CDKN2A and metastatic malignant neoplasm in the lymph nodes: In 224 vulvar squamous cell carcinomas stained with p16, p21, and p27, Knopp et al., noted a high expression of p16 as indicator of a better prognosis in the multivariate analysis (RR = 0.5, 95% CI = 0.2–1.0) and less risk of developing lymph node metastasis (OR = 0.3, 95% CI = 0.2–0.7) [25].