Genetic and molecular biomarker characterization of KRAS mutant non-small cell lung carcinoma (NSCLC) tumors.

11026 Background: Preclinical studies demonstrated Brahma related gene 1 (BRG1) mutations or loss of expression, and mutations of LKB1 may be associated with lack of sensitivity for MEK inhibitor trametinib in a subset of KRAS mutant NSCLC lines. This study aimed to evaluate the frequency of KRAS, LKB1 and BRG1 mutations in NSCLC tumors; and determine whether KRAS mutations in corresponding plasma samples could be detected by evaluating circulating cell-free DNA (cfDNA). Methods: Human NSCLC FFPE tumor tissue and matched plasma samples were procured from Indivumed GmbH. KRAS mutation status of 101 NSCLC tumors and matched plasma were determined by direct sequencing of genomic DNA (gDNA) from tissue and/or BEAMing on tissue gDNA or plasma cfDNA. Genetic mutations of LKB1 and BRG1 were determined by direct sequencing. Additional mutations were determined using the Ion Torrent AmpliSeq Cancer Panel. BRG1 protein expression was evaluated by IHC. Results: By direct sequencing and BEAMing we found 27/101 (28.4%...