First experience with cobas® EGFR Mutation Test v2 

Introduction

„Liquid biopsy“ became a buzzword in predictive oncogenetics. Clinicians from Lung Department are looking forward to receive timely and dynamic information about EGFR mutation status from blood that is less invasive and less difficult to obtain than tissue biopsy. To satisfy this need, Roche started to sell CEIVD certified cobas EGFR mutation Test v2. We were lucky to have the possibility to test this kit on plasma samples obtained from Olomouc NSCLC patients.

Materials/methods

100 FFPE and plasma samples were gathered in the time of tissue biopsy during years 2013-15. Plasma was divided into halves and frozen. FFPE bioptical tissue was genotyped within week of surgery using EGFR cobas version 1. When mutationpositive, the first plasma aliquot was EGFR genotyped using the same version of the kit. 24 samples with sufficient plasma discrepancy between FFPE and plasma result using EGFR cobas v1 kit were further testd: the second aliquot of plasma sample was processed in October 2015 using cobas EGFR Mutation Test v2 that includes modified DNA extraction and PCR protocol optimized for circulating DNA in plasma. Results of three tests from each patient were compared.

Results and conclusions

Differences in three types of results from patients are described and discussed in context of our previous experience with in-house test for EGFR and KRAS mutations in plasma.

Acknowledgements: Authors thank Roche for providing free EGFR v2 kit for testing. Roche has no influence on this testing apart from the initial single day training course. Project was partially supported by grants LO1304, CZ.1.05/3.1.00/14.0307, IGA MZ ČR/NT13569, and LM2010004.