Detection of prostate stem cell antigen expression in human prostate cancer using quantum-dot-based technology.

Quantum dots (QDs) are a new class of fluorescent labeling for biological and biomedical applications. In this study, we detected prostate stem cell antigen (PSCA) expression correlated with tumor grade and stage in human prostate cancer by QDs-based immunolabeling and conventional immunohistochemistry (IHC), and evaluated the sensitivity and stability of QDs-based immunolabeling in comparison with IHC. Our data revealed that increasing levels of PSCA expression accompanied advanced tumor grade (QDs labeling, r = 0.732, p < 0.001; IHC, r = 0.683, p < 0.001) and stage (QDs labeling, r = 0.514, p = 0.001; IHC, r = 0.432, p = 0.005), and the similar tendency was detected by the two methods. In addition, by comparison between the two methods, QDs labeling was consistent with IHC in detecting the expression of PSCA in human prostate tissue correlated with different pathological types (K = 0.845, p < 0.001). During the observation time, QDs exhibited superior stability. The intensity of QDs fluorescence remained stable for two weeks (p = 0.083) after conjugation to the PSCA protein, and nearly 93% of positive expression with their fluorescence still could be seen after four weeks.