Li et al. noticed that EGFR mutation length fragments were detected with a size range below 80 bp.66 Epidermal growth factor receptor (EGFR) gene mutations in saliva-derived ctDNA were detected and were consistent with that of plasma ctDNA.67 They could not be applied in the diagnosis of NSCLC. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.