STAT3 and thyroid tumor: HFD vs. LFD: - Higher thyroid weight in HFD animals- Metformin delayed thyroid cancer progression by reducing in capsular invasion, abrogating development of vascular invasion and anaplasia, reducing p-STAT3 signals in thyroid tumor cells in animals on HFD, and decreasing extent of epithelial-mesenchymal-transition by vimentin inhibition.