangements, and amplifications. In this review, we will give an overview of the main FGFR alterations described in human cancer to date and discuss their contribution to cancer progression.

The fibroblast growth factor receptor-4 Arg388 allele is associated with gastric cancer progression

BACKGROUND

Fibroblast growth factor receptor 4 (FGFR4) Gly388Arg polymorphism, located in the FGFR4 gene exon 9, was reported to be associated with malignant tumors prognosis; however, there has been no relevant research for gastric cancer. The purpose of this study was to investigate the clinical significance of FGFR4 Gly388Arg polymorphism as well as the mRNA expression of FGFR4 in patients with gastric cancer.

METHODS

The mRNA expression of FGFR4 in 103 gastric cancer tissues and corresponding normal tissues were measured by reverse transcription polymerase chain reaction (PCR) and real-time quantitative PCR. PCR-restriction fragment length polymorphism analysis was performed to detect the FGFR4 Gly388Arg in 103 gastric cancer tissues.

RESULTS

In 57.3% of patients, homozygous or heterozygous Arg388 allele was present. FGFR4 expressions in mRNA levels were higher in gastric cancer tissues compared with those in relevant normal tissues. However, there is no significantly statistical difference compared with mRNA expression of FGFR4 in different genotypes. Associations between FGFR4 Gly388Arg polymorphism and overall survival exist in patients with gastric cancer (P = 0.046).The FGFR4 Arg allele (hazard risk (HR), 2.324; 95% confidence interval (CI), 1.054-4.125; P = 0.037) and TNM stage (HR, 5.516; 95% CI 3.658-7.409; P = 0.005) were independent prognostic factors in patients with gastric cancer.

CONCLUSIONS

Based on this study, FGFR4 Arg388 genotype-a marker for gastric cancer progression-may predict prognosis of gastric cancer.

FGFR4 transmembrane domain polymorphism and cancer risk: a meta-analysis including 8555 subjects

Fibroblast growth factor receptor 4 (FGFR4), belonging to the receptor tyrosine kinase family, is involved in cancer initiation and progression. The FGFR4 Gly388Arg polymorphism in the transmembrane domain of the receptor was shown to contribute to genetic susceptibility to cancer but the results were inconsistent. We performed a meta-analysis using 12 eligible case-control studies with a total of 4892 patients and 3663 controls to summarise the data on the association between the FGFR4 Gly388Arg polymorphism and cancer risks. The overall odds ratio (OR) with a 95% confidence interval (CI) showed statistical association between the FGFR4 Gly388Arg polymorphism and cancer risks under homozygote comparison, allele contrast and the recessive genetic model. In the subgroup analysis by ethnicity, statistically significantly increased cancer risks were found among Asians for homozygote comparison (OR = 1.43, 95% CI = 1.13-1.80, P(heterogeneity)=0.24), allele contrast (OR = 1.16, 95% CI = 1.04-1.29, P(heterogeneity) = 0.25) and the recessive genetic model (OR = 1.47, 95% CI = 1.19-1.81, P(heterogeneity) = 0.15). In the subgroup analysis for different tumour types, Arg(388) allele had an effect of increasing the risks of breast (homozygote comparison OR = 1.57, 95% CI = 1.04-2.37, P(heterogeneity) = 0.83 and the recessive model OR = 1.51, 95% CI = 1.02-2.24, P(heterogeneity) = 0.80) and prostate cancer (Gly/Arg versus Gly/Gly: OR = 1.16, 95% CI = 1.02-1.32, P(heterogeneity)=0.74; Arg versus Gly: OR = 1.17, 95% CI = 1.07-1.29, P(heterogeneity) = 0.18 and the dominant model: OR = 1.20, 95% CI = 1.06-1.35, P(heterogeneity) = 0.89). Our meta-analysis suggests that the FGFR4 Gly388Arg polymorphism most likely contributes to susceptibility to cancer, especially in Asians. Besides, the Arg(388) allele might be associated with increased risks of breast and prostate cancer.

FGFR4 Arg388 genotype is associated with pathological complete response to neoadjuvant chemotherapy for primary breast cancer

BACKGROUND

A single-nucleotide polymorphism (SNP) in the FGFR4 gene is associated with poor prognosis in solid tumors. A recent study presented the first evidence that FGFR4 Arg388 could predict resistance to adjuvant chemotherapy in breast cancer. The present study evaluates the potential of this SNP to predict response to neoadjuvant chemotherapy (NCT) for primary breast cancer (PBC).

