SKP2 and oral cavity squamous cell carcinoma: Overexpression of Skp2 has been reported in several human malignant tumors, including oral squamous cell carcinoma [14,23], ovarian adenocarcinoma [24], lymphoma [25], colorectal carcinomas [26,27], gastric carcinoma [28], soft tissue sarcomas [29], acute myelogenous leukemia [30], and breast cancer [31].