Fibroblast Growth Factor Receptor 1 Gene Copy Number Research Articles

Abstract 3937: Diversity index as a novel predictor of tumor progression in breast cancer

Abstract Intratumoral genetic heterogeneity leads to tumor progression and therapeutic resistance. However, due to the difficulty associated with its assessment, application of intratumoral genetic heterogeneity as a prognostic or predictive marker is limited. We investigated the significance of Shannon diversity index as a tool for measuring genetic heterogeneity by performing fluorescence in situ hybridization of c-Myc gene in invasive breast cancers, and correlated the Shannon diversity index for c-Myc copy number variation with clinicopathologic features of tumor including patient survival. Shannon index for c-Myc copy number variation strongly correlated with average c-Myc copy number and was significantly higher in tumors with c-Myc genetic or regional heterogeneity than in those without c-Myc amplification. High Shannon index was associated with high histologic grade, lymphovascular invasion, p53 overexpression, high Ki-67 proliferation index, hormone receptor negativity, and HER2 amplification. In survival analyses, c-Myc amplification or c-Myc copy number gain was not associated with patient survival. However, a high level of Shannon index was associated with poor disease-free survival. In subgroup analyses, it was found to be an adverse prognostic factor in hormone receptor-positive group, but not in hormone receptor-negative group. In a validation set, high Shannon diversity index for c-Myc copy number variation was also found to be associated with poor survival of the patients. We further investigated the correlation with clinicopathologic features and predictive power of Shannon index using another gene, fibroblast growth factor receptor 1 (FGFR1) and observed that high Shannon index for FGFR1 gene copy number variation was an independent prognostic factor for poor clinical outcome in a whole group and in hormone receptor-positive subgroup. In conclusion, this study demonstrated that higher diversity index was associated with adverse pathologic parameters of breast cancer and poor clinical outcome suggesting that Shannon diversity index, which represents intratumoral genetic heterogeneity, can be used as a potential biomarker for tumor progression and prognostication in patients with breast cancer. Citation Format: Yul Ri Chung, Hyun Jeong Kim, Young A Kim, Mee Soo Chang, Ki-Tae Hwang, So Yeon Park. Diversity index as a novel predictor of tumor progression in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3937. doi:10.1158/1538-7445.AM2017-3937

Amplification of FGFR1 gene and expression of FGFR1 protein is found in different histological types of lung carcinoma

Although lung cancer continues to be the leading cause of cancer-related death, accurate diagnosis followed by personalized treatment is expected to raise the 5-year survival rate. Targeted therapies are now in routine clinical use, in particular for lung adenocarcinoma (ADC). Fibroblast growth factor receptor 1 (FGFR1) has recently emerged as a molecular target, especially in squamous cell/epidermoid carcinoma (SQC) of the lung. This paper evaluates FGFR1 expression and gene copy number in adenocarcinomas, squamous cell carcinomas, pleomorphic carcinomas (PLEOMC) and adenosquamous carcinomas (ADSQC) of the lung and also explores the epithelial-mesenchymal transition (EMT) pathway. We studied 76 lung carcinomas: 34 ADC, 24 SQC, 10 PLEOMC and 8 ADSQC. FGFR1 expression was evaluated by immunohistochemistry and gene amplification by fluorescence in situ hybridization (FISH). Higher FGFR1 protein expression was observed in all tumour types compared to non-tumour tissue. FGFR1 expression was higher in ADC and PLEOMC than in SQC. We found a tendency to higher expression in ADC than in SQC and significantly higher expression in PLEOMC than in other histological subtypes. FISH-based amplification of FGFR1 was identified in 15 (20%) lung carcinomas: 5 (15%) ADC, 5 (21%) SQC, 3 (30%) PLEOMC and 2 (25%) ADSQC. Amplification was more frequent in SQC without significant differences. FGFR1 protein is expressed in the majority of lung carcinomas, though it is higher in ADC and PLEOMC (the latter may reflect the importance of FGFR1 control of the EMT pathway). FGFR1 amplification was identified in all types of lung carcinoma. Although FGFR1 is most frequently amplified in SQC, other histological types merit assessment of FGFR1 amplification, in order to select patients that might benefit from targeted therapy.

