Next-generation sequencing of tissue and circulating tumor DNA: Resistance mechanisms to EGFR targeted therapy in a cohort of patients with advanced non-small cell lung cancer

Expert consensus on the use of third-generation EGFR-TKIs in EGFR-mutated advanced non-small cell lung cancer with various T790M mutations post-resistance to first-/second-generation EGFR-TKIs

Third-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have emerged as the mainstay of treatment for advanced EGFR-mutant advanced non-small cell lung cancer (NSCLC), effectively overcoming the problems of acquired threonine-to-methionine (T790M) mutations associated with the first- or second-generation TKIs. Evidence from several studies suggests that these agents, including osimertinib and aumolertinib, also show potential benefits in T790M-negative or unknown populations, particularly those with brain metastases, where the high permeability of the blood-brain barrier allows effective control of intracranial lesions. Despite the encouraging results, further high-quality research, including prospective trials, is warranted to fully elucidate the efficacy profiles of these third-generation TKIs in T790M-negative or unknown NSCLC patients after first- or second-line TKI failure. The present expert consensus highlights the evolving role of third-generation EGFR-TKIs in overcoming therapeutic resistance and optimizing patient outcomes.

PIK3CA mutation as an acquired resistance driver to EGFR-TKIs in non-small cell lung cancer: Clinical challenges and opportunities

Epithelial growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have significantly enhanced the treatment outcomes in non-small cell lung cancer (NSCLC) patients harboring EGFR mutations. However, the occurrence of acquired resistance to EGFR-TKIs is an unavoidable outcome observed in these patients. Disruption of the PI3K/AKT/mTOR signaling pathway can contribute to the emergence of resistance to EGFR TKIs in lung cancer. The emergence of PIK3CA mutations following treatment with EGFR-TKIs can lead to resistance against EGFR-TKIs. This review provides an overview of the current perspectives regarding the involvement of PI3K/AKT/mTOR signaling in the development of lung cancer. Furthermore, we outline the state-of-the-art therapeutic strategies targeting the PI3K/AKT/mTOR signaling pathway in lung cancer. We highlight the role of PIK3CA mutation as an acquired resistance mechanism against EGFR-TKIs in EGFR-mutant NSCLC. Crucially, we explore therapeutic strategies targeting PIK3CA-mediated resistance to EGFR TKIs in lung cancer, aiming to optimize the effectiveness of treatment.

Machine learning-based radiomics strategy for prediction of acquired EGFR T790M mutation following treatment with EGFR-TKI in NSCLC

The epidermal growth factor receptor (EGFR) Thr790 Met (T790M) mutation is responsible for approximately half of the acquired resistance to EGFR-tyrosine kinase inhibitor (TKI) in non-small-cell lung cancer (NSCLC) patients. Identifying patients at diagnosis who are likely to develop this mutation after first- or second-generation EGFR-TKI treatment is crucial for better treatment outcomes. This study aims to develop and validate a radiomics-based machine learning (ML) approach to predict the T790M mutation in NSCLC patients at diagnosis. We collected retrospective data from 210 positive EGFR mutation NSCLC patients, extracting 1316 radiomics features from CT images. Using the LASSO algorithm, we selected 10 radiomics features and 2 clinical features most relevant to the mutations. We built models with 7 ML approaches and assessed their performance through the receiver operating characteristic (ROC) curve. The radiomics model and combined model, which integrated radiomics features and relevant clinical factors, achieved an area under the curve (AUC) of 0.80 (95% confidence interval [CI] 0.79-0.81) and 0.86 (0.87-0.88), respectively, in predicting the T790M mutation. Our study presents a convenient and noninvasive radiomics-based ML model for predicting this mutation at the time of diagnosis, aiding in targeted treatment planning for NSCLC patients with EGFR mutations.

The Role of Serine Protease 8 in Mediating Gefitinib Resistance in Non-small Cell Lung Cancer

OBJECTIVE

This investigation aims to explore the expression levels of serine protease 8 (PRSS8) in gefitinib-resistant Non-Small Cell Lung Cancer (NSCLC) cell lines (PC9/GR) and elucidate its mechanism of action.

