211P Transcriptional and epigenetic landscape of neuroendocrine transformation during emergence of resistance to targeted therapies in EGFR mutant lung adenocarcinoma

Histological transformation from lung adenocarcinoma (LUAD) to small cell carcinoma (SCLC) is a signature example of lineage plasticity (LP) and the primary mechanism of acquired resistance in up to 15% of EGFR-mutant LUADs. It is a dynamic process controlled by transcriptional and epigenetic dysregulation. We determine the transcriptional and epigenetic regulators of LP and their interplay with tumor microenvironment.