KLRK1 and neoplasm: In addition to the increased ratio of activated CD8+NKG2D+ cells within the tumour masses, the number of tumour-infiltrative CD8+NKG2D+ cells was also significantly increased, as determined by anti-human CD3 staining of tumour tissues (Fig. 4c), and quantified by qRT-PCR for human CD3 expression in tumour tissue (Fig. 4d).