Outcomes on AZD9291:If cfDNA EGFR T790M-positive, ORR of 63% and median PFS of 9.7 monthsIf tumor EGFR T790M-positive, ORR of 62% and median PFS of 9.7 monthsConclusions: If cfDNA is T790M-positive, no need for tumor genotyping. However, if cfDNA is T790M-negative, tumor genotyping is warranted. The gene discussed is EGFR; the disease is neoplasm.