Preliminary Results of NGS Gene Panel Test Using NSCLC Sputum Cytology and Therapeutic Effect Using Corresponding Molecular-Targeted Drugs

Clinical utility of rapid on-site evaluation of brush cytology during bronchoscopy using endobronchial ultrasound with a guide sheath

Previous studies have shown that rapid on-site evaluation (ROSE) improves the diagnostic yield of bronchoscopy using endobronchial ultrasound with a guide sheath (EBUS-GS) for peripheral pulmonary lesions (PPL). While ROSE of imprint cytology from forceps biopsy has been widely discussed, there are few reports on ROSE of brush cytology. This study investigated the utility of ROSE of brush cytology during bronchoscopy. We retrospectively analyzed data from 214 patients who underwent bronchoscopy with EBUS-GS for PPL. The patients in the ROSE group had significantly higher diagnostic sensitivity through the entire bronchoscopy process than in the non-ROSE group (96.8% vs. 83.3%, P = 0.002). The use of ROSE significantly increased the sensitivity of brush cytology with Papanicolaou staining (92.9% vs. 75.0%, P < 0.001). When ROSE was sequentially repeated on brushing specimens, initially negative ROSE results converted to positive in 79.5% of cases, and the proportion of specimens with high tumor cell counts increased from 42.1 to 69.0%. This study concludes that ROSE of brush cytology improves the diagnostic accuracy of bronchoscopy and enhances specimen quality through repeated brushing.

EML4-ALK Gene Mutation Detected with New NGS Lung Cancer Panel CDx Using Sputum Cytology in a Case of Advanced NSCLC

The detection of driver gene mutations has become essential for lung cancer; however, insufficient sample sizes make gene panel tests difficult to use. We previously reported that the lung cancer compact panel TM (LCCP) could detect EGFR and MET gene mutations with sputum cytology. To date, the detection of gene mutation using RNA from sputum samples is considered practically difficult. We report a case in which the EML4-ALK fusion gene was successfully detected from a sputum sample using the LCCP that was just released in Japan as a new next-generation sequencing lung cancer panel, CDx.

Analytical Performance of a Highly Sensitive System to Detect Gene Variants Using Next-Generation Sequencing for Lung Cancer Companion Diagnostics

The recent increase in the number of molecular targeted agents for lung cancer has led to the demand for the simultaneous testing of multiple genes. Although gene panels using next-generation sequencing (NGS) are ideal, conventional panels require a high tumor content, and biopsy samples often do not meet this requirement. We developed a new NGS panel, called compact panel, characterized by high sensitivity, with detection limits for mutations of 0.14%, 0.20%, 0.48%, 0.24%, and 0.20% for EGFR exon 19 deletion, L858R, T790M, BRAF V600E, and KRAS G12C, respectively. Mutation detection also had a high quantitative ability, with correlation coefficients ranging from 0.966 to 0.992. The threshold for fusion detection was 1%. The panel exhibited good concordance with the approved tests. The identity rates were as follows: EGFR positive, 100% (95% confidence interval, 95.5-100); EGFR negative, 90.9 (82.2-96.3); BRAF positive, 100 (59.0-100); BRAF negative, 100 (94.9-100); KRAS G12C positive, 100 (92.7-100); KRAS G12C negative, 100 (93.0-100); ALK positive, 96.7 (83.8-99.9); ALK negative, 98.4 (97.2-99.2); ROS1 positive, 100 (66.4-100); ROS1 negative, 99.0 (94.6-100); MET positive, 98.0 (89.0-99.9); MET negative 100 (92.8-100); RET positive, 93.8 (69.8-100); RET negative, 100 (94.9-100). The analytical performance showed that the panel could handle various types of biopsy samples obtained by routine clinical practice without requiring strict pathological monitoring, as in the case of conventional NGS panels.

