Abstract A144: Anti-NMP antibodies in association with tumor-associated neoangiogenesis detects ovarian cancer at early stage
Authors: Barua Animesh , Abramowicz Jacques S. , Bitterman Pincas , Bahr Janice M. , Braderic Michael J. , Edassery Seby L. , Hales Dale B. , Luborsky Judith L. 
Published: May 2012

Background: The lack of an effective early detection test is one of the main reasons of high mortality due to ovarian cancer (OVCA). Changes in nuclear morphology including nuclear matrix proteins (NMPs) followed by the establishment of tumor associated neoangiogenesis (TAN) are the two earlier events in malignant transformation and progression of OVCA. NMPs are released in circulation, elicit autoimmune responses and anti-NMP antibodies are produced. Anti-NMP antibodies and ovarian TAN represent the potential marker of early stage OVCA. Identification of Patients at early stage OVCA is very difficult and laying hens have been shown to develop spontaneous OVCA with histopathology similar to humans.

Objectives: The goals of the study were to determine the prevalence of anti-NMP antibodies and the feasibility of Doppler ultrasound (DUS) imaging in detecting ovarian TAN related to early stage OVCA in laying hens.

Materials and Methods: Experiment-1: White Leghorn laying hens (3 years old with normal, low or stopped egg-laying) were scanned by DUS, sera were collected, hens were euthanized, ovarian tissues were processed for paraffin and frozen sections, and NMP extraction. Ovarian tumors with their stages were confirmed at gross and routine histology. Samples were divided into 3 groups: hens with normal ovaries (n= 8, control), with early stage OVCA [microscopic or tumors limited to the ovaries, n =7], with late stage OVCA (n = 5), with non-tumor ovarian abnormalities (atrophied ovaries, n = 2) and with non-ovarian tumors (gastrointestinal tumors, GI, n = 2). Sera were tested for the presence of anti-NMP antibodies against extracted ovarian NMP antigens by immunoassay and immunoreactivities were confirmed by 2D-Western blot (WB). Ovarian expression of TAN markers (VEGF and αvβ-integrins) was determined by immunohistochemistry (IHC). Experiment-2: Hens without any detectable ovarian abnormality were selected by DUS and divided into hens with (n =6) or without circulating anti-NMP antibodies (n = 3). Hens were monitored by DUS scanning at 15 week interval until they developed ovarian TAN or up to 45weeks and confirmed by gross, histology and IHC.

Results: Sera from normal hens were negative for anti-NMP antibodies while 72% hens with early and 80% with late stage OVCA were positive against ovarian NMP antigens. Hens with ovarian atrophy or with GI tumors were negative for anti-NMP antibodies suggesting that these antibodies in OVCA hens are ovarian tumor specific. While no reactivity of sera from normal hens was observed in 2D-WB, sera from hens with early OVCA or late stage OVCA reacted against several ovarian NMP antigens with molecular weight range between 15–25 and 40–50 (kDa). In longitudinal study, 5 out 6 hens developed ovarian TAN between 30–45 weeks from initial scan.

Conclusion: Anti-NMP antibodies appear in circulation in association with preneoplastic and microscopic ovarian lesions followed by the development of ovarian TAN before the tumor becomes detectable by ultrasound imaging. Anti-NMP antibodies together with ovarian TAN may constitute an early detection tool for OVCA.

Citation Information: Cancer Prev Res 2010;3(1 Suppl):A144.