Lymphoma in Australian Border Collies: survey results and pedigree analyses.

OBJECTIVES: The aims of this study were to (1) describe the results of a survey on the clinical features of lymphoma in Australian Border Collies and (2) investigate familial clustering of lymphoma-affected dogs by means of pedigree analyses.

METHODS: Clinical and pedigree information was collected from surveys completed by owners or breeders of Australian Border Collies. Relationships between dogs were derived from pedigree data and kinship was analysed by network and cluster-based algorithms.

RESULTS: A total of 246 respondents completed the survey and 57 lymphoma-affected Australian Border Collies were identified. The mean age of diagnosis was 9.16 (SD ± 3.43) years and the median was 9.7 years (range 2-15 years). The odds of female dogs affected with lymphoma were twice those of males in the reported data (OR = 2.06; 95% CI = 1.13-3.73; P = 0.02). Multicentric, high-grade B-cell lymphoma was the most common form in these dogs. Pedigree analyses identified 21 affected dogs that descended from two sires and 28 cases with a common female ancestor. Average inbreeding between both affected and unaffected dogs was similar (0.16, SD ± 0.06 and 0.15, SD ± 0.06, respectively).

CONCLUSION: The survey confirmed the presence of a relatively large number of cases of lymphoma in Australian Border Collies, consistent with our previous report of increased risk in this breed. Some dogs were diagnosed at a very young age, but the age ranged over the normal lifespan. Pedigree analyses identified multiple cases within family groups, suggesting a heritable component of the disease in this breed.