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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Fibroblast Growth Factor Receptor 1 (FGFR1) Amplification Detected by Droplet Digital Polymerase Chain Reaction (ddPCR) Is a Prognostic Factor in Colorectal Cancers

PURPOSE

The purpose of this study was to reveal the clinicopathological characteristics and prognostic implications associated with fibroblast growth factor receptor 1 (FGFR1) amplification in colorectal cancers (CRCs).

MATERIALS AND METHODS

We measured the copy number of FGFR1 by droplet digital polymerase chain reaction (ddPCR), and analyzed the FGFR1 expression by immunohistochemistry, in 764 surgically resected CRCs (SNUH2007 dataset, 384 CRCs; SNUH Folfox dataset, 380 CRCs).

RESULTS

CRCs with ≥ 3.3 copies of the FGFR1 gene were classified as FGFR1 amplified. FGFR1 amplification was found in 10 of the 384 CRCs (2.6%) in the SNUH2007 dataset, and in 28 of the 380 CRCs (7.4%) in the SNUH Folfox dataset. In the SNUH2007 dataset, there was no association between the FGFR1 copy number status and sex, gross appearance, stage, or differentiation. High FGFR1 expression was associated with female sex and KRAS mutation. At the molecular level, FGFR1 amplification was mutually exclusive with BRAF mutation, microsatellite instability, and MLH1 methylation, in both SNUH2007 and SNUH Folfox datasets. Survival analysis revealed that FGFR1 amplification was associated with significantly worse clinical outcome compared with no FGFR1 amplification, in both SNUH2007 and SNUH Folfox datasets. Within the SNUH2007 dataset, CRC patients with high FGFR1 expression had an inferior progression-free survival compared with those with low FGFR1 expression. The FGFR inhibitor, PD173074, repressed the proliferation of a CRC cell line overexpressing FGFR1, but not of cells with FGFR1 amplification.

CONCLUSION

FGFR1 amplification measured by ddPCR can be a prognostic indicator of poor clinical outcome in patients with CRCs.

Targeted Therapies in Non-small-Cell Lung Cancer

The treatment landscape for non-small-cell lung cancer (NSCLC) has dramatically shifted over the past two decades. Targeted or precision medicine has primarily been responsible for this shift. Older paradigms of treating metastatic NSCLC with cytotoxic chemotherapy, while still important, have given way to evaluating tumor tissues for specific driver mutations that can be treated with targeted agents. Patients treated with targeted agents frequently have improved progression-free survival and overall survival compared to patients without a targetable driver mutation, highlighting the clinical benefit of precision medicine. In this chapter, we explore the historic landmark trials, the current state of the field, and potential future targets under investigation, in this exciting, rapidly evolving discipline of precision medicine in lung cancer.

Targeting FGFR in Squamous Cell Carcinoma of the Lung

Unlike for adenocarcinomas of the lung, no molecular targeted therapies have yet been developed for squamous cell lung cancers, because targetable oncogenic aberrations are scarce in this tumor type. Recent discoveries have established that the fibroblast growth factor (FGF) signaling pathway plays a fundamental role in cancer development by supporting tumor angiogenesis and cancer cell proliferation via different mechanisms. Through comprehensive genomic studies, aberrations in the FGF pathway have been identified in various tumor types, including squamous cell lung cancer, making FGF receptor (FGFR) a potentially druggable target in this malignancy. Several multi-targeted tyrosine kinase inhibitors include FGFR in their target spectrum and a number of these compounds have been approved for clinical use in different cancers. Novel agents selectively targeting FGFRs have been developed and are currently under investigation in clinical trials, showing promising results. This article reviews FGFR aberrations and the clinical data involving selective and multikinase FGFR inhibitors in squamous cell lung cancer.

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

Background

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

Patients and methods

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

Results

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

Conclusions

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

Co-clinical trials demonstrate predictive biomarkers for dovitinib, an FGFR inhibitor, in lung squamous cell carcinoma

Background

We conducted co-clinical trials in patient-derived xenograft (PDX) models to identify predictive biomarkers for the multikinase inhibitor dovitinib in lung squamous cell carcinoma (LSCC).

Methods

The PDX01-02 were established from LSCC patients enrolled in the phase II trial of dovitinib (NCT01861197) and PDX03-05 were established from LSCC patients receiving surgery. These five PDX tumors were subjected to in vivo test of dovitinib efficacy, whole exome sequencing and gene expression profiling.

