Inclusion criteria were histologic diagnosis of benign nodule (control) and stage I or II adenocarcinoma harboring either p.L858R or exon19 delEGFR mutations.
The coexpression of HER2 and EGFR L858R in a solitary nodule removed from the lung, whose mutation was not confirmed by molecular techniques, made us think about the possible existence of a cross-reaction between HER2 and the EGFR L858R-specific antibody.