This invention provides a novel membrane-type serine protease (designated MT-SP1) elevated expression of which is associated with cancer. In one embodiment, this invention provides a method obtaining a prognosis or of detecting or staging a cancer in an organism. The method involves providing a biological sample from the organism and detecting the level of a membrane type serine protease 1 (MT-SP1) in the sample, where an elevated level of the membrane-type serine protease, as compared to the level of the protease in a biological sample from a normal healthy organism indicates the presence or stage of the cancer.