Altogether, our findings provided insight into the role of PAX3 as a novel functional tumor suppressor in thyroid cancer through modulating the activities of PI3K/Akt and MAPK signaling pathways and transcription factor FOXO3a, and demonstrated that epigenetic alterations such as promoter methylation should be a major mechanism of PAX3 inactivation in this cancer. This evidence concerns the gene AKT1 and thyroid gland carcinoma.