Quantitation of rare circulating tumor cells by folate receptor α ligand-targeted PCR in bladder transitional cell carcinoma and its potential diagnostic significance

Abstract

Numerous attempts for detection of circulating tumor cells (CTC) have been made to develop reliable assays for early diagnosis of cancers. In this study, we validated the application of folate receptor α (FRα) as the tumor marker to detect CTC through tumor-specific ligand PCR (LT-PCR) and assessed its utility for diagnosis of bladder transitional cell carcinoma (TCC). Immunohistochemistry for FRα was performed on ten bladder TCC tissues. Enzyme-linked immunosorbent assay (ELISA) for FRα was performed on both urine and serum specimens from bladder TCC patients (n = 64 and n = 20, respectively) and healthy volunteers (n = 20 and n = 23, respectively). Western blot analysis and qRT-PCR were performed to confirm the expression of FRα in bladder TCC cells. CTC values in 3-mL peripheral blood were measured in 57 bladder TCC patients, 48 healthy volunteers, and 15 subjects with benign urologic pathologies by the folate receptor α ligand-targeted PCR. We found that FRα protein was overexpressed in both bladder TCC cells and tissues. The levels of FRα mRNA were also much higher in bladder cancer cell lines 5637 and SW780 than those of leukocyte. Values of FRα were higher in both serum and urine specimens of bladder TCC patients than those of control. CTC values were also higher in 3-mL peripheral blood of bladder TCC patients than those of control (median 26.5 Cu/3 mL vs 14.0 Cu/3 mL). Area under the receiver operating characteristic (ROC) curve for bladder TCC detection was 0.819, 95 % CI (0.738-0.883). At the cutoff value of 15.43 Cu/3 mL, the sensitivity and the specificity for detecting bladder cancer are 82.14 and 61.9 %, respectively. We concluded that quantitation of CTCs through FRα ligand-PCR could be a promising method for noninvasive diagnosis of bladder TCC.

Liquid biopsy: a step forward towards precision medicine in urologic malignancies

“…Levels of CTCs were higher in both serum and urine of urothelial carcinoma patients relative to controls. Quantification of CTC based on the high expression of folate receptor α (FRα) had an 82% sensitivity and 62% specificity for bladder cancer detection [49]. CTC enumeration in peripheral blood was also found to be a powerful predictor of early urothelial carcinoma recurrence and cancer-specific and overall mortality [50].…”

Circulating tumor cell levels and carcinoembryonic antigen: An improved diagnostic method for lung adenocarcinoma

“…FR‐positive CTCs can be detected by ligand‐targeted enzyme‐linked polymerization and have shown diagnostic promise for various cancers . For instance, FR expression is higher in both the serum and urine specimens of patients with bladder transitional cell carcinoma compared to a control group . FR‐positive CTCs are used as a novel diagnostic biomarker for lung cancer .…”

The role of circulating tumour cells and nucleic acids in blood for the detection of bladder cancer: A systematic review

“…Only one study has enumerated CTCs. Qi et al analysed a cohort of 20 bladder cancer patients and 23 healthy volunteers, they reported a sensitivity and specificity of 82.1% and 61.9% respectively [44], with an ROC of 0.819 (0.738-0.883), using the CTC unit (Cu) developed by GenoSaber Biotech (Shanghai, China). Their publication included patients with NMIBC, MIBC and metastatic bladder cancer, but performance of their test for individual cohorts was not stated.…”