WES showed that the tumor from patient CTC15063EGFR L858R, T790M, the osimertinib-sensitive CTC15063EGFR L858R, T790M xenograft tumors, and the osimertinib-resistant osimertinib-3 tumor had the EGFR mutations, L858R and T790M. The gene discussed is EGFR; the disease is neoplasm.