When patients present to their physician with symptoms of cancer at a later stage of development, survival tends to be poorer. Earlier diagnosis of cancer is expected to provide improved survival of patients due to earlier treatment intervention. However, implementation of this screening process is impaired by access and by cost. A simple and inexpensive test would serve as a screening tool that could be safely repeated at regular intervals to identify persons for whom more expensive and less accessible diagnostic investigations might become more appropriately directed. The specificity for an enzyme that increases markedly in cancer tissue, and the ease of administration of an already licensed pharmaceutical prescription product, amantadine hydrochloride, would appear to provide promise of such a desirable screening test.