EGFR and non-small cell lung carcinoma: The COBAS® EGFR Mutation Test v2 (Roche Diagnostics), the first ctDNA-based diagnostic test used in clinics, was approved by FDA in 2017 for monitoring the response to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer patients harboring EGFR-TKI sensitizing mutations 34.