Furthermore, it has been well documented in vivo through FDG-PET studies in mice and humans that early drop in glucose metabolism in NSCLC tumors after EGFR-TKI treatment is closely associated with their response to EGFR-TKIs, of which EGFR mutation status is a major determinant [22, 23]. This evidence concerns the gene EGFR and non-small cell lung carcinoma.