RET and thyroid gland carcinoma: In benign thyroid cell models, Akt signalling is important for cell growth in response to insulin, insulin-like growth factor-1, and serum (Kimura et al, 1999, 2001; Coulonval et al, 2000; Saito et al, 2001) and is activated by several oncogenes involved in thyroid cancer, including activated p21ras and chimeric rearrangements involving the ret gene (RET/PTC oncogenes) (Borrello et al, 1994; Rodriguez-Viciana et al, 1994).