Isolation and Characterization of Circulating Tumor Cells in Squamous Cell Carcinoma of the Lung Using a Non-EpCAM-Based Capture Method.

IntroductionThe exclusion of circulating tumor cells (CTCs) that have lost epithelial antigens during the epithelial-to-mesenchymal transition (EMT) process by using Epithelial Cell Adhesion Molecule (EpCAM) based capture methods is still a matter of debate. In this study, cells obtained after depletion procedure from blood samples of squamous cell lung cancer (SQCLC) patients were identified based on morphology and characterized with the combination of FISH assessment and immunophenotypic profile.Materials and MethodsFive mL blood samples, collected from 55 advanced SQCLC patients, were analyzed by a non-EpCAM-based capture method. After depletion of leukocytes and erythroid cells, the negative fraction was characterized by both FISH using a fibroblast growth factor receptor 1 (FGFR1) probe and by immunocytochemistry. Thirty healthy donors were also tested.ResultsBased on morphology (nuclear dimension ≥10 μm, shape and hypercromatic aspect) suspicious circulating cells clearly distinguishable from contaminant leukocytes were observed in 49/55 (89%) SQCLC patients. Thirty-four of the 44 (77%) samples evaluable for FGFR1 FISH showed ≥ 6 FGFR1 gene copy number on average per cell. Vimentin expression involved 43% (18/42) of pooled circulating SQCLC cells, whereas only 29% (14/48) were EpCAM positive. Confocal microscopy confirmed the localization of FGFR1 probe in suspicious circulating cells. Suspicious circulating elements were also observed in healthy donors and did not show any epithelial associated antigens. A significantly lower number of suspicious circulating cells in healthy donors compared to SQCLC patients was found.ConclusionsAmong the heterogeneous cell population isolated by depletion procedure, the coexistence of cells with epithelial and/or mesenchymal phenotype suggests that EMT may participate to transendothelial invasion and migration of tumor cells in advanced SQCLC. The finding of cells with neither EpCAM or EMT phenotype, retrieved after non-EpCAM-based systems, underlines the presence of suspicious elements in the blood of both SQCLC patients and healthy donors. Further phenotyping and molecular analyses are necessary to fully characterize these circulating elements.

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.

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.

Abstract 921: Fibroblast growth factor receptor 1 (FGFR1) protein expression and gene copy number in small cell lung cancer

Abstract PURPOSE: Small cell lung cancer (SCLC) comprises approximately 15% of all lung cancers, corresponding to &amp;gt;30,000 new cases per year in the United States. No major therapeutic progress has been achieved in SCLC in the past 30 years. Identification of new therapies in SCLC is urgently needed. Fibroblast growth factor receptor 1 (FGFR1) is a tyrosine kinase receptor implicated in the pathogenesis of several cancer types and is potentially an attractive target for cancer treatment. FGFR1 amplification and overexpression are known as a frequent event in lung squamous cell carcinoma. However, very little is known about FGFR1 protein expression and gene copy number in SCLC. One difficulty with research on SCLC is the limited availability of tumor specimens sufficient for molecular studies. METHODS: We investigated FGFR1 protein expression and gene copy number in a tissue microarray of resected SCLC tumors from 90 patients (67 men and 23 women) from Poland with limited stage. FGFR1 protein expression was assessed by immunohistochemistry (IHC) with H scores ranging from 0 (no expression) to 300 (strong expression in all tumor cells) using a FGFR1 antibody (clone EPR806Y, Origene) . FGFR1 gene copy number was evaluated by dual-color ISH assay using a cocktail of FGFR1 DNP probe (FGFR1 locus on 8p12) and chromosome 8 DIG probe (centromere 8), ultraView SISH DNP detection kit and ultraView Red ISH DIG detection kit (Tucson, AZ, US). Positive FGFR1 protein expression was defined as having an H-score ≥11. FGFR1 gene amplification was defined as FGFR1/CEN8 ratio ≥2.2, or average FGFR1 signals ≥4 per nucleus. RESULTS: FGFR1 protein expression was evaluable in 83 of the 90 patients and gene copy number was evaluable in 77 patients. FGFR1 protein expression was positive in 6 cases (7.2%) (mean H score=129, median 70, range: 40-285). FGFR1 gene amplification was observed in 6 cases (7.8 %) of evaluable SCLCs. There were 30%-90% tumor cells containing clusters in the amplified cases. Four of the 6 cases were positive for both FGFR1 protein expression and FGFR1 gene amplification. FGFR1 protein and gene copy number were not associated with patient age, sex, tumor size or overall survival (all p-values &amp;gt;0.15).FGFR1 gene copy number was significantly associated with protein expression (p=0.03, based on a t-test). CONCLUSIONS: A small subset of patients with SCLC is characterized by tumors with FGFR1 gene amplification and/or FGFR1 protein expression. Further studies are needed to determine whether or not this subset of patients would benefit from FGFR1-directed targeted therapy. Citation Format: Liping Zhang, Andrzej Badzio, Theresa Boyle, Xian Lu, Rafal Dziadziuszko, Jacek Jassem, Fred R. Hirsch. Fibroblast growth factor receptor 1 (FGFR1) protein expression and gene copy number in small cell lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 921. doi:10.1158/1538-7445.AM2014-921

