Published online Nov 7, 2021. doi: 10.3748/wjg.v27.i41.7134
Peer-review started: May 14, 2021
First decision: July 14, 2021
Revised: July 21, 2021
Accepted: August 30, 2021
Article in press: August 30, 2021
Published online: November 7, 2021
The clinical application of liquid biopsy is becoming more widespread. However, it remains unclear which factors, such as tumor volume and tumor invasion, influence circulating tumor DNA (ctDNA), and the origin of ctDNA in liquid biopsy is always problematic.
It will be very important to address the origin and dynamics of ctDNA for further clinical application of liquid biopsy.
A xenograft mouse model was used to assess the origin of ctDNA, clarify the dy
Tumor xenotransplants were established by inoculating BALB/c-nu/nu mice with the TE11 cell line (esophageal squamous cell carcinoma). Analysis of ctDNA was per
Mice given two-site xenografts were sacrificed for ctDNA at week 4 and week 8. No hTERT was detected at week 4, but it was detected at week 8. However, in four-site xenograft mice, hTERT was detected both at week 4 and week 6. These experiments revealed that both tumor invasion and tumor volume were associated with the detection of ctDNA. In resection experiments, hTERT was detected at resection, but had decreased by 6 h, and was no longer detected 1 and 3 d after resection. The half-life of ctDNA was estimated to be 1.8-3.2 h.
We clarified the origin and dynamics of ctDNA, showing that not only tumor invasion but also tumor volume was an important factor. Also, ctDNA could be measured at 1 d after tumor resection to evaluate the residuals.
In the clinical application of liquid biopsy, early-stage cancers could be targeted, and post-treatment monitoring should be performed 1 d after treatment.