Hayato Koba

Next-generation sequencing analysis identifies genomic alterations in pathological morphologies: A case of pulmonary carcinosarcoma harboring EGFR mutations

OBJECTIVES Pulmonary carcinosarcoma is a rare lung malignancy and little analysis has been performed to identify associated genomic alterations. We used next-generation sequencing (NGS) to analyze a pulmonary carcinosarcoma harboring an epidermal growth factor receptor (EGFR) mutation. MATERIALS AND METHODS The lung carcinosarcoma used for this study contained components of adenocarcinoma and chondrosarcoma and originated from a 73-year-old female. Both components carried deletion mutations in exon 19 of EGFR and both had equally strong EGFR protein expression. This study analyzed the biological and genetic characteristics of both components, using NGS and immunohistochemical (IHC) staining. RESULTS AND CONCLUSION IHC staining revealed that both total EGFR and deletion mutation specific EGFR proteins were equally expressed in both components. Intriguingly, identification of genomic alterations with NGS found five identical alterations in four genes (EGFR, CBLB, TP53, and MEN1) that were shared by the two components, and that each component had a large number of individual alterations. Additionally, we focused on an alpha-thalassemia/mental retardation syndrome X-linked (ATRX) mutation which was only present in the sarcoma component. ATRX protein expression was also only detected in the sarcoma component. This is the first report of the exhaustive genomic alterations in a pulmonary carcinosarcoma harboring an EGFR mutation. The results show that our case had the same EGFR status in both components. The EGFR mutation is the driver mutation in both components. In our case, we found that TP53 may be a common alteration and ATRX may be a specific alteration in the sarcoma component.

Selective gene amplification to detect the T790M mutation in plasma from patients with advanced non-small cell lung cancer (NSCLC) who have developed epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) resistance

Background The epidermal growth factor receptor (EGFR) T790M mutation is associated with resistance to EGFR tyrosine kinase inhibitors (EGFR-TKIs) in non-small cell lung cancer (NSCLC). However, tissues for the genotyping of the EGFR T790M mutation can be difficult to obtain in a clinical setting. The aims of this study were to evaluate a blood-based, non-invasive approach to detecting the EGFR T790M mutation in advanced NSCLC patients using the PointMan™ EGFR DNA enrichment kit, which is a novel method for the selective amplification of specific genotype sequences. Methods Blood samples were collected from NSCLC patients who had activating EGFR mutations and who were resistant to EGFR-TKI treatment. Using cell-free DNA (cfDNA) from plasma, EGFR T790M mutations were amplified using the PointMan™ enrichment kit, and all the reaction products were confirmed using direct sequencing. The concentrations of plasma DNA were then determined using quantitative real-time PCR. Results Nineteen patients were enrolled, and 12 patients (63.2%) were found to contain EGFR T790M mutations in their cfDNA, as detected by the kit. T790M mutations were detected in tumor tissues in 12 cases, and 11 of these cases (91.7%) also exhibited the T790M mutation in cfDNA samples. The concentrations of cfDNA were similar between patients with the T790M mutation and those without the mutation. Conclusions The PointMan™ kit provides a useful method for determining the EGFR T790M mutation status in cfDNA.

A Single Institution Retrospective Study of the Clinical Efficacy of Tiotropium Respimat in Never-Smoking Elderly Asthmatics with Irreversible Airflow Limitation

OBJECTIVE In Japan, most asthma deaths occur among the elderly. We should improve the control of asthma in elderly patients to reduce the number of deaths due to asthma. This retrospective study aimed to evaluate the efficacy of tiotropium RespimatⓇ (Tio-Res) in symptomatic, never-smoking, elderly asthmatics with irreversible airflow limitation despite the use of high-dose inhaled corticosteroids (ICS) plus long-acting β2-adrenoceptor agonists (LABA). METHODS The Asthma Control Test™ (ACT), pulmonary function tests, morning and evening peak flow (mPEF, ePEF, respectively, evaluated with an ASSESS® peak flow meter), and respiratory impedance (assessed with MostGraph®) were measured before and after a minimum of one year of Tio-Res 5 µg/day administration. Sixteen symptomatic, never-smoking asthmatics, aged 75 or over with irreversible airflow limitation despite the use of high-dose ICS plus LABA, were analyzed. RESULTS All patients were female (mean age, 81.6 years). Tio-Res led to statistically significant improvements in the total ACT score (19.9 to 23.6), FVC and FEV1 (1.97 to 2.14 L and 1.13 to 1.23 L, respectively), and mPEF and ePEF (229.9 to 253.8 L/min and 259.8 to 277.4 L/min, respectively). Tio-Res also resulted in statistically significant improvements in respiratory resistance at 5 Hz (R5), respiratory resistance at 20 Hz (R20), R5-R20, low-frequency reactant indices at 5 Hz (X5), resonant frequency (Fres) and low-frequency reactance area (ALX). CONCLUSIONS Our retrospective study suggests that Tio-Res improves symptoms, pulmonary function, and respiratory impedance in symptomatic asthmatics aged 75 or over with irreversible airflow limitation despite the use of high-dose ICS plus LABA.

