Although bladder cancer (BC) is a common urological disease, there are deficiencies of current methods used for its detection, especially the non-invasive ones are missing. We have recently discovered a novel biomarker, circulating cellular-free (ccf) alpha satellite DNA, that enables timely and efficient diagnosis of BC from the plasma of the patients (mostly from Italy). Alpha satellite DNA is a major human satellite DNA whose aberrant overexpression in cancers and increased release into the circulation is proposed. Within the proposed project, using sensitive digital PCR, we plan to expand on our biomarker research by: 1) using our established procedure on plasma from BC patients and healthy control cohorts, make more solid the case of ccf satellite DNA as a reliable biomarker for BC diagnosis, while assessing the possible universality of the biomarker by checking its applicability for the Croatian population, in addition to the Italian. 2) establish the procedure for determining ccf satellite DNA in urine from the BC patients as well as from the healthy control, and consequently establish whether urine can serve as a reliable sample source for ccf alpha satellite DNA biomarker. 3) assess whether ccf alpha satellite DNA can be employed as a reliable biomarker for early diagnosis of other types of urinary tract tumors (such as kidney, prostate etc.) 4) follow the ccf alpha satellite DNA biomarker’s levels in BC patients undergoing therapeutic procedure to evaluate the usefulness of the biomarker in assessing the course of therapy. The proposed project will characterize the ccf alpha satellite DNA biomarker in a much deeper and broader manner, which would facilitate its translation into clinical medical practice.