The present invention aims to provide a novel reagent for tumor testing and a novel pharmaceutical composition for tumor prevention.The present invention provides a reagent for tumor detection, which comprises a probe for the FEAT gene or amplification primers for the FEAT gene, or an antibody against the FEAT protein or a fragment of the antibody. Moreover, the present invention also provides a pharmaceutical composition for tumor prevention, which is configured to use the FEAT gene or the FEAT protein as a tumor marker to thereby recognize tumor cells.
