CD8A and neoplasm: In keeping with NK-cell origin in many cases, the tumour stains positive for CD2, CD3ε, CD7, CD56, cytotoxic granules (TIA1, granzyme, perforin), CD158/KIR and CD335/NKp46 but is usually negative for sCD3, CD4, CD8, CD57 and TCR [93,101,102,103,104,105].