Prognostic value of FGFR1 gene copy number in patients with non-small cell lung cancer: a meta-analysis.

A number of studies have investigated the relationship between fibroblast growth factor receptor1 (FGFR1) gene copy number and survival in non-small cell lung cancer (NSCLC) patients. However, conclusions reported by different parties seem to be inconsistent, especially regarding the differences among different histopathologic subtypes. To derive a more precise estimate of the prognostic significance of FGFR1 gene copy number, we have reviewed published studies and carried out a meta-analysis. The meta-analysis was conducted in accordance with PRISMA guidelines. The required data for estimation of individual hazard ratios (HRs) for survival were extracted from the publications and an overall HR was calculated. We identified 6 eligible studies, all dealing with NSCLC. The global quality score ranged 32.5-80%, with a median of 53.33%. For FGFR1 amplification in three studies including differed according to histological type, the overall RR was 0.86 which 95% confidence interval (CI) was 0.75 to 0.99 and P value was 0.048. Combined HR for the six evaluable studies was 1.17 (95% CI: 0.95 to 1.43). In the subgroup of squamous cell lung cancer (SQCC), the combined HR was 1.24 (95% CI: 0.89 to 1.73). For the Asian populations' studies, the combined HR was 1.67 (95% CI: 1.1 to 2.52). FGFR1 amplification significantly was more frequent in SQCC. FGFR1 was not associated with poorer survival in patients with NSCLC. Furthermore studies will be needed in terms of survival implications.

Characterization of Fibroblast Growth Factor Receptor 1 in Small-Cell Lung Cancer

There remains a significant therapeutic need for small-cell lung cancer (SCLC). We and others have reported high frequency of copy number gains in cytogenetic bands encoding fibroblast growth factor receptor 1 (FGFR1) in SCLC tumors and cell lines. Thirteen SCLC cell lines and 68 SCLC patient tumor samples were studied for FGFR1 amplification. Growth inhibition assays were performed using PD173074, a pan-FGFR inhibitor to determine the correlation between FGFR1 expression and drug sensitivity. We did not detect FGFR1 mutations in SCLC cell lines. Focal amplification of FGFR1 gene was found in five tumor samples (7%), with high-level focal amplification in only one tumor sample (1%). Amplification owing to polysomy of chromosome 8, where FGFR1 locates, was observed in 22 tumor samples (32%). There was no correlation between FGFR1 gene copy number and messenger RNA expression or protein expression in SCLC cells. FGFR inhibitor sensitivity correlated with FGFR1 copy number determined by real-time polymerase chain reaction assay (r= -0.79; p = 0.01). FGFR1 gene mutations and focal amplification are rare in SCLC, but polysomy of chromosome 8 is relatively common. FGFR1 copy number gain predicts sensitivity to FGFR inhibition, and FGFR expression correlates inversely with chemosensitivity.

