Abstract 1918: Lymphocyte content differs in normal ovaries and ovarian tumor stages in spontaneous ovarian cancer in the chicken
Authors: Bradaric Michael J. , Barua Animesh , Penumatsa Krishna , Bitterman Pincas , Abramowicz Jacques S. , Bahr Janice M. , Luborsky Judith L. 
Published: February 2011

Background: The immune system responds to tumor development. Ovarian cancer (OvCa) is lethal since it has no symptoms and is diagnosed in advanced stages. Therefore, studies of early OvCa are difficult in humans. The naturally occurring OvCa in chickens resembles human tumors both histologically and biochemically and affords an opportunity to study all stages of OvCa development. The goal of this study was to determine if there are differences in lymphocyte content among normal ovaries, early and late stage ovarian tumors, as a basis for understanding the role of immunity in OvCa development in women.

Methods: Hens (n=12) with reduced egg-laying rates (&lt;3 eggs per clutch) as an indicator of reduced ovarian function, and 2.5-3 years old, were evaluated by Gray scale trans-vaginal ultrasound to determine if they had normal or abnormal ovarian morphology. As a measure of neo-angiogenesis, blood flow velocity was measured by color Doppler ultrasound as the Resistive [RI] and pulsatility [PI] indices. Reduced RI and PI values are an indication of angiogenesis and were used as a surrogate marker of tumor development. The RI and PI values were compared to a previous study of 50 hens in which RI and PI values, Gray scale morphology and histopathology were evaluated to determine the values associated with ovarian tumors. Lymphocytes were isolated from whole normal ovaries, and early (I/II) and late stage (III/IV) ovarian tumors. Lymphocyte numbers were measured by flow cytometry using fluorochrome conjugated antibodies to avian CD4, CD8, and Bu1a (B cell marker). In another study, hens (n=25) were similarly scanned with ultrasound, and ovarian tissues were immunostained for with the same markers to identify lymphocyte location, and to confirm the flow cytometry results.

Results: Flow cytometric analyses showed that there were more B cells in early stage OvCa (mean ± SEM = 0.20% ± 0.10) and late stage OvCa (0.63% ± 0.35) than in normal ovaries (0.11% ± 0.03). There were less CD4 (0.57% ± 0.5) and CD8 (0.27% ± 0.10) T cells in early stage tumors than in both normal (CD4: 0.95% ± 0.036; CD8: 0.94% ± 0.51) and late stage-stage tumors (CD4: 0.98% ± 0.23; CD8: 1.02% ± 0.028). Immunohistochemistry confirmed that immune cells were in the ovarian stroma, and not in ovarian blood vessels. B cells were observed in clusters of ovarian stroma, while CD4 and CD8 T cells were uniformly distributed.

Conclusions: The results of this cross-sectional study suggest there are differences in the content of immune cells in both normal ovaries and ovarian tumors. There were more B cells in both early and late-stage ovarian tumors than in normal ovaries. Interestingly, early-stage tumors had the lowest number of T lymphocytes than either normal ovaries or late stage tumors suggesting there are differences in immune infiltration during tumor development.

Support: NIH R01AI055060, DOD OC073325 and Segal Foundation (JL); Prevent Cancer Foundation (AB)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1918.