In conclusion, thyroid cancer cell lines and well-differentiated human tumour specimens showed high levels of Akt phosphorylation on Ser473 and high Akt activity levels, which supported the findings of several other studies (Dahia et al, 1997; Liaw et al, 1997; Ringel et al, 2001), indicating that the Akt signalling pathway plays a role in thyroid cancer progression. This evidence concerns the gene AKT1 and neoplasm.