Abstract

Antitumor antibodies are associated with tumors in human cancers. There is relatively little information on the timing and progression of antibody response to tumors. The objective of the study was to determine if spontaneous ovarian cancer in the egg-laying hen is associated with antitumor antibodies. Antibodies were detected by immunoassay and immunoblotting using proteins from normal ovary and ovarian tumors. Candidate antigens were identified by mass spectrometry of immunoreactive spots cut from 2-dimensional gels and Western blot. Antitumor (serum reacting against tumor ovarian extract) and antiovarian (serum reacting against normal ovarian extract) antibodies were significantly associated with ovarian cancer (67%; P ≤ 0.001) compared with normal control hens. Hens with abnormal histology but no gross tumor had antitumor antibodies (63%; P ≤ 0.025) but not antiovarian antibodies. There were common as well as different immunoreactions against normal ovary and homologous and heterologous tumor proteins in 2-dimensional Western blots. The candidate antigens included those commonly associated with human cancers and other diseases such as vimentin, apolipoprotein A1, Annexinn II, enolase, DJ-1, and so on. The results suggest that antitumor antibodies are associated with ovarian cancer in hens, similar to human ovarian cancer. The egg-laying hen may be a model for understanding the antitumor humoral immune response, particularly at early tumor stages that are not readily accessible in human ovarian cancer.