Fibroblast Growth Factor Receptor 1 Amplification Research Articles

Abstract P4-09-02: Concordance in fibroblast growth factor receptor 1 (FGFR1) and 2 (FGFR2) status in breast cancer during tumor progression

Abstract BACKGROUND: In recent years, changes in HER2 and hormone receptor (HR) status between primary and metastatic breast cancer (BC) have been extensively reported. Additionally, current advances in BC biology have identified emerging biomarkers with clinical and prognostic implications, particularly the PI3K-AKT-mTOR and the FGF/FGFR pathways. FGFR1 and FGFR2 gene amplifications represent the most frequent genomic aberrations in BC. The 8p11-12 chromosomal region harboring the FGFR1 gene locus is amplified in about 10-18% of human BC, mainly in HR-positive/HER2-negative subtype, whereas the FGFR2 gene, located on chromosome 10q26, is amplified in approximately 4% of triple negative BC. To our knowledge, there is a lack of data regarding the concordance of FGFR1 and FGFR2 status between primary and metastatic tumors. METHODS: Tumor samples from 205 and 67 advanced BC patients diagnosed at our institution between 2010 and 2014 were screened for FGFR1 and FGFR2 amplification by FISH using the ZytoLight SPEC FGFR1/CEN8 and FGFR2/CEN10 probes, respectively. FGFR1 and FGFR2 amplification were defined as a ratio of FGFR1/CEN8 and FGFR2/CEN10 ≥ 2.2. We investigated the correlation of FGFR1 and FGFR2 status between primary and metastatic tumors in 16 and 13 patients, respectively, for whom paired samples were available. RESULTS: A total of 47 FGFR1-amplified patients (22.9%) and 3 FGFR2-amplified patients (4.5%) were identified. Patients with paired samples were classified according to FGFR1 and FGFR2 status in primary tumor. Regarding FGFR1 amplification, eight patients were FGFR1-amplified and eight were FGFR1-non-amplified. One patient in each group showed discordance in FGFR1 status in the metastatic tumor. Overall rate of concordance between primary and metastatic tumors was 87.5% (14/16). In relation to FGFR2 status, two patients were FGFR2-amplified and 11 were FGFR2-non-amplified with a 100% overall rate of concordance between paired samples (13/13). These data are summarized in Table 1. Table 1 Metastases PrimaryAmplifiedNon-amplifiedFGFR1Amplified (n=8)71 Non-amplified (n=8)17FGFR2Amplified (n=2)20 Non-amplified (n=11)011 CONCLUSIONS: Results suggest a high concordance in FGFR1 and FGFR2 status between primary and metastatic BC. The potential impact of these findings on the development of FGFR inhibitors merits further investigation. Citation Format: Zamora E, Aura C, Perez-Garcia J, Prudkin L, Meire A, Muñoz Cosuelo E, Jimenez J, Diaz-Delgado M, Ortega V, Soberino J, Farinas L, Salva F, Bellet M, Cruz C, Gomez P, Oliveira M, Vidal MJ, Saura C, Cortes J, Nuciforo P. Concordance in fibroblast growth factor receptor 1 (FGFR1) and 2 (FGFR2) status in breast cancer during tumor progression. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-09-02.

Prognostic implications of FGFR1 and MYC status in esophageal squamous cell carcinoma.

AIMTo investigate the clinicopathological features and prognostic implications of combined MYC and fibroblast growth factor receptor 1 (FGFR1) status in esophageal squamous cell carcinomas (ESCCs).METHODSAll patients with ESCC (n = 180) underwent surgical resection at Seoul National University Hospital sometime between 2000 and 2013. A tissue microarray was constructed using cores obtained from representative tumor areas of formalin-fixed, paraffin-embedded tissue blocks. FGFR1 and MYC copy numbers were quantified using fluorescence in situ hybridization. The level of MYC expression was determined using immunohistochemistry. FGFR1 and MYC amplification status was compared between primary and metastatic lymph nodes. Univariate and multivariate survival analyses were performed according to adjuvant therapy status.RESULTSFGFR1 and MYC amplifications were observed in 21.4% (37/173) and 54.2% (91/168) of patients, respectively, while MYC expression was observed in 58.9% (106/180) of patients. There was a positive correlation between MYC amplification and overexpression (P = 0.002). Although FGFR1 amplification was not associated with MYC amplification or expression, 12.3% (20/163) of patients exhibited both FGFR1 amplification and MYC expression. There was also a correlation in FGFR1 amplification status between matched primary tumors and metastatic lymph nodes (P < 0.001). MYC expression was higher in ESCCs with pT1 (P < 0.001) and in those with no lymph node metastasis (P = 0.023). MYC expression was associated with prolonged disease-free survival (P = 0.036) and overall survival (OS) (P = 0.017) but was not an independent prognostic factor. FGFR1 amplification was an independent predictor for prolonged OS in all patients (P = 0.029) and in those who did not receive adjuvant therapy (P = 0.013). Combined FGFR1 amplification and MYC expression predicted better OS in patients who did not receive adjuvant therapy (P = 0.034) but not in those who did receive adjuvant therapy.CONCLUSIONFGFR1 amplification and MYC expression have prognostic implications in resected ESCCs with respect to adjuvant therapy. The role of FGFR1-targeted therapy in ESCC remains to be explored.

