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

The role of circulating cell-free DNA as an inflammatory mediator after stroke

Stroke is the second leading cause of death worldwide and a leading cause of disability. Clinical and experimental studies highlighted the complex role of the immune system in the pathophysiology of stroke. Ischemic brain injury leads to the release of cell-free DNA, a damage-associated molecular pattern, which binds to pattern recognition receptors on immune cells such as toll-like receptors and cytosolic inflammasome sensors. The downstream signaling cascade then induces a rapid inflammatory response. In this review, we are highlighting the characteristics of cell-free DNA and how these can affect a local as well as a systemic response after stroke. For this purpose, we screened literature on clinical studies investigating cell-free DNA concentration and properties after brain ischemia. We report the current understanding for mechanisms of DNA uptake and sensing in the context of post-stroke inflammation. Moreover, we compare possible treatment options targeting cell-free DNA, DNA-sensing pathways, and the downstream mediators. Finally, we describe clinical implications of this inflammatory pathway for stroke patients, open questions, and potential future research directions.

Sputum cell-free DNA for detection of alterations of multiple driver genes in lung adenocarcinoma

BACKGROUND

Sputum cell-free DNA (cfDNA) has been confirmed to be a valued surrogate sample for detection of EGFR mutations in patients with lung adenocarcinoma (LAC). Whether it is suitable for detection of mutations of multiple driver genes has not been reported.

METHODS

A total of 83 patients with LAC were enrolled and their sputum and paired tumor samples were collected. A next-generation sequencing (NGS)-based 10-gene panel was used to test sputum supernatant-derived cfDNA and paired tumor DNA. The sputum sediments were used for cytological evaluation.

RESULTS

The total positive rates of hotspot mutations of the 10 driver genes in sputum cfDNA and matched tissue samples were 65.1% and 77.1%, respectively. The overall detection sensitivity of variants in sputum cfDNA was 81.3% (95% confidence interval [CI], 69.2%, 89.5%) and the specificity was 100% (95% CI, 79.1%, 100%). The sensitivities of testing sputum cfDNA from patients with stage IIIB-IV was 87.0% (95% CI, 74.5%, 94.1%); the sensitivities of testing sputum cfDNA from patients with malignant sputum was 92.3% (95% CI, 78.0%, 98.0%); and the sensitivity of testing sputum cfDNA from patients with malignant sputum in stage IIIB-IV were 94.1% (95% CI, 78.9%, 99.0%).

CONCLUSIONS

This study demonstrated that sputum cfDNA were successfully used for the detection of multiple driver genes by NGS. Sputum cfDNA could be a valuable surrogate clinical sample for all-in-one test of mutations to guide target therapies, especially for patients with advanced LAC and malignant sputum.

Comprehensive characterization reveals sputum supernatant as a valuable alternative liquid biopsy for genome profiling in advanced non-small cell lung cancer

BACKGROUND

Sputum biopsies offer unique advantages such as non-invasiveness and convenient collection. The one investigation so far on sputum for genome profiling in advanced non-small cell lung cancer (aNSCLC) suggested promising performance. However, it remains undefined whether clinicohistologic characteristics were associated with performance and how this knowledge could help guide choice of liquid biopsy.

METHODS

Targeted sequencing with a 520-gene panel was performed on prospectively collected matched tumor tissue (TIS), plasma (PLA), and sputum supernatant (SPU) from 71 aNSCLC patients (NCT05034445). Genomic alteration detection was characterized in a series of aspects and interrogated for association with 14 clinicohistologic features. Nomograms were constructed with logistic regression for predicting the liquid biopsy type with greater sensitivity.

RESULTS

Compared with PLA, SPU showed comparable quality control metrics, mutation detection rate (SPU: 67.6%, PLA: 70.4%), concordance with tumor tissue (67.6% vs. 73.2%), and correlation with tissue-based tumor mutation burden levels (r = 0.92 vs. 0.94). For driver alterations, detection was less sensitive with SPU (50.0%) than PLA (63.5%) in the entire cohort but similarly or more sensitive in patients with centrally located lung tumors or smoking history or for altered ALK or KRAS. Two nomograms were constructed and enabled predicting the probability of superior sensitivity with SPU with moderate to borderline high accuracy.

CONCLUSION

In addition to demonstrating comparable performance in multiple aspects, this study is the first to propose nomograms for choosing liquid biopsy based on clinicohistologic characteristics. Future research is warranted to delineate the clinical utility of sputum for genome profiling.

Liquid biopsy assay for pulmonary adenocarcinoma using supernatants from core‐needle biopsy specimens

Background

Genomic testing is the cornerstone of the treatment of patients with non‐small‐cell lung cancer. However, comprehensive molecular testing of small specimens may be inadequate due to limited tissue. Liquid biopsy has emerged as a new method of genotyping. In this study, we evaluate the feasibility of using supernatants from core needle biopsy samples of lung adenocarcinoma for genomic testing.

Methods

Core needle biopsy specimens and their supernatants were collected from patients (n = 48) with lung adenocarcinoma. Genomic testing results of the supernatant samples were compared with results derived from paired tissue samples from the same patient.

Result

All 48 supernatant samples yield adequate cell‐free DNA, but the concentration of cell‐free RNA did not meet the criteria for analysis. The concordance rate between the genomic testing results of supernatants and the corresponding tissue samples was 95.8% (kappa = 0.899). The coincidence rate of detectable mutations at the DNA level in the supernatants was up to 100%.

Conclusion

Core needle biopsy supernatants can provide a valuable specimen source for genotyping pulmonary adenocarcinoma. However, the method of preserving and extracting RNA from supernatant specimens needs further improvement.

Effective early diagnosis for NSCLC: an algorithm

INTRODUCTION

Lung cancer still remains undiagnosed for most patients until the disease is inoperable.

AREAS COVERED

We performed search on PubMed with the keywords: EBUS, radial-EBUS, bronchoscopy, lung cancer, electromagnetic navigation, ct-biopsy, transthoracic biopsy. We present diagnostic equipment and imaging techniques such as positron emission tomography, endoscopical navigation systems, endobronchial ultrasound, radial-endobronchial ultrasound, transthoracic ultrasound biopsy, and computed tomography guided biopsies.

EXPERT OPINION

However, lack of early disease symptoms remains the most important issue and therefore we should direct our efforts to screening and early disease diagnosis. An algorithm is proposed for biopsy upon initial disease diagnosis.