A new bright-field dual-colour chromogenic and silver in situ hybridization method for the detection of FGFR1 gene copy number status

Recently, the fibroblast growth factor receptor 1 (FGFR1) has been identified as the first actionable target in squamous cell lung cancer. Clinical trials testing specific FGFR inhibitors are in progress, and patients are selected based on their FGFR1 gene copy number status. Fluorescent in situ hybridization is the most commonly used method for detecting FGFR1 amplifications, but it has its limitations. In this paper, we describe a new non-fading and easy to assess assay for detecting FGFR1 amplification using a combination of chromogenic and silver in situ hybridization. We assessed 394 patients diagnosed with head and neck squamous cell carcinoma with the new assay and compared the results with those obtained by FGFR1 fluorescent in situ hybridization. We could assess copy number by the fluorescent in situ hybridization in 86.8 % (342/394) of cases, whereas with chromogenic and silver in situ hybridization, this was 79.4 % (313/394). By fluorescent in situ hybridization, a FGFR1 amplification was detected in 12.6 % (43/342) of cases, a low-level amplification (LLA) in 7.6 % (26/342) and a high-level amplification (HLA) in 5.0 % (17/342). By chromogenic and silver in situ hybridization, a FGFR1 amplification was found in 10.2 % (32/313) (5.7 % LLA, 4.5 % HLA). The two techniques showed highly concordant results (Pearson's correlation coefficient = 0.971, p < 0.01).

Fibroblast growth factor receptor 1 (FGFR1) copy number is an independent prognostic factor in non-small cell lung cancer

Fibroblast growth factor receptor 1 (FGFR1) is an oncogene that can potentially be targeted by tyrosine kinase inhibitors. We aimed to investigate the prevalence and prognostic significance of alterations in FGFR1 copy number in non-small cell lung cancer (NSCLC). FGFR1 status was evaluated by chromogenic silver in situ hybridisation (ISH) in tissue microarray sections from a retrospective cohort of 304 surgically resected NSCLCs and results were correlated with the clinicopathological features and overall survival. High FGFR1 gene copy number (amplification or high-level polysomy) was significantly more frequent in squamous cell carcinomas (SCC) (24.8%) and large cell carcinomas (LCC) (25%) compared to adenocarcinomas (11.3%) (p=0.01 and p=0.03 respectively). Among NSCLC there was no significant correlation between FGFR1-positive status and other clinicopathological features including age, gender, smoking history, tumour size, lymph node status, stage, grade, vascular, lymphatic or perineural invasion. FGFR1-positive patients showed a tendency to longer overall survival in univariate analysis (p=0.14). Multivariate survival analysis using Cox regression model confirmed FGFR1-positive patients had a significant reduction in the risk of death compared to FGFR1-negative patients (HR 0.6; p=0.02). High FGFR1 gene copy number is a common finding in SCC and LCC and is an independent favourable prognostic factor.

Fibroblast growth factor receptor 1 (FGFR1) and SRY-related HMG-box (SOX2) amplification in squamous cell carcinoma (SCC) of the lung.

11025 Background: SOX2 is a key transcription factor that is amplified in lung SCC. FGFR1 is a receptor tyrosine kinase that promotes cell proliferation, survival and apoptotic resistance through the PLCγ/PKC, RAS/MAPK and PI3K-AKT pathways, respectively. FGFR1 is amplified in 15-25% of lung SCC. Pre-clinical studies of targeted inhibitors showed a growth dependency on FGFR1 amplification both in vitro and in vivo. A European, multicenter clinical trial of second-line treatment with BIBF1120, an FGFR1 inhibitor, will be performed in p with lung SCC with FGFR1 amplification. Methods: We have examined FGFR1 and SOX2 gene copy number (GCN) in 76 lung SCC p by multiplex ligation-dependent probe amplification (MLPA). Genomic DNA (gDNA) was isolated from enriched tumor cells by laser capture microdissection from formalin-fixed paraffin embedded (FFPE) tumor tissue. 50-100 ng of gDNA was analyzed in each of three independent replicates per tumor sample. Two independent probe sets were used for each gene analyzed. For inter-patient GCN comparisons, the results from each patient were normalized against the GCN values derived from FFPE peripheral blood leukocytes. In order to study intra-tumor heterogeneity (TH), we examined FGFR1 and SOX2 GCN in different areas of 4 tumors. In 2 p, TH was examined in serial tumor biopsies and/or resections obtained at different points of disease progression. Results: High FGFR1 amplification was detected in 13/76 (17.10%) and low amplification in 7/76 (9.21%) p. High SOX2 amplification was observed in 38/63 (60.32%) and low amplification in 9/63 (14.28%) p. 46.15% of the FGFR1-amplified tumors were also co-amplified for SOX2. Intra-TH was observed in 2/4 tumors. Survival according to FGFR1 and SOX2 GCN will be presented. In addition, GCN changes in FGFR1, SOX2, PIK3CA, PDGFRA, KDR, EGFR and MET over 10 years of follow-up will be presented for one surgically resected SCC lung p. Conclusions: FGFR1 and SOX2 co-amplification could represent a novel therapeutic target and warrants further research.