Results

The PDX tumors recapitulate histopathological properties and maintain genomic characteristics of originating tumors. Concordant with clinical outcomes of the trial enrolled-LSCC patients, dovitinib produced substantial tumor regression in PDX-01 and PDX-05, whereas it resulted in tumor progression in PDX-02. PDX-03 and -04 also displayed poor antitumor efficacy to dovitinib. Mutational and genome-wide copy number profiles revealed no correlation between genomic alterations of FGFR1-3 and sensitivity to dovitinib. Of note, gene expression profiles revealed differentially expressed genes including FGF3 and FGF19 between PDX-01 and 05 and PDX-02-04. Pathway analysis identified two FGFR signaling-related gene sets, FGFR ligand binding/activation and SHC-mediated cascade pathway were substantially up-regulated in PDX-01 and 05, compared with PDX-02-04. The comparison of gene expression profiles between dovitinib-sensitive versus -resistant lung cancer cell lines in the Cancer Cell Line Encyclopedia database also found that transcriptional activation of 18 key signaling components in FGFR pathways can predict the sensitivity to dovitinib both in cell lines and PDX tumors. These results highlight FGFR pathway activation as a key molecular determinant for sensitivity to dovitinib.

Conclusions

FGFR gene expression signatures are predictors for the response to dovitinib in LSCC.

Targeting Novel but Less Common Driver Mutations and Chromosomal Translocations in Advanced Non-Small Cell Lung Cancer

Discovery of the epidermal growth factor receptor gene mutation and the anaplastic lymphoma kinase chromosomal translocation in non-small cell lung cancer has prompted efforts around the world to identify many less common targetable oncogenic drivers. Such concerted efforts have been variably successful in both non-squamous and squamous cell carcinomas of the lung. Some of the targeted therapies for these oncogenic drivers have received regulatory approval for clinical use, while others have modest clinical benefit. In this mini-review, several of these targets will be reviewed.

Advances in the Development of Molecularly Targeted Agents in Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) remains a significant global health challenge and the leading cause of cancer-related mortality. The traditional 'one-size-fits-all' treatment approach has now evolved into one that involves personalized strategies based on histological and molecular subtypes. The molecular era has revolutionized the treatment of patients harboring epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK) and ROS1 gene aberrations. In the appropriately selected population, anti-tumor agents against these molecular targets can significantly improve progression-free survival. However, the emergence of acquired resistance is inevitable. Novel potent compounds with much improved and rational selectivity profiles, such as third-generation EGFR T790M resistance mutation-specific inhibitors, have been developed and added to the NSCLC armamentarium. To date, attempts to overcome resistance bypass pathways through downstream signaling blockade has had limited success. Furthermore, the majority of patients still do not harbor known driver genetic or epigenetic alterations and/or have no new available treatment options, with chemotherapy remaining their standard of care. Several potentially actionable driver aberrations have recently been identified, with the early clinical development of multiple inhibitors against these promising targets currently in progress. The advent of immune checkpoint inhibitors has led to significant benefit for advanced NSCLC patients with durable responses observed. Further interrogation of the underlying biology of NSCLC, coupled with modern clinical trial designs, is now required to develop novel targeted therapeutics rationally matched with predictive biomarkers of response, so as to further advance NSCLC therapeutics through the next decade.

Investigational therapies for squamous cell lung cancer: from animal studies to phase II trials

INTRODUCTION

It remains challenging to treat squamous cell lung cancer (SCC) with limited therapeutic options. However, recent breakthroughs in targeted therapies and immunotherapies have shed some light on the management of this deadly disease. Areas covered: The article first reviews the current treatment options for advanced SCC, especially recent FDA approved molecular agents (afatinib, ramucirumab and necitumumab) and immunotherapies (nivolumab, pembrolizumab and atezolimumab). We then provide an overview on investigational therapies with data ranging from preclinical to phase II studies, focusing on new cytotoxic agents, emerging molecularly targeted agents (including a PARP inhibitor for Homologous Recombinant Deficiency positive SCC) and novel immunotherapeutic strategies. Expert opinion summary: Identification of potential therapeutic targets, development of novel clinical trials and the rapid approvals of immune checkpoint inhibitors have shifted the management paradigm for squamous cell lung cancer. On the other hand, continued efforts are needed to identify the predictive biomarkers and to investigate novel mechanistically-driven mono- and combination therapies. We need to learn more about the biology behind immune checkpoint blockade and tumor genomics in SCC for better patient selection and future trial design.

