CCND1 and papilloma: In Papillomas, Cyclin D1 exhibited a mean 11.42% (11.42% ± 10.17%) co-expression rate with Cytokeratin 8/18 compared with a mean 2.50% (2.50% ± 3.24%) co-expression rate with Cytokeratin 5/6 (p < 0.01).