Over-expression of Skp2 is often associated with higher grades and a greater malignancy of tumors as well as a poor prognosis of cancers, such as breast cancer [37,38], nasopharyngeal carcinoma [33], rectal cancer treated with chemoradiotherapy [39], oral squamous cell carcinomas [40], and non-small-cell lung cancer [41], which suggests that Skp2 engages in tumorigenic activity and is a promising target for cancer therapy. Here, SKP2 is linked to oral cavity squamous cell carcinoma.