Environmental\nExposures and Canine Bladder Cancer:\nA Case Control Study Using Silicone Passive Samplers

Pet\ndogs offer valuable models for studying environmental impacts\non human health due to shared environments and a shorter latency period\nfor cancer development. We assessed environmental chemical exposures\nin a case–control study involving dogs at high risk of urothelial\ncarcinoma, identified by a BRAF V595E mutation in urinary epithelial\ncells. Cases (<i>n</i> = 25) exhibited low-level BRAF mutations,\nwhile controls (<i>n</i> = 76) were matched dogs without\nthe mutation. Each dog wore a silicone sampler for five continuous\ndays to assess environmental exposures. Silicone samplers were analyzed\nusing targeted and suspect screening (i.e., nontargeted) methods.\nOf 115 targeted chemicals, 39 were detected in >50% of samplers,\nwith\ncases showing significantly higher levels (2–3×) of BDE-47,\nBDE-99, anthracene, and benzyl butyl phthalate (<i>p</i> < 0.05). Suspect screening identified that cases were exposed\nto more chemicals, often at higher exposure levels. For example, cases\nhad significantly higher levels of 25 chemical features compared to\ncontrols (<i>p</i> < 0.05). This is the largest study\nto date to quantify such a wide breadth of contaminant exposure levels\nassociated with canine urothelial carcinoma and the first to assess\na population with subclinical disease, highlighting pet dogs as models\nto study environmental contributions to cancer risk, advancing both\nhuman and veterinary health.