The functional and clinical roles of liquid biopsy in patient-derived models

The liquid biopsy includes the detection of circulating tumor cells (CTCs) and CTC clusters in blood, as well as the detection of, cell-free DNA (cfDNA)/circulating tumor DNA (ctDNA) and extracellular vesicles (EVs) in the patient's body fluid. Liquid biopsy has important roles in translational research. But its clinical utility is still under investigation. Newly emerged patient-derived xenograft (PDX) and CTC-derived xenograft (CDX) faithfully recapitulate the genetic and morphological features of the donor patients' tumor and patient-derived organoid (PDO) can mostly mimic tumor growth, tumor microenvironment and its response to drugs. In this review, we describe how the development of these patient-derived models has assisted the studies of CTCs and CTC clusters in terms of tumor biological behavior exploration, genomic analysis, and drug testing, with the help of the latest technology. We then summarize the studies of EVs and cfDNA/ctDNA in PDX and PDO models in early cancer diagnosis, tumor burden monitoring, drug test and response monitoring, and molecular profiling. The challenges faced and future perspectives of research related to liquid biopsy using patient-derived models are also discussed.

Automated summary

Liquid biopsy, including the detection of CTCs, CTC clusters, cfDNA/ctDNA, and EVs, plays an important role in translational research. Patient-derived xenograft (PDX) and CTC-derived xenograft (CDX) models faithfully recapitulate the features of tumors, while patient-derived organoid (PDO) models mimic tumor growth and drug response. These patient-derived models have greatly aided in the exploration of tumor behavior, genomic analysis, and drug testing. Moreover, studies on EVs and cfDNA/ctDNA in PDX and PDO models have shown promise in early cancer diagnosis, tumor burden monitoring, drug response monitoring, and molecular profiling. The challenges and future perspectives of liquid biopsy using patient-derived models are also discussed.