Iraqi Journal of Veterinary Sciences

Canine osteosarcoma is an extremely malignant bone tumor that often arises in the bones of the limbs. It is a highly metastatic disease distinguished by proliferative bone lesions and a tendency for pulmonary metastasis. Overexpression of proliferative proteins are associated with bad prognosis in human osteosarcoma. Here, we tested the expression of the different proliferative proteins (p53, p16, vimentin, and mdm2) in nine archival samples with canine osteosarcoma. Paraffin-embedded tissue sections were confirmed by histopathology and stained by immunohistochemistry for p53, p16, vimentin and mdm2. Positive expression of these proteins was evaluated as the ratio of positive cancer cells and the intensity staining was assessed in several areas. Histopathologically, 95% of samples were grade II and III. All high-grade osteosarcomas were particularly cellular. The cancer cells were generally large spindle-shaped and large nucleus with distribution of osteoid between the cancer cells. Immunohistochemical detection of p53, p16, vimentin and mdm2 was 89%, 56%, 78%, and 89% of samples respectively. The staining intensity for p53, p16, vimentin and mdm2 was particularly nuclear in 81%, 66%, 78%, and 79% of the cancer cells respectively. Our present work suggests that p53, p16, vimentin, and mdm2 were detected in grade III canine osteosarcomas samples. In addition, these proliferative markers are the significant biomarkers in canine osteosarcomas and can be used as a predictor for diagnostic and prognostic value and allowing cancer differentiation. This primary data supports that both canine and human osteosarcomas share same molecular characters which are approved by expression of proliferative genes.

We aim in the current study to investigate the pathology and incidence of tumors that are excised surgically in Veterinary Teaching Hospital. This study collected the tissue samples from animals from 1 October 2020 until 1 April 2021. These samples were collected from animals that undergo surgical procedures to remove neoplastic growths in their body. After tissue grossing, samples were collected from tumor mass, then fixed in neutral buffered 10% formalin for 72 hours, then processed to embedded in paraffin wax. A routine Harris’s hematoxylin and eosin stain were also used, histochemical stains such as Masson’s trichrome and PAS techniques were used as needed. In exceptional cases, IHC protocol was used for diagnostic steps to some types of tumors included in the current study. The antibodies that were used are Vimentin for canine osteosarcoma, P53 for squamous cell carcinoma, Mdm2 for ovine pulmonary adenocarcinoma, and CD10 for neoplastic lymphocytes. The result of the current study showed that the prevalence of tumor recorded was Marek’s diseases 22.8%, squamous cell carcinoma 22.8%, ovine pulmonary adenocarcinoma 15.4%, third eyelid adenoma 15.4%, canine osteosarcomas 7.4%, venereal transmitting tumors 7.4%, and feline mammary gland tumor 7.4%. Histological examination of feline mammary gland tumor composed from server infiltration of neoplastic cells, these neoplastic cells identified as lymphocytes in a fibrous stroma. Third eyelid adenomas in cats and dogs were composed of well-demarcated nodules containing neoplastic sebaceous cells present in glandular form and combined by hyperplasia of epidermis extended inside the neoplastic mass. Venereal transmitting tumor in cat composed from cells with a round to oval shape and the cytoplasm is poorly defined by routine stain, with dense fibrous tissue. Osteosarcoma in a dog has a pleomorphic nature with an anaplastic form composed of islands of osteoid materials, and the tumor is composed of three types of osteoblast, chondroblast, and fibroblast. Pulmonary adenocarcinoma in sheep composed of a nodular formation containing dense collagen fiber deposition with transformation of cells lining alveoli into cuboidal or columnar cells can also be observed in other air passages. Squamous cell carcinomas are primarily found in skin lesions associated with the formation of pathognomic lesions known as keratin pearls. This lesion is composed of the acentric layer of keratin produced by neoplastic keratinocytes. Marek’s disease was observed in visceral organs such as liver, lung, kidney, intestines, and spleen composed from pleomorphic lymphocytes, diffusely proliferating small-to-medium-size lymphoblast. In conclusion, the incidence of tumor in animals that attending Veterinary Teaching Hospital belong to the College of Veterinary Medicine, the University of Mosul was in general high in comparison to other studies in Iraq and other countries, this high incidence should pay attention to the causes of these cancerous conditions and their relation to environmental etiology. 

Ovine pulmonary adenocarcinoma (OPA) is a cancer disease in sheep caused by Jaagsiekte sheep retrovirus (JSRV). The retrovirus is distinctive among viruses for inducing carcinogenesis of lung epithelial cells and cause a lung adenocarcinoma. OPA has numerous characters same as human lung adenocarcinoma, involving a similar histological organization and motivation of most cell signalling pathways. P53 pathway is frequently changed in human lung adenocarcinoma, in specific due to the increase expression of MDM2 and it is the main regulator of P53. Here, we have a go at something new to confirm the possible expression of p53 and MDM2 in OPA as a translational animal model for human lung adenocarcinoma, and to identify the correlation between P53 and MDM2 expression. 1645 of lung samples from different breeds were macroscopically tested. OPA was recognized in 21 samples and further assessed by histology and immunohistochemistry. Histologically, proliferative cancer foci were distributed and contained of cuboidal or columnar cells and arising papillary to acinar patterns. The nuclear expression of P53 and MDM2 was detected in 90% and 95% respectively in the cancer epithelial cells of OPA respectively. Detectable immunoreactivity for P53 was detected in 6 out of 7 grade I, 7 out of 8 grade II, and 6 out of 6 grade III cancers. In reverse with P53, MDM2 was detected in 18 cases with moderate and high expression. In addition, there was statistically relationship between both protein expressions. Our findings suggested that overexpression of MDM2 plays an essential part in OPA carcinogenesis and is dependable on the grading system, and its overexpression can be convinced by P53 expression.