#AI Reads Urine# Using C. elegans as Surveillance Tool for Gastric and Esophageal Cancers Recurrence

Gastric and esophageal cancers have high incidences and mortality rates. Postoperative surveillance is crucial for early recurrence detection, but current methods have limitations. Novel diagnostics like N-NOSE, which uses the olfactory abilities of C. elegans, show promise. However, reports on its clinical performance for gastroesophageal cancer detection and recurrence surveillance are scarce.

Patients aged ≥ 20, histologically diagnosed with gastric or esophageal cancer, ECOG PS 0 - 1, with preserved organ function, and planned for radical resection were enrolled from October 2020 to December 2021. Exclusion criteria included synchronous/metachronous cancers (except certain cases), active systemic infectious disease, etc. Urine samples were collected at multiple time points before and after chemotherapy/surgery and frozen until N - NOSE analysis. C. elegans was cultured on NGM with E. coli. Chemotaxis assays were performed on agar plates with sodium azide and urine samples at 10 - and 100 - fold dilutions. The chemotaxis index was calculated, and assays were conducted blindly.

Forty patients were included (18 gastric, 17 esophageal, 5 esophagogastric junction cancer). Chemotaxis assays were done on urine samples. Most patients had a positive chemotaxis index preoperatively, which decreased postoperatively. In recurrent cases, the chemotaxis index was positive and showed trends related to recurrence and treatment.

Overall, no significant difference in chemotaxis index was found between recurrence and non - recurrence groups. But in patients with vascular invasion, the 100 - fold diluted urine chemotaxis index was significantly higher in the recurrence group before chemotherapy/surgery. ROC analysis determined a cutoff value, and only CEA was also significantly different among tumor markers.

In five of seven recurrent cases, the chemotaxis index decreased after surgery, increased before recurrence, and decreased again after treatment, suggesting a correlation with recurrence and treatment response. However, in two cases, nematodes showed avoidance behavior after recurrence.

The study's findings suggest N - NOSE may be a viable biomarker for monitoring patients with vascular invasion. The differences in nematode response at 100 - fold dilution may be due to C. elegans' olfactory response and the nature of cancer - related VOCs. However, the study had limitations like a small sample size and few recurrence cases. Future studies should consider other factors affecting nematode response and define testing conditions for clinical application.

If nematodes can sense it, could we also detect it with a machine? At the very least, this is yet another piece of supporting evidence that there is recurrence information of gastric cancer and esophageal cancer exist in the urine.

The original publication link: https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2024.1364333/full

Youhe Gao

Statement: During the preparation of this work the author(s) used Doubao / AI reading for summarizing the content. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the published article.