LILRB1 and neoplasm: However, it was previously reported that a broad spectrum of tumours often up-regulates the expression of non-classical HLA class I, like HLA-G which dampens the NK-cell responses by engaging inhibitory receptors ILT-2 and KIR2DL4 (Rouas-Freiss et al, 2005; Urosevic and Dummer, 2008).