Patients will be recruited from the patient pool that is being screened for the AZD9291 AURA3 randomized clinical trial (RCT). Biopsy tissues and consents have already been obtained from patients to use samples for future research as part of the AURA3 trial screening processes. During the RCT screening process, the patients sign a full consent to participate in the AURA3 trial, and have their tumour tested as part of the main screening.