Precursor Isoform of Prostate-Specific Antigen and Human Kallikrein 2: Two New Promising Biomarkers for the Unsolved Challenge of Early Prostate Cancer Detection

A novel urinary long non-coding RNA transcript improves diagnostic accuracy in patients undergoing prostate biopsy

BACKGROUND

Long non-coding RNA (LncRNA) PCA3 has been a well-established urine biomarker for the detection of prostate cancer (PCa). Our previous study showed a novel LncRNA FR0348383 is up-regulated in over 70% of PCa compared with matched benign tissues. The aim of this study was to evaluate the diagnostic value of urinary FR0348383 for men undergoing prostate biopsy due to elevated PSA (PSA > 4.0 ng/ml) and/or abnormal digital rectal examination (DRE).

METHODS

Post-DRE first-catch urine specimens prior to prostate biopsies were prospectively collected. After the whole transcriptome amplification, quantitative real time polymerase chain reaction was applied to quantify urine FR0348383 and PSA levels. The FR0348383 score was calculated as the ratio of PSA and FR0348383 mRNA (PSA mRNA/FR0348383 mRNA × 1000). The diagnostic value of FR0348383 score was evaluated by logistic regression and decision curve analysis.

RESULTS

213 cases with urine samples containing sufficient mRNA were included, 94 cases had serum PSA level 4.0-10.0 ng/ml. PCa was identified in 72 cases. An increasing FR0348383 score was correlated with an increasing probability of a positive biopsy (P < 0.001). Multivariable logistic analysis indicated FR0348383 score (P < 0.001), PSA (P = 0.004), age (P = 0.007), prostate volume (P < 0.001) were independent predictors of PCa. ROC analysis demonstrated FR0348383 score outperformed PSA, %free PSA, and PSA Density in the prediction of PCa in the subgroup of patients with grey area PSA (AUC: 0.815 vs. 0.562 vs. 0.599 vs. 0.645). When using a probability threshold of 30% in the grey zone cohort, The FR0348383 score would save 52.0% of avoidable biopsies without missing any high grade cancers.

CONCLUSIONS

FR0348383 transcript in post-DRE urine may be a novel biomarker for detection of PCa with great diagnostic value, especially in the grey zone cohort. The application of FR0348383 score in clinical practice might avoid unnecessary prostate biopsies and increase the specificity of PCa diagnosis.

Extended biopsy based criteria incorporating cumulative cancer length for predicting clinically insignificant prostate cancer

What's known on the subject? and What does the study add? The criteria used for selecting patients with prostate cancer for active surveillance (AS) are still not satisfactory due to the difficulty in predicting the significance of the prostate cancer. Urologists could predict insignificant prostate cancer by incorporating cumulative cancer length and biopsy Gleason score, derived from extended biopsy. The present study has added new criteria for predicting insignificant prostate cancer, which would lead to a better selection of candidates for AS.

OBJECTIVE

• To develop extended biopsy based criteria for predicting insignificant cancer (IC) using extended biopsy findings.

PATIENTS AND METHODS

• From 2000 to 2009, 1575 patients with prostate cancer were primarily treated by radical prostatectomy in two referral hospitals. • Of these, the study cohort comprised 499 patients with extended biopsy confirmed, clinically organ-confined (cT1-2N0M0) prostate cancer with PSA levels of <20 ng/mL. • Cancer information obtained through extended biopsy included cumulative cancer length (CCL) divided by the number of biopsy cores (CCL/core).

RESULTS

• Pathological examination revealed 39 ICs (7.8%). All these ICs fell in a category of prostate cancer with clinical stage ≤ T2a and 2005 International Society of Urological Pathology Consensus Conference (ISUP) modified biopsy Gleason score ≤ 7. • Accordingly, we analysed predictors of IC in a subset cohort of 370 patients in this category. A multivariate logistic regression analysis revealed that 2005 ISUP modified biopsy Gleason score and CCL/core were independently significant predictors of IC. • We determined a threshold value of CCL/core of 0.20 mm for predicting IC using receiver operating characteristic analysis. • Based on these findings, we developed simple extended biopsy based criteria for predicting IC as follows: (i) PSA level of <20 ng/mL; (ii) Clinical stage ≤ T2a; (iii) 2005 ISUP modified biopsy Gleason score ≤ 6; (iv) CCL/core of <0.20 mm. • The specificity of the criteria was 91%, which was significantly higher than the value from a subset of criteria without item iv (P < 0.001).

CONCLUSION

• We have developed extended biopsy based criteria for predicting IC incorporating the 2005 ISUP modified biopsy Gleason score and CCL/core.