Furthermore, we also found that low expression of Per1 was obviously correlated with deeper depth of invasion (OR=2.12, 95%CI: 1.62∼2.77, Ρ<0.001; Ι2=28.8%) and low Per2 expression was significantly associated with more advanced TNM stage (OR=3.47, 95%CI: 1.88∼6.42, Ρ<0.001; Ι2=74.8) and more lymph node metastasis (OR=2.35, 95%CI: 1.35∼4.11, Ρ=0.003; Ι2=79.4). Here, PER2 is linked to metastatic malignant neoplasm in the lymph nodes.