FGFR Signaling as a Target for Lung Cancer Therapy

Lung cancer is the leading cause of cancer-related death in developed countries. Recently, molecular targeted therapies have shown promising results in the management of lung cancer. These therapies require a clear understanding of the relevant pathways that drive carcinogenesis and maintenance of the malignant phenotype. The fibroblast growth factor receptor (FGFR) signaling axis is one such pathway that plays a central role in normal cellular function. Alterations in this pathway have been found in many cancers. In this review article, we focus on the role of this pathway in lung cancer. We present the molecular structure of FGFR, the interaction of the receptor with its ligands (the fibroblast growth factors), its downstream signaling, and aberrations in the FGFR pathway. We also discuss clinical trials involving selective and multikinase FGFR inhibitors in lung cancer treatment.

Activation of the Met kinase confers acquired drug resistance in FGFR-targeted lung cancer therapy

Aberrant fibroblast growth factor receptor (FGFR) activation/expression is a common feature in lung cancer (LC). In this study, we evaluated the antitumor activity of and the mechanisms underlying acquired resistance to two potent selective FGFR inhibitors, AZD4547 and BAY116387, in LC cell lines. The antitumor activity of AZD4547 and BAY1163877 was screened in 24 LC cell lines, including 5 with FGFR1 amplification. Two cell lines containing FGFR1 amplifications, H1581 and DMS114, were sensitive to FGFR inhibitors (IC50<250 nm). Clones of FGFR1-amplified H1581 cells resistant to AZD4547 or BAY116387 (H1581AR and H1581BR cells, respectively) were established. Receptor tyrosine kinase (RTK) array and immunoblotting analyses showed strong overexpression and activation of Met in H1581AR/BR cells, compared with that in the parental cells. Gene set enrichment analysis against the Kyoto Encyclopedia of Genes and Genomes (KEGG) database showed that cytokine-cytokine receptor interaction pathways were significantly enriched in H1581AR/BR cells, with Met contributing significantly to the core enrichment. Genomic DNA quantitative PCR and fluorescent in situ hybridization analyses showed MET amplification in H1581AR, but not in H1581BR, cells. Met amplification drives acquired resistance to AZD4547 in H1581AR cells by activating ErbB3. Combination treatment with FGFR inhibitors and an anaplastic lymphoma kinase (ALK)/Met inhibitor, crizotinib, or Met-specific short interfering RNA (siRNA) synergistically inhibited cell proliferation in both H1581AR and H1581BR cells. Conversely, ectopic expression of Met in H1581 cells conferred resistance to AZD4547 and BAY1163877. Acquired resistance to FGFR inhibitors not only altered cellular morphology, but also promoted migration and invasion of resistant clones, in part by inducing epithelial-to-mesenchymal transition. Taken together, our data suggest that Met activation is sufficient to bypass dependency on FGFR signaling. Concurrent inhibition of the Met and FGFR pathways may have synergistic clinical benefits when targeting FGFR-dependent LC.

Efficacy and safety of dovitinib in pretreated patients with advanced squamous non-small cell lung cancer with FGFR1 amplification: A single-arm, phase 2 study

BACKGROUND

Fibroblast growth factor receptor 1 (FGFR1) amplification is a potential driving oncogene in squamous cell cancer (SCC) of the lung. The current phase 2 study evaluated the efficacy and tolerability of dovitinib, an FGFR inhibitor, in patients with advanced SCC of the lung.

METHODS

Patients with pretreated advanced SCC of the lung whose tumors demonstrated FGFR1 amplification of > 5 copies by fluorescence in situ hybridization were enrolled. Dovitinib at a dose of 500 mg was administered orally, once daily, on days 1 to 5 of every week, followed by 2 days off. The primary endpoint was overall response. Secondary endpoints were progression-free survival, overall survival, and toxicity.

RESULTS

All 26 patients were men with a median age of 68 years (range, 52-80 years). The majority of patients were ever-smokers. The median duration of dovitinib administration (28 days per cycle) was 2.5 months (range, 0.7-8.6 months). The overall response rate was 11.5% (95% confidence interval [95% CI], 0.8%-23.8%) and the disease control rate was 50% (95% CI, 30.8%-69.2%), with 3 patients achieving partial responses. Response durations for the patients with partial responses were ≥4.5 months, ≥ 5.1 months, and 6.1 months, respectively. After a median follow-up of 15.7 months (range, 1.2-25.6 months), the median overall survival was 5.0 months (95% CI, 3.6-6.4 months) and the median progression-free survival was 2.9 months (95% CI, 1.5-4.3 months). The most common grade 3 or higher adverse events were fatigue (19.2%), anorexia (11.5%), and hyponatremia (11.5%) (event severity was graded based on National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0]).

CONCLUSIONS

Treatment with dovitinib demonstrated modest efficacy in patients with advanced SCC with FGFR1 amplification. Further studies to evaluate other biomarkers correlated with the efficacy of dovitinib in patients with SCC are warranted. Cancer 2016;122:3024-3031. © 2016 American Cancer Society.

