PLK1 and thyroid gland carcinoma: Since the pro-metastatic properties of PLK1 overexpression were also reported in other different types of cancers, including breast and thyroid cancers [46,49], this suggests that targeting cancer’s ability to activate invasion and metastasis by PLK1 inhibition could be generalized to a growing list of a variety of cancers that have PLK1 overexpression implicated in their metastatic progression.