Abstract 1966: Dr
Authors: Roumeliotou Argyro , Pantazaka Evangelia , Xagara Anastasia , Makatsoris Thomas , Koutras Angelos , Georgoulias Vassilis , Kotsakis Athanasios , Kallergi Galaktia 
Published: June 2022

Abstract
Background: According to recent publications of our group, JUNB and CXCR4 were overexpressed in CTCs and DTCs isolated from breast cancer patients. This expression was related with patients’ clinical outcome. Current study investigates for the first time, the expression of JUNB and CXCR4 in CTCs from patients with Non-Small Cell Lung cancer (NSCLC) and Small Cell Lung Cancer (SCLC).
Methods: Forty four patients were enrolled in this study (30 NSCLC and 14 SCLC patients, before the initiation of 1st line treatment). ISET system was used for NSCLC patients' samples preparation, while the CTCs from SCLC patients were isolated using Ficoll density gradient. Triple immunofluorescence experiments were performed, using CK, JUNB, and CXCR4 antibodies. Results conducted using confocal laser scanning microscopy for NSCLC samples and the VyCAP system for SCLC samples.
Results: Sixteen out of 30 NSCLC patients (53.33%), were positive for CTCs, while all SCLC patients harbored CK-positive cells. Most common phenotypes in CK-positive NSCLC patients were the [(CK+/JUNB+/CXCR4+): 50% (8/16patients)], [(CK+/JUNB+/CXCR4-): 43.75%, (7/16)] and the [(CK+/JUNB-/CXCR4-): 37.5% (6/16)]. Less frequent phenotype was the [(CK+/JUNB-/CXCR4+): 6.25%, (1/16)]. Analysis of the mean isolated CTCs/patient revealed that most of the isolated CTCs belonged to the (CK+/JUNB+/CXCR4+) phenotype (42.19%), while less frequent were the (CK+/JUNB+/CXCR4-): 33.13%, (CK+/JUNB-/CXCR4-): 18.44% and the (CK+/JUNB-/CXCR4+): 6.25% phenotypes. Survival analysis revealed that the presence of (CK+/JUNB+/CXCR4+) was related to poorer OS (cox regression: p=0.008) and PFS (Log Rank, p=0.014) All SCLC patients had detectable CTCs in their blood with 13 out of 14 of them having the (CK+/JUNB-/CXCR4-) phenotype (92.86%). The rest of CTC’s phenotypes (CK+/JUNB+/CXCR4+), (CK+/JUNB+/CXCR4-) and (CK+/JUNB-/CXCR4+) where found in 10 out of 14 patients (71.43%) each. Examination of the mean percentage of the total isolated CTCs/patient indicated that the (CK+/JUNB-/CXCR4-) phenotype was the most frequent (49.71%), while the percentages for the rest phenotypes were [(CK+/JUNB+/CXCR4-): 25.94%], [(CK+/JUNB-/CXCR4+): 12.65%] and (CK+/JUNB+/CXCR4+): 11.70%].
Conclusion: JUNB and CXCR4 were upregulated in CTCs from NSCLC and SCLC patients. However, in NSCLC the most frequent phenotype (CK+/JUNB+/CXCR4+) was also related to patients’ outcome, underlying the key role of these molecules in metastatic dissemination. Further examination will determine the role of this expression in all lung cancer subtypes. Acknowledge: This research has been co-financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH - CREATE - INNOVATE (project code: T2ΕΔΚ-01562).
Citation Format: Argyro Roumeliotou, Evangelia Pantazaka, Anastasia Xagara, Thomas Makatsoris, Angelos Koutras, Vassilis Georgoulias, Athanasios Kotsakis, Galaktia Kallergi. Dr [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1966.