PLK4 and metastatic malignant neoplasm in the lymph nodes: Remarkably, the percentage of patients with high PLK4 expression among the high-risk subgroups of patients with positive lymph node metastasis status, ruptured-capsule tumors elevated CEA (≥ 5 ng/ml) or advanced TMN stage (stage III & IV) was significantly higher than that in the corresponding low-risk subgroups (Figure S2I-L).