Performance of Survivin mRNA as a Biomarker for Bladder Cancer in the Prospective Study UroScreen

BACKGROUND: Urinary biomarkers have the potential to improve the early detection of bladder cancer. Most of the various known markers, however, have only been evaluated in studies with cross-sectional design. For proper validation a longitudinal design would be preferable. We used the prospective study UroScreen to evaluate survivin, a potential biomarker that has multiple functions in carcinogenesis. METHODS/RESULTS: Survivin was analyzed in 5,716 urine samples from 1,540 chemical workers previously exposed to aromatic amines. The workers participated in a surveillance program with yearly examinations between 2003 and 2010. RNA was extracted from urinary cells and survivin was determined by Real-Time PCR. During the study, 19 bladder tumors were detected. Multivariate generalized estimation equation (GEE) models showed that β-actin, representing RNA yield and quality, had the strongest influence on survivin positivity. Inflammation, hematuria and smoking did not confound the results. Survivin had a sensitivity of 21.1% for all and 36.4% for high-grade tumors. Specificity was 97.5%, the positive predictive value (PPV) 9.5%, and the negative predictive value (NPV) 99.0%. CONCLUSIONS: In this prospective and so far largest study on survivin, the marker showed a good NPV and specificity but a low PPV and sensitivity. This was partly due to the low number of cases, which limits the validity of the results. Compliance, urine quality, problems with the assay, and mRNA stability influenced the performance of survivin. However, most issues could be addressed with a more reliable assay in the future. One important finding is that survivin was not influenced by confounders like inflammation and exhibited a relatively low number of false-positives. Therefore, despite the low sensitivity, survivin may still be considered as a component of a multimarker panel

Potential predictors of a positive survivin test result based on GEE models that included only urine samples with complete information on all variables (190 positive survivin tests in 4546 samples from 1273 participants of UroScreen).

<p>This analysis was performed with samples of subcohort A only because not all parameters were available for the full data set. N_pos: number of samples positive for survivin, OR: odds ratio, CI: confidence interval.</p>*<p>Bladder cancer detected during UroScreen.</p>**<p>After standardization.</p

Selected sample characteristics of false-negative cases.

1<p>For cases 1 and 12 no samples were available for survivin determination.</p>2<p>Negative at last (0 months), positive at previous screen (14 months).</p

Cancer predictive values of the last survivin test before diagnosis of bladder cancer.

<p>Cancer predictive values of the last survivin test before diagnosis of bladder cancer.</p

ROC curve for log₁₀ (survivin) in the last screening round before diagnosis, adjusted for log₁₀ (β-actin) and age in 10-year classes.

<p>Analysis was performed for all tumors entities. The resulting area under curve (AUC) was 0.74 with a 95% CI (confidence interval) of 0.61–0.86.</p

Characteristics and test results of cases.

<p>Results are from the last screening round before diagnosis.</p>1<p>Cases number 1 and 12 are omitted because no samples were available for survivin determination.</p>2<p>Traces = 1–5 leukocytes, medium = 5–<250 leukocytes, abundant ≥250 leukocytes (dipstick or microscopic sediment analysis).</p>3<p>cut-off: 10,000 (Qiagen/FDI), 40,000 (Invitek/FDI), 100,000 (Invitek/IPA).</p

Characteristics of male participants of UroScreen with former occupational exposure to aromatic amines.

*<p>One person with two tumors.</p