Expression of HES1 mRNA in canine normal bone and osteosarcoma (RT-qPCR). (A) HES1 mRNA expressed as 2(-ΔCT) normalized to HPRT1 in normal bone (n = 9), matched tumors (n = 9), tumors from dogs with DFI > 300 days (n = 10), tumors from dogs with DFI < 100 days (n = 10), 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 reduced fold-change in DFI < 100 relative to DFI > 300 group. (B) Fold change in expression calculated using the comparative Ct (2(-ΔΔCt)) method between each canine tumor and its matched normal bone sample (normalized to HPRT1). Bars represent mean ± SEM.