S950 Journal of Thoracic Oncology Vol. 13 No. 10S Table 1. Tumor heterogeneity profile in lung cancer patients case Hetrogenety in different organ date obtained tissue Gene mutation EGFR KRAS ROS negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative R233* negative negative negative negative negative D2033N negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative PTEN AKT 1 RLL lobectomy Right lung 12-Jun-2012 4-May-2016 2 lymph node Bone Right upper lung biopsy Lung biopsy lymph node skin 16-Mar-2017 9-Apr-2017 20-Jan-2016 31-Mar-2017 13-Jan-2016 17-Jan-2016 Exon 19 Deletion Exon 19 Deletion T790M negative negative Exon 19 Deletion T790M negative negative left humerous RML lobectomy LUL lobectomy 30-Jun-2016 13-Nov-2013 14-May-2014 negative Exon 19 Deletion negative LUL lobectomy 14-May-2014 negative 10 Right pleura biopsy RUL biopsy RUL biopsy Left pleural fluid cell block Right pleural fluid cell block Left pleural fluid cell block RML lobectomy RLL wedge resectionRLL lo RLL lobectomy 11-Jan-2016 1-Mar-2017 28-Sep-2015 27-Jun-2016 25-Mar-2016 9-Dec-2016 14-Mar-2013 30-Mar-2017 26-Aug-2013 Exon 19 Deletion Exon 19 Deletion L858R negative Exon 19 Deletion T790M negative G719A L861Q negative 9-Oct-2014 negative 11 Left lingular lobe segmental resection LUL wedge resection LUL lobectomy LLL resection Right pleural cell block negative negative negative negative G12A G12V G12D G12V G13D G12D G13D G12V G12D negative negative negative negative negative negative G13S negative G12C G12D G12D 11-Feb-2016 4-Jun-2017 9-Oct-2014 21-Jul-2014 negative negative negative L858R G12D G12D G12D negative negative negative negative negative negative negative negative negative negative negative negative negative Ascites LUL biopsy Lt lung biopsy RLL biopsy 9-Jun-2017 24-Feb-2015 8-Jul-2016 14-Oct-2015 T790M L858R L858R L858R negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative pleural fluid cell block 15-Nov-2016 Exon 19 Deletion T790M negative negative negative negative 3 4 5 6 7 8 9 12 13 P3.09-09 “Prevalence of Epidermal Growth Factor Receptor Mutation in Non-Small Cell Carcinoma Lungs at a Cancer Center in Nepal” B. Gurung,1 R. Shrestha,1 S. Shrestha,1 M. Singh,1 A. Koirala,2 S. Chataut,2 S. Tuladhar,3 S. Shrestha,4 B. Ghimire,4 M. Shrestha,5 M. Gautam,6 H. Dhakal1 1Department of Pathology and Lab Medicine, Nepal Cancer Hospital and Research Center, Lalitpur/NP, 2Department of Diagnostic and Interventional Radiology, Nepal Cancer Hospital and Research Center, Lalitpur/NP, 3Department of Thoracic Surgery, Nepal Cancer Hospital and Research Center, Lalitpur/NP, 4Department of Medical Oncology, Nepal Cancer Hospital and Research Center, Lalitpur/ NP, 5Devision of Preventive Oncology, Nepal Cancer Hospital and Research Center, Lalitpur/NP, 6Research Unit, Nepal Cancer Hospital and Research Center, Lalitpur/NP Background: Mutations in the epidermal growth factor receptor (EGFR) gene are commonly observed in non-small-cell lung cancer (NSCLC), particularly in adenocarcinoma (AC). The prevalence of EGFR mutations in different parts of the world is well documented but there is lack of information for patients in Nepal. This study aims at exploring the proportion of EGFR mutation among Nepalese patients with NSCLC/AC. Method: A retrospective study was conducted in patients with all lung primary lesions