CD274 and neoplasm: When patients were categorized into a PD-L1-positive group and a PD-L1-negative group for the correlation between PD-L1 expression and clinicopathological characteristics, the results showed that PD-L1 expression was not correlated with sex, age, tumor location, tumor depth, lymphatic metastasis, distant metastases, necrosis, or tumor stage (Table 1).