Abstract 53: FGFR1 and SOX2 amplification in squamous cell carcinoma (SCC) of the lung.

Abstract SRY-related HMG-box (SOX2) gene is a key transcription factor that coordinates development, differentiation and self-renewal of normal non-alveolar epithelium of the airway. SOX2 amplification has been reported in lung squamous cell carcinoma (SCC). Fibroblast growth factor receptor 1 (FGFR1) is a receptor tyrosine kinase that, upon activation, promotes cell proliferation, survival and apoptotic resistance through PLCγ/PKC, RAS/MAPK and PI3K-AKT pathways, respectively. FGFR1 is also amplified in 15-25% of lung SCC and pre-clinical data with targeted inhibitors showed a growth dependency on FGFR1 amplification either in vitro and in vivo. A clinical trial with BIBF1120 (which also inhibits FGFR1), will be developed in the Netherlands and Spain in second line SCC of the lung with FGFR1 amplified by FISH. Genetic heterogeneity in solid tumors is a major research area and therefore its assessment in SCC of the lung is of great relevance. We have examined FGFR1 and SOX2 gene copy number (GCN) in 76 lung SCC by multiplex ligation-dependent probe amplification (MLPA). Analysis of mutations in DDR2, PIK3CA, BRAF, EGFR, KRAS, and TP53 is ongoing. Genomic DNA (gDNA) was isolated from enriched tumor cells by laser captured microdisection from formalin-fixed paraffin embedded (FFPE) tumor tissue sections. 50-100 ng of gDNA was analyzed in each of the three independent replicates per tumor sample. Two independent probe sets were used for each gene analyzed. For inter-patient GCN value comparisons, the tumor results from each patient was normalized against the GCN values derived from FFPE peripheral blood leukocytes control. We also used MLPA technique to study intra-tumor heterogeneity (TH) by analyzing FGFR1 and SOX2 in different tumor areas. In particular, in 4 cases FGFR1 and SOX2 were co-amplified. Also, TH was examined in serial tumor biopsies and/or resections obtained at different points of disease progression in two patients. Of the 76 patients evaluable for FGFR1 and SOX2 GCN, FGFR1 high amplification was detected in 13/76 (17.10%) and low amplification in 7/76 (9.21%). SOX2 presented high amplification in 38/63 (60.32%) and low amplification in 9/63 (14.28%). Interestingly, 46.15% of the FGFR1-amplified tumors were also co-amplified for SOX2. An important degree of TH was found in 2 of the 4 tumors analyzed. GCN changes in FGFR1, SOX2, PIK3CA, PDGFRa, KDR, EGFR and MET over 10 years follow-up will be presented for one surgically resected SCC lung cancer patient. Frequencies of FGFR1 and SOX2 gene amplifications detected are in agreement with previously published data. Survival according to FGFR1 and SOX2 status will also be presented. FGFR1 and SOX2 co-amplification, together with the TH, warrants further research and could represent a novel therapeutic target. Citation Format: Pedro Méndez, José L. Ramirez, Amaya Gascó, Teresa Morán, Enric Carcereny, Miquel Taron, José Luís Mate, Irene Sansano, María Pérez, Mónica Botia, Montserrat Tierno, Harry J.M Groen, Rafael Rosell. FGFR1 and SOX2 amplification in squamous cell carcinoma (SCC) of the lung. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 53. doi:10.1158/1538-7445.AM2013-53

FGFR1 amplifications in squamous cell carcinomas of the lung: diagnostic and therapeutic implications.

