Differences in the geographic distribution of lymphoma subtypes in Golden retrievers in the USA.

The purpose of this cross-sectional study was to examine differences in the geographic distribution of two distinct subtypes of canine lymphoma (CL), B-cell lymphoma (BCL) and T-zone lymphoma (TZL), in the USA while accounting for heritable risks associated with the outcome of disease through inclusion of only one breed of dog. This study included 454 Golden retrievers and associations between geographic areas of the USA and the phenotypic variant of lymphoma were examined using multivariable logistic regression. There was a detectable difference in the geographic distribution of BCL and TZL with dogs in the Northeast [odds ratio (OR) = 3.4, 95% confidence interval (CI) = 1.6-7.0] and East North Central regions (OR = 12.1, 95%CI = 3.6-40.5) being more likely to be diagnosed with TZL as compared to dogs in the Mountain region of the USA. The finding of non-random geographic distribution of lymphoma subtypes suggest that environmental risk factors may contribute to the development of different types of CL.