PLAU and osteosarcoma: The osteosarcoma-bearing dogs had significantly higher serum uPA at diagnosis (median 1905.4 pg/ml [95%CI 1767.2–2043.6 pg/ml]) than the clinically healthy control (median 1439.5 pg/ml [95%CI 1071.8–1807.3 pg/ml], p = 0.008; Fig 1A), while no difference was seen in suPAR level between the two groups (median 3179.4 pg/ml vs 3086.9 pg/ml, p = 0.866; Fig 1B).