FGFR1 Amplification Is Often Homogeneous and Strongly Linked to the Squamous Cell Carcinoma Subtype in Esophageal Carcinoma.

Background and AimsAmplification of the fibroblast growth factor receptor 1 (FGFR1) is believed to predict response to multi-kinase inhibitors targeting FGFR1. Esophageal cancer is an aggressive disease, for which novel targeted therapies are highly warranted.MethodsThis study was designed to investigate the prevalence and clinical significance of FGFR1 amplification in a tissue microarray containing 346 adenocarcinomas and 254 squamous cell carcinomas of the esophagus, using dual-labeling fluorescence in situ hybridization (FISH) analysis.Results FGFR1 amplification, defined as a ratio of FGFR1:centromere 8 copy numbers ≥ 2.0, was more frequently seen in squamous cell carcinoma (8.9% of 202 interpretable cases) than in adenocarcinoma (1.6% of 308; p<0.0001). There was no association between FGFR1 amplification and tumor phenotype or clinical outcome. To study potential heterogeneity of FGFR1 amplification, all available tumor blocks from 23 FGFR1 amplified tumors were analyzed on conventional large sections. This analysis revealed complete homogeneity of FGFR1 amplification in 20 (86.9%) primary tumors and in all available lymph node metastases. Remarkably, FGFR1 amplification was also seen in dysplasia adjacent to tumor in 6 of 9 patients with FGFR1 amplified primary cancers.ConclusionsIn conclusion, FGFR1 amplification occurs in a relevant subgroup of carcinomas of the esophagus and may play a particular role for development of squamous cell cancers. The high homogeneity of FGFR1 amplification suggests that patients with FGFR1 amplified esophageal cancers may particularly benefit from anti-FGFR1 therapies and prompt for clinical studies in this tumor type.

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.

Abstract 1861: Estrogen modulation of fibroblast growth factor signaling in non-small cell lung cancer

