Investigation of Characteristic Volatile Organic Compounds in Esophageal Cancer Organoids by Mass Spectrometry

Volatilomics, an emerging field in the study of noninvasive biomarkers, holds significant promise for identifying esophageal cancer (EC) through the detection of volatile organic compounds (VOCs). This study investigates common characteristic VOCs of EC cells by analyzing VOCs from three-dimensional organoid and spheroid models as well as two-dimensional monolayer cultures. The VOC profiles were measured by using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) in an untargeted approach. In the organoid, spheroid, and monolayer culture models, 21, 9, and 8 metabolically differential VOCs were identified between EC and normal esophageal (NE) cells, respectively. Correlation analysis across these three models revealed a shared characteristic VOC of EC: ethyl 2-methylbutyrate. This VOC was markedly increased in EC, demonstrating excellent diagnostic potential with an area under the curve (AUC) ranging from 0.93 to 0.99. Furthermore, transcriptomic data analysis of EC and NE tissues revealed the upregulation of protein degradation and absorption in EC tissues, supporting the hypothesis that ethyl 2-methylbutyrate arises from abnormalities within this metabolic pathway. This study not only supplies potential VOC biomarkers for EC identification but also provides a scientific basis for further elucidating the biochemical mechanisms underlying EC metabolic disturbances, potentially facilitating the gaseous biopsy technique development for EC diagnosis.