RESUMO
OBJECTIVES: To develop a semi-quantitative method for prostate cancer diagnosis and to validate this technique in clinical protocols with the use of multiplex RT-PCR assays for five different biomarkers associated with carcinogenesis, including the PCA3 gene. DESIGN AND METHODS: AR, SRD5A2, KLK2, PSMA, and PCA3 transcripts were analyzed by multiplex RT-PCR assay in 73 prostatic tissue samples from patients with prostate cancer (PCa) and benign hyperplasia (BPH). RESULTS: Significant differences were observed between cancerous and hypertrophic tissues in the relative expression of these genes. AR, KLK2, PSMA, and PCA3 genes displayed increased transcriptional levels in the cancer specimens; on the other hand, SRD5A2 mRNA levels were higher in the BPH samples. CONCLUSIONS: Our results suggest that the most promising marker for PCa diagnosis was positive PCA3 detection associated with serum PSA levels, which showed 28-fold higher chances for cancer occurrence, with 92% specificity and 94% positive predictive value.