Differential display code 3 (DD3/PCA3) in prostate cancer diagnosis

Early diagnosis of prostate cancer (PCa) in an organ-confined stage following radical treatment is the only potential curative approach in PCa. Prostatic-specific antigen (PSA) is very helpful in early diagnosis, but the main disadvantage is that it has a low positive predictive value in the range of the grey zone of 2.5-10 ng/mL, which results in a high number of needless biopsies. For this reason, new tests with better parameters are needed. One promising test is that for differential display code 3 (DD3(PCA3)), which is a prostate-specific non-coding mRNA that is highly overexpressed in prostate tumor cells. The aim of the present study was to evaluate the potential of DD3(PCA3) for mRNA in PCa diagnosis.

A total of 186 patients were examined. In a group of patients with suspected PCa, one tissue specimen core was collected for testing DD3(PCA3) expression. According to the histological verification there were 100 patients with benign prostatic hyperplasia, 12 patients with prostatic intraepithelial neoplasia and 74 patients with PCa. The total RNA was isolated and DD3(PCA3) and PSA expressions were quantified using quantitative RT real-time PCR method. The DD3(PCA3)/PSA mRNA ratio was determined for all groups.

It was found that the levels of the mRNA expression of DD3(PCA3) were significantly higher (p<0.045) in patients with PCa than in patients with benign prostatic hyperplasia. No statistically significant differences in levels of mRNA expression of DD3(PCA3) between patients with organ-confined and those with advanced or metastatic disease, nor according to Gleason score, were found.

DD3(PCA3) appears to be a promising marker for early detection of PCa and also for differential diagnosis between patients with benign prostate hyperplasia and those with PCa.