Abstract: A method of treating cancers by administering to a patient an anti-tumor effective amount ot at least one of a thermostable macromolecular antigen complex or a fragment of such a complex which is interspecific for microorganisms of the Mycobacteria, Nocardia and Corynebacteria group and which exhibits after immunoelectrophoresis an immunoelectrophoretic precipitation pattern corresponding to that of the antigen complex 60 of Mycobacteria bovis Calmette Guerin Bacillus strain. Preferably, the patient is also treated with an additional therapeutic agent which is specific against the patient's cancer such as a tumoral antigen or a non-proliferative tumor cell.