Although there was overlap in Cyclin D1 expression between these two lesions, a small number of papilloma cases exhibited higher Cyclin D1 expression than the average Cyclin D1 expression of the papillary carcinomas and vice versa, the Cyclin D1 together with CK 5/6 staining could be used to distinguish between papillary carcinoma and papilloma samples. Here, CCND1 is linked to papilloma.