MTOR and thyroid tumor: The phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT)/mechanistic target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1/2 (ERK1/2) cascades are pivotal drivers of thyroid tumor growth, survival, and metastasis (3).