Epidermal growth factor receptor T790M testing in progressed lung cancer: A review of sensitive methods for analysis of tissue and liquid biopsy samples

Correlation Analysis between T790M Status and Clinical Characteristics of Patients with EGFR-sensitive Mutation Advanced NSCLC who Progressed after the First Generation and First-line EGFR-TKIs Administration: A Real-world Exploratory Study

AIM

The present study is to investigate the association between T790M status and clinical characteristics of patients with EGFR-sensitive advanced non-small cell lung cancer (NSCLC) who progressed the initial epidermal growth factor receptor tyrosine kinase inhibitors (EGFRTKIs) administration.

METHODS

A total of 167 patients with EGFR-sensitive mutations advanced NSCLC who had successful genetic tests and progressed the initial EGFR-TKI treatment were included in this study retrospectively. The clinical and demographic characteristics of these patients were collected, which were manifested as pathological type, metastasis location, initial biopsy method, initial genetic test specimens, and baseline gene mutations status. Correlation analysis between T790M status and these characteristics was performed and prognostic analysis regarding the different subgroups was carried out accordingly.

RESULTS

The prevalence of secondary T790M after resistance to initial EGFR-TKIs among the 167 patients was 52.7%. Correlation analysis indicated that the median progression-free Survival (PFS) to initial EGFR-TKIs >12 months were more likely to develop secondary T790M in univariate analysis. However, the conclusion failed to show statistically significant in multivariate analysis. Additionally, patients with intracranial progression of initial EGFR-TKIs therapy were associated with secondary EGFR-T790M. However, it should be noted that those whose best overall response was partial response (PR) during the EGFR-TKI therapy were relevant to secondary T790M. Furthermore, The median PFS of the initial EGFR-TKIs administration was longer among patients with T790M positive mutation and patients with PR reaction than those without T790M mutation and patients with stable disease (SD), respectively (median PFS: 13.6 vs. 10.9 months, P=0.023) and (median PFS: 14.0 vs. 10.1 months, P=0.001).

CONCLUSION

This retrospective study highlighted the real-world evidence that the best efficacy and intracranial progression with initial EGFR-TKIs therapy among patients with advanced NSCLC might be the promising indicators to predict the occurrence of EGFR-T790M. Patients with PR reaction and T790M positive mutation conferred longer PFS of the initial EGFR-TKIs administration. Also, the conclusion should be confirmed in more patients with advanced NSCLC subsequently.

Liquid Biopsy: A Multi-Parametric Analysis of Mutation Status, Circulating Tumor Cells and Inflammatory Markers in EGFR-Mutated NSCLC

The liquid biopsy has the potential to improve patient care in the diagnostic and therapeutic setting in non-small cell lung cancer (NSCLC). Consented patients with epidermal growth factor receptor (EGFR) positive disease (n = 21) were stratified into two cohorts: those currently receiving EGFR tyrosine kinase inhibitor (TKI) therapy (n = 9) and newly diagnosed EGFR TKI treatment-naïve patients (n = 12). Plasma genotyping of cell-free DNA was carried out using the FDA-approved cobas® EGFR mutation test v2 and compared to next generation sequencing (NGS) cfDNA panels. Circulating tumor cell (CTC) numbers were correlated with treatment response and EGFR exon 20 p.T790M. The prognostic significance of the neutrophil to lymphocyte ratio (NLR) and lactate dehydrogenase (LDH) was also investigated. Patients in cohort 1 with an EGFR exon 20 p.T790M mutation progressed more rapidly than those with an EGFR sensitizing mutation, while patients in cohort 2 had a significantly longer progression-free survival (p = 0.04). EGFR exon 20 p.T790M was detected by liquid biopsy prior to disease progression indicated by computed tomography (CT) imaging. The cobas® EGFR mutation test detected a significantly greater number of exon 20 p.T790M mutations (p = 0.05). High NLR and derived neutrophil to lymphocyte ratio (dNLR) were associated with shorter time to progression and worse survival outcomes (p < 0.05). High LDH levels were significantly associated with shorter time to disease progression (p = 0.03). These data support the use of liquid biopsy for monitoring EGFR mutations and inflammatory markers as prognostic indicators in NSCLC.

Mutation differences in circulating tumor DNAs from non-small cell lung cancer patients between Uygur and Han populations

BACKGROUND

The incidence of non-small cell lung cancer (NSCLC) in Uygur population is gradually increasing recently. In view of the great diagnostic and prognostic values of cell-free DNAs (cfDNA) detection, this study focus on a liquid biopsy to explore the value of cfDNA mutation in healthy and NSCLC patients in 2 ethnicities.