Abstract The estrogen signaling pathway induces proliferation in non-small cell lung cancer (NSCLC) and represents a novel therapeutic target for lung cancer. Estrogen receptor β (ERβ) is the predominant ER isoform in lung cancer and we have previously shown that high cytoplasmic ERβ combined with low progesterone receptor (PR) expression is a poor prognostic marker for NSCLC patients. To further elucidate the biological differences between ERβ high/PR low versus ERβ low/PR high expressing lung tumors, a mRNA microarray analysis using the Illumina HT-12 V4 Bead Chip platform was performed using RNA extracted from 64 cases. 165 genes were differentially expressed between these two groups at P&amp;lt;001. Fibroblast growth factor receptor 1 (FGFR1) was a highly over-expressed gene associated with ERβ high tumors (2.1-fold, P&amp;lt;0.004), while the decoy receptor for FGFR ligands, fibroblast growth factor receptor like-1 (FGFR5), was down-regulated (0.54-fold, P&amp;lt;0.0001). Ingenuity Pathway analysis revealed a network among the 165 differentially expressed genes that linked FGFR1 and FGFR5 to the ER. To analyze cross-talk between the FGF and E2 pathways, we determined the FGF/FGFR profile in a panel of three FGFR1 amplified and five non-amplified NSCLC cell lines. FGF2, 3, 10, and 19 were the most highly secreted FGFs in the cell line panel. FGFR1 amplified cells secreted statistically more FGF3, 6 and 10 compared to non-amplified cells. β-estradiol (E2) induced secretion of FGF2 in a cell line without FGFR1 amplification. FGFR3 and 5 were ubiquitously expressed across all cell lines while FGFR1, 2 and 4 expression was higher in amplified cell lines. There was no relationship between ERβ protein expression and FGFR1 amplification status or FGFR1-5 protein expression. Because FGF signaling has been shown to increase stem cell-like phenotypes in breast cancer, we determined basal and E2-stimulated expression of the stem cell markers, SOX2 and OCT4. Basal SOX2 and OCT4 were more highly expressed in FGFR1 amplified cells compared to non-amplified cells. SOX2 and OCT4 protein expression were increased by E2 treatment in FGFR1 non-amplified cells, with lesser effects in FGFR1 amplified H520 cells. SOX2 expression was also down-regulated in lung sections from mice treated with a combination of the anti-estrogen fulvestrant and the aromatase inhibitor anastrozole. Finally, we have shown that in FGFR1 non-amplified cells, the anti-proliferative effect of a pan-FGFR inhibitor, AZD4547, can be enhanced in the presence of the anti-estrogen fulvestrant. These results suggest that there is an interaction between the estrogen and FGF signaling pathways in lung cancer and provides a rationale for combination treatment of NSCLC tumors. Further characterization of the molecular types of NSCLC that will benefit from joint therapy is warranted. This work was supported by P50 CA090440. Citation Format: Laura P. Stabile, Natalie J. Rothenberger, Marjorie Romkes, Lisa Koodie, Mariya Farooqui, Sanja Dacic, Jill M. Siegfried. Estrogen modulation of fibroblast growth factor signaling in non-small cell lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1861. doi:10.1158/1538-7445.AM2015-1861

Abstract 769: In vivo response and molecular characterization of a Caucasian NSCLC squamous cell carcinoma PDX sensitive to FGFR inhibitors

Abstract BACKGROUND: The fibroblast growth factor receptor (FGFR) family are reported to be involved in key cellular processes such as proliferation, differentiation, migration &amp; survival with the deregulation of signalling through genetic modification or amplification being observed in cancer. FGFR1 has been reported to be amplified in squamous cell non-small cell lung cancer (NSCLC) as well as other indications (e.g. breast) and there are several FGFR inhibitors currently in clinical trial. It is therefore essential to develop relevant in vivo models for the development and characterisation of new FGFR agents and/or combination strategies which may prolong benefit and delay the emergence of resistance. METHODS: Patient derived xenograft (PDX) models were maintained subcutaneously in vivo in serial passage and their growth monitored by calliper measurements three times weekly; mice were recruited to treatment groups when the mean tumour volume was approximately 200mm3. Response to treatment was evaluated by tumour growth inhibition in response to FGFR inhibitors such as AZD4547 and chemotherapy. Resistance to both chemotherapy (Paclitaxel/Carboplatin) and AZD4547 in the squamous cell carcinoma (SCC) PDX model, LU6429, was generated in vivo through repeated dosing and the resulting models characterised for their treatment response. Molecular characterisation was carried out by RNA sequencing. RESULTS: A number of novel PDX models have been developed which harbour FGFR amplification and mutations including LU6429, a Caucasian NSCLC SCC PDX model which has modest FGFR1 and FGFR2 amplification and responds to FGFR inhibitors. LU6429 PDX tumours (SCC confirmed by IHC) exhibited reproducible sensitivity to AZD4547 (p&amp;lt;0.001) which was maintained in continuous serial passage and following cryogenic storage. FGFR expression and mutational analysis was assessed in naïve tumours, tumours following continuous AZD4547 treatment and in the acquired chemo-resistance setting. Other models show differential response to FGFR inhibitors. CONCLUSIONS: Pre-clinical models such as LU6429, a novel patient-derived NSCLC SCC xenograft model with moderate FGFR amplification which showed significant sensitivity to the FGFR inhibitor AZD4547, are invaluable in assessing novel agents targeting the FGFR pathway and in the development of new combination strategies which may prevent or overcome resistance. Citation Format: Andrew McKenzie, Nektaria Papadopoulou, Yinfei Yin, Simon Jiang, Jane Wrigley, Jie Cai, Martin Page, Henry Li, Rajendra Kumari. In vivo response and molecular characterization of a Caucasian NSCLC squamous cell carcinoma PDX sensitive to FGFR inhibitors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 769. doi:10.1158/1538-7445.AM2015-769

Fibroblast Growth Factor Receptor 1 and Related Ligands in Small-Cell Lung Cancer

