Genotypic and Histological Evolution of Lung Cancers Acquiring Resistance to EGFR Inhibitors (original) (raw)
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Mechanisms of resistance to EGFR-targeted drugs: lung cancer
ESMO open, 2016
Despite the improvement in clinical outcomes derived by the introduction of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKIs) in the treatment of patients with advanced non-small cell lung cancer (NSCLC) whose tumours harbour EGFR-activating mutations, prognosis remains unfavourable because of the occurrence of either intrinsic or acquired resistance. We reviewed the published literature and abstracts of oral and poster presentations from international conferences addressing EGFR-TKIs resistance mechanisms discovered in preclinical models and in patients with NSCLC. The molecular heterogeneity of lung cancer has several implications in terms of possible mechanisms of either intrinsic or acquired resistance to EGFR-targeted inhibitors. Several mechanisms of resistance have been described to EGFR-TKIs, such as the occurrence of secondary mutation (T790M, C797S), the activation of alternative signalling (Met, HGF, AXL, Hh, IGF-1R), the aberrance of the down...
Cells
The discovery of activating mutations in the epidermal growth factor receptor (EGFR) gene and the development of EGFR tyrosine kinase inhibitors (TKIs) have led to a paradigm shift in the treatment of non-small cell lung cancer (NSCLC). EGFR mutation-positive NSCLC is common in East Asia, and approximately 50% of adenocarcinomas harbor EGFR mutations. Undoubtedly, EGFR-TKIs, with their promising efficacy, are the mainstay of primary therapy. However, even if tumor shrinkage is achieved, most patients become resistant to EGFR-TKIs and relapse; hence, EGFR-TKIs do not achieve a radical cure. The problem of the development of resistance to targeted drugs has been a persistent challenge. After the role of EGFR T790M mutation in acquired drug resistance was reported, osimertinib, a third-generation irreversible EGFR-TKI, was designed to overcome the resistance conferred by T790M mutation. In addition, some studies have reported the mechanism of drug resistance caused by mutations other t...
Drug resistance to EGFR tyrosine kinase inhibitors for non-small cell lung cancer
Acta medica Okayama, 2014
Non-small cell lung cancer (NSCLC) harboring an activating mutation within the epidermal growth factor receptor (EGFR) was defined as a clinically distinct molecular group. These lesions show oncogene addiction to EGFR and dramatic responses to the EGFR tyrosine kinase inhibitors (TKIs). Several large Phase III trials have shown that EGFR-TKIs improved the progression-free survival of patients with EGFR mutant NSCLC compared to conventional chemotherapy. However, the long-term effectiveness of EGFR-TKIs is usually limited because of acquired drug resistance. To overcome this resistance to EGFR-TKIs, it will be essential to identify the specific mechanisms underlying the resistance. Many investigators have attempted to identify the mechanisms using preclinical models and drug-resistant clinical samples. As a result, several mechanisms have been showed to be responsible for the resistance, but not all of the relevant mechanisms have been uncovered. In this review, we provide an overvi...
2014
The discovery of mutated oncogenes has opened up a new era for the development of more effective treatments for non-small cell lung cancer patients (NSCLC) harbouring EGFR mutations. However, patients with EGFR-activating mutation ultimately develop acquired resistance (AR). Several studies have identified some of the mechanisms involved in the development of AR to EGFR tyrosine kinase inhibitors (TKI) that can be potential therapeutic strategies, although in up to 30% of cases, the underlying mechanism of AR are still unexplained. In this review we aim to summarize the main mechanisms of AR to EGFR TKI and some clinical strategies that can be used in the daily clinical practice to overcome this resistance and try to prolong the outcomes in this subgroup of patients.
Current Drug Targets, 2011
EGFR somatic mutations define a subset of NSCLCs that are most likely to benefit from EGFR tyrosine kinase inhibitors (TKIs). These tumors are dependent on EGFR-signaling for survival. Recently, tyrosine kinase domain somatic mutations have been approved as criterion to decide first-line therapy in this group of advanced NSCLCs. Anyway, all patients ultimately develop resistance to these drugs. Acquired resistance is linked to a secondary EGFR mutation in about a half of patients. Uncontrolled activation of MET, another tyrosine kinase receptor, has been implicated in neoplastic invasive growth. MET is overexpressed, activated and sometimes mutated in NSCLC cell lines and tumor tissues. MET increased gene copy number has also been documented in NSCLC and has been studied as negative prognostic factor. It has also been found in about 20% of patients developing acquired resistance to TKIs inhibitors. In this group, it seems to display a new mechanism, which is able to mark tumor independence from EGFR signaling.
