CD56 staining representative of NK infiltration in the tumour area. (A) Representative whole section showing a paucity of NK cells in the tumour. (B) Number of tumours in each category of NK (CD56+) staining. The CD56 stained sections were categorised based on the number of positive cells in a high power field as follows: grade 0 (none), grade 1 (rare, <5); grade 2 (moderate, 5-10) and grade 3 (many, >10).