Our ChIP-seq and WGS analyses identified five candidate variants strongly associated with histiocytic sarcoma in FCRs and predicted to impact TF binding sites proximal to PIK3R6. While these variants were also detected in FCRs and golden retrievers with lymphoma and golden retrievers with histiocytic sarcoma, supporting the hypothesis that variants within the shared risk haplotype underly susceptibility to both diseases in the retrievers, we note that sample sizes were small. Here, PIK3R6 is linked to lymphoma.