CLINICAL PATHOLOGICAL FEATURES OF CANINE HEMATOPOIETIC NEOPLASMS ASSESSED VIA FLOW CYTOMETRY

Flow cytometry (FC) is an advanced diagnostic technique widely used in human medicine to confirm, classify and stage hematopoietic neoplasms (HNs): it supplies an objective evaluation of the size and internal complexity of the cells and identifies the antigenic pattern expressed by each cell, which is specific for cellular lineage and maturative stage. FC is presently spreading also in veterinary medicine and is mostly used to confirm the diagnosis and determine the immunophenotype of canine HNs. Aim of this study was to apply FC to the study of specific clinical pathological features of canine HNs. In particular, we focused on three points: 1) staging of diffuse large B-cell lymphoma. We validated a FC technique to assess peripheral blood and bone marrow infiltration by neoplastic cells and proved its prognostic value. 2) antigen aberrancies. We investigated the prognostic role of specific antigen aberrancies in canine lymphomas and found the dogs with CD4+CD8+ T-cell lymphomas had a poorer prognosis compared to other T-cell aberrant lymphomas. In addition, we highlighted an important diagnostic role for antigen aberrancies in canine small clear cell lymphoma. 3) CD44 expression. We proved that CD44, which has a role in the pathogenesis and dissemination of many human and canine neoplasms, is expressed at different degrees on neoplastic cells from different canine HNs, with acute leukemias showing the highest degree of expression. Overall, our results suggest that FC can be a useful tool not only to confirm the diagnosis and assess the immunophenotype of canine HNs, but also to assess clinical pathological aspects and additional prognostic parameters specific for the neoplastic subtype identified.