Comparison of quantum dots and FITC Fluorescence labeling for detection of PSA protein expression in human prostate cancer

Abstract

Objective To compare quantum clots and fluorescein isothioeyanate （FITC） fluores- cence labeling for detection of prostate specific antigen （PSA） protein expression in prostate cancer correlated with different tumor stage and grade, and to investigate the value of quantum dots as a new type of fluorescent markers for biomedical applications. Methods Seventy-two eases of prostate cancer were divided into 3 groups （ A, B and C ） according to Gleason score, which corresponding to Gleason 2-4 points （ 19 cases） , 5-7 points （28 eases） and 8-10 points （25 cases）. Quantum dots and FITC fluorescence labeling were performed to analyze the expression of PSA protein on the entire specimens, respectively. The intensity of fluorescence was interpreted immediately after labeling, and the fluorescence intensity decay was observed and recorded at 4 time points in within one month. Results The results of quantum dots and FITC fluores- cence labeling were consistent and demonstrated that the decreases in the positive rate and intensity of PSA expression accompanied with increased Gleason score and clinical stage of the tissue samples. The FITC fluo- rescence under continuous illumination faded quickly and became undeteetable after 6 min, however, only one ease with the fluorescence intensity change within 10 days for quantum dots fluorescence. Moreover, even to one month, the quantum dots fluorescence still could be seen in all except 9 specimens. Conclusion Fluorescent quantum dots have good sensitivity and stability for practical applications in biomedicine. Key words: Quantum dots ; FITC ; Prostate carcinoma