Recent studies found Cdk5 protein up-regulation in 66 out of 95 (69.5%) NSCLC samples, and that Cdk5 expression correlated with decreased 5-year survival, poor differentiation, lymph node metastasis, and poor prognosis [44,45,48,49]. Here, CDK5 is linked to metastatic malignant neoplasm in the lymph nodes.