GRM4 and osteosarcoma: These included genes previously associated with osteosarcoma in canine GWASs (CDKN2A, CDKN2B), genes associated with osteosarcoma based on a human GWAS (GRM4, NFIB) and genes associated with osteosarcoma in known human hereditary cancer syndromes (BLM, RB1, TP53 and WRN) [32,33,47].