EZH2 and metastatic malignant neoplasm in the lymph nodes: RT-qPCR results revealed that low circGSK3B and high EZH2 expression were associated with tumor size (P = 0.018 and P = 0.018, respectively; Additional file 2: Supplementary Table S7), lymph node metastasis (P = 0.029, P = 0.006) and TNM stage (P = 0.031, P = 0.007).