The electronic nose: emerging biomarkers in lung cancer diagnostics

Abstract

Lung cancer is very common and the most common cause of cancer death worldwide. Despite recent progress in the systemic treatment of lung cancer (checkpoint inhibitors and tyrosine kinase inhibitors), each year, >1.5 million people die due to this disease. Most lung cancer patients already have advanced disease at the time of diagnosis. Computed tomography screening of high-risk individuals can detect lung cancer at an earlier stage but at a cost of false-positive findings. Biomarkers could lead towards a reduction of these false-positive findings and earlier lung cancer diagnosis, and have the potential to improve outcomes and treatment monitoring. To date, there is a lack of such biomarkers for lung cancer and other thoracic malignancies, although electronic nose (e-nose)-derived biomarkers are of interest.E-nose techniques using exhaled breath component measurements can detect lung cancer with a sensitivity ranging from 71% to 96% and specificity from 33 to 100%. In some case series, such results have been validated but this is mostly using internal validation and hence, more work is needed. Furthermore, standardised sampling and analysis methods are lacking, impeding interstudy comparison and clinical implementation. In this narrative review, we provide an overview of the currently available data on E-nose technology for lung cancer detection.

C. elegans as a Powerful Tool for Cancer Screening

“…The first electronic nose with chemical sensors able to detect patterns of chemicals was first announced in 1982 [ 46 ]. For the last two decades, in parallel to discoveries of specific VOCs associated with cancer found in urine and exhaled breath, technologies on electronic noses to detect these VOCs have seen rapid development [ 47 , 48 ]. The volatilome is complex, and the e-nose must be sensitive, specific, and selective [ 49 , 50 , 51 ].…”

Liquid Biopsy — A Novel Diagnostic Tool for Management of Early-Stage Peripheral Lung Cancer

“…There are several promising methods, for example, "electronic nose" and exhaled breath condensate analysis. Although these methods can distinguish lung cancer patients from patients with other lung diseases and healthy controls, they do not provide data on morphology and they are not available for clinical use (Rocco, 2018;Tirzîte et al, 2018;van Geffen et al, 2019;Cainap et al, 2020).…”

Prognostic and Predictive Biomarkers in Non-Small Cell Lung Cancer Patients on Immunotherapy—The Role of Liquid Biopsy in Unraveling the Puzzle

“…VOCs were identified in 1970 and since then, breath analysis has transformed from a relatively unknown area to a high-throughput breath omics research field [ 102 ]. Nowadays, more than 3000 different VOCs in human breath have been identified [ 102 , 103 , 104 ]. These volatile compounds are produced by several metabolic processes within the human body.…”

“…Furthermore, the lack of standardized sampling and analysis methods needs to be addressed to implement this technique in clinic. After resolving these challenges, it seems that eNose will find its way to routine practice [ 102 ].…”

“…Exhaled breath consists of thousands of volatile organic compounds (VOCs). VOCs were identified in 1970 and since then, breath analysis has transformed from a relatively unknown area to a high-throughput breath omics research field [102]. Nowadays, more than 3000 different VOCs in human breath have been identified [102][103][104].…”