Anti-tumor antibodies and ovarian cancer in Women and Hens

A40 Background: The high mortality rate of OVCA reflects a lack of early detection tests. Anti-tumor antibodies (aTAB) are a potential diagnostic for early detection of OVCA. Since there is no method to identify patients with early stage disease, it is difficult to validate aTAB as an early marker of OVCA. Laying hens are the only animal that spontaneously develops OVCA. We evaluated the association of anti-tumor antibodies with OVCA in humans and hens, in order to determine the feasibility of (a) aTAB as a diagnostic and (b) pre-clinical validation studies in hens.Methods: Sera were obtained from patients (ages 35-85, n=80) undergoing examination for gynecologic tumors and control women without ovarian pathology (ages 25-60, n=24). Normal ovarian and tumor tissues were obtained at surgery. Serum aTAB were detected by immunoassay described previously (Luborsky et al, 1990; Barua et al 2001). Two dimensional Western blots (2D-WB) were performed to identify potential antigens by standard methods (Barua et al, 2006). The aTAB were assessed similarly in sera from laying hens (2.5 years old, 16 hens with ovarian cancer, 18 normal control hens, 6 young hens for immunoassay control). Sections of hen ovary and tumors were stained with hematoxylin & eosin to evaluate tumor histology.Results: Significantly more patients with malignant ovarian cancer had aTABs than patients with malignant endometrial cancer (78% and 44%, respectively) or patients with benign ovarian tumors (29%) and controls (25%) (p≤0.001). The molecular weight and pI of immunoreactive spots in 2D-WB had major similarities and minor differences among patients. Significantly more hens with ovarian cancer had aTABs than control hens (65% and 22%, respectively) (p≤0.001). Serous, endometrioid, clear cell and poorly differentiated tumors were observed in hens and the histological appearances of these tumors were microscopically similar to humans. The primary reaction in 2D-WB was a common group at 50kD (pI 6-8) against proteins from both normal ovary and tumors suggesting that antigens are similar in humans and hens.Conclusion: The results suggest that anti-tumor antibodies are more prevalent in women and hens with malignant OVCA. Further study of the time course of anti-tumor antibody appearance in the hen will facilitate the validation of anti-tumor antibodies as a diagnostic marker for OVCA. Support: NIH R01-AI055060 and Rice Foundation.