IMMUNOPHENOTYPIC CLASSIFICATION OF CANINE MALIGNANT-LYMPHOMA ON FORMALIN-FIXED PARAFFIN WAX-EMBEDDED TISSUE BY MEANS OF CD3 AND CD79A CELL MARKERS

Canine malignant lymphoma (CML) is a common lymphoid tumour, Identific ation of the immunophenotype is of prognostic importance; T-cell lymph omas have a worse prognosis than B-cell lymphomas. Until recently, ide ntification of T- or B-cell lymphomas was undertaken by means of flow cytometry or fluorescent immunocytochemistry on frozen sections. Whils t valid in the research field, these methods are impractical for routi ne diagnostic histopathology in CML. Commercially available GD3 antibo dy has been successfully employed in T-cell identification in dogs in formalin-fixed paraffin wax-embedded tissue sections, but the lack of a B-cell marker has been a hindrance until the recent introduction of a commercially available pan-B cell marker, CD79a (DAKO M7051), suitab le for diagnostic application upon formalin-fixed paraffin wax-embedde d material. Antibody markers to GD3 and GD79a show cross-reactivity ac ross species lines for B cells and T cells respectively. In this group of five selected canine cases, two were identified as B-cell and the other three as T-cell lymphoma, by means of CD3 and CD79a. To the best of our knowledge application of CD79a in cases of CML has not been re ported.