Expression of NOTCH1 , NOTCH2 and HEY1 mRNA in canine normal bone and osteosarcoma (RT-qPCR). NOTCH1, NOTCH2, and HEY1 mRNA expressed as 2(-ΔCT) normalized to HPRT1 is shown for normal bone (n = 9), matched tumors (n = 9), tumors from dogs with DFI > 300 days, tumors from dogs with DFI < 100 days, and combined DFI group tumors. Comparisons of each tumor group relative to normal bone and DFI < 100 relative to DFI > 300 day groups were analyzed with REST 2009 software and significant fold changes are indicated by brackets on the graph. Values in blue indicate the reduced fold-change expression in DFI < 100 compared to normal bone. Bars represent mean ± SEM.