Long-lasting shrinkage in tumor mass after discontinuation of nivolumab treatment

We report the case of a 62-year-old man treated with nivolumab as fourth-line therapy for stage IV squamous cell carcinoma of the lung. Because of the onset of nivolumab-induced pneumonitis after 2 doses, nivolumab was discontinued. After discontinuation, the tumor gradually continued to decrease in size without any additional treatment for lung cancer. The patient obtained a long-lasting shrinking of the tumor over 6 subsequent treatment-free months after only 2 administrations of nivolumab. This type of response has not been seen for conventional anticancer drug treatments for NSCLC, and we speculate that a small group of patients with NSCLC will obtain sufficient efficacy from a few doses of nivolumab.

The measurement of cough response to bronchoconstriction induced by methacholine inhalation in healthy subjects: An examination using the Astograph method

ABSTRACT Background: We demonstrated that heightened cough response to bronchoconstriction is a fundamental feature of cough variant asthma (CVA). To evaluate this physiological feature of CVA in daily clinical practice, it is necessary to clarify the cough response to bronchoconstriction in healthy subjects. We evaluated cough response to methacholine (MCh)-induced bronchoconstriction in healthy subjects. A forced oscillometry technique was used to measure airway resistance changes with Mch. Methods: Healthy never-smokers (21 men, 20 women; mean 22.3 ± 3.7 years) participated. None had a >3-week cough history, clinically significant respiratory or cardiovascular disorders, or disorders that might put subjects at risk or influence the study results or the subjects’ ability to participate. Twofold increasing concentrations of Mch chloride diluted in phosphate-buffered saline (0.039 to 160 mg/mL) were inhaled from nebulizers at 1-minute intervals during subjects’ tidal breathing after the baseline respiratory resistance (Rrs) was recorded. Mch inhalation continued until Rrs reached twice the baseline value and forced expiratory volume in 1 second (FEV1) decreased to <90% of baseline value. Spirometry was measured before Mch inhalation and immediately after Rrs had increased twofold. Coughs were counted during and for 30 minutes after Mch inhalation. The cough reflex sensitivity to capsaicin was also examined. Results: The number of coughs was 11.1 ± 14.3 (median, 7.0; range, 0 to 71; reference range, 0 to 39.7). There was no significant difference in the cough response between the sexes. The reproducibility of the cough response to bronchoconstriction was sufficient. No correlation existed between the bronchoconstriction-induced cough response and capsaicin cough-reflex sensitivity. Conclusions: Using the Astograph method, cough response to bronchoconstriction could be measured easily, safely and highly reproducibly in healthy subjects.

Abstract 2467: Mutation analysis using next-generation sequencing in histologically heterogeneous of primary lung cancers

Rare cases of primary lung cancer are known to have different histological types. Recently, small cell carcinoma was reported to be developed in adenocarcinoma patients with epidermal growth factor receptor (EGFR) mutations after EGFR tyrosine kinase inhibitor (EGFR-TKI) treatment. The purposes of this study are to evaluate mutational status in two different histological types separately, and to further understand the molecular pathogenesis. Twelve tumor samples from 6 patients were collected in our institution. 4 patients had primary adenocarcinoma and small cell carcinoma transformed after EGFR-TKI. One patient had primary adenocarcinoma and squamous cell carcinoma transformed after EGFR-TKI. The other one patient had carcinosarcoma in a surgically resected tumor. Two samples per patient were collected from histologically different areas within a resected tumor or the 2 distinct metastatic sites. DNA was extracted from formalin-fixed, paraffin-embedded tumor tissues. Next-generation sequencings in the 12 samples were performed on 160 cancer-related genes using GeneRead™ DNAseq Targeted Panels V2 Human comprehensive Cancer Panel (QIAGEN). In a carcinosarcoma case with deletional mutation in EGFR gene, a total 504 in adenocarcinoma and 595 in sarcoma variants in 160 genes were detected with high confidence. The gene of identical alterations, as truncal alterations, were EGFR, CBLB, TP53 and MEN1 and the number of that as an unique alteration corresponding to each histology is 25 for adenocarcinoma and 85 for sarcoma. We show relations between the histological types and the genomic alterations, identical alterations and unique alterations, in each patient. Furthermore, we raise essential factors for the histological transformation. Citation Format: Hayato Koba, Hideharu Kimura, Kazuo Kasahara. Mutation analysis using next-generation sequencing in histologically heterogeneous of primary lung cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2467. doi:10.1158/1538-7445.AM2017-2467

Postoperative Recurrence of Invasive Thymoma with Cold Agglutinin Disease and Autoimmune Hemolytic Anemia.

