CCND1 and oral cavity cancer: The highest percentage of Cyclin D1 positives cases (defined as CyclinD1 IRS ≥ 7) was observed in oral cavity cancer (77%, 13/17) with fewer positive cases of laryngeal cancer (46%, 16/35), hypopharyngeal cancer (39%, 9/23), and oropharyngeal cancer (36%, 28/78).