Correlations between numerical chromosomal aberrations in the tumor and peripheral blood in canine lymphoma

Lymphoma is the most frequently diagnosed hematopoietic malignancy in dogs. Untreated, the survival times are approximately one month. Chemotherapy is the current standard of care and can initiate and temporarily maintain remission, with average remission times of one year. Canine lymphoma is an established model of human non-Hodgkin's lymphoma, and studying this disease in dogs can provide insight to both human and canine disease. Cytogenetic abnormalities can aid in diagnosing tumors as well as in giving a more accurate prognosis for the specific mutations present. Evaluating peripheral lymphocytes instead of tumor cells is less invasive for the affected dog and technically easier. This study was designed to investigate a correspondence between numerical aberrations detected in the tumor and the peripheral blood in dogs with lymphoma. Twenty-five dogs with lymphoma had one lymph node excised, a peripheral blood sample drawn, and a bone marrow aspirate performed. Portions of the lymph node were submitted for immunophenotyping and cytogenetic analysis. The peripheral blood sample was cultured for cytogenetic analysis and the bone marrow aspirate was used for staging purposes. A significant correspondence between the numerical aberrations in the tumor and the peripheral blood was found. The findings in this study pave the way toward an alternative method for evaluating lymphoma. When tumor analysis is not possible, the peripheral blood offers a viable option for cytogenetic assessment. Additionally, this may provide a method to evaluate the efficacy of the treatment protocol during the course of treatment.