METHODS

As part of a randomized phase II trial, 257 patients received either doxorubicin-cyclophosphamide (AC) or doxorubicin-pemetrexed (AP) followed by docetaxel (Doc; Taxotere) as NCT for T2-4/N0-2/M0 PBC. FGFR4 genotype analyzed on germline DNA was correlated with clinicopathologic variables, clinical response, and pathological complete response (pCR) using univariate and multivariate analyses.

RESULTS

Only axillary lymph node status was associated with FGFR4 Arg388 [odds ratio (OR) 1.82, P = 0.03]. Joint analysis of both treatment arms revealed a correlation of FGFR4 Arg388 with clinical response (OR 2.14, P = 0.03) but not with pCR. In the AC-Doc arm, however, FGFR4 Arg388 was a strong predictor of pCR in the multivariate analysis (OR 3.79, P = 0.03). A significant interaction between FGFR4 genotype and treatment (P = 0.01) was found, indicating a therapy-specific effect.

CONCLUSION

We provide the evidence that FGFR4 388Arg is an independent predictor of pCR following AC-Doc as NCT in PBC.

Cancer genomics identifies regulatory gene networks associated with the transition from dysplasia to advanced lung adenocarcinomas induced by c-Raf-1

BACKGROUND

Lung cancer is a leading cause of cancer morbidity. To improve an understanding of molecular causes of disease a transgenic mouse model was investigated where targeted expression of the serine threonine kinase c-Raf to respiratory epithelium induced initially dysplasia and subsequently adenocarcinomas. This enables dissection of genetic events associated with precancerous and cancerous lesions.

METHODOLOGY/PRINCIPAL FINDINGS

By laser microdissection cancer cell populations were harvested and subjected to whole genome expression analyses. Overall 473 and 541 genes were significantly regulated, when cancer versus transgenic and non-transgenic cells were compared, giving rise to three distinct and one common regulatory gene network. At advanced stages of tumor growth predominately repression of gene expression was observed, but genes previously shown to be up-regulated in dysplasia were also up-regulated in solid tumors. Regulation of developmental programs as well as epithelial mesenchymal and mesenchymal endothelial transition was a hall mark of adenocarcinomas. Additionally, genes coding for cell adhesion, i.e. the integrins and the tight and gap junction proteins were repressed, whereas ligands for receptor tyrosine kinase such as epi- and amphiregulin were up-regulated. Notably, Vegfr- 2 and its ligand Vegfd, as well as Notch and Wnt signalling cascades were regulated as were glycosylases that influence cellular recognition. Other regulated signalling molecules included guanine exchange factors that play a role in an activation of the MAP kinases while several tumor suppressors i.e. Mcc, Hey1, Fat3, Armcx1 and Reck were significantly repressed. Finally, probable molecular switches forcing dysplastic cells into malignantly transformed cells could be identified.

CONCLUSIONS/SIGNIFICANCE

This study provides insight into molecular pertubations allowing dysplasia to progress further to adenocarcinoma induced by exaggerted c-Raf kinase activity.

Genetic variants in FGFR2 and FGFR4 genes and skin cancer risk in the Nurses' Health Study

Background

The human fibroblast growth factor (FGF) and its receptor (FGFR) play an important role in tumorigenesis. Deregulation of the FGFR2 gene has been identified in a number of cancer sites. Overexpression of the FGFR4 protein has been linked to cutaneous melanoma progression. Previous studies reported associations between genetic variants in the FGFR2 and FGFR4 genes and development of various cancers.

Methods

We evaluated the associations of four genetic variants in the FGFR2 gene highly related to breast cancer risk and the three common tag-SNPs in the FGFR4 gene with skin cancer risk in a nested case-control study of Caucasians within the Nurses' Health Study (NHS) among 218 melanoma cases, 285 squamous cell carcinoma (SCC) cases, 300 basal cell carcinoma (BCC) cases, and 870 controls.

Results

We found no evidence for associations between these seven genetic variants and the risks of melanoma and nonmelanocytic skin cancer.

Conclusion

Given the power of this study, we did not detect any contribution of genetic variants in the FGFR2 or FGFR4 genes to inherited predisposition to skin cancer among Caucasian women.