diagnosed as NSCLC/AC and treated at negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative negative E17K negative negative negative negative negative negative negative negative E17K negative negative MET negative negative negative c.3028G>A exon 14 splicing negative negative negative c.3028+1G>T exon 14 splicing negative BRAF negative V600E negative negative negative Nepal Cancer Hospital and Research Center from March, 2015 till Feb, 2018. The related information on age, gender, histomorphological diagnosis, geographic distribution, ethnicity and EGFR mutational analysis were collected from the Department of Pathology and Laboratory Medicine at Nepal Cancer Hospital and Research Center, Nepal and were analyzed. Result: Total 106 cases of primary malignant lung lesions diagnosed as NSCLC/AC were evaluated for EGFR mutational analysis. 3%, 12% and 86% were well, moderately and poorly differentiated NSCLC/AC respectively. 21% metastasized to lymphnodes, bone, liver and others and 8% had local invasion into pleura. EGFR mutation were seen in 36%(n38 out of 106) of NSCLC/AC, most common in exon 19(55%) followed by exon 21(37%), exon 20(5%) and both exon 19and20(3%). There was no mutation found in exon 18. Malignancies were predominant in males (M: F¼1.3:1) with median age 66years. However, EGFR mutation were predominant in female (M:F¼0.6:1). Most of the patients were from Brahman/Chetri community(42%) followed by Newar(30%), Tarai Madhesi(11%), Janajati(10%), Dalit(6%) and Tamang(1%). Despite of being second in population for NSCLC/AC Newars had the most number of EGFR mutation of 16% followed by 10%, 5%, 3% and 2% in Brahman/Chetri, Janajati, Tarai Madhesi and Dalit respectively. Most of the patients were from central Nepal(Kathmandu, Lalitpur, Bhaktapur)(52%) followed by East Nepal(32%) and West Nepal(19%). Conclusion: EGFR mutation in lung cancer in our center was more than one third(36%) which is relatively high when compared to other parts of the world. Most of October 2018 Abstracts them were female from Newar community from central part of Nepal. Though rare, mutation in both the exons 19 and 20 were also observed. To our knowledge this is the first report in Nepalese population about EGFR mutation. A detail population base and multicentric studies are recommended to know about the actual prevalence of EGFR mutation and it’s types in the Nepalese lung cancer patients. Keywords: Adenocarcinoma, EGFR, Non small cell lung carcinoma P3.09-10 Circulating Cell-Free DNA (cfDNA) Molecular Profile of Thai NSCLC Patients Using Difference Variant Frequency of NGS N. Iemwimangsa,1 N. Trachu,2 V. Pairoj,1 A. Charoenyingwattana,1 P. Incharoen,3 S. Detarkom,4 S. Lukrak,4 L. Arsa,3 N. Monnamo,2 S. Techasurungkul,4 T. Reungwetwattana,4 W. Chantratita1 1Center for Medical Genomics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok/TH, 2Ramathibodi Research Center, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok/TH, 3 Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol S951 University, Bangkok/TH, 4Medical Oncology Unit, Department of Internal Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok/TH Background: Detecting cfDNA in the liquid biopsy has become a promising method to explore the genetic landscape of tumor heterogeneity. We developed a pilot-study to find the suitable cutoff of