Clinicopathologic Features of Advanced Squamous NSCLC

Lung cancer remains the leading cause of cancer-related death worldwide. NSCLC accounts for more than 85% of all lung cancers, and the prognosis for advanced-stage disease is typically poor. In recent years, the importance of histologic subtypes of NSCLC has been recognized, and the distinction between squamous and other NSCLC histologic subtypes is now critical to patient management. Squamous cell lung cancer (sqCLC) represents approximately 25% to 30% of NSCLC. The prognosis for patients with advanced NSCLC is poorer for those with sqCLC than for those with adenocarcinoma. This is partly due to a number of clinical characteristics that distinguish sqCLC from other NSCLC histologic subtypes, such as smoking history, comorbid diseases, age, and molecular profile. Together, these factors make sqCLC an especially challenging disease to manage. Herein, we review some of the key clinicopathologic features of sqCLC. Understanding these features to optimally address many of the unique therapeutic challenges of this disease is likely to be central to ultimately improving outcomes for patients with squamous NSCLC.

Personalized Therapy of Non-small Cell Lung Cancer (NSCLC)

Lung cancer remains the most common cause of cancer related deaths in both men and women in the United States and non-small cell lung cancer (NSCLC) accounts for over 85 % of all lung cancers. Survival of these patients has not significantly altered in over 30 years. This chapter initially discusses the clinical presentation of lung cancer patients. Most patients diagnosed with lung cancer due to symptoms have advanced stage cancer. Once diagnosed, lung cancer patients need imaging studies to assess the stage of the disease before decisions regarding therapy are finalized. The most important prognostic factors are stage of the disease and performance status and these factors also determine therapy. The chapter subsequently discusses management of each stage of the disease and the impact of several pathologic, clinical factors in personalizing therapy for each individual patient. Transition from chemotherapy for every patient to a more personalized approach based on histology and molecular markers has occurred in the management of advanced stage NSCLC. It is expected that such a personalized approach will extend to all stages of NSCLC and will likely improve the outcomes of all NSCLC patients.

FGFR1 inhibition in lung squamous cell carcinoma: questions and controversies

Although the incidence of lung cancer has decreased due to the reduction of tobacco use, lung cancer remains the leading cause of cancer-related death. Lung squamous cell carcinoma represents 30% of lung cancers and only recently have possible drug-targetable mutations been identified in this disease, including fibroblast growth factor receptor 1 (FGFR1) gene amplification and genetic alterations in the phosphoinositide-3 kinase pathway. These discoveries have generated a great interest in the clinic and the initiation of clinical trials using FGFR tyrosine kinase inhibitors to treat FGFR-altered lung cancers. However, preliminary results from these studies have shown that not all patients respond to therapy. Here we review current unresolved questions on the selection of patients for their recruitment in FGFR tyrosine kinase inhibitor trials, how FGFR inhibitors could be combined with other targeted therapies or immunotherapies to improve patient outcome, and how the current preclinical models can help address these questions.

Kinome RNAi Screens Reveal Synergistic Targeting of MTOR and FGFR1 Pathways for Treatment of Lung Cancer and HNSCC

The FGFR1 is a therapeutic target under investigation in multiple solid tumors and clinical trials of selective tyrosine kinase inhibitors (TKI) are underway. Treatment with a single TKI represents a logical step toward personalized cancer therapy, but intrinsic and acquired resistance mechanisms limit their long-term benefit. In this study, we deployed RNAi-based functional genomic screens to identify protein kinases controlling the intrinsic sensitivity of FGFR1-dependent lung cancer and head and neck squamous cell cancer (HNSCC) cells to ponatinib, a multikinase FGFR-active inhibitor. We identified and validated a synthetic lethal interaction between MTOR and ponatinib in non-small cell lung carcinoma cells. In addition, treatment with MTOR-targeting shRNAs and pharmacologic inhibitors revealed that MTOR is an essential protein kinase in other FGFR1-expressing cancer cells. The combination of FGFR inhibitors and MTOR or AKT inhibitors resulted in synergistic growth suppression in vitro. Notably, tumor xenografts generated from FGFR1-dependent lung cancer cells exhibited only modest sensitivity to monotherapy with the FGFR-specific TKI, AZD4547, but when combined with the MTOR inhibitor, AZD2014, significantly attenuated tumor growth and prolonged survival. Our findings support the existence of a signaling network wherein FGFR1-driven ERK and activated MTOR/AKT represent distinct arms required to induce full transformation. Furthermore, they suggest that clinical efficacy of treatments for FGFR1-driven lung cancers and HNSCC may be achieved by combining MTOR inhibitors and FGFR-specific TKIs.

