Figure 5

CD56⁺ NK cells in the sections of LLABCs, using IHC staining, at ×400 magnification. Briefly, heat-mediated antigen retrieval was performed using citrate buffer, pH 6 (20 min). The sections were then incubated with MAbs to CD56 (Dako, M7304) at a 1:50 dilution for 30 min at RT. Polymeric HRP-linker antibody conjugate was used as secondary antibody. DAB chromogen was used to visualize the staining. The sections were counterstained with haematoxylin. a Low level of CD56⁺ NK cell infiltration, b high level of CD56⁺ NK cell infiltration. The total number of brown membrane-stained cells, regardless of intensity, in contact with tumour cells or within tumour cell nests (Itu: intratumoural) and in the interstitial stroma (Str: peritumoural) in 5 HPFs were counted.