The purpose of the present invention is to identify a cancer antigen protein specifically expressed on the surface of cancer cells and to provide a use for an antibody that targets said cancer antigen protein as an agent for treating and/or preventing cancer. The present invention relates to a pharmaceutical composition and the like for treating and/or preventing cancer. The pharmaceutical composition is characterized by comprising the following as active ingredients: an MCEMP1 protein comprising any of the amino acids sequences represented by an even sequence number among SEQ ID NOs. 2-8 or an amino acid sequence having at least 80% sequence identity with these amino acid sequences, or a fragment of said MCEMP1 protein containing 7 or more continuous amino acids； and an antibody having immunological reactivity or a fragment thereof.
