Chemoprevention of spontaneous ovarian cancer in the domestic hen

The hen is an attractive animal model for in vivo testing of agents that thwart ovarian carcinogenesis because ovarian cancer in the domestic hen features clinical and molecular alterations that are similar to ovarian cancer in humans, including a high incidence of p53 mutations. The objective of the study was to test the potential ovarian cancer chemopreventive effect of the p53 stabilizing compound CP-31398 on hens that spontaneously present the ovarian cancer phenotype. Beginning at 79 wk of age, 576 egg-laying hens (Gallus domesticus) were randomized to diets containing different amounts of CP-31398 for 94 wk, 5 d, comprising a control group (C) (n = 144), which was fed a diet containing 0 ppm (mg/kg) of CP-31398; a low-dose treatment (LDT) group (n = 144), which was fed a diet containing 100 ppm of CP-31398; a moderate-dose treatment (MDT) group (n = 144) which was fed a diet containing 200 ppm of CP-31398; and a high-dose treatment (HDT) group (n = 144), which was fed a diet containing 300 ppm of CP-31398. Hens were killed at 174 wk of age to determine the incidence of ovarian and oviductal adenocarcinomas. Whereas the incidence of localized and metastatic ovarian cancers in the MDT and HDT groups was significantly lower (up to 77%) compared to levels in the C and LDT groups (P < 0.05), the incidence of oviductal cancer was unaffected by CP-31398. CP-31398 appears to be an effective tool for chemoprevention against ovarian malignancies, but does not appear to affect oviductal malignancies.

The hen as a model of ovarian cancer

The domestic laying hen is the only non-human animal that spontaneously develops ovarian cancer with a high prevalence. Hens ovulate prolifically, and this has made the hen intuitively appealing as a model of this disease in light of epidemiological evidence that ovulation rate is highly correlated with the risk of human ovarian cancer. As in women, ovarian cancer in the hen is age-related and it is also grossly and histologically similar to that in humans. In both women and hens, the cancer metastasizes to similar tissues with an accumulation of ascites fluid. Some aggressive ovarian cancers in women arise from cells in the oviduct; this is intriguing because ovarian cancers in the hen express an oviductal protein that is normally absent in the ovary.

Some observations on naturally occurring neoplasms of domestic fowls in the State of Victoria, Australia (1977-87)

In the 10 years to November 1987, 33 different types of naturally occurring neoplasms were diagnosed in 2281 domestic fowls submitted for necropsy examination. The most prevalent type was lymphoma (1825/2281 = 80%) including two cases in chickens from a flock free from Marek's disease virus, exogenous avian leukosis viruses and reticuloendotheliosis virus; the remaining lymphomas were diagnosed on gross and/or histological criteria as Marek's disease (1069) or lymphoid leukosis (754). Of the non-lymphoid neoplasms, leiomyomas of the ventral ligament of the oviduct (99) were the most common followed closely by metastatic abdominal adenocarcinomas (93) and haemangiomas or haemangiosarcomas (91). A large number of fibromas and fibrosarcomas (40), and a smaller number of myxomas and myxosarcomas (17) were observed. Three fibrosarcomas and two myxosarcomas were presented as metastatic abdominal neoplasms, and two fibromas and seven myxomas were found on the rostral extremity of the upper beak of hens, including five cases of myxoma from one flock. Other less prevalent neoplasms described were myelocytomas or myeloblastomas (12), avian keratoacanthomas (11), granulosa-theca cell tumours (11), oviduct adenomatosis and adenocarcinomas (10) and ovarian adenocarcinomas (8). Small numbers of some neoplasms or well-characterized variants were encountered, namely histiocytic sarcomas (5), lipomas (4), liposarcomas (2), reticulum cell sarcomas (3), plasmacytomas (3), intracutaneous keratinizing epitheliomas (3), feather folliculomas (2), proventricular adenomas (2), hepatocellular adenocarcinomas (2), cholangiocellular adenomas and adenocarcinomas (6), pancreatic adenocarcinomas (3), nephroblastomas (7), astrocytomas (5), pinealomas (3), Schwannomas (3) and multifocal melanomas (3). Single examples were found of osteoma, osteosarcoma, rhabdomyosarcoma, leiomyoma of the gizzard wall, intestinal adenocarcinoma, renal adenocarcinoma, adrenocortical adenoma and ultimobranchial cyst.

Nodular lesions found in Irish poultry during veterinary inspection at poultry meat plants

This investigation was carried out on three categories of old birds including cage layers, game birds (ducks and pheasants) and free-range birds. During the study 137,918 carcasses were examined grossly at slaughterhouses and 2040 condemned carcasses underwent detailed post-mortem examination. A total of 419 of the condemned carcasses had nodular lesions. On histological examination of the nodular lesions, one case of bacterial granuloma in a free-range layer, two cases of parasitic granulomata in ducks, 337 cases of different types of tumours and 79 cases of miscellaneous lesions with a nodular appearance were diagnosed. Overall, there was a total condemnation rate of 1.5%. The prevalence of various types of nodular lesions was discussed.

