EGFR and lung carcinoma: Genome-wide CRISPR knockout (CRISPRn) and activation (CRISPRa) screens were performed in the EGFR mutant lung cancer cell lines PC-9 and HCC827 as well as isogenic clones (PC-9T790M and HCC827T790M) harbouring the secondary EGFR T790M resistance mutation (which is responsible for resistance in the majority of patients treated with gefitinib in the 1st line setting).