CDKN2A and metastatic malignant neoplasm in the lymph nodes: Multivariate analysis has demonstrated that lymph node metastasis (HR 1–2.74, 95 % CI 1.50–5.02, p = 0.019), tumor grade (HR 1–2.80, 95 % CI 1.33–5.90, p = 0.007) and p16ink4a-overexpression (HR 1–2.11, 95 % CI 1.13–3.95, p = 0.001) are independent prognostic factors.