EGFR and non-small cell lung carcinoma: For example, acquired RET fusion proteins (e.g., CCDC6-RET fusion) in NSCLC cells bearing both primary and acquired EGFR mutations (e.g., del19 and L858R/T790M) confer resistance to both first- and second-generation TKIs (e.g., AZD9291/osimertinib) (18, 28).