Proteome analysis has rapidly developed in the post-genome era and is widely accepted as a complementary technology to genetic profiling. Sera from tumor patients contain tumor specific antibodies directly against antigenic proteins. Immunoproteomics, which defines the subset of proteins involved in the immune response, holds considerable promise for the discovery of tumor-associated antigens, suggesting that this approach may be a useful tool for identification of prognostic, diagnostic markers and novel therapeutic targets. Recently, various different approaches are developed to identify tumor-associated antigens by autoantibodies from tumor patients' sera. More than one hundred tumor-associated antigens have been found in various tumors by with antibody-based strategy nowadays. However, some autoantibodies are also found in health subjects, even some of them with high antibody occurrence. So, it is necessary to undergo sufficiently detailed validation schemes for these novel tumor-associated antigens.