P114-43 A Novel Patient Derived Synchronous Cell Pair with Different Mutations in an ALK-Rearranged Lung Adenocarcinoma Underlines Tumor Heterogeneity

ALK targeted therapy can provide prolonged clinical response rates in ALK-rearranged lung adenocarcinoma (ADC) patients. However, most tumors relapse within a few years of treatment pressure due to a variety of resistance mechanisms, including intratumoral heterogeneity. Understanding these mechanisms is of utmost importance to more precisely tailor future targeted therapies.This study is the first evidence of the synchronous establishment of two highly distinct patient-derived ALK translocated lung ADC cell lines carrying different resistant mutations. This concept supports the paramount significance of spatiotemporal intratumoral heterogeneity under targeted therapy. Furthermore, our findings showed that HDAC inhibition could enhance sensitivity of resistant tumor cells to ALK targeted therapy in vitro. Altogether, our findings provide strong evidence for the synchronous emergence of multiple resistance mechanisms and emphasize the importance of multiple site re-biopsies to better identify acquired resistance mechanisms under targeted therapy. READ ARTICLE

Journal of Thoracic Oncology DOI:10.1016/j.jtho.2019.08.1194

Authors: P. Stockhammer, C.S.L. Ho, A. Bankfalvi T. Plönes, L. Hegedus, M. Schuler, C. Aigner, A. Schramm, B. Hegedus