RESUMEN
OBJECTIVES: To evaluate, in a multicenter study, the diagnostic performance of a new molecular test uPM3 for detecting prostate cancer cells in urine because of the need for better methods to identify patients at risk of prostate cancer. METHODS: The uPM3 test is a nucleic acid amplification assay detecting simultaneously in the urine the relative expression of prostate-specific antigen (PSA) mRNA as a marker of prostate cells and PCA3RNA, which is selectively expressed in most types of prostate cancer. The test is performed using the isothermic nucleic acid-based amplification method, and the two targets are simultaneously detected in real-time fluorescence using specific beacons as probes in a thermostated spectrofluorometer. The test was performed on the first voided urine obtained after careful digital rectal examination of the prostate in men undergoing transrectal ultrasound-guided prostate biopsy. RESULTS: Of 517 patients undergoing biopsy at five centers, 443 (86%) had an assessable sample. Of those, 21%, 55%, and 24% had a total PSA level of less than 4 ng/mL, between 4 and 10 ng/mL, and greater than 10 ng/mL. The corresponding percentage of biopsies positive for cancer in these three groups was 20%, 35%, and 44%. The overall uPM3 sensitivity and specificity was 66% and 89%, respectively. In men with a PSA level less than 4 ng/mL, the sensitivity was 74% and specificity 91%. In those with a PSA level of 4 to 10 ng/mL, the sensitivity was 58% and specificity 91%. In those with a PSA level greater than 10 ng/mL, the sensitivity and specificity was 79% and 80%, respectively. The positive predictive value of uPM3 was 75% compared with 38% for total PSA, and the negative predictive value was 84% compared with 89% and 80% for a PSA cutoff of 2.5 and 4.0 ng/mL, respectively. The overall accuracy was 81% compared with 43% and 47% for total PSA at a cutoff of 2.5 and 4.0 ng/mL, respectively. CONCLUSIONS: These results suggest that the uPM3 molecular urine test may be an important adjunct to current methods for the detection of early prostate cancer.
Asunto(s)
Adenocarcinoma/orina , Antígenos de Neoplasias/genética , Biomarcadores de Tumor/orina , Proteínas de Neoplasias/genética , Técnicas de Amplificación de Ácido Nucleico , Antígeno Prostático Específico/genética , Neoplasias de la Próstata/orina , ARN Mensajero/orina , ARN Neoplásico/orina , Adenocarcinoma/diagnóstico , Área Bajo la Curva , Biopsia con Aguja , Estudios de Cohortes , Sistemas de Computación , Humanos , Masculino , Palpación , Valor Predictivo de las Pruebas , Pronóstico , Próstata/diagnóstico por imagen , Próstata/patología , Neoplasias de la Próstata/diagnóstico , Curva ROC , Recto , Ultrasonografía IntervencionalRESUMEN
OBJECTIVES: Serum tPSA lacks specificity. The DD3(PCA3) gene is highly specific for prostate cancer and is detectable in prostate cancer cells shed into urine after rectal palpation. A newly developed nucleic acid sequence based amplification assay (uPM3) for detecting DD3(PCA3) RNA in urine samples was evaluated prospectively in patients referred for prostate cancer detection. METHODS: The uPM3 assay simultaneously detects the relative expression of DD3(PCA3) RNA and PSAmRNA as a marker for prostate cells in urine. Urine samples were collected after attentive digital rectal palpation prior to transrectal guided prostate biopsy. Samples were provided as a single void specimen (20-30 ml), stabilized in phosphate buffer and centrifuged. Lysis was performed on cell pellets DD3(PCA3) RNA and PSAmRNA were extracted and amplification was performed using isothermic nucleic acid based amplification (NASBA). The two targets were detected in real-time using specific beacons as probes in a thermostated spectrofluorimeter. Parameters of the amplification curve were defined after a logistic curve fitting routine and a classification tree model was constructed to predict the outcome of patients (i.e. cancer and non-cancer). RESULTS: 201 patients were included in this prospective study. 158/201 analyzed urine samples contained enough prostate cells sufficient for DD3(PCA3) analysis (79% adequacy rate). Prostate cancer was found in 62 (39%) of the evaluable patients. Overall sensitivity, specificity, positive predictive value and negative predictive value for the uPM3 assay at a cut-off 0.5 probability were 82%, 76%, 67% and 87% respectively as compared to 98%, 5%, 40% and 83% respectively for tPSA (at a cutoff of 2.5 ng/ml). In the tPSA categories <4, 4-10 and >10 ng/ml sensitivity was 73%, 84% and 84% and specificity was 61%, 80% and 70%, respectively. The AUC (area under the curve) was 0.87 (CI 0.81-0.92). CONCLUSION: The uPM3 assay showed excellent clinical performances and a specificity far superior to tPSA.
Asunto(s)
Antígenos de Neoplasias/genética , Neoplasias de la Próstata/orina , ARN/orina , Adulto , Anciano , Anciano de 80 o más Años , Humanos , Masculino , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
We have recently developed from red blood cells a new delivery system called nanoErythrosomes. These nanovesicles offer a high degree of versatility for the encapsulation of biological or nonbiological compounds and for the binding of targeting agents. In particular, polyethyleneglycols can be conjugated by a covalent link to the basic amino acid residues constitutive of the different proteins. The binding of polyethyleneglycols to the nanoErythrosome membrane could be interesting for the therapeutic use of this delivery system since it could overcome heterologous immunogenicity and reduce rapid clearance from circulation. In the present study, we have investigated the effect of temperature on the nanoErythrosome behavior in the absence and presence of conjugated polyethyleneglycols. More specifically, Fourier transform infrared (FTIR) spectroscopy has been used to evaluate the lipid order and dynamics, the hydration and the degree of protein aggregation of the nanoErythrosomes after covalent binding of polyethyleneglycols having molecular weights of 2000 and 5000 g mol(-1). The results indicate that the nanoErythrosome lipid chain order is not significantly affected by heating the nanoErythrosomes at temperatures up to 50 degrees C. They also indicate that the nanoErythrosome proteins aggregate irreversibly at temperatures above 37 degrees C, this effect being abolished in the presence of polyethyleneglycols. The presence of polyethyleneglycols decreases the accessibility of water to the lipid head groups. On the other hand, 31P-nuclear magnetic resonance (NMR) and electron microscopy results reveal that the presence of polyethyleneglycols prevents the aggregation of the nanoErythrosome structures.