METHODS

The concentration and sequencing of cfDNA in NSCLC and healthy subjects was assessed with a standard information analysis procedure, including detection, annotation, and statistical analysis. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were conducted to analyze the function of mutant genes and related pathways. Totally, 133 subjects, including 35 Uygur NSCLC patients, 10 Uygur healthy subjects, 63 cases of Han NSCLC patients and 25 Han health control, were admitted to the hospital.

RESULTS

There were a lower proportion of adenocarcinoma and higher percentage of smoking rate for Uygur patients. For cfDNA level between NSCLC and healthy subjects, Han patients exhibited sharp increase while there was no statistical difference in Uygur population. In addition, the mutation frequency of cfDNA in Han patients (72.6%) was significantly higher than Uygur patients (45.7%). There were 5 gene mutations only found in Han patients and ABCC11 showed a higher mutation frequency in Uygur population as a common one. Finally, Go and Kyoto Encyclopedia of Genes and Genomes analysis showed apprent functional enrichments and pathway changes between 2 ethnicities.

CONCLUSION

There existed distinct distributions of cancer subtypes, smoking proportion, cfDNA level, and mutation patterns between Han and Uygur patients. The results may be a useful tool in NSCLC patients' diagnosis as well as individualized therapy between ethnicities in future.

Influence of Biopsy Technique on Molecular Genetic Tumor Characterization in Non-Small Cell Lung Cancer-The Prospective, Randomized, Single-Blinded, Multicenter PROFILER Study Protocol

The detection of molecular alterations is crucial for the individualized treatment of advanced non-small cell lung cancer (NSCLC). Missing targetable alterations may have a major impact on patient's progression free and overall survival. Although laboratory testing for molecular alterations has continued to improve; little is known about how biopsy technique affects the detection rate of different mutations. In the retrospective study detection rate of epidermal growth factor (EGFR) mutations in tissue extracted by bronchoscopic cryobiopsy (CB was significantly higher compared to other standard biopsy techniques. This prospective, randomized, multicenter, single blinded study evaluates the accuracy of molecular genetic characterization of NSCLC for different cell sampling techniques. Key inclusion criteria are suspected lung cancer or the suspected relapse of known NSCLC that is bronchoscopically visible. Patients will be randomized, either to have a CB or a bronchoscopic forceps biopsy (FB). If indicated, a transbronchial needle aspiration (TBNA) of suspect lymph nodes will be performed. Blood liquid biopsy will be taken before tissue biopsy. The primary endpoint is the detection rate of molecular genetic alterations in NSCLC, using CB and FB. Secondary endpoints are differences in the combined detection of molecular genetic alterations between FB and CB, TBNA and liquid biopsy. This trial plans to recruit 540 patients, with 178 evaluable patients per study cohort. A histopathological and molecular genetic evaluation will be performed by the affiliated pathology departments of the national network for genomic medicine in lung cancer (nNGM), Germany. We will compare the diagnostic value of solid tumor tissue, lymph node cells and liquid biopsy for the molecular genetic characterization of NSCLC. This reflects a real world clinical setting, with potential direct impact on both treatment and survival.

Early Monitoring Drug Resistant Mutation T790M with a Two-Dimensional Simultaneous Discrimination Nanopore Strategy

With the aim of detecting low frequency of drug resistant mutation T790M against wild-type sequences, we reported a two-dimensional signal analysis strategy by combining a three locked nucleic acids (LNAs)-modified probe (LP15-3t) and an α-HL nanopore. The specific hybridization of the LP15-3t probe with the T790M generated unique long two-level signals, including characteristic blocking current and characteristic dwell time. Due to the significant dwell time difference (114.2-fold) and the blocking current difference ranging from 81% to 96%, this two-dimensional signal analysis strategy can simultaneously distinguish T790M sequences with a sensitivity of 0.0001% against wild-type sequences. The LOD of T790M was 0.1 pM. This high discrimination capability would have great potential in the detection of rare mutation sequences and the early monitoring of clinical outcome of NSCLC patients with TKI drug resistance.

