Targeted Deep Sequencing As A Diagnostic And Research Method For Detecting Egfr And Alk Pathway Driver Genes In Ffpe Tissue Of Lung And Colorectal Carcinomas

39 Background: Molecular targeted tyrosine kinase inhibitor (TKI) treatments have made it crucial to perform diagnostic tests of multiple molecular targets. In lung carcinoma there are close to ten clinically relevant gene mutations, copy number alterations and/or gene fusions, such as ALK, EGFR, ERBB2, KRAS, BRAF, MET, PTEN, PI3KCA, ROS1 and RET. Presently, several different tests are utilized, requiring a high amount of tumor material and long turnaround time. Next generation sequencing or targeted deep sequencing (TDS) has opened a new era for rapid genome-wide analyses of mutations, copy number alterations and gene fusions. Our aimwas to 1) prove feasibility for applying TDS to FFPE samples, 2) compare mutations detected by prevalent methods & TDS, and 3) mine novel clinically and biologically relevant genes in lung and colorectal carcinoma.For TDS, we selected 192 lung carcinoma and colorectal carcinoma related genes and microRNA genes, focusing on the EGFR and ALK pathways. In total, 98 FFPE specimens were studied. Agilent SureSelect system and Illumina sequencing was adopted for the analysis. For diagnostic validation the following genes were selected: EGFR, KRAS, BRAF, PTEN, PI3K, RET and ALK. TDS results were confirmed by PCR, FISH and IHC.We focused on the genes selected for diagnostic validation. Successful results were obtained from all specimens. The results from TDS correlated significantly with those obtained from PCR, FISH, and IHC. Importantly, TDS revealed novel mutations not detected by targeted PCR.An enormous advantage of TDS is that multiple mutation screening can be achieved in one analysis (saving time and material), and most importantly, provides enormous amounts of novel information, for example understanding mechanisms for drug resistance. This study was supported by Finnish Academy, Sigrid Jusélius Foundation, Finnish Cancer Organizations, the special governmental subsidy research funds appropriated to the Helsinki and Uusimaa Hospital District (HUS EVO), Pfizer Oy, AstraZeneca AS, Lab21 Ltd, Abbott Molecular Inc.