EGFR and lung cancer: The test involves the detection of EGFR mutations in lung cancer patients whose tumors have the exon 18 (G719X) substitutions, exon 19 deletions, exon 20 insertions and substitutions (T790M, S768I) and exon 21 substitutions (L858R, L861Q) and is indicated to select patients who are candidates for EGFR inhibitor therapy [15,16].