Additionally the conflict and controversial results could be attributed to the fact that the detection of PD-L1 expression in tumors is affected by spatial factors (heterogeneity of PD-L1 expression within the tumor and between different tumor sites) and temporal factors (hetrogenity of PD-L1 expression from before to after chemotherapy) leading to erroneous interpretation of the results [42, 43]. Here, CD274 is linked to neoplasm.