A Prospective, Single-centre，Single-blinded Study of PROUD for Prostate Carcinoma Diagnosis

The traditional diagnostic methods of PC include serum PSA and prostatic biopsy (PB). To screen the PC in high risk population, PSA is commonly used. The early detection of PC is actually carried out by the association of digital rectal examination (DRE) and serum total prostate-specific antigen (tPSA) level. The usual upper limit for tPSA is 4 ng ml-1. However, between 4 and 10 ng ml-1, there exists a diagnostic grey zone with an estimated probability of only 40% of PC in men with normal findings on DRE. Prostrate cancer can only be accurately differentiated from benign prostate hyperplasia(BPH) and prostatitis by pathological proof, usually obtained by subsequent invasive PB. To refine the indications for PB, and therefore to reduce morbidity, new indicators based on tPSA were developed: age-adjusted tPSA cutoffs, tPSA velocity or tPSA density where the elevated tPSA is indexed to the gland size. The most commonly used indicator is free/total PSA ratio (f/tPSA), which may help to predict PC or BPH in its extreme values. However, the probability of PC at biopsy among men with a PSA value between 4 and 10 ng ml-1 and normal findings on DRE ranged from 56% for men with an f/tPSA ratio of \<10% to 8% for men with a ratio \>25%, underlying the lack of accuracy of the f/tPSA indicator. PB is the "gold standard" diagnostic procedure, which is invasive, uncomfortable and with possible adverse side effects as local bleeding and infectious complications including drug resistant bacterial strains. Furthermore, repeated tissue biopsy is needed in some cases for the missed diagnosis of PC, in the other hand, causing over diagnosis of the insignificant clinical PC cases. The difficulty of estimating the risk of PC when there is a suspicious DRE without nodule, when tPSA ranges between 4 and 10 ng ml-1 or when f/tPSA has an average value (between 15 and 25%), taken together with the morbidity due to PB, highlights the need of new predictive markers for PC. In urine samples, it is reported than whole-genome gene expression analysis, as noninvasive method, obtained from PC, BPH,and control groups by using the microarray system, showed the differences of gene expression profiles.To improve the specificity of prostate cancer diagnosis, prostate-cancer-specific markers, such as prostate cancer gene 3 (PCA3),are needed. The strong association between PCA3 mRNA overexpression and malignant transformation of prostate epithelium indicates its potential as a diagnostic biomarker. The PCA3 test of PC has a sensitivity ranged from 47%-69% and specificity from 72%-83%. Copy number variations (CNVs) refers to the ongoing acquisition of genomic alterations ranging from point mutations to gross chromosomal rearrangements, is a hallmark of cancer which is found in 60-80% of human cancer, and it positively correlates with high tumor stage, poor prognosis, metastasis and therapeutic resistance. Several researches have investigated the value of detecting chromosomal instability with sWGS in either cell-free (cf)DNA or genomic DNA as a noninvasive diagnostic method for cancers and yielded quite fine results. Our previous research has also proved the PROUD model reached performance of AUC=0.928, with sensitivity, specificity and accuracy of 82.5%, 96.9% and 89.0%, respectively. This test also showed superiority in diagnosing upper tract urothelial carcinoma compared with urinary cytology test. Here we intended to conduct a prospective, multicenter, single-blinded research to further validate the value of PROUD in diagnosing PC by analyzing the CNV level of patient DNA extracted from urine exfoliated cells.