variant frequencies detected from liquid biopsy by NGS to track tumor-associated mutations in NSCLC patients. Method: Ninety-four samples (24 early-stage NSCLC, 70 late-stage NSCLC) were collected from Ramathibodi Hospital, Thailand. Profiling cfDNA using Ion Proton NGS platform. Overall average base coverage depth from NGS was 10,000x, all variants selected have read depths >10x in order to reach 0.1% sensitivity. Each of selected variants has threshold variant quality (QUAL) >20. Droplet digital PCR (ddPCR) was performed for EGFR-mutation testing to determine the appropriated cutoff variant frequency from NGS. Result: In early-stage NSCLC, a minimum-threshold variant frequencies at 0.1% could detect EGFR exon19 deletion in all samples (24,100%), with BRAF (12,50%), KRAS (21,87.5%) and other mutations in AKT1, MET, PIK3CA, PTEN, ROS1 (14,58%). None of these mutations identified when using Table 1. Mutations detected BRAF (V600E) early stage total N¼24 BRAF (V600E) late stage total N¼70 KRAS early stage KRAS late stage AKT1 (E17K) early stage AKT1 (E17K) late stage MET exon 14 early stage splicing MET exon 14 late stage splicing PIK3CA early stage PIK3CA late stage PTEN (R233*) early stage PTEN (R233*) late stage ROS1 early stage ROS1 late stage EGFR Exon 19 early stage Deletion EGFR Exon 19 late stage Deletion EGFR L858R early stage EGFR L858R late stage EGFR T790M early stage EGFR T790M late stage EGFR Exon18 early stage (G719X) EGFR Exon18 late stage (G719X) EGFR Exon 20 early stage Insertion EGFR Exon 20 late stage Insertion variant allele frequencies detected from liquid biopsy by NGS at minimum threshold cut-off 0.1% variant allele frequencies detected from liquid biopsy by NGS at minimum threshold cut-off 0.1% variant allele frequencies detected from liquid biopsy by NGS at conventional level detection of somatic variants cut-off 3% variant allele frequencies detected from liquid biopsy by NGS at conventional level detection of somatic variants cut-off 3% variant allele frequencies detected from liquid biopsy by ddPCR (EGFR only) variant allele frequencies detected from liquid biopsy by ddPCR (EGFR only) N (%) 12 (50%) median (range) 0.8 (0.3-2.5) N (%) 0 (0%) median (range) 0 N (%) NA median (range) NA 11 (15.7%) 0.6 (0.1-1.1) 0 (0%) 0 NA NA 21 (87.5%) 50 (71.4%) 7 (29.2%) 12 (17.1%) 4 (16.7%) 0.1 0.2 0.1 0.1 0.1 0 3 0 0 0 0 11.1 (5.8-14.3) 0 0 0 NA NA NA NA NA NA NA NA NA NA 3 (4.3%) 0.2 (0.2-0.2) 0 (0%) 0 NA NA 9 (37.5%) 19 (27.1%) 6 (25.0%) 11 (15.7%) 0 (0%) 4 (5.7%) 24 (100%) 0.2 (0.1-0.8) 0.3 (0.1-0.7) 0.1 (0.1-0.4) 0.1 (0.1-0.2) 0 0.55 (0.1-0.7) 0.35 (0.1-2.1) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 NA NA NA NA NA NA 1 (4.2%) NA NA NA NA NA NA 0.5 (0.5-0.5) 25 (35.7%) 0.6 (0.1-49.0) 6 (8.6%) 9.4 (4.5-49.5) 20 (28.6%) 0.65 (0-49.0) 5 (20.8%) 21 (30%) 8 (33.3%) 30 (42.9%) 6 (25%) 0.2 1.4 0.1 0.1 0.2 0 4 0 2 0 0 4.6 (4.4-6.4) 0 7.5 (5.3-9.7) 0 0 (0%) 14 (20%) 0 (0%) 16 (22.9%) 1 (4.2%) 0 1.8 (0.3-9.7) 0 0.15 (0-4.1) 0.4 (0.4-0.4) 4 (5.7%) 4.5 (0.1-49.2) 2 (2.9%) 27.9 (6.7-49.2) 2 (2.9%) 25.6 (2-49.2) 0 (0%) 0 0 (0%) 0 0 (0%) 0 1 (1.4%) 73.8 (73.8-73.8) 1 (1.4%) 91.7 (91.7-91.7) 0 (0%) 0 (0.1-0.5) (0.1-13.6) (0.1-0.7) (0.1-0.7) (0.1-0.1) (0.1-0.5) (0.1-9.7) (0.1-0.2) (0.1-4.6) (0.1-0.4) (0%) (4.3%) (0%) (0%) (0%) (0%) (0%) (0%) (0%) (0%) (0%) (0%) (0%) (5.7%) (0%) (2.9%) (0%)