Combined plasma and tissue genotyping of EGFR T790M benefits NSCLC patients: a real-world clinical example

Acquired resistance to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) is a prevalent clinical problem in the management of advanced non-small-cell lung cancer (NSCLC) with TKI-sensitizing mutations in the EGFR gene. Third-generation EGFR-TKIs have demonstrated potent activity against TKI resistance mediated by the EGFR T790M mutation, and standard rebiopsy and liquid biopsy are utilized to assess the T790M status of the NSCLC patients who experienced progressive disease (PD). Here, we conducted a retrospective study to assess 375 patients whose initial biopsy indicated a TKI-sensitizing mutation (either EGFR 19del or L858R) and who developed PD after treatment with first-generation TKIs, and assayed for T790M status. We adopted a combination approach in which tissue rebiopsy is preferred, utilizing liquid biopsies when tissue rebiopsy is not feasible. We analyzed the potential predictive clinical factors affecting T790M detection, evaluated the standard rebiopsy and liquid biopsy methods in T790M genotyping, and reported the clinical performance of osimertinib. Our results suggested that primary EGFR 19del, brain metastasis, and longer progression-free survival of initial EGFR-TKI treatment are associated with acquired T790M resistance. T790M-positive patients significantly benefited from osimertinib. In conclusion, the real-world clinical adoption of the combination approach with both tissue rebiopsy and liquid biopsy for T790M genotyping may provide significant benefits to patients who have developed PD after first-generation TKI treatments.

The diagnostic value of circulating tumor cells and ctDNA for gene mutations in lung cancer

PURPOSE

Detecting gene mutations by two competing biomarkers, circulating tumor cells (CTCs) and ctDNA has gradually paved a new diagnostic avenue for personalized medicine. We performed a comprehensive analysis to compare the diagnostic value of CTCs and ctDNA for gene mutations in lung cancer.

METHODS

Publications were electronically searched in PubMed, Embase, and Web of Science as of July 2018. Pooled sensitivity, specificity, and AUC, each with a 95% CI, were yielded. Subgroup analyses and sensitivity analyses were conducted. Quality assessment of included studies was also performed.

RESULTS

From 4,283 candidate articles, we identified 47 articles with a total of 7,244 patients for qualitative review and meta-analysis. When detecting EGFR, the CTC and ctDNA groups had pooled sensitivity of 75.4% (95% CI 0.683-0.817) and 67.1% (95% CI 0.647-0.695), respectively. When testing KRAS, pooled sensitivity was 38.7% (95% CI 0.266-0.519) in the CTC group and 65.1% (95% CI 0.558-0.736) in the ctDNA group. The diagnostic performance of ctDNA in testing ALK and BRAF was also evaluated. Heterogeneity among the 47 articles was acceptable.

CONCLUSION

ctDNA might be a more promising biomarker with equivalent performance to CTCs when detecting EGFR and its detailed subtypes, and superior diagnostic capacity when testing KRAS and ALK. In addition, the diagnostic performance of ctDNA and CTCs depends on the detection methods greatly, and this warrants further studies to explore more sensitive methods.

Biomarkers in Non-Small Cell Lung Cancers: Indian Consensus Guidelines for Molecular Testing

Novel molecular targets and promising targeted therapies have reshaped diagnostics in patients with advanced non-small cell lung cancer (NSCLC). Despite this progress, the implementation of molecular screening to identify predictive biomarkers in Indian clinical and pathology settings has been challenging due to operational and logistical constraints. This consensus guideline brings together medical oncologists, molecular pathologists and pathologists from India to provide a quick and competent reference for biomarker testing in NSCLC. The guideline summarizes the importance of targetable mutations in NSCLC such as epidermal growth factor receptor (EGFR), rearrangements in anaplastic lymphoma kinase and receptor tyrosine kinase encoded by ROS-1 gene, overexpression of programmed cell death ligand-1 and resistant EGFR mutations. It reaffirms recommendations from international working groups, discusses vulnerable pre-analytical procedures and provides a balanced review on the pros and cons of different diagnostic tests (immunohistochemistry, fluorescence in situ hybridization, polymerase chain reaction-based testing and next-generation sequencing). The document also provides an algorithm to aid diagnostic decision-making and a checklist to assess the quality of testing laboratories that will help the medical oncologists make an informed choice. Overall, these recommendations are based on evidence and clinical experience and will aid policymakers, oncologists, health care practitioners and pathologists who strive to implement molecular strategies and make informed decisions for improved care in NSCLC in India.Funding: AstraZeneca Pharma India Limited.

Scar tissue to lung cancer; pathways and treatment

Lung cancer still remains diagnosed at a late stage although we have novel diagnostic techniques at our disposal. However; for metastatic disease we have novel therapies based on pharmacogenomics. Tumor heterogenity provides us different treatments. There are several reasons for carcinogenesis; fibrosis and scar tissue provides an environment that induces malignancy. In the current review we will try and elucidate the pathways involved from scar tissue to carcinogenesis.