A circulating miRNA signature to help prognosticate at prostate cancer diagnosis.

108 Background: Prostate cancer (PCa) is the most commonly diagnosed cancer in men. Around 80% of PCas are diagnosed as early, localised stage yet a subset of these will metastasise and eventually prove fatal. Management decisions are based on risk stratification systems. However, these systems are not able to clearly distinguish indolent from aggressive PCa’s and as a result many patients with indolent cancers may be over treated. Circulating microRNAs (miRNA) may be an easily accessible, suitable biomarker to distinguish true indolent from clinically significant early prostate cancers (PCa) thus reducing overtreatments. Methods: Blood samples from 24 men with benign prostatic hypertrophy (BPH, n = 8), localised PCa (n = 8) or metastatic PCa (n = 8) were collected at time of diagnosis. All men had intact prostates and were naïve to any endocrine or other cancer therapy. A platform of circulating miRNAs were analysed in serum using Abcam Firefly technology. Data collected were independently verified using real-time qPCR (Exiqon). The miRNAs identified as being significantly different between groups were then analysed in a published dataset. Results: Serum levels of seven of the miRs examined were significantly different in patients with prostate cancer compared to control across both platforms (miR-10b, miR-125b, miR-210, miR-21, miR-378a, miR-483 and miR93 all with P values < 0.005). A further four miRNAs could differentiate between the benign and metastatic cohorts (miR-126 P = 0.008, miR-150 P = 0.05, miR375 P = 0.007). Kaplein-Meier analysis further identified that the serum levels of four miRNAs showed significant association with survival rates (miR-21 P = 0.032, miR-126 P = 0.032, miR-150 P = 0.032, miR-93 P = 0.019). On examination in a cohort of 280 men from The Cancer Genome Atlas (TCGA), four miRs from the cohort had significantly different expression in patients who eventually relapsed (miR-21 P = 0.048, miR-375 P = 0.021, miR-210 P = 0.0003, miR-93 P = 0.008) Conclusions: Our circulating miRNA based signature could be used to stratify men at prostate cancer diagnosis and help identify those who are likely to harbour micro metastases and would benefit more from an early radical treatment. The data is being validated in larger cohorts.