Fibroblast growth factor receptor 1 (FGFR1) is a type 4 receptor tyrosine kinase. The receptor and its ligands play an important role in development and physiology. However, constitutive activation of FGFR1 by gene amplification, translocation or mutation is associated with various malignancies as, for example, breast cancer or myeloproliferative diseases. We have recently reported that FGFR1 amplification occurs in 20% of pulmonary squamous cell carcinomas, and preclinical tests have shown that these alterations are therapeutically tractable. These findings make FGFR1 amplification a potential biomarker for lung cancer treatment. Squamous cell carcinomas of the lung are characterized by an uneven FGFR1 gene copy number distribution. Therefore, fluorescence in situ hybridization assays need to address focality and heterogeneity of FGFR1 in these tumors. Here, we review our proposal for a reading and evaluation strategy. Furthermore, we highlight the emerging landscape of clinical trials with selective and unselective FGFR inhibitors and provide first response data from early clinical trials.

Abstract B31: Fibroblast growth factor receptor-1 (FGFR1) gene amplification is frequent in lung squamous cell carcinoma and high gene copy number indicates a better prognosis in early stage NSCLC.

Abstract Introduction: Lung cancer is the leading cause of cancer death globally. Non-small cell lung cancer (NSCLC) accounts for 85% of all lung cancers. Histologically NSCLC is divided into five subtypes, with adenocarcinoma (AD) and squamous cell carcinoma (SCC) representing the predominant subclasses, 40% and 30%, respectively. Several molecular targets have been identified in AD but such targets in SCC are lacking and there are no FDA-approved targeted agents for SCC. FGFR1 is a druggable receptor tyrosine kinase purported to be an oncogenic driver in lung cancer and the gene has been shown to be amplified in SCC. Methods: Resection specimens from 32 SCC and 27 non-SCC tumors (22 AD) were evaluated for FGFR1 and chromosome (CH) 8 copy number status using dual-color silver in situ hybridization, black and red, respectively. FGFR1 gene copy number (GCN) and the ratio of FGFR1:CH8 was compared to clinical and pathological characteristics and related to survival. Results: Of the 59 cases 2 were non-evaluable due to weak staining (one SCC specimen) and lack of sufficient tumor (one non-SCC specimen). The mean and median GCN for FGFR1 were 2.81 (SD±1.17) and 2.36 (range 1.18–6.64) genes/nucleus, respectively, and 1.34 (±0.73) and 1.14 (0.52–5.19) for the FGFR1:CH8 ratio. The average FGFR1 GCN for SCC vs. non-SCC tumors was 3.16 vs 2.38, p=0.02, and the average FGFR1:CH8 ratio was 1.54 vs. 1.10, p=0.03 There were 5 tumors with true FGFR1 amplification, as defined by clusters (all of these SCCs), with an average GCN &amp;gt;4/nucleus. Interestingly, only 3 of these amplified tumors had a FGFR1:CH8 ratio &amp;gt;2. There were 10 tumors, 7 of which were SCC, that contained FGFR1 GCN &amp;gt;3, however only 2 of these had a FGFR1:CH8 ratio &amp;gt;2. There were no associations of FGF1R GCN with age, sex, smoking status, stage or grade. There was a positive association between increased FGFR1 GCN and both DFS and OS (log-rank p= 0.01 and p=0.03, respectively) when using the median (2.36) as the cut-point. However, no associations were seen when evaluating the median (1.14) of the FGFR1:CH8 ratio (log-rank p= 0.93 and p=0.98, respectively). Conclusions: FGFR1 GCN is highly increased in SCC with 16% of the SSC tumors showing amplification and 48% showing gain (&amp;gt;3). Increased FGFR1 GCN associated with increased DFS and OS but a larger study is warranted to validate this finding. FGFR1 GCN alone appears better at showing gene gain compared to the FGFR1:CH8 ratio. FGFR1 SISH may be a feasible assay to validate whether FGFR1 is a bona fide biomarker for prediction of response and/or outcome to FGFR1 inhibitor therapy in SCC of the lung. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B31.