Abstract: The present invention relates to a pharmaceutical composition for treating a radiation- or drug-resistant cancer, containing an agent capable of inhibiting the expression of hepatoma-derived growth factor (HDGF)-related protein-3 (HRP-3), a method of treating a radiation- or drug-resistant cancer by administering the pharmaceutical composition, and the use of an HRP-3 inhibitor for preparing an agent for treating a radiation- or drug-resistant cancer. The use of the pharmaceutical composition of the present invention enables to treat a resistant cancer in combination with a conventional anticancer chemotherapy or radiotherapy. Accordingly, the pharmaceutical composition of the present invention can reduce both the costs for developing anticancer agents against resistant cancers and the costs for treating cancers in patients, thus being useful for the economic and effective treatment of resistant cancers.

Abstract: The present invention provides a method for generating a functionally modifying antibody to an ion channel comprising immunizing a host with a cyclic peptide comprising at least part of an extracellular sequence of said ion channel.