EGFR and non-small cell lung carcinoma: Second, if the authors did not perform further work to identify the somatic mutation, the percentage of Q787Q should be much higher than what they reported because of the high prevalence of background germline variant In a study on exon 20 mutations in EGFR, the authors detected a high percentage of the EGFR Q787Q polymorphism (rs1050171 (c.2361 A>G)) in peripheral blood samples from NSCLC patients after chemotherapy.