Fig. 1

Mutation-specific peptide nucleic acid (PNA)-positive staining in epidermal growth factor receptor (EGFR) mutation-positive lung cancer tissues. Formalin-fixed paraffin-embedded (FFPE) tissues from patients with non-small cell lung cancer were stained with EGFR mutation-specific PNA probes, anti-cytokeratin antibodies, and DAPI. PNA-positive staining rates in cytokeratin-stained cancer tissues were determined. (A) Cytokeratin-positive rate in DAPI-stained cancer tissues from the EGFR-mutated (L858R or exon19-deletion) and no mutation tumor groups. (B) EGFR mutation probe positive rates in cytokeratin-stained cancer tissues from the EGFR-mutated (L858R or exon19-deletion) and no mutation tumor groups. The positive staining rate for each EGFR mutation-specific PNA probe in the EGFR-mutated (L858R or exon19-deletion) and no mutation tumor groups were compared using the Mann–Whitney U test. **P < 0.01.