In recent years, the safety problem of infant formula powder has provoked panic among Chinese citizens. One of the most notorious incidents was the 2008 Chinese milk scandal which harmed thousands of infants. Therefore the development of a fast, high throughput screening method towards melamine and other harmful chemicals is of paramount importance. Microsphere-based flow cytometry is a new multiplexing immunochemical method for food-testing. Through competition between the free analyte in the sample and analyte-coupled microspheres, the content of the analyte can be indirectly quantified by measuring the fluorescence emitted from labelled antibodies. This developed method of high sensitivity (limit of detection = 0.70 ng ml−1) has already been validated and successfully applied to screen for melamine in various brands of infant formula powder analysis fulfilling the legislated tolerance level in a simple, fast, high throughput and organic solvent-free manner.
INTRODUCTION AND OBJECTIVE: To evaluate the performance of a novel non-prostate massage urine biomarker Spermine in predicting prostate cancer(PCa) METHODS: 556 consecutive men in 2 hospitals were prospectively recruited. The first 30ml of urine without prior prostatic massage was saved before a 10 core systematic prostate biopsy. The performance of the urine Spermine in predicting PCa and Gleason 7 or above PCa (HGPCa) was evaluated using Area-under-curve (AUC) and Multivariate analyses. Spermine density was Spermine/prostate volume. RESULTS: Data on 390 men with PSA 4-20ng/mL was analysed. Median age was 68 (Interquartile range (IQR) 64-72), PSA was 8.5 (IQR 6.2-11.8)ng/mL, normalized Spermine level was 2.36 (IQR 0.93-5.36). PCa and HGPCa diagnosed was 32.6% and 16.7% respectively. Normalized spermine was inversely associated with prostate cancer. Mean Spermine level was 2.27 in PCa and 7.8 in non-PCa 7.8 (t-test, p=0.003). A clear distinction of PCa and HGPCa risks was observed when Spermine level was divided into 4 quartile groups(Table 1). Multivariate analyses showed Age, PSA, Prostate volume and Spermine were all independent predictors of PCa. The AUC for PCa prediction was 0.52 (PSA), 0.71 (Spermine), and 0.76 (Spermine density), and 0.80 (Multivariate Spermine score: Age, PSA, Prostate volume and Spermine). The AUC for HGPCa was 0.60 (PSA), 0.67 (Spermine), 0.72 (Spermine density), and 0.81 (Multivariate Spermine score). In decision curve analyses (DCA) for PCa (Figure 1) or HGPCa, the multivariate Spermine score provided the best net clinical benefit. At 90% sensitivity (multivariate Spermine score), the negative predictive values were 91.3% (PCa) and 96.7% (HGPCa), while avoiding 35.4% and 50.7% unnecessary biopsies respectively. CONCLUSIONS: The novel urine Spermine test predicts PCa and HGPCa well without the need of prior prostate massage. Using a multivariate Spermine risk score including simple clinical parameters could further improve the predictive performance and avoid 50% unnecessary biopsies.Source of Funding: None
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