AKT1 and neoplasm: Firstly, both canine and human tumours show immunohistochemical evidence of constitutive phospho-ERK1/2 and/or phospho-AKT in 52–95% of tumours [2,39,44,54,58,59,61,94], and this is also seen in both cell lines and xenograft models [31], with PI3K-AKT signalling influencing the phenotype of the cancer stem cell compartment [35].