Blood-based liquid biopsy: A promising noninvasive test in diagnosis, surveillance, and prognosis of patients with upper tract urothelial carcinoma.

OBJECTIVES:To assess the efficacy of blood-based liquid biopsy in the diagnosis, surveillance, and prognosis of upper tract urothelial carcinoma (UTUC). METHODS AND MATERIALS:In this prospective study, peripheral blood samples were collected from patients with primary UTUC before surgery with curative intent and follow-up visits at University of Southern California between May 2021 and September 2022. The samples were analyzed using the third-generation comprehensive high-definition single-cell assay (HDSCA3.0) to detect rare events, including circulating tumor cells (CTCs) and oncosomes, based on the immunofluorescence signals of DAPI (D), cytokeratin (CK), CD45/CD31 (CD), and vimentin (V). The findings of pre-surgery liquid biopsies were compared with those of blood samples from normal donors (NDs) and matched follow-up liquid biopsies. The association between liquid biopsy findings and clinical data, including recurrence-free survival (RFS), was also assessed. RESULTS:Twenty-eight patients with UTUC were included, of whom 21 had follow-up samples. Significant differences in specific rare analytes were detected in the preoperative samples compared to the NDs. In the post- vs. presurgery matched analysis, a significant decrease was detected in total-, CK-, and CK|V oncosomes, as well as in D-, D|V-, and D|V|CD cells. With a median follow-up of 11 months, 8 patients had disease recurrence. Survival analysis demonstrated that patients with >1.95 preoperative CK|V oncosomes (p = 0.020) and those with >4.18 D|CK|V cells (p = 0.050) had worse RFS compared to other patients. CONCLUSIONS:This study demonstrated promising initial evidence for the biomarker role of CTCs and oncosomes in the diagnosis and surveillance of patients with UTUC.