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Diagnostic and Prognostic Performance of Secreted Protein Acidic and Rich in Cysteine (SPARC) Assay for Detecting
Elena Critselis1, Marta Rava2, Mirari Marquez2
1Proteomics Laboratory, Biotechnology Division, Biomedical Research Foundation of the Academy of Athens, Athens, 11527, Greece.
Purpose:
To evaluate the diagnostic and prognostic performance of Secreted Protein Acidic and Rich in Cysteine (SPARC) in detecting urinary bladder cancer (UBC).
Methods:
The Integrated Study on Bladder Cancer (n = 571; mean age:69.4 ± 12.2 years) evaluates cross-sectionally SPARC diagnostic performance in primary (n = 264) and recurrent (n = 307) UBC. SPARC prognostic performance is evaluated in a nested cohort (n = 250) prospectively followed for 80 months to detect tumor relapse, recurrence and/or progression. Baseline urine samples are analyzed blindly using a commercially available SPARC ELISA assay, characterized for its analytical performance according to clinical test regulatory requirements (R&D Manufactures Inc.).
Results:
While higher mean SPARC levels are detected in primary (p = 0.008) and recurrent (p < 0.0001) UBC, the assay has limited diagnostic performance (AUC:0.593; 95% CI:0.524-0.663). SPARC positive patients undergoing disease monitoring are more likely to develop tumor relapse (age and gender Adj. HR:1.52; 95% CI:1.04-2.22) and progression (Adj. HR:1.83; 95% CI:1.02-3.27). However, prognostic performance is affected by hematuria.
Conclusions:
SPARC diagnostic performance for detecting UBC appears insufficient for clinical implementation. In patients undergoing disease monitoring, SPARC is a promising prognostic marker for tumor relapse and/or progression, but is affected by hematuria.
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