CD274 and metastatic malignant neoplasm in the lymph nodes: High expression of PD-L1 on cancer cell membranes correlated with lymph node metastasis (P = 0.033) and strongly correlated with poor-differentiation (P = 0.008), but did not correlate with patient's gender, age, tumor location, T stage, distant metastasis, vascular invasion and nervous invasion (P > 0.05) (Table 3).