This article was originally published here
Cancer Med. October 7, 2021. doi: 10.1002 / cam4.4330. Online ahead of print.
Background: Bronchoscopy is a minimally invasive procedure for diagnosing lung cancer. It sometimes fails to obtain tissue samples, but easily collects cytological samples.
METHODS: We developed a PNA-LNA double PCR (PLDP), which amplified mutant sequences by high fidelity DNA polymerase in the presence of a peptide nucleic acid (PNA) oligomer having a wild type sequence. Mutations are detected either by locked nucleic acid probes (LNAs) for rapid detection of a limited number of mutations, which are EGFR, KRAS and BRAF mutations in the present study, or by direct sequencing for complete screening. . Out of a total of 233 lung cancer samples, the results of cytological samples by PLDP were compared to those of tissue samples by the cobas® EGFR mutation assay (cobas) or by the PNA-LNA PCR clamp method (P- LPC). In addition, the performance of PLDP using cell-free DNA (cfDNA) was investigated.
RESULTS: Peptide nucleic acid-LNA double PCR was able to detect each synthesized mutant sequence with high sensitivity. PLDP detected EGFR mutations in 80 of 149 clinical samples, while cobas or P-LPC detected in 66 matched. The accuracy of the PLDP was confirmed by both the clinical response and by the results of sequencing using a next-generation sequencer. PLDP detected mutations in cfDNA in approximately 70% of patients with mutations in the tumor.
CONCLUSIONS: The peptide nucleic acid-LNA double PCR showed excellent performance, even using cytological samples. The PLDP is applicable for the study of cfDNA. The combination of bronchoscopy and PLDP is attractive and will expand the utility of bronchoscopy in clinical practice.