METHODS

We measured PRSS8 expression in gefitinib-resistant (PC9/GR) and sensitive (PC9) NSCLC cell lines using Western blot analysis. PRSS8-specific small interfering RNA (PRSS8-siRNA), a recombinant plasmid, and a corresponding blank control were transfected into PC9/GR cells. Subsequently, Western blot analyses were conducted to assess the expression levels of PRSS8, phosphorylated AKT (p-AKT), AKT, phosphorylated mTOR (p-mTOR), mTOR, and various apoptosis-related proteins within each group. Additionally, a cell proliferation assay utilizing Cell Counting Kit-8 (CCK8) was performed on each group treated with gefitinib.

RESULTS

PRSS8 expression was markedly higher in PC9/GR cells compared to PC9 cells (p < 0.05). The group treated with PRSS8-siRNA exhibited significantly reduced protein expression levels of PRSS8, p-AKT, p-mTOR, β-catenin, and BCL-2 compared to the control siRNA (Con-siRNA) group, whereas expressions of Caspase9 and Bax were significantly increased. In the untransfected PC9/GR cells, protein expressions of PRSS8, p-AKT, pmTOR, and BCL-2 were significantly elevated when compared with the plasmid-transfected group, which also showed a significant reduction in Bax expression. The proliferative activity of the PRSS8-siRNA group postgefitinib treatment was significantly diminished at 24, 48, and 72 hours in comparison to the Con-siRNA group.

CONCLUSION

The findings indicate that PRSS8 contributes to the acquisition of resistance to gefitinib in NSCLC, potentially through regulation of the AKT/mTOR signaling pathway.

Epidermal growth factor receptor compound and concomitant mutations: advances in precision treatment strategies

ABSTRACT

Epidermal growth factor receptor ( EGFR ) mutations are common oncogenic driver mutations in patients with non-small cell lung cancer (NSCLC). The application of EGFR-tyrosine kinase inhibitors (TKIs) is beneficial for patients with advanced and early-stage NSCLC. With the development of next-generation sequencing technology, numerous patients have been found to have more than one genetic mutation in addition to a single EGFR mutation; however, the efficacy of conventional EGFR-TKIs and the optimal treatments for such patients remain largely unknown. Thus, we review the incidence, prognosis, and current treatment regimens of EGFR compound mutations and EGFR concomitant mutations to provide treatment recommendations and guidance for patients with these mutations.

Survival Analysis of 159 Patients With Advanced Non-Small-Cell Lung Cancer Resistant to First-Generation Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor

Background

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have limited or no response in some certain patients of non-small-cell lung cancer (NSCLC). However, real-world survival analyses comparing clinical data and EGFR-plasma mutation are still lacking.

Methods

In total, 159 patients with advanced NSCLC resistant to first-generation EGFR-TKIs were included for consecutive blood sampling in this study. Super-amplification refractory mutation system (Super-ARMS) was used to detect EGFR-plasma mutations and correlations between survival and circulating tumor DNA (ctDNA) were analyzed.

Results

Among 159 eligible patients, the T790M mutation was detected in 27.0% (43/159) of patients. The median progression-free survival (mPFS) was 10.7 months in all patients. Survival analysis revealed that patients with the T790M mutation had shorter progression-free survival (PFS) than those with the T790M wild-type (10.6 months vs 10.8 months, P = .038). Patients who cleared EGFR-plasma mutation had prolonged PFS compared with those with nonclearing EGFR-plasma mutation (11.6 months vs 9.0 months, P = .001). Cox multivariate analysis showed that the nonclearance of EGFR-plasma mutations was an independent risk factor for PFS (RR = 1.745, 95% CI: [1.184, 2.571], P = .005). The T790M mutation was associated with nonclearance of the EGFR-plasma mutation (χ2 = 10.407, P = .001).

Conclusion

Patients with advanced NSCLC who were resistant to the first-generation EGFR-TKI had a prolonged PFS with clearance of EGFR-plasma mutation. Those nonclearers were more likely to harbor T790M mutations in plasma.

