2010, Number 5
Initial experience in prostate cancer detection in Mexican patients at the Hospital General Dr. Manuel Gea González using a low-cost PCA3 test
Saavedra-Briones DV, Rodríguez-Dorantes M, Morales-Montor JG, Miranda-Ortiz H, Salido-Guadarrama I, Merayo-Chalico CE, Hernández-Castellanos VA, Sánchez-Turati GJ, Ahumada-Tamayo S, Fernández-Noyola G, Martínez J A, García-Edgar VN, Cantellano-Orozco M, Pacheco-Gahbler C, Calderón-Ferro F
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Language: Spanish
References: 21
Page: 328-335
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ABSTRACT
Introduction: Serum prostate specific antigen lacks specificity. The prostate cancer gene 3 is highly prostate cancer specific and is detectable in urine after prostate massage. The prostate cancer gene 3 assay is based on the amplification of nucleic acid sequences for detecting prostate cancer gene 3 messenger RNA. It holds promise as an aid to prostate cancer diagnosis, identifying patients with a high probability of positive biopsy.Objective: To establish the potential clinical usefulness of the prostate cancer gene 3 test in urine developed at the National Institute of Genomic Medicine (Instituto Nacional de Medicina Genómica) (INMEGEN) in predicting prostate biopsy result in Mexican prostate cancer patients.
Methods: A longitudinal, experimental study was carried out from April 2008 to August 2009 on patients programmed for prostate biopsy with serum prostate specific antigen above 4 ng/dL and/or suspicious digital rectal examination. After prostate massage 30 mL of urine from each of the 78 patients was collected. Total RNA extraction was carried out and complementary DNA was obtained using reverse transcriptase. Real-time polymerase chain reaction experiments used complementary DNA to amplify prostate cancer gene 3 and prostate specific antigen. With the resulting data on number of cycles, analysis was made and receiver operating characteristic curves were constructed to establish test specificity and sensitivity. The ability of prostate cancer gene 3 score to predict biopsy result was evaluated and compared with serum total prostate specific antigen, grey area prostate specific antigen, percentage of free prostate specific antigen and prostate specific antigen above 10 ng/mL.
Results: Initial results were reported on 78 men included in the study with a serum prostate specific antigen value above 4 ng/dL and/or suspicious digital rectal examination who underwent prostate biopsy within the time frame of April 2008 to August 2009. The RNA used was adequate for analyzing urine samples in 70 of the 78 patients. Biopsy revealed prostate cancer in 18 of the 70 patients (25%) and 16 of those 18 patients amplified for prostate cancer gene 3. Receiver operating characteristic curve showed an area under curve of 0.72 for prostate cancer gene 3. In contrast area under curve for serum prostate specific antigen was 0.69. Using a prostate cancer gene 3 cut-off score of 31, test sensitivity was 83% and specificity was 44%. Biopsy positive predictive value was 39% and negative predictive value was 93%. Serum prostate specific antigen specificity in this same group of patients was 33%.
Conclusions: Prostate cancer gene 3 score was superior to serum prostate specific antigen determination for predicting biopsy result in patients suspected of prostate cancer. Its high specificity indicates that prostate cancer gene 3 could play an important role in prostate cancer diagnosis and promises to be a useful tool for the molecular analysis of urine and the reduction of unnecessary biopsies. At the present time there is no information in the Latin American literature on the use of prostate cancer gene 3 in urine as an aid in prostate cancer detection. With the development of this low-cost and rapid test, studies on larger numbers of patients and for longer follow-up periods should be carried out in order to evaluate its potential usefulness and application as a tumor marker.
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