Fukudo et al. previously reported that among NSCLC patients with EGFR mutations, those with the middle range of erlotinib concentrations (Q2–Q3, 848–1684 ng/mL) had better objective response rate (84%) than those with low (Q1, 67%) and high (Q3, 67%) concentrations [12]. This evidence concerns the gene EGFR and non-small cell lung carcinoma.