Introduction:Small-cell lung cancer (SCLC) accounts for 15% of all lung cancers and has been understudied for novel therapies. Signaling through fibroblast growth factors (FGF2, FGF9) and their high-affinity receptor has recently emerged as a contributing factor in the pathogenesis and progression of non–small-cell lung cancer. In this study, we evaluated fibroblast growth factor receptor 1 (FGFR1) and ligand expression in primary SCLC samples.Methods:FGFR1 protein expression, messenger RNA (mRNA) levels, and gene copy number were determined by immunohistochemistry (IHC), mRNA in situ hybridization, and silver in situ hybridization, respectively, in primary tumors from 90 patients with SCLC. Protein and mRNA expression of the FGF2 and FGF9 ligands were determined by IHC and mRNA in situ hybridization, respectively. In addition, a second cohort of 24 SCLC biopsy samples with known FGFR1 amplification by fluorescence in situ hybridization was assessed for FGFR1 protein expression by IHC. Spearman correlation analysis was performed to evaluate associations of FGFR1, FGF2 and FGF9 protein levels, respective mRNA levels, and FGFR1 gene copy number.Results:FGFR1 protein expression by IHC demonstrated a significant correlation with FGFR1 mRNA levels (p < 0.0001) and FGFR1 gene copy number (p = 0.03). The prevalence of FGFR1 mRNA positivity was 19.7%. FGFR1 mRNA expression correlated with both FGF2 (p = 0.0001) and FGF9 (p = 0.002) mRNA levels, as well as with FGF2 (p = 0.01) and FGF9 (p = 0.001) protein levels. There was no significant association between FGFR1 and ligands with clinical characteristics or prognosis. In the second cohort of specimens with known FGFR1 amplification by fluorescence in situ hybridization, 23 of 24 had adequate tumor by IHC, and 73.9% (17 of 23) were positive for FGFR1 protein expression.Conclusions:A subset of SCLCs is characterized by potentially activated FGF/FGFR1 pathways, as evidenced by positive FGF2, FGF9, and FGFR1 protein and/or mRNA expression. FGFR1 protein expression is correlated with FGFR1 mRNA levels and FGFR1 gene copy number. Combined analysis of FGFR1 and ligand expression may allow selection of patients with SCLC to FGFR1 inhibitor therapy.

KIAA1549: BRAF Gene Fusion and FGFR1 Hotspot Mutations Are Prognostic Factors in Pilocytic Astrocytomas.

Up to 20% of patients with pilocytic astrocytoma (PA) experience a poor outcome. BRAF alterations and Fibroblast growth factor receptor 1 (FGFR1) point mutations are key molecular alterations in Pas, but their clinical implications are not established. We aimed to determine the frequency and prognostic role of these alterations in a cohort of 69 patients with PAs. We assessed KIAA1549:BRAF fusion by fluorescence in situ hybridization and BRAF (exon 15) mutations by capillary sequencing. In addition, FGFR1 expression was analyzed using immunohistochemistry, and this was compared with gene amplification and hotspot mutations (exons 12 and 14) assessed by fluorescence in situ hybridization and capillary sequencing. KIAA1549:BRAF fusion was identified in almost 60% of cases. Two tumors harbored mutated BRAF. Despite high FGFR1 expression overall, no cases had FGFR1 amplifications. Three cases harbored a FGFR1 p.K656E point mutation. No correlation was observed between BRAF and FGFR1 alterations. The cases were predominantly pediatric (87%), and no statistical differences were observed in molecular alterations–related patient ages. In summary, we confirmed the high frequency of KIAA1549:BRAF fusion in PAs and its association with a better outcome. Oncogenic mutations of FGFR1, although rare, occurred in a subset of patients with worse outcome. These molecular alterations may constitute alternative targets for novel clinical approaches, when radical surgical resection is unachievable.

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.

