The invention relates to the field of biology and medicine, specifically to oncology, and can be used for diagnosing prostate cancer. Use is made for this purpose of a novel prostate-cancer marker which can be identified in the undiluted urine of a patient and constitutes integrin-alpha V or a fragment thereof. A method of diagnosing prostate cancer, comprising identifying integrin-alpha V in the undiluted urine of a patient, and a kit for carrying out the diagnosis, comprising at least one antibody specific to integrin-alpha V, or a functional fragment thereof, are also proposed. The invention makes it possible to carry out a non-invasive diagnosis of prostate cancer using a simple, sensitive and reliable method which can be used under standard clinical laboratory conditions in inpatient or outpatient medical institutions.
