Immunohistochemical Studies of Round Cell Tumours in Canines

Assessment of cell kinetics is the field of interest in modern oncology. A total of 24 samples were collected from genital organs and skin of canines in Hyderabad to carryout the immunohistochemical studies. Chromosome nucleolar organizer regions stained with silver stain (AgNORs), and anti-proliferating cell nuclear antigen (PCNA) were evaluated as indicators of prognosis for neoplasms. AgNORs estimated in 100 cells, and PCNA-labeled fraction estimated in five high power fields (HPFs) were counted and were significantly different in various tumors. Among 24 samples, 18 samples were collected from genital organs and revealed round tumour cells arranged in sheets with indistinct cytoplasm with few mitotic figures indicating the transmissible venereal tumour. The AgNOR and PCNA counts were 12.46±1.76 and 364.12±12.96 respectively. 4 samples collected from skin were canine cutaeneous histiocytoma revealing uniform sheets of cells infiltrated in dermis and sub cutis displacing collagen fibers. The cells at epidermis were round to ovoid in shape arranged in rows with large nucleus and pale cytoplasm. The AgNOR and PCNA counts were 16.89±2.58 and 437.96±8.54 respectively. The 2 samples collected from hind limbs were mast cell tumours with proliferating mast cells in round, ovoid in shape, well defined cytoplasmic borders, crowded cytoplasmic metachromatic granules that stained blue with toludene blue. The cells are loosely arranged and separated by large collagen fibers. The AgNOR and PCNA counts were 3.23±1.46 and 267.96±10.54 respectively. Canine cutaeneous histiocytoma showed highest AgNOR and PCNA counts. There exist a significant (P<0.01) correlation between the AgNOR and PCNA counts and increased counts associated with malignancy and poor prognosis.