The Evolution of Therapies in Non-Small Cell Lung Cancer

The landscape of advanced non-small lung cancer (NSCLC) therapies has rapidly been evolving beyond chemotherapy over the last few years. The discovery of oncogenic driver mutations has led to new ways in classifying NSCLC as well as offered novel therapeutic targets for anticancer therapy. Targets such as epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) gene rearrangements have successfully been targeted with appropriate tyrosine kinase inhibitors (TKIs). Other driver mutations such as ROS, MET, RET, BRAF have also been investigated with targeted agents with some success in the early phase clinical setting. Novel strategies in the field of immune-oncology have also led to the development of inhibitors of cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed death-1 receptor (PD-1), which are important pathways in allowing cancer cells to escape detection by the immune system. These inhibitors have been successfully tried in NSCLC and also now bring the exciting possibility of long term responses in advanced NSCLC. In this review recent data on novel targets and therapeutic strategies and their future prospects are discussed.

Next-Generation Sequencing of Stage IV Squamous Cell Lung Cancers Reveals an Association of PI3K Aberrations and Evidence of Clonal Heterogeneity in Patients with Brain Metastases

Large-scale genomic characterization of squamous cell lung cancers (SQCLC) has revealed several putative oncogenic drivers. There are, however, little data to suggest that these alterations have clinical relevance. We performed comprehensive genomic profiling (including next-generation sequencing) of 79 stage IV SQCLCs and analyzed differences in the clinical characteristics of two major SQCLC subtypes: FGFR1 amplified and PI3K aberrant. Patients with PI3K-aberrant tumors had aggressive disease marked by worse survival (median overall survival, 8.6 vs. 19.1 months, P < 0.001), higher metastatic burden (>3 organs, 18% vs. 3%, P = 0.025), and greater incidence of brain metastases (27% vs. 0% in others, P < 0.001). We performed whole-exome and RNA sequencing on paired brain metastases and primary lung cancers to elucidate the metastatic process to brain. SQCLC primaries that gave rise to brain metastases exhibited truncal PTEN loss. SQCLC brain metastases exhibited a high degree of genetic heterogeneity and evidence of clonal differences between their primary sites.

SIGNIFICANCE

We performed next-generation sequencing of metastatic SQCLCs and primary lung-brain metastasis pairs, identifying PI3K-aberrant tumors as an aggressive subset associated with brain metastases. We identified genetic heterogeneity between lung primaries-brain metastases as well as clonal populations that may highlight alterations important in the metastatic process.

FGFR as potential target in the treatment of squamous non small cell lung cancer

To date therapeutic options for squamous cell lung cancer patients remain scarce because no druggable targets have been identified so far. Aberrant signaling by FGFs (fibroblast growth factors) and FGFRs (fibroblast growth factors receptors) has been implicated in several human cancers and, particularly, in squamous non-small cell lung cancer (NSCLC). FGFR gene amplifications, somatic missense mutations, chromosomal translocations are the most frequent mechanisms able to induce aberrant activation of this pathway. Data from literature have established that the presence of an aberrant FGFR signaling has to be considered a possible negative prognostic factor but predictive of potential sensitivity to FGFR inhibitors. In the last years, clinical research efforts allowed to identify and evaluate promising FGFR inhibitors, such as monoclonal antibodies, ligand traps, non-selective or selective tyrosine kinase inhibitors. This review summarizes the current knowledge about FGFR alterations in NSCLC and the relative inhibitors in development, in particular in squamous NSCLC.

Best practice in the treatment of advanced squamous cell lung cancer

The management of advanced stage nonsmall cell lung cancer (NSCLC) has been altered by the recognition of histology-based treatment and the use of targeted therapy. Whilst outcomes have improved with adenocarcinoma, treatment options are still limited in advanced stage squamous cell lung cancer. With advances in the molecular characterization of squamous cell cancers (SCCs), new potential targets have been identified. In this review, we discuss the role of histology in the treatment of NSCLC, cytotoxic chemotherapy, existing targeted therapies, the new molecular subsets and novel inhibitors in squamous cell lung carcinoma, and the emerging role of immune checkpoint inhibitors. Based on the results of two recent studies, nivolumab, a programmed death 1 (PD-1) immune checkpoint inhibitor, has been approved by the US Food and Drug Administration (FDA) in the treatment of squamous cell NSCLC in the second-line setting. Well-designed biomarker driven studies are needed to accelerate the development and approval of novel therapies for patients with lung SCC.