PTEN and thyroid cancer: Molecular abnormalities are believed to be involved in radioiodine-refractory thyroid cancer, such as, activating mutations in BRAF, RAS and PTEN, RET-PTC rearrangements, PPARγ-PAX8 rearrangements, mutations of PI3KCA and AKT1, and most of them have been noted in genes related to MEK/ERK and PI3K/Akt pathway (16, 17).