Matritech (Amex: MZT - News), a leading developer of protein-based diagnostic products for the early detection of cancer, today announced that the U.S. Patent and Trademark Office has issued the company U.S. Patent No. 6,936,424 covering methods of using the NMP66(TM) protein for the detection of breast cancer. Products covered by claims in this patent will be protected until the year 2020. This most recent patent issuance brings the number of U.S. patents owned or exclusively licensed to Matritech to 21. Matritech's patent portfolio also includes numerous foreign patents issued in Europe, Japan, and Canada.