FGFR4 Gly388Arg polymorphism may affect the clinical stage of patients with lung cancer by modulating the transcriptional profile of normal lung

The association of the fibroblast growth factor receptor 4 (FGFR4) Gly388Arg polymorphism with clinical stage and overall survival in a series of 541 Italian lung adenocarcinoma (ADCA) patients indicated a significantly decreased survival in patients carrying the rare Arg388 allele as compared to that in Gly/Gly homozygous patients [hazard ratio (HR) = 1.5; 95% confidence interval (CI) 1.1-1.9], with the decrease related to the association of the same polymorphism with clinical stage (HR = 1.8, 95% CI 1.3-2.6). By contrast, no significant association was detected in small series of either Norwegian lung ADCA patients or Italian lung squamous cell carcinoma (SQCC) patients. Single nucleotide polymorphisms of known FGFR4 ligands expressed in lung (FGF9, FGF18 and FGF19) were not associated with clinical stage or survival and showed no interaction with FGFR4. Analysis of gene expression profile in normal lungs according to FGFR4 genotype indicated a specific transcript pattern associated with the allele carrier status, suggesting a functional role for the FGFR4 polymorphism already detectable in normal lung. These findings confirm the significant association of the FGFR4 Gly388Arg polymorphism with clinical stage and overall survival in an Italian lung ADCA population and demonstrate a FGFR4 genotype-dependent transcriptional profile present in normal lung tissue.

Polymorphisms of fibroblast growth factor receptor 4 have association with the development of prostate cancer and benign prostatic hyperplasia and the progression of prostate cancer in a Japanese population

Fibroblast growth factor receptor 4 (FGFR4) is a member of a family of transmembrane receptors with ligand-induced tyrosine kinase activity. The Glycine (Gly) to Arginine (Arg) polymorphism at codon 388 (Gly388Arg), which encodes an amino acid in the transmembrane part of the FGFR4 gene, was reported to be associated with an increased risk in some carcinomas. We investigated the association between the Gly388Arg polymorphism or the G or A polymorphism at intron 11 (rs2011077) of FGFR4, which was located 1,213 base pairs apart from the Gly388Arg polymorphism, and the risk of prostate cancer or benign prostate hyperplasia (BPH), and the prostate cancer disease status in Japanese men. Genotypes of Gly388Arg and rs2011077 polymorphisms of FGFR4 were determined in 492 patients with prostate cancer, 165 patients with BPH and 179 male controls. Regarding the Gly388Arg polymorphism, individuals with the ArgArg genotype had a 2.207- and 1.958-fold increased risk of prostate cancer and BPH, and a 1.804-fold increased risk of metastatic prostate cancer compared with those with the GlyGly genotype. Regarding the rs2011077 polymorphism, individuals with the GG genotype had a 6.260- and 3.033-fold increased risk of prostate cancer and BPH, and a 5.550-fold increased risk of metastatic prostate cancer compared with those with the AA genotype. Our results indicate that the FGFR4 Arg allele of the Gly388Arg polymorphism and the G allele of the rs2011077 polymorphism have a significant impact on the development of prostate cancer and BPH, and the progression of prostate cancer in a Japanese population.

Association of FGFR4 genetic polymorphisms with prostate cancer risk and prognosis

The fibroblast growth factor receptor 4 (FGFR4) is thought to be involved in many critical cellular processes and has been associated with prostate cancer risk. Four single nucleotide polymorphisms (SNPs) within or near FGFR4 were analyzed in a population-based study of 1458 prostate cancer patients and 1352 age-matched controls. We found no evidence to suggest that any of the FGFR4 SNP genotypes were associated with prostate cancer risk or with disease aggressiveness, Gleason score or stage. A weak association was seen between rs351855 and prostate cancer-specific mortality. Subset analysis of cases that had undergone radical prostatectomy revealed an association between rs351855 and prostate cancer risk. Although our results confirm an association between FGFR4 and prostate cancer risk in radical prostatectomy cases, they suggest that the role of FGFR4 in disease risk and outcomes at a population-based level appears to be minor.

Polymorphism of FGFR4 in cancer development and sensitivity to cisplatin and radiation in head and neck cancer

The aim of this study was to investigate the predisposition of the FGFR4 Gly/Arg polymorphism for development of head and neck squamous cell carcinoma (HNSCC) and, furthermore, to examine if the FGFR4 Arg(388) allele can be associated with resistance to chemo- and radiotherapy. When analysing 110 tumour biopsies a significant 1.7-fold increased risk to develop HNSCC in individuals carrying the Gly(388) allele (p=0.026) was found. Moreover a 2-fold increased risk for males harbouring the Gly(388) allele (p=0.031) to develop HNSCC was detected. In 39 HNSCC cell lines the role of the Arg(388) allele for radiation and cisplatin sensitivity was investigated. Our results show no role of the Arg(388) allele for the radiosensitivity (p=0.996) but indicate a tendency to increased cisplatin sensitivity (p=0.141). When screening the transmembrane and kinase domains in the FGFR4 gene a novel mutation, probably generating a truncated protein lacking exons 14-18, was found in six of eight selected cell lines. Taken together, we have here identified a marker that predicts the risk to develop HNSCC and possibly the sensitivity to cisplatin as well as a novel mutation in the FGFR4 gene.