Ovarian tumor expression of an oviductal protein in the hen: a model for human serous ovarian adenocarcinoma

OBJECTIVE

We hypothesized that ovarian tumors without oviductal involvement would not express the oviductal protein ovalbumin, the major protein found in the magnum of the hen's oviduct.

METHODS

On the basis of gross visual examination, tissues samples were removed from hens determined to have ovarian tumors and were processed, embedded in paraffin, sectioned, mounted on glass slides, and stained with hematoxylin and eosin. Ovarian tumors and other peritoneal lesions were evaluated histologically. Paraffin sections of ovarian and oviductal tissue were deparaffinized and evaluated for the protein expression of ovalbumin, proliferating cell nuclear antigen (PCNA), and progesterone receptor (PR).

RESULTS

Hens with ovarian adenocarcinoma without (n = 10) or with (n = 6) oviductal involvement were positive for ovalbumin in the ovary. Ovary sections from normal hens (n = 9) were negative, and oviductal sections from normal hens (n = 3) were positive for ovalbumin. Expression of PCNA protein was abundant in all ovarian tumors (16 of 16). Oviductal epithelial cells strongly expressed PCNA protein. Expression of PR was observed in 9 of 14 ovarian tumors.

CONCLUSION

The presence of ovalbumin in ovarian tumors in the absence of any oviductal involvement suggests that ovarian tumors dedifferentiate during the disease process and thereby resemble serous-type ovarian tumors in women.

Immunohistochemical expression of molecular markers in an avian model: a potential model for preclinical evaluation of agents for ovarian cancer chemoprevention

OBJECTIVE

A significant obstacle confronting the evaluation of potential chemopreventive compounds in ovarian carcinoma is the absence of an animal model of spontaneous ovarian carcinogenesis. A potential model of adenocarcinoma has been described in the laying hen (Gallus domesticus). The purpose of this study was to evaluate the immunohistochemical expression of available antibodies that have been utilized in chemoprevention studies in this potential model of epithelial carcinoma.

METHODS

Two hundred 2-year-old hens were sacrificed at Auburn University in accordance with IUACUC guidelines. Of these hens, 8 animals were thought grossly to have ovarian carcinoma and ascites. The tumors from these 8 hens were fixed in neutral-buffered formalin and processed to paraffin blocks. Hematoxylin and eosin stains were used to document the histologic presence of adenocarcinoma. Immunohistochemical evaluation for expression of antigen was performed using the following antibodies: CA125, CEA, cytokeratin, EGFR, erbB-2, Ki-67, Lewis Y, p27, PCNA, Tag 72, TGF-alpha, Muc 1, and Muc 2.

RESULTS

Upon microscopic examination by a pathologist eight specimens were documented as adenocarcinomas. Several antibodies to antigens that are frequently expressed in human ovarian cancer were cross-reactive in the laying hen. Of these, cytokeratin AE1/AE3, pan cytokeratin, EGFR, Lewis Y, CEA, Tag 72, and erbB-2 stained the chicken carcinomas. EGFR and p185erbB-2 stained diffusely, and cytokeratin AE1/AE3, pan cytokeratin, Lewis Y, CEA, and Tag 72 were focally positive in the tumor. The aforementioned antibodies which have been useful as surrogate endpoints in chemoprevention trials and which also stained the chicken carcinomas included PCNA, p27, and TGF-alpha Antibodies that were not cross-reactive include CA 125, Ki-67, Muc 1, and Muc 2.

CONCLUSION

The data presented in this pilot study support the potential utility of an avian model of spontaneously arising adenocarcinoma in which to study chemopreventive agents. More importantly, the influence of chemoprevention protocols on the expression of relevant antigens can be determined using available antibodies that are cross-reactive in this model. Thus, changes in the phenotypic expression of surrogate endpoint biomarkers as identified by cross-reactive antibodies can aid in the development of chemoprevention trials for human ovarian cancer.

Involvement of gicerin, a cell adhesion molecule, in development and regeneration of oviduct and metastasis of oviductal adenocarcinomas of the chicken

Gicerin is a novel cell adhesion molecule in the immunoglobulin superfamily and has both homophilic adhesion and heterophilic adhesive activity to neurite outgrowth factor (NOF), an extracellular matrix protein in the laminin family. We investigated the possible involvement of gicerin in oviductal development, regeneration, and metastasis of oviductal adenocarcinomas of the chicken. In the oviductal epithelium, gicerin was expressed strongly during development, disappeared after maturation, and reappeared during regeneration. NOF was constitutively expressed in the basement membrane of the epithelium. These molecules were expressed strongly in oviductal adenocarcinomas in both primary and metastatic lesions in the mesentery. An anti-gicerin antibody inhibited the attachment of adenocarcinoma cells to the mesentery in vitro. Many cells migrated from adenocarcinoma tissues on NOF, which were inhibited by an anti-gicerin antibody. These results suggest that gicerin might play a role in oviductal development and regeneration and also in the metastasis of adenocarcinomas.