Expressional profiling and clinical relevance of RNase κ in prostate cancer: a novel indicator of favorable progression-free survival

Considering the unmet need for novel molecular tumor markers capable of improving prostate cancer (CaP) patients' management along with the fruitful results regarding the future use of ribonucleases (RNases) as molecular diagnostic and prognostic markers in CaP, we aimed to study the expressional profile of RNase kappa in CaP and BPH and to investigate its clinical significance in CaP. Total RNA was extracted from 212 prostatic tissue samples (101 BPH and 111 CaP) and, following cDNA synthesis, quantitative real-time PCR (qPCR) was performed for the expressional quantification of RNase kappa. Extensive statistical analysis, including bootstrap resampling, was performed to investigate the differential expression of RNase kappa in patients with BPH and CaP and its associations with patients' clinicopathological and survival data. RNase kappa was significantly downregulated (P = 0.002) in CaP patients compared to BPH ones. RNase kappa overexpression was associated with decreased risk of CaP development and can discriminate between CaP and BPH independently of serum PSA levels (crude odds ratio = 0.93, P = 0.001). RNase kappa upregulation was also associated with less advanced (P = 0.018) and less aggressive (P = 0.001) tumors as well as with longer progression-free survival (PFS) (P = 0.003). Finally univariate bootstrap Cox regression confirmed that RNase kappa was associated with favorable prognosis (HR = 0.85, P = 0.002). RNase kappa is a biomarker of favorable prognosis in CaP, which is significantly associated with less advanced and aggressive disease, as well as with enhanced PFS.