For example, human CMV encodes several molecules and microRNAs that prevent the expression of NKG2DLs at the infected cell-surface [132,139] and tumours can express proteases that cleave NKG2DLs from the cell-surface, or release cytokines, such as TGF-β, that downregulate NKG2D, or simply switch off the expression of NKG2DLs as they grow and metastasise [140,141,142,143]. The gene discussed is KLRK1; the disease is neoplasm.