Key Points
• In the current study, researchers aimed to show the presence of EGFR or KRAS mutations in non-tumoral lung cells in patients with adenocarcinoma and negative mutational status.
• Via CAST-PCR, the investigators identified EGFR or KRAS mutations in the normal lung in 9.7% of the subjects, with exon 21 substitution L858R in EGFR exhibited in two patients, whereas exon 19 deletion E746-A750 in the EGFR, the G12C, and G12D substitutions in KRAS were noted in one patient. Of note, the researchers observed no differences during 18 months of follow up with respect to progression, progression-free survival or overall survival. This lack of difference could be due to the small sample size of the study (n=31), which was a limitation of the study.
• “This study confirms the presence of driver mutations in the histologically normal lung parenchyma cells coexisting with the absence of mutations in the primary tumor,” the authors wrote. “Our findings are consistent with the hypothesis that during the carcinogenesis process multiple cells can gain somatic mutations without necessarily producing a clonal expansion. In a previous study, we confirmed that the same driver mutation detected in the lung adenocarcinoma was also present in non-tumoral samples in a fifth of the subjects.”
• A main limitation of this study was the possibility of contamination/sample mix-up with tumor cells.