Molecular pathology of lung cancer: key to personalized medicine (original) (raw)
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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.
Genotypic and Histological Evolution of Lung Cancers Acquiring Resistance to EGFR Inhibitors
Science Translational Medicine, 2011
Lung cancers harboring mutations in the epidermal growth factor receptor (EGFR) respond to EGFR tyrosine kinase inhibitors, but drug resistance invariably emerges. To elucidate mechanisms of acquired drug resistance, we performed systematic genetic and histological analyses of tumor biopsies from 37 patients with drug-resistant non-small cell lung cancers (NSCLCs) carrying EGFR mutations. All drug-resistant tumors retained their original activating EGFR mutations, and some acquired known mechanisms of resistance including the EGFR T790M mutation or MET gene amplification. Some resistant cancers showed unexpected genetic changes including EGFR amplification and mutations in the PIK3CA gene, whereas others underwent a pronounced epithelial-to-mesenchymal transition. Surprisingly, five resistant tumors (14%) transformed from NSCLC into small cell lung cancer (SCLC) and were sensitive to standard SCLC treatments. In three patients, serial biopsies revealed that genetic mechanisms of resistance were lost in the absence of the continued selective pressure of EGFR inhibitor treatment, and such cancers were sensitive to a second round of treatment with EGFR inhibitors. Collectively, these results deepen our understanding of resistance to EGFR inhibitors and underscore the importance of repeatedly assessing cancers throughout the course of the disease.
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.
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...
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.
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...
Visnav, 2021
Lung cancer based on physiological appearance and areas of the tissues affected are classified as small cell lung cancer and non-small cell lung cancer. Different types of tumours arise due to varied genetic mutations involved in tumour progression which is specific for cancer subtypes. Non-small cell lung cancer exhibits mutations in the tyrosine kinase domain of epidermal growth factor receptor. Hence, tyrosine kinase inhibitors are used to suppress tumour progression. Due to variation in mutation, responsiveness to drug therapy efficacy is different in different individuals and hence leads to poor prognosis of cancer. This review aims to summarize the EGFR mutations involved in the progression of non-small cell lung cancer and tyrosine kinase inhibitor drugs approved for the treatment.
British Journal of Cancer, 2021
BACKGROUND: Tumour heterogeneity impacts the efficacy of metastatic cancer treatment even if actionable mutations are identified. Clinicians need to understand if assessing one lesion provides reliable information to drive a therapeutic decision in nonsmall-cell lung cancer (NSCLC) patients. METHODS: We analysed inter-tumour heterogeneity from five autopsied individuals with NSCLC-harbouring mutations in the epidermal growth factor receptor (EGFR), treated with EGFR tyrosine kinase inhibitors (TKIs). Through a comprehensive nextgeneration sequencing (NGS) oncopanel, and an EGFR panel for digital droplet PCR (ddPCR), we compared metastases within individuals, longitudinal biopsies from the same lesions and, whenever possible, the primary naive tumour. RESULTS: Analysis of 22 necropsies from five patients revealed homogeneity in pathogenic mutations and TKI-resistance mechanisms within each patient in four of them. In-depth analysis by whole-exome sequencing from patient 1 confirmed homogeneity in clonal mutations, but heterogeneity in passenger subclonal alterations. Different resistance mechanisms were detected depending on the patient and line of treatment. Three patients treated with a c-MET inhibitor in combination with TKI lost MET amplification upon progression. CONCLUSION: At a given point and under selective TKI pressure, a single metastasis biopsy in disseminated tumours from EGFRmutated NSCLC patients could provide a reasonable assessment of actionable alterations useful for therapeutic decisions.