EGFR and cancer: Silvia La Monica et al. treated PC9 cell lines (characterized by E746-A750 deletion) and PC9-T790 M cell lines (characterized by E746-A750 deletion and T790M mutation) (produced by exposing PC9 cells to high concentrations of gefitinib) carrying in-frame deletions in exon 19 of the EGFR gene with osimertinib and observed that the drug showed strong antitumor effects on those two cancer cell lines.