The invention refers to the production of antibodies named F5 in a cancer carrier and the effect they exert on the development of guest's tumor. F5 may down regulate the proliferation and life of cancer cells regardless the histological nature of the malignancy and the stage of tumor growth. The novel antibody may be raised exclusively in a tumor-carrier guest by challenge with the immunoglobin antigen FIV Abs. This kind of immunization imitates at a certain extent the scheme of classical vaccination with an extern pathogen justifying thus by a semantic derogation the anti-cancer therapeutic vaccination name. The uniqueness of F5 is the result of the adjustment between the conventional antigen FIV to the reactivity in cancer known as premunition. Theoretical considerations and experimental data bring evidence of the efficiency of multi clonal F5 Abs in the treatment of primary or metastatic tumors. The anticancer effect of F5 is only possible as a result of the structural mimicry of the agent with the cancer autocrine growth factors. The blocking of cancer receptors with F5 Abs may produce regression of the primary or metastatic tumors, or arrest of cancer proliferation for indefinite periods of time or, according to circumstances to reduce quantitatively the radio-chemo therapy and the extension of surgical intervention in case of necessity.