Identification of molecular targets in urologic oncology

Nuclear Stat5a/b predicts early recurrence and prostate cancer-specific death in patients treated by radical prostatectomy

There is an urgent need for reliable markers to identify patients whose prostate cancer (PCa) will recur after initial therapy and progress to lethal disease. Gleason score (GS) is considered the most accurate predictive marker for disease-specific mortality after primary treatment of localized PCa. Most PCas cluster into groups of GS 6 and 7 with considerable variation in the disease recurrence and disease-specific death. In preclinical PCa models, Stat5a/b promotes PCa growth and progression. Stat5a/b is critical for PCa cell viability in vitro and for tumor growth in vivo and promotes metastatic dissemination of cancer in nude mice. Here, we analyzed the predictive value of high nuclear Stat5a/b protein levels in 2 cohorts of PCas: Material I (n = 562) PCas treated by radical prostatectomy (RP), and Material II (n = 106) PCas treated by deferred palliative therapy. In intermediate GS PCas treated by radical prostatectomy, high levels of nuclear Stat5a/b predicted both early recurrence (univariable analysis; P < .0001, multivariable analysis; HR = 1.82, P = .017) and early PCa-specific death (univariable analysis; P = .028). In addition, high nuclear Stat5a/b predicted early disease recurrence in both univariable (P < .0001) and multivariable (HR = 1.61; P = .012) analysis in the entire cohort of patients treated by RP regardless of the GS. Patients treated by deferred palliative therapy, elevated nuclear Stat5a/b expression was associated with early PCa-specific death by univariable Cox regression analysis (HR = 1.59; 95% CI = [1.04, 2.44]; P = .034). If confirmed in future prospective studies, nuclear Stat5a/b may become a useful independent predictive marker of recurrence of lethal PCa after RP for intermediate GS PCas.

Predicting prostate biopsy outcome: prostate health index (phi) and prostate cancer antigen 3 (PCA3) are useful biomarkers

Indication for prostate biopsy is presently mainly based on prostate-specific antigen (PSA) serum levels and digital-rectal examination (DRE). In view of the unsatisfactory accuracy of these two diagnostic exams, research has focused on novel markers to improve pre-biopsy prostate cancer detection, such as phi and PCA3. The purpose of this prospective study was to assess the diagnostic accuracy of phi and PCA3 for prostate cancer using biopsy as gold standard. Phi index (Beckman coulter immunoassay), PCA3 score (Progensa PCA3 assay) and other established biomarkers (tPSA, fPSA and %fPSA) were assessed before a 18-core prostate biopsy in a group of 251 subjects at their first biopsy. Values of %p2PSA and phi were significantly higher in patients with PCa compared with PCa-negative group (p<0.001) and also compared with high grade prostatic intraepithelial neoplasia (HGPIN) (p<0.001). PCA3 score values were significantly higher in PCa compared with PCa-negative subjects (p<0.001) and in HGPIN vs PCa-negative patients (p<0.001). ROC curve analysis showed that %p2PSA, phi and PCA3 are predictive of malignancy. In conclusion, %p2PSA, phi and PCA3 may predict a diagnosis of PCa in men undergoing their first prostate biopsy. PCA3 score is more useful in discriminating between HGPIN and non-cancer.

Age-specific PCA3 score reference values for diagnosis of prostate cancer

PURPOSE

We evaluated the impact of age on PCA3 score and the utility of age-specific reference values in predicting initial prostate biopsy (pBx) outcomes.

PATIENTS AND METHODS

This single-center, retrospective study included 205 men who underwent an initial 14-core TRUS-guided pBx due to PSA > 3.0 ng/ml or suspicious digital-rectal examination (DRE). PCA3 scores were measured with the Progensa assay. Linear regression models were fit to identify factors that impact PCA3 score and to determine age-specific reference values. Predictive accuracies of logistic regression models predicting presence of prostate cancer (PCa) were analyzed.

RESULTS

The positive biopsy rate was 37%. In multivariable linear regression, age (P < 0.001), presence of PCa (P < 0.001), and multifocal HG-PIN (P = 0.012) were independent predictors of PCA3 score. Age showed the strongest impact on PCA3 score (T = 4.77). The upper 95% confidence interval of PCA3 score in each age category was defined as the age-specific limit. A PCA3-score over the age-specific limit (PCA3-age) was associated with an 4.17-fold increased odds of being diagnosed with PCa (P < 0.001). In multivariable logistic regression models predicting the presence of PCa, predictive accuracy of a base model (age, DRE, PSA, volume) increased from 69.6 to 75.4% (P = 0.037) by adding the continuous PCA3 score, to 73.9% (P = 0.098) with the 35 cutoff (PCA3-35) and to 77.1% (P = 0.008) with PCA3-age.

CONCLUSIONS

PCA3 score increases with age, independent of PCa presence. Age-specific PCA3 score reference values are superior to PSA, continuous PCA3 score, and PCA3-35 in predicting initial pBx outcome. Therefore, an age-adjusted PCA3 score should be used for interpretation of the results.