Advances in liquid biopsy-based markers in NSCLC

Lung cancer is the second most-frequently occurring cancer and the leading cause of cancer-associated deaths worldwide. Non-small cell lung cancer (NSCLC), the most common type of lung cancer is often diagnosed in middle or advanced stages and have poor prognosis. Diagnosis of disease at an early stage is a key factor for improving prognosis and reducing mortality, whereas, the currently used diagnostic tools are not sufficiently sensitive for early-stage NSCLC. The emergence of liquid biopsy has ushered in a new era of diagnosis and management of cancers, including NSCLC, since analysis of circulating tumor-derived components, such as cell-free DNA (cfDNA), circulating tumor cells (CTCs), cell-free RNAs (cfRNAs), exosomes, tumor-educated platelets (TEPs), proteins, and metabolites in blood or other biofluids can enable early cancer detection, treatment selection, therapy monitoring and prognosis assessment. There have been great advances in liquid biopsy of NSCLC in the past few years. Hence, this chapter introduces the latest advances on the clinical application of cfDNA, CTCs, cfRNAs and exosomes, with a particular focus on their application as early markers in the diagnosis, treatment and prognosis of NSCLC.

Can Liquid Biopsy Based on ctDNA/cfDNA Replace Tissue Biopsy for the Precision Treatment of EGFR-Mutated NSCLC?

More and more clinical trials have explored the role of liquid biopsy in the diagnosis and treatment of EGFR-mutated NSCLC. In certain circumstances, liquid biopsy has unique advantages and offers a new way to detect therapeutic targets, analyze drug resistance mechanisms in advanced patients, and monitor MRD in patients with operable NSCLC. Although its potential cannot be ignored, more evidence is needed to support the transition from the research stage to clinical application. We reviewed the latest progress in research on the efficacy and resistance mechanisms of targeted therapy for advanced NSCLC patients with plasma ctDNA EGFR mutation and the evaluation of MRD based on ctDNA detection in perioperative and follow-up monitoring.

Effectiveness and Safety of EGFR-TKI Rechallenge Treatment in Elderly Patients with Advanced Non-Small-Cell Lung Cancer Harboring Drug-Sensitive EGFR Mutations

Background and Objectives: Epidermal growth factor receptor–tyrosine kinase inhibitors (EGFR-TKIs) are effective first-line chemotherapeutic agents for patients with advanced non-small-cell lung cancer (NSCLC) harboring drug-sensitive EGFR mutations. However, the effectiveness of EGFR-TKI rechallenge after first-line EGFR-TKI treatment is not sufficient in elderly patients (over 75 years of age) harboring drug-sensitive EGFR mutations. Therefore, we investigated the effectiveness and safety of EGFR-TKI rechallenge after first-line EGFR-TKI treatment in elderly patients with advanced NSCLC harboring drug-sensitive EGFR mutations. Materials and Methods: Between April 2008 and December 2015, we analyzed 78 elderly patients with advanced NSCLC harboring drug-sensitive EGFR mutations with first-line EGFR-TKI treatment at four Japanese institutions. We retrospectively evaluated the clinical effectiveness and safety profiles of EGFR-TKI rechallenge after first-line EGFR-TKI treatment in elderly patients with advanced NSCLC harboring drug-sensitive EGFR mutations (exon 19 deletion/exon 21 L858R mutation). Results: Twenty-two patients in the cohort were rechallenged with EGFR-TKI. The median age was 79.5 years (range 75–87 years). Despite the fact that it was a retrospective analysis, even with EGFR-TKI rechallenge treatment the response rate was 23%, progression-free survival was 5.3 months, and overall survival was 14.4 months. Common adverse events included rash acneiform, paronychia, diarrhea, and anorexia. There were no treatment-related deaths. Due to the occurrence of adverse events of grade 2 or more, dose reduction was performed in 15 (68.2%) of 22 cases. Conclusions: EGFR-TKI rechallenge treatment after first-line EGFR-TKI treatment in elderly patients with advanced NSCLC harboring drug-sensitive EGFR mutations was one of the limited, safe and effective treatment options for elderly EGFR-positive lung cancer patients.