RET fusion mutation detected by re-biopsy 7 years after initial cytotoxic chemotherapy: A case report

Personalized medicine using molecular-targeted drugs to achieve better therapeutic response and long-term prognosis is common practice for lung cancer treatment. However, in cases before gene batch tests were available, medical treatment continued without the detection of rare mutations. We report a sixty-seven-old year man diagnosed with adenocarcinoma T1cN3M1a, stage IVA. Initial screening performed 7 years earlier using EGFR mutation and ALK immunohistochemical tests were negative. Although first-line cytotoxic combination chemotherapy was remarkably effective, a gradual regression of the primary lesion was noted. After a recent bronchoscopic re-biopsy, RET fusion was detected by gene panel test. In addition, we were able to confirm RET from FFPE specimens obtained from 7-year-old pleural effusion cell blocks. Subsequent administration of the molecular-targeted drug selpercatinib, was highly effective for the primary lesion and all metastatic lesions including brain metastases. We describe a case of RET fusion-positive lung cancer where molecular targeted therapy and cytotoxic drug showed a drastic response and long-term therapy was well maintained. Next generation sequencing was able to correctly diagnose RET fusion mutation using re-biopsy specimen after going undiagnosed for 7 years.

A Prospective Validation Study of Lung Cancer Gene Panel Testing Using Cytological Specimens

Background: Genetic panel tests require sufficient tissue samples, and therefore, cannot always be performed. Although collecting cytological specimens is easier than tissue collection, there are no validation studies on the diagnostic accuracy of lung cancer gene panel tests using cytology samples. Methods: Using an amplicon-based high-sensitivity next-generation sequencing panel test capable of measuring eight druggable genes, we prospectively enrolled consecutive patients who underwent diagnostic procedures. We evaluated the analysis accuracy rate, nucleic acid yield, and the quality of cytological specimens under brushing, needle aspiration, and pleural effusion. We then compared these specimens with collected tissue samples. Results: In 163 prospectively enrolled cases, nucleic acid extraction and analysis accuracy was 100% in cases diagnosed with adenocarcinoma. Gene mutations were found in 68.7% of cases with 99.5% (95% CI: 98.2-99.9) concordance to companion diagnostics. The median DNA/RNA yield and DNA/RNA integrity number were 475/321 ng and 7.9/5.7, respectively. The correlation coefficient of the gene allele ratio in 64 cases compared with tissue samples was 0.711. Conclusion: The success of gene analysis using cytological specimens was high, and the yield and quality of the extracted nucleic acid were sufficient for panel analysis. Moreover, the allele frequency of gene mutations in cytological specimens showed high correlations with tissue specimens.

Clinical utility of liquid biopsy-based companion diagnostics in the non-small-cell lung cancer treatment

Recently, technological advances in the detection and biological characterization of circulating tumor DNA (ctDNA) have enabled the implementation of liquid biopsy testing into clinical practice. Methods for analysis of liquid biopsies have rapidly evolved over the past few years and have continued to advance, thus providing details about tumor biological characteristics such as tumor progression, metastasis, tumor heterogeneity, genomic mutation profile, clonal evolution, etc. In tandem with technological advances, the implementation of liquid biopsy in routine clinical settings has proceeded. In 2016, the Food and Drug Administration (FDA) approved the first ctDNA liquid biopsy test to detect epidermal growth factor receptor (EGFR) gene mutations in patients with non-small-cell lung cancer (NSCLC) as a companion diagnostic for molecular targeted drug of EGFR-tyrosine kinase inhibitor (TKI, EGFR-TKI). More recently, multigene panel assays of liquid biopsy have been approved as companion diagnostics and have been used in routine clinical settings. The estimation of blood tumor mutation burden (bTMB) to predict the efficacy of immune checkpoint inhibitor (ICI) treatment can be one of the promising approaches to liquid biopsy. The next stage of implementation of liquid biopsy for routine clinical settings is for monitoring of ctDNA after surgical treatment to predict prognosis and to detect disease relapse earlier than conventional imaging diagnosis. Its clinical utility is under assessment in several clinical trials. This review introduces recent advances in liquid biopsy methodology, the development of biomarkers, and its clinical utility in the treatment of NSCLC patients.