Współczesna Onkologia, 2012
Abnormalities of epidermal growth factor receptor (EGFR) in non-small-cell lung cancer (NSCLC) patients consist of EGFR overexpression and EGFR (HER1) gene mutations. Structural dysfunction of the tyrosine kinase domain of EGFR is associated with the clinical response to tyrosine kinase inhibitors (TKI) in patients with NSCLC. The most common EGFR gene mutations occur as either deletions in exon 19 or as substitution L858R in exon 21 and cause a clinically beneficial response to gefinitib or erlotinib treatment. Unfortunately, the majority of patients finally develop resistance to these drugs. Acquired resistance is linked to secondary mutations localised in the EGFR gene, mainly substitution T790M in exon 20. Through intense research a few different mechanisms of resistance to reversible tyrosine kinase inhibitors have been identified: amplification of MET or IGF-1R genes, abnormalities of PTEN and mTOR proteins as well as rare mutations in EGFR and HER2 genes. Extensively investigated new drugs could be of significant efficiency in NSCLC patients with secondary resistance to reversible EGFR TKI. K Ke ey y w wo or rd ds s: : epidermal growth factor receptor, EGFR gene mutations, tyrosine kinase inhibitors, resistance mechanisms.
Tumori, 2017
In non-small cell lung cancer (NSCLC), the identification of epidermal growth factor receptor (EGFR) mutations and the parallel development of EGFR tyrosine kinase inhibitors (TKIs) have radically changed the therapeutic management strategies. Currently, erlotinib, gefitinib, and afatinib are all approved as standard first-line treatment in EGFR-mutated NSCLC. However, despite the proven efficacy, some EGFR-mutated NSCLCs do not respond to EGFR TKIs, while some patients, after a favorable and prolonged response to EGFR TKIs, inevitably progress within about 10-14 months. Epidermal growth factor receptor-dependent mechanisms, activation of alternative pathways, or phenotypic transformation can cause the resistance to EGFR TKIs. The exon 20 p.Thr790Met point mutation (T790M) is responsible for about 60% of cases of resistance when progression occurs. A third-generation TKI, osimertinib, improved outcome in patients harboring T790M after first- and second-generation TKI treatment. Howe...
Lung Cancer
Patients with epidermal growth factor receptor (EGFR) gene-mutated non-small cell lung cancer (NSCLC) obtain substantial clinical benefit from EGFR tyrosine-kinase inhibitors (TKIs), but will ultimately develop TKI-resistance resulting in median progression-free survival of 9-15 months during first-line TKI-therapy. However, type and timing of TKI-resistance cannot be predicted and several mechanisms may simultaneously/subsequently occur during TKI-treatment. In this respect, we present a 49 year-old Caucasian male ex-smoker with metastatic pulmonary adenocarcinoma (ADC) that concomitantly harbored an EGFR exon 19-mutation (p.E746_A750delELREA) and a previously unreported 2 bp frame-shift microdeletion in the fibroblast growth factor receptor 3 (FGFR3; p.D785fs*31) gene. Interestingly, FGFR3-mutations have previously been described in other cancer types of Caucasian patients and may represent an alternative pathway to EGFR-signaling. The patient received first-line erlotinib but after only 7 weeks showed metastatic pleural effusion, in which transformation to small cell lung cancer (SCLC) that retained the EGFR-and FGFR3-mutations was identified. Consequently, standard carboplatin-etoposide regimen for SCLC combined with erlotinib continuation was implemented obtaining significant objective response. However, after completing 6 cycles of this combination, new pulmonary and hepatic metastases appeared and showed persistence of the original EGFR-and FGFR3mutated ADC phenotype together with acquisition of the erlotinib-resistant T790M EGFR-mutation. The patient rapidly deteriorated and deceased. Thus, this advanced EGFR-mutated NSCLC displayed very rapid onset and heterogeneous genetic and phenotypic mechanisms of TKI-resistance occurring at different times and locations of metastatic disease: concomitant FGFR3-mutation before and during TKI-treatment as potential intrinsic mechanism for the rapid progression; transformation to SCLC at first progression during TKI-therapy; acquired T790M EGFR-mutation at second progression. Our case also underlines that, when achievable, rebiopsies of progressive sites during TKI-treatment are important for identifying heterogeneous histopathological and molecular resistance mechanisms and better defining possible treatment modifications.
Clinical Cancer Research, 2011
The management of non-small cell lung carcinoma (NSCLC) has been transformed by the observation that lung adenocarcinomas harboring mutations in epidermal growth factor receptor (EGFR) are uniquely sensitive to EGFR tyrosine kinase inhibitors (TKI). In these patients, acquired resistance to EGFR-TKI develops after a median of 10 to 14 months, at which time the current standard practice is to switch to conventional cytotoxic chemotherapy. Several possible mechanisms for acquired resistance have been identified, the most common being the development of an EGFR T790M gatekeeper mutation in more than 50% of cases. In this review, we discuss recent advances in the understanding of acquired TKI resistance in EGFR-mutant lung cancer and review therapeutic progress with second generation TKIs and combinations of targeted therapies. Clin Cancer Res; 17(17); 5530-7. Ó2011 AACR.