Immunocytochemical and cytomorphometric diagnostics of malignant lymphomas in dogs

Monoclonal antibodies are used to determine whether tumour cells of malignant lymphomas in dogs belong to B or T lymphocytes, to define the proliferative potential of the cells (Ki-67 protein, PCNA antigen, AgNORs) and to demonstrate effects of potential mutations of the p53 gene. Among 76 examined cases, 58 tumours (76.32%) were lymphomas of lymphocytes B; the remaining 18 (23.68%) cases were qualified as originating from lymphocytes T. Lymphomas with a high grade of malignancy prevailed (54 cases, 71.06%), and also in this group of lymphomas of lymphocytes B prevailed (48 cases, 88.89%). The remaining 22 cases (28.95%) represented less malignant lymphomas, including 12 cases of lymphocyte T lymphomas (54.54%). In the group of highly malignant lymphomas, high values of Ki- 67 and PCNA indices were demonstrated. Positive reactions of low intensity with anti-p53 protein were obtained in 31 cases (57.4%) of highly malignant and in 9 cases (40.9%) of less malignant lymphomas. In dogs, most frequently malignant centroblastic B receptor lymphomas are encountered. The extent of malignancy is determined by young forms and their proliferation exponents are Ki-67 and PCNA proteins.