Dataset Information

Sputum cell-free DNA: Valued surrogate sample for the detection of EGFR exon 20 p.T790M mutation in patients with advanced lung adenocarcinoma and acquired resistance to EGFR-TKIs.

ABSTRACT:

Background

Sputum cell-free DNA (cfDNA) is a valuable surrogate sample for assessing EGFR-sensitizing mutations in patients with advanced lung adenocarcinoma. Detecting EGFR exon 20 p.T790 M (p.T790 M) is much more challenging due to its limited availability in tumor tissues. Exploring sputum cfDNA as an alternative for liquid-based sample type in detecting p.T790 M requires potential improvement in clinical practice.

Methods

A total of 34 patients with EGFR-sensitive mutation-positive lung adenocarcinoma and acquired resistance to the first generation of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) were enrolled. The sputum samples, and paired tumors and/or plasma samples were tested for p.T790 M mutation and concordance of p.T790 M status among the three sample types was analyzed.

Results

The overall concordance rate of p.T790 M mutation between sputum cfDNA and tumor tissue samples was 85.7%, with a sensitivity of 66.7% and a specificity of 100%. The sensitivity for detecting p.T790 M in sputum cfDNA was 100%, 66.7%, and 0% in the three sputum groups of malignant, satisfactory but no malignant cells, and unsatisfactory, respectively. The combined results of plasma cfDNA testing and sputum cfDNA testing further increased the sensitivity to 100% for p.T790 M detection in satisfactory but no malignant cells sputum group.

Conclusion

These findings revealed that cfDNA from malignant or satisfied but no malignant cells sputum is considered suitable for detecting p.T790 M mutation in patients with acquired resistance to first or second-generation EGFR-TKIs. The sputum cytological pathological evaluation-guided sputum cfDNA testing assists in significantly improving the sensitivity of p.T790 M detection, bringing significant value for the maximal application of third-generation EGFR-TKIs in second-line treatment.

SUBMITTER: Wang Z

PROVIDER: S-EPMC8124129 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundEpidermal growth factor receptor exon 20 insertions (EGFR ex20ins) occur in about 4-14% of lung adenocarcinoma (LUAD) patients with EGFR mutations. Recently some targeted drugs have been approved for the treatment of LUAD patients with EGFR ex20ins. However, the heterogeneity of EGFR ex20ins mutations and resultant challenges in identifying them have led to the underestimation of their frequency.MethodsWe investigated the molecular and clinicopathologic features of EGFR ex20ins in 3,892 Chinese LUAD patients using next-generation sequencing (NGS). The frequency and distribution of EGFR ex20ins mutations between Chinese and Western LUAD patients were also compared by integrating the data of this study and the data of previous studies.ResultsA total of 23 unique EGFR ex20ins were identified in 77 LUAD patients, accounting for 1.98% of all LUAD patients and 3.49% of EGFR mutant LUDA patients. The 2 most common EGFR ex20ins subtypes were S768_D770dup and A767_V769dup, which together accounted for 55.84% of the EGFR ex20ins cases. About 61% (14/23) of the EGFR ex20ins subtypes occurred only once. Additionally, 8 of the EGFR ex20ins subtypes were not recorded in the COSMIC database. These results showed that the EGFR ex20ins mutations were highly heterogeneous. There was no significant difference in the frequency and distribution of EGFR ex20ins mutations between Chinese and Western LUAD patients, but the frequency of EGFR ex20ins mutations was significantly lower in EGFR-mutant Chinese LUAD patients than Western LUAD patients. The co-mutation analysis showed that EGFR ex20ins occurred significantly and exclusively with certain driver genes in LUAD, including ALK fusion (χ2=7.133, P=0.008), KRAS (χ2=8.468, P=0.004), and PIK3CA (χ2=5.792, P=0.016). No gene was observed to be significantly co-mutated with EGFR ex20ins. In general, patients with EGFR ex20ins shared a similar age and gender to patients with other EGFR mutations or without EGFR ex20ins.ConclusionsOverall, our results revealed the molecular and clinicopathologic features of EGFR ex20ins in Chinese LUAD patients, which will be helpful for drug development and in clinical trials targeting EGFR ex20ins.