Fibroblast Growth Factor Receptor 1 Gene Copy Number and mRNA Expression in Primary Colorectal Cancer and Its Clinicopathologic Correlation

Objectives: Fibroblast growth factor receptor 1 (FGFR1) has been reported to be overexpressed in colorectal cancer (CRC) and suggested to be a therapeutic target. In this study, we investigated FGFR1 expression and amplification in CRC and its correlation with clinicopathologic parameters. Methods:FGFR1 dual-color fluorescence in situ hybridization and mRNA in situ hybridization were performed on tissue array blocks composed of 291 consecutive primary CRCs. Results: Of the 291 CRC cases, FGFR1 gene amplification was found in 11 (3.8%) cases, high FGFR1 polysomy in 4 (1.4%) cases, and FGFR1 gene copy number (GCN) gain (GCN >2) in 77 (26.5%) cases. FGFR1 GCN gain was significantly associated with left-sided location, lymph node metastasis, distant metastasis, and higher TNM stage (p < 0.05). FGFR1 GCN gain also correlated with poor patient survival (p = 0.015). FGFR1 mRNA overexpression (score 3-4) was present in 11.7% (34/291) of the patients and was significantly associated with FGFR1 GCN alteration (Pearson correlation coefficient, r = 0.463; p < 0.001). Conclusion:FGFR1 GCN gain was more frequently found (26.5%) than gene amplification (3.8%) and correlated with aggressive clinical behavior in consecutive CRC patients. FGFR1 GCN alteration was associated with a high FGFR1 mRNA level.

Programmed cell death-1 (PD-L1) expression and Fibroblast growth factor receptor 1 (FGFR1) amplification in Chinese stage III/IV lung squamous lung carcinoma (SQC).

e19127 Background: Status of PD-L1 expression and FGFR1 amplification in stage IIIB/IV Chinese SQC is still unknown, neither does the correlation of these molecular parameters with clinicpothologic...

A randomized, open-label phase II study of AZD4547 (AZD) versus Paclitaxel (P) in previously treated patients with advanced gastric cancer (AGC) with Fibroblast Growth Factor Receptor 2 (FGFR2) polysomy or gene amplification (amp): SHINE study.

4014 Background: The prognosis for AGC patients failing 1st line treatment is poor. FGFR2 amplification occurs in ~5-10% and polysomy in > 20% of gastric cancers (GCs). AZD is a selective FGFR1-3 i...

Triple-negative breast cancer: molecular subtypes and new targets for therapy.

Triple-negative breast cancer (TNBC) is a molecularly diverse disease. This heterogeneity has limited the success of targeted therapy in unselected patients to date. Recent transcriptional analysis has divided TNBC into transcriptionally similar subtypes that may have different sensitivity to neoadjuvant chemotherapy and targeted therapy. At present, chemotherapy is the mainstay of treatment for early-stage and advanced TNBC; however, several actionable targets show promise in preclinical studies. Novel therapeutic strategies are currently being tested in phase II and phase III trials and will likely require patient stratification before therapy. Examples of these tailored approaches include poly(ADP-ribose) polymerase inhibitors for BRCA-mutated TNBC, antiandrogens for androgen receptor (AR)-positive TNBC, fibroblast growth factor receptor (FGFR) inhibitors for TNBC harboring FGFR amplifications, and gamma-secretase inhibitors for TNBC with mutations in the PEST domain of NOTCH proteins. Treatment of TNBC based on molecular subsets represents a potential algorithm for the future. Well-designed clinical trials with incorporation of integrated biomarkers are necessary to advance the development of molecularly targeted therapy for different subgroups of TNBC.

The frequency and impact of FGFR1 amplification on clinical outcomes in Korean patients with small cell lung cancer.

Fibroblast growth factor receptor 1 (FGFR1) plays a critical role in many human cancers. We tried to identify the frequency of FGFR1 amplifications among Korean patients with small cell lung cancer (SCLC). Additionally, we examined the clinical significance of FGFR1 amplifications for overall survival (OS) and progression-free survival (PFS) among SCLC patients who received standard chemotherapies. Tumor tissues from 158 Korean patients diagnosed with SCLC from September 2009 to February 2013 were collected and analyzed using an FGFR1 FISH assay with a probe that hybridized to chromosome region 8p12-8p11.23 (Abbott Molecular, Abbott Park, IL). FGFR1 amplification was detected in three patients (1.9%) harboring extensive disease (ED). A multivariate analysis showed that among the patients with ED, FGFR1 amplification was associated with shorter disease-free survival to first-line chemotherapy with etoposide plus cisplatin or carboplatin (hazard ratio [HR]=7.1; 95% confidence interval [CI]=2.0-25.4; P=0.003). The median overall survival time of the patients with ED was 8.2 and 10.2 months among patients with and without FGFR1 amplification, respectively (P=0.37). Although FGFR1 amplification is rare in SCLC compared to non-small cell lung cancer or other malignancies with squamous histology, it is associated with poor survival following standard chemotherapy in SCLC. Further studies in large cohorts of patients with SCLC are needed to verify these results. Our results imply that FGFR1 may be a potential therapeutic target in SCLC and it could be confirmed in a clinical trial.