A 50-year-old man presented to our hospital in 1995. Invasive thymoma was diagnosed and extended thymectomy and left upper lobe partial resection were performed. In 2013, he complained of dyspnea. Chest computed tomography showed postoperative recurrence of invasive thymoma. Several chemotherapies were administered. Severe anemia and an increase in the total bilirubin level were observed with chemotherapies. In additional, an examination showed that the direct Coombs test was positive. Cold agglutinin was also high. We herein experienced a rare case of postoperative recurrence of invasive thymoma with cold agglutinin disease and autoimmune hemolytic anemia.

Abstract 2268: Detection of T790M mutation in EGFR gene, an EGFR-TKI resistant mutation, in tumor samples unexposed to EGFR TKIs

Background: T790M mutation in EGFR gene is the commonest mechanism of resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) patients with EGFR mutation. The third-generation EGFR-TKIs are expected to overcome the resistance caused by T790M existence. On the other hand, several reports using highly sensitive detection assays showed a minute amount of T790M mutation alleles was detected in tumor tissues obtained before EGFR-TKI treatment. Aim: To clear whether T790M dominancy in tumor cells before EGFR-TKI treatment reflects between about the EGFR-mutated lung cancer which was not until exposed EGFR TKI therapy and actual resistance mechanism. Methods: We assessed T790M dominancy in tumor cells from 29 NSCLC patients with EGFR mutations, who had not received EGFR-TKIs. T790M mutation and common mutations, such as deletional mutations in exon 19 and L858R, were detected by droplet digital PCR (ddPCR) separately. T790M dominancy was calculated from each level of mutation-alleles about common mutation and T790M mutation. Results: We can detect the T790M mutation in initial biopsy tissues from 21 cases (72%). The mean value of T790M mutation dominancy ratio before EGFR-TKI treatment was 0.48% (0.00-69.09%) and it is not difference between in patients with T790M-positive at resistance and in that with negative (p = 0.87). Conclusions: T790M mutation was detected in most of the tumor tissues unexposed to EGFR TKIs. T790M mutation dominancy calculated by our assays in tumor tissues before EGFR-TKI treatment may not be related to induce T790M resistance to EGFR-TKIs. Citation Format: Hayato Koba, Hideharu Kimura, Shingo Nishikawa, Taro Yoneda, Takashi Sone, Kazuo Kasahara. Detection of T790M mutation in EGFR gene, an EGFR-TKI resistant mutation, in tumor samples unexposed to EGFR TKIs. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2268.

Abstract 2411: Non-invasive analysis for T790M mutations of EGFR using a selective amplification method

Epidermal growth factor receptor (EGFR) T790M mutation is associated with EGFR tyrosine kinase inhibitors (EGFR-TKIs) resistance in non-small cell lung cancer (NSCLC). However, tissue availability limits the genotyping of EGFR T790M mutation in a clinical setting. The aims of this study are to develop a blood-based, non-invasive approach to detecting the EGFRT790M mutation in advanced NSCLC patients, using PointMan™ EGFR DNA Enrichment Kit, which is a novel method for selective amplification of genotype specific sequences. Methods: Blood samples were collected from NSCLC patients with activating EGFR mutations, who were resistant to EGFR-TKIs treatment. EGFR T790M mutations in plasma DNA were detected using the kit. The concentrations of plasma DNA were determined using quantitative real-time PCR. Results: 21 (87.5%) of the patients had EGFR T790M mutations in their plasma DNA as detected using the kit. In all 6 cases detected T790M mutations from tumor tissues, the T790M mutations ware detected also in plasma DNA. The concentrations of plasma DNA were higher in patients with T790M mutations than without the mutations. Conclusions: The PointMan™ is an easily and useful method for determining the plasma EGFR T790M mutation status. Citation Format: Shingo Nishikawa, Hideharu Kimura, Hayato Koba, Taro Yoneda, Takashi Sone, Chris Booth, Andrew Webb, Kazuo Kasahara. Non-invasive analysis for T790M mutations of EGFR using a selective amplification method. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2411. doi:10.1158/1538-7445.AM2015-2411