Immunohistochemical assessment of PD-L1 was predominantly conducted on formalin-fixed paraffin-embedded tumor sections (FFPE) in most of the studies (64.28%).11,13,15 Other studies employed tissue microarray (TMA) (21.42%),21,22,24 while some did not specify the method used (14.28%).14,25. Here, CD274 is linked to neoplasm.