In Golden Retrievers, we found a QTL on CFA4 associated with lymphoma in 34 cases and 48 controls (P=4.0 × 10−7, β=0.49, Wald test; Fig. 2c) containing several candidate genes, including MCC, MXD3 and FGFR4. Finally, GWAS of MCT in Labrador Retrievers (152 cases, 106 controls) revealed a significant QTL on CFA36 (P=1.7 × 10−7, β=0.36, Wald test; Fig. 2d), within 30 kb of the candidate gene ITGA6. The gene discussed is MXD3; the disease is lymphoma.