CCNB1 and oral cavity squamous cell carcinoma: Cyclin B1 overexpression is observed in basal and parabasal layers of VC and peripheral layers of islands of WDSCC, compared to invasive tumor front of oral squamous cell carcinoma by Watanabe et al. (23) and esophageal carcinoma by Song et al. (10) Interestingly, VC had not showed any statistical significant difference with WDSCC and MDSCC.