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Lung cancer is the leading cause of mortality world-wide. Non Small Cell Lung Cancer (NSCLC) is a particularly aggressive cancer, the optimum management of which is still being determined. In the next years modest survival improvement can be expected by chemotherapy. Advances in understanding of the molecular pathogenesis of lung cancer have led to the identification of several specific targets for therapeutic agents. Targeting the epidermal growth factor receptor (EGFR) has played a central role in advancing NSCLC research, treatment, and patient outcome over the last several years. In lung cancer, 10-15% of NSCLC contain activating mutations in the EGFR kinase conferring hypersensitivity to the oral TKIs gefitinib and erlotinib, have been demonstrated to be important predictive factors when selecting patients to be treated with these two agents. More recently, another molecular abnormality, the translocation of the anaplastic lymphoma kinase (ALK) gene that drives NSCLC in a different group of patients has been found in 4 to 5% of NSCLC. The rearrangement results in an EML4 - AKL fusion gene, which increases ALK activity. Inhibitors of ALK kinase have been developed and investigated. Crizotinib, an orally ALK and met proto-oncogene (MET) inhibitor, was very well tolerated and produced dramatic antitumor activity in early-stage trials which facilitated a faster than normal move into late-stage trials for EML4-ALK -positive NSCLC patients treatment. In a phase III randomized that showed progression free survival benefit as compared to chemotherapy in second-line setting. Several novel selective inhibitors of ALK kinase are currently in preclinical or early clinical testing. Since the discovery that Met pathway is one of the most frequently dysregulated pathways in human cancer, Met inhibitors, with varying kinase selectivity profiles ranging from highly selective to multi-targeted have been studied in the clinic and good progress has been achieved. A number of studies suggest that the PI3K/Akt signaling pathway is central to NSCLC growth and survival. Given the importance of activated PI3K signaling in cancer, several PI3K inhibitors are currently one of the most recent drug targets in oncology, with several small molecules in early stages of clinical development. This review will focus on the role of EGFR, ALK, MET, and PI3K inhibitors in the treatment of NSCLC.

Lung cancer, of which non-small-cell lung cancer (NSCLC) is the most common form, remains the leading cause of cancer-related mortality worldwide, with many patients presenting with advanced disease at initial diagnosis. In advanced NSCLC patients whose tumors harbor activating epidermal growth factor receptor (EGFR) mutations, the use of EGFR tyrosine kinase inhibitors (TKIs) as first-line treatment has provided an unusually large progression-free-survival (PFS) benefit, a significantly high response rate (RR) and decreased toxicity when compared with cytotoxic chemotherapy in several phase III randomized trials; however, resistance invariably occurs. There are multiple mechanisms defined by which tumor cells may become independent of EGFR such as the well-characterized example of mesenchymal-epithelial transition factor (MET) amplification. Upon initial diagnosis of NSCLC, MET gene amplification is uncommon; however, acquired MET amplification has been noted in up to 20% of EGFR-mutated tumors that have been pretreated with an EGFR TKI. In tumors containing MET gene amplification, stimulation of the tumor occurs via the co-receptor HER-3 resulting in activation of the phosphatidylinositol-3-kinase (PI3K) signaling pathway, thereby circumventing the effects of an EGFR TKI. Recently, the targeting of the MET pathway has been attempted with small molecules and with monoclonal antibodies. This review will explain the MET signaling pathway and biology in cancer and the recent clinical development and advances of MET/HGF targeting agents in the treatment of advanced NSCLC.

