MO37-3 Is bronchoscopic cytology pellets useful for oncomine comprehensive assay? – from the samples submitted to LC-SCRUM

Abstract

Gene mutation screening in lung cancer is performed on formalin-fixed paraffin-embedded (FFPE), but there are some cases that cannot be analyzed. Lung cancer genomic screening project for individualized medicine in Japan (LC-SCRUM) is nationwide cancer genome screening project as academic industrial collaboration for individualized medicine in Japan. In LC-SCRUM, fresh frozen tissues or bronchoscopic pellet samples are analyzed by Oncomine Comprehensive Assay version 3 (OCA v3) Thermo Fisher SCIENTIFIC, and the measurement principle is the same as that of Oncomine Dx Target Test. We investigated the amount of extracted DNA/RNA and the feasibility of gene mutation analysis in fresh frozen tissues and pellet samples prepared from lavage of bronchoscopic device. We compared the background factors of frozen tissues or pellet samples submitted to LC-SCRUM after being diagnosed with lung cancer from May 2016 to March 2020 at our hospital. DNA/RNA concentration and the success rate of gene mutation analysis by OCA v3 were examined. There were 67 enrolled cases, 26 frozen tissues and 41 pellets. The DNA analysis rate was 100%, the RNA analysis rate was 81%, and the overall analysis success rate for both was 78%. The median DNA /RNA extraction amount was 0.065/0.01 (μg/μL) in the tissues and 0.07/0.01 (μg/μL) in the pallets with no significant differences. The analysis success rate was 76.9% in the tissues and 78% in the pellets. In the pellets group, the samples from EBUS-TBNA was 34%, which was higher than that in the tissue group (8%). The amount of DNA extracted from the EBUS-TBNA samples was significantly larger than that from transbronchial biopsy (0.16 vs 0.03 (μg/μL), P<0.001). In OCA, gene mutation analysis using bronchial pellets may be as useful as that in frozen tissues, especially in the EBUS-TBNA samples.