TGFB1 and obstructive sleep apnea syndrome: Thus, based on the aforementioned evidence, we hypothesized that levels of nuclear phosphorylated Smad2 (pSmad2, indicative of activated TGFβ signalling), TAZ, YAP or combinations of these markers, will associate with established markers of poor prognosis, metastatic disease and overall patient survival in canine OSA.