Targeting bladder tumor cells in voided urine of Chinese patients with FITC-CSNRDARRC peptide ligand

Abstract

Objective: To study the practicality of the FITC-CSNRDARRC peptide ligand (containing the Cys-Ser-Asn-Arg-Asp-Ala-Arg-Arg-Cys nonapeptide) in diagnosing and monitoring bladder tumors.

Materials and methods: Between March 2011 and September 2011, 80 consecutive patients with radiographic abnormalities, localizing hematuria, other symptoms, or signs were studied using the FITC-CSNRDARRC ligand, urinary cytology (UC), and fluorescence in situ hybridization (FISH). The sensitivity and specificity of these three technologies were determined and compared. Cystoscopy and tissue biopsy were taken as the "gold standards" for bladder tumor diagnosis in this study.

Results: Twenty-nine out of 80 patients were diagnosed with a bladder tumor via histopathological examination. The FITC-CSNRDARRC ligand was positive in 23 out of 29 bladder tumor patients and produced false negatives in six (20.69%) patients. The UC was positive in six out of 29 bladder tumor patients and produced false negatives in 23 (79.31%) patients. The FISH was positive in 21 out of 29 bladder tumor patients and produced false negatives in eight (27.59%) patients. The overall sensitivity as verified by the FITC-CSNRDARRC ligand was much higher than in UC (79.31% versus 20.69%, P < 0.001) and was slightly higher than in FISH (79.31% versus 72.41%, P = 0.625). The sensitivity of FISH was significantly higher than that of UC (72.41% versus 20.69%, P < 0.001). Sensitivities of the FITC-CSNRDARRC ligand and UC by grade were 58.33% versus 8.3% for low-grade (LG) tumors (P = 0.031) and 94.12% versus 29.41% for high-grade (HG) tumors (P = 0.003), respectively. The advantage was maintained in terms of the detection of invasive tumors between the FITC-CSNRDARRC ligand and UC (90.48% versus 23.81%, P = 0.001) as well as between FISH and UC (85.71% versus 23.81%, P = 0.003). The specificities for the FITC-CSNRDARRC ligand, UC, and FISH were 100%.

Conclusion: Results show that the FITC-CSNRDARRC ligand is a promising noninvasive tool for diagnosis and surveillance in patients suspected of having a new bladder tumor.

Keywords: FITC-CSNRDARRC ligand; bladder tumor; fluorescent probe; tumor-targeting.

Figure 1

The FITC-CSNRDARRC ligand. (A and C) The nuclei counterstaining was achieved with DAPI. The light colored area in (B) is the nuclei. (D) DAPI was not used in the nuclei. Notes: The CSNRDARRC peptide is selectively bound to the nuclei of bladder tumor cells. The bright dot pointed at by the arrows indicate where the peptides bind. Magnification ×1000 (A–D). Abbreviations: DAPI, 4′, 6-diamidino-2-phenylindole.

Figure 2

UC. (A and B) Hematoxylin stain, (C and D) Papanicolaou stain. (A, B and D) Three examples of normal cells and an example of tumor cells (C). Note: Magnification ×400 (A and D) and ×200 (B and C). Abbreviation: UC, urinary cytology.

Figure 3

FISH. Chromosome 3 and p16 (rhodamine), chromosome 7 and 17 (FITC). (A and B) Example of the same urine specimen cell, in which the percentage of FISH signals are greater than the cut-off value (CSP3, 23%; CSP7, 21%; GLPp16, 7%; CSP17, 9%). (C and D) Example of the same urine specimen cell, in which the percentage of FISH signals are lower than the cut-off value (CSP3, 3%; CSP7, 2%; GLPp16, 4%; CSP17, 2%). Note: Magnification ×1000 (A–D). Abbreviation: FISH, fluoresceuce in situ hybridization.