Abstract: The invention relates to a new method for combating tumor illnesses through the use of molecular biological associations during formation of the tumor. The aim of the invention is to develop a method for controlling the regulation of ?-catenine in body cells. The object of the invention is a new protein which bonds to ?-catenine and the subsequent cytoplasmic decomposition of said protein. This protein has the amino-acid sequence according to FIG. 1 and is designated as conductine. Agents for diagnosing and treating tumor illnesses are developed from the occurrence and the action of conductine in body cells.