Platinum-based chemotherapy, with or without the antiangiogenetic drug bevacizumab, is the standard first-line therapy for patients with advanced non-small-cell lung cancer (NSCLC). The epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) gefitinib has been recently approved as treatment of patients with EGFR mutated tumors (including first-line). Three agents are approved for treating non-selected patients who progress after one prior regimen: docetaxel, pemetrexed, and the EGFR-TKI erlotinib. Gefitinib can be used as second-line treatment in patients with EGFR mutated tumors. Although these agents have yelded similar outcomes in terms of antitumor activity and efficacy in unselected NSCLC patients, they have different toxicity profiles, and recently some strong factors that can help in the choice among them have been detected. In particular, the hystotype, the EGFR gene mutational status, the response to previous first-line chemotherapy and the correlation of the safety profile of the agents with Performance Status and comorbidities of the patients, are the most important factors that drive the choice of the second-line treatment. Obviously, the drugs administered in the first-line treatment strongly influence the choice of the second-line treatment because some of the currently available drugs can be used in both settings. Thus, more than in the past, first and second-line treatment of advanced NSCLC are linked, and the choice of second-line treatment is part of a strategy decided when beginning the first-line treatment.

Erlotinib is an orally small molecule inhibiting the tyrosine kinase activity of the epidermal growth factor receptor (EGFR). Currently, erlotinib, at a standard oral daily dose of 150 mg, is licensed for the treatment of unselected recurrent non-small cell lung cancer (NSCLC) patients, however, it is being investigated in all stages of NSCLC. Erlotinib is well tolerated, with common toxicities including rash and diarrhoea. The optimization of the therapeutic impact of erlotinib in NSCLC will be more defined when reliable predictive factors are identified. An important step has been made in the molecular characterization of potentially sensitive NSCLC patients. In fact, we have learned that activation, somatic EGFR gene mutations within the tyrosine kinase domain, are associated with a high possibility of a long lasting therapeutic response to erlotinib. The present review discusses the role of erlotinib in the treatment of NSCLC.

In recent years, the epidermal growth factor receptor (EGFR) has been recognized as a central player and regulator of cancer cell proliferation, apoptosis and angiogenesis and, therefore, as a potentially relevant therapeutic target. Several strategies for EGFR targeting have been developed, the most succesful being represented by monoclonal antibodies, that directly interfere with ligand-receptor binding and small molecule tyrosine kinase inhibitors, that interfere with activation/phosphorylation of EGFR. These agents have been authorized in advanced chemorefractory cancers, including colorectal cancer, non-small-cell lung cancer and head and neck cancer. However, evidence of resistance to these drugs has been described and extensive studies have been performed to investigate whether resistance to EGFR-targeted therapy is primary or secondary. Cellular levels of EGFR do not always correlate with response to the EGFR inhibitors. Indeed, in spite of the over expression and efficient inhibition of EGFR, resistance to EGFR inhibitors may occur. Moreover, given the genetic instability of cancer cells, genetic modifications could enable them to acquire a resistant phenotype to anti-EGFR therapies. Taken together, these findings support the importance of understanding the molecular mechanisms affecting cancer cell sensitivity or resistance to such inhibitors. This review will focus on the most relevant mechanisms contributing to the acquisition of sensitivity/resistance to EGFR inhibitors.

Lung cancer is the most common cancer in the world. One third of patients with non-small cell lung cancer (NSCLC) are diagnosed with locally or regionally advanced unresectable disease at presentation. Currently, in this stage of disease, a combination of chemotherapy and radiotherapy is the standard treatment approach for patients with good performance status, and concomitant chemo-radiotherapy has demonstrated to be the best therapeutic approach. However, despite improvements in treatment, local tumor control remains suboptimal and distant metastases remain the major site of failure. The diversity of molecular abnormalities in NSCLC may partly contribute to its resistance to therapy. It is therefore widely accepted that one approach to improve the efficacy of cancer therapy is the development of rational combinations of anticancer agents that may exhibit synergistic interactions. The introduction of several biologic agents represents an important advance in the management of NSCLC and some of them have shown to have a synergistic effect when given in combination with radiotherapy and chemotherapy in preclinical and in clinical models. In the present review we discuss the rationale and the feasibility of these combinations and the first results available from clinical trials. [ABSTRACT FROM AUTHOR]