Mouse models have been developed over the years that recapitulate how human FTCs progress from benign follicular adenoma (at one year of age) in the Pten-TpoKO [23] to locally invasive FTC as in the R1a-TpoKO [46] and subsequently to invasive and distantly metastatic FTC. Here, PTEN is linked to thyroid cancer, nonmedullary, 2.