The 1.65 Å resolution structure of the complex of AZD4547 with the kinase domain of FGFR1 displays exquisite molecular recognition.

The fibroblast growth factor receptor (FGFR) family are expressed widely in normal tissues and play a role in tissue repair, inflammation, angiogenesis and development. However, aberrant signalling through this family can lead to cellular proliferation, evasion of apoptosis and induction of angiogenesis, which is implicated in the development of many cancers and also in drug resistance. The high frequency of FGFR amplification or mutation in multiple cancer types is such that this family has been targeted for the discovery of novel, selective drug compounds, with one of the most recently discovered being AZD4547, a subnanomolar (IC50) FGFR1 inhibitor developed by AstraZeneca and currently in clinical trials. The 1.65 Å resolution crystal structure of AZD4547 bound to the kinase domain of FGFR1 has been determined and reveals extensive drug-protein interactions, an integral network of water molecules and the tight closure of the FGFR1 P-loop to form a long, narrow crevice in which the AZD4547 molecule binds.

New targets in breast cancer

In the past few years, the therapeutic strategies for breast cancer have broadened substantially beyond endocrine therapy, chemotherapy, and human epidermal growth factor receptor 2-targeted agents to include several new drugs with unique mechanism of actions including antibody–drug conjugates, inhibitors of the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin pathway, cyclin-dependent kinases 4/6, histone deacetylases and the poly ADP ribose polymerase as well as immune checkpoint modulators. Novel clinical trial designs are also being implemented in the clinic to assess the therapeutic potential of targeting rare molecular abnormalities observed in breast cancers (fibroblast growth factor receptor amplification, inactivating mutations in BRCA, activating mutations in HER2, epidermal growth factor receptor, c-Kit, Akt, etc.).

Fibroblast growth factor receptor (FGFR) gene amplifications are rare events in bladder cancer.

Activating point mutations and protein overexpression of fibroblast growth factor receptors (FGFRs), especially FGFR3, are frequent events in bladder cancer. Little is known about gene amplifications, therefore we characterized amplification of FGFR1-3 by fluorescence in-situ hybridization (FISH). Tumours of 153 patients (n=65 pTa low-grade, n=15 pTa high-grade, n=37 pT1, n=20 pT2, n=10 pT3, n=6 pT4) were analysed by FISH for FGFR1-3 copy numbers and screened for FGFR3 mutations and immunohistochemical protein expression. Amplifications of FGFR1 were found in 1.6% (two of 122), FGFR2 in 0.8% (one of 121) and FGFR3 in 3.4% (five of 145). All amplifications were high-level amplifications, not overlapping with polysomy. Amplifications were found in papillary/papillary-invasive tumour parts, and predominantly in tumours with enhanced Ki67 index (>10%), aberrant CK20 expression, and low p53 expression. All FGFR3-amplified samples showed concomitant FGFR3 mutations and FGFR3 protein overexpression. FGFR amplifications were not associated significantly with gender, age, grade or stage in statistical analyses. FGFR amplifications are rare events in bladder cancer, with FGFR3 amplification being the most prevalent (3.4% of cases). Concomitant FGFR3 mutations and protein overexpression indicate that FGFR3-mediated signalling in these tumours would probably be highly active. This patient subgroup may be particularly suited to FGFR-targeted pharmacotherapy.

The Role of FGFR1 Gene Amplification as a Poor Prognostic Factor in Squamous Cell Lung Cancer: A Meta-Analysis of Published Data.

Objectives. The prognostic factors of the fibroblast growth factor receptor 1 (FGFR1) in non-small cell lung cancer (NSCLC) remain controversial. Methods. We conducted a meta-analysis of published studies from 1974 to February 2015. In absence of quality difference between studies of reporting significant and nonsignificant results, the relationship between FGFR1 amplification and clinicopathological parameters in NSCLC was analyzed. And also the combined hazard ratio (HR) and their corresponding 95% confidence interval (CI) were calculated in terms of overall survival. Results. 3178 patients (12 studies) were included in the analysis. It was shown that FGFR1 amplification was significantly more prevalent among male patients (RR 2.03, 95% CI 1.57–2.63) with squamous cell lung cancer (SQCC) (RR 3.49, 95% CI 2.62–4.64) and current smokers (RR 2.63, 95% CI 1.92–3.60). The pooled data also showed that the FGFR1 amplification was a poor prognostic factor in SQCC (HR 1.38, 95% CI 1.07–1.78), Asian patients (HR 1.78, 95% CI 1.22–2.60), and fluorescence in situ hybridization (FISH) method (HR 1.30, 95% CI 1.06–1.58). Conclusions. This meta-analysis strongly suggests that FGFR1 amplification occurs more frequently in male, SQCC and smokers, and it is a risk factor for poor prognosis among Asian patients with SQCC.

Fibroblast growth factor receptor 1 gene amplification is associated with poor survival in patients with resected esophageal squamous cell carcinoma.

To investigate the frequency and the prognostic impact of fibroblast growth factor receptor 1 (FGFR1) gene amplification in 526 curatively resected esophageal squamous cell carcinoma (ESCC). Using fluorescent in situ hybridization, high amplification was defined by an FGFR1/centromer 8 ratio is ≥ 2.0, or average number of FGFR1 signals/tumor cell nucleus ≥ 6.0, or percentage of tumor cells containing ≥ 15 FGFR1 signals or large cluster in ≥ 10%. Low amplification was defined by ≥ 5 FGFR1 signals in ≥ 50%. FGFR2 and FGFR3 mutations were assessed by direct sequencing in 388 cases and no mutation was detected. High and low amplification were detected in 8.6% and 1.1%, respectively. High FGFR1 amplification had significantly shorter disease-free survival (34.0 vs 158.5 months P=0.019) and overall survival (52.2 vs not reached P=0.022) than low/no amplification group. After adjusting for sex, smoking, stage, histology, and adjuvant treatment, high FGFR1 amplification had a greater risk of recurrence (adjusted hazard ratio [AHR], 1.6; P=0.029) and death (AHR, 1.53; P=0.050). High amplification was significantly higher in current smokers than former and never-smokers (Ptrend<0.001) and increased proportional to smoking dosage. High FGFR1 amplification is a frequent oncogenic alteration and an independent poor prognostic factor in resected ESCC.

Prevalence, morphology, and natural history of FGFR1-amplified lung cancer, including squamous cell carcinoma, detected by FISH and SISH

The aim of this study was to investigate the prevalence of fibroblast growth factor receptor 1 (FGFR1) amplification by fluorescence in situ hybridization (FISH) in a lung cancer patient cohort and to correlate results with morphology, silver in situ hybridization (SISH), and patient outcome. FGFR1 FISH and SISH were performed in 406 and 385 lung cancer cases, respectively, and the results were compared. High-level FGFR1 amplification was defined as the ratio of FGFR1/centromere 8 ≥2, or tumor cell percentage with ≥15 signals ≥10%, or average number of signals/tumor cell nucleus ≥6. Low-level amplification was defined as tumor cell percentage with ≥5 signals ≥50%. Of 406 tumors tested, there were 191 squamous cell carcinomas, 28 carcinomas with focal squamous morphology, 24 large cell carcinomas with squamous immunoprofile, 115 adenocarcinomas, 17 neuroendocrine tumors, and 31 carcinomas without squamous morphology or immunoprofile. FGFR1 FISH was assessable in 368 tumors, with FGFR1 amplification identified in 50, including 48 tumors with either squamous morphology or immunoprofile (48 of 225, 21.3%), and two ‘marker-null' tumors without squamous or glandular morphology or immunoprofile (2 of 143, 1.4%; P<0.0001). FGFR1 SISH was assessable in 347 tumors. All 46 FGFR1 FISH-amplified tumors with tumor available for testing showed amplification with SISH, while all other tumors were negative. There was no relationship between FGFR1 amplification status and disease-free (P=0.88, HR=1.04, 95% confidence interval (CI)=0.67–1.60) or overall survival (P=0.97, HR=1.01, 95% CI=0.65–1.58) in surgically radically treated patients with tumors with any squamous morphology or immunoprofile. FGFR1 amplification is a common abnormality in tumors with any squamous morphology or immunoprofile, but it is also present in ‘marker-null' tumors. The results of FGFR1 SISH showed 1:1 correlation with the results of FGFR1 FISH, indicating that SISH may be an alternative method to detect FGFR1 amplification. No relationship was detected between patient outcome and FGFR1 amplification.