The presence of pre-treatment EGFR T790M mutation in NSCLC has been discovered in several studies using highly sensitive detection methods, such as mass spectrometry, the scorpion amplification refractory mutation system, colony hybridization assays, etc.; the reported prevalence ranges from 20 to 80% [32,33,34,35]. This evidence